merge: convex chat history sync

backlog/tasks/task-1 - Add-complete-chat-transaction-context.md

@@ -1,10 +1,10 @@
 ---
 id: TASK-1
 title: Add complete chat transaction context
-status: In Progress
+status: Done
 assignee: []
 created_date: '2026-06-15 13:52'
-updated_date: '2026-06-15 14:02'
+updated_date: '2026-06-15 19:54'
 labels: []
 dependencies: []
 priority: high
@@ -61,3 +61,9 @@ Final review:
 - Prior blocker resolved: effective-basis loading now includes rows without effectiveMonth via bookingDate fallback queries.
 - Fresh full npm run lint still fails only on unrelated existing files; no SavingsChatPage issue remains.
 <!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-2 - Render-category-expense-chart-values-as-positive-slices.md

@@ -1,10 +1,10 @@
 ---
 id: TASK-2
 title: Render category expense chart values as positive slices
-status: In Progress
+status: Done
 assignee: []
 created_date: '2026-06-15 14:34'
-updated_date: '2026-06-15 14:48'
+updated_date: '2026-06-15 19:54'
 labels: []
 dependencies: []
 priority: high
@@ -60,3 +60,9 @@ Verification after layout update:
 
 Note: npm run build still emits the existing Vite chunk-size warning for the main bundle.
 <!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-3 - Build-read-only-savings-agent-with-tool-calls.md

@@ -0,0 +1,59 @@
+---
+id: TASK-3
+title: Build read-only savings agent with tool calls
+status: Done
+assignee: []
+created_date: '2026-06-15 19:02'
+updated_date: '2026-06-15 19:54'
+labels: []
+dependencies: []
+priority: high
+ordinal: 3000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Convert Talk to Savings from a prompt-packed chat into a read-only AI SDK tool-calling agent with deterministic transaction retrieval, spending summaries, forecasts, and compact frontend tool traces.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Savings chat action uses AI SDK tool calls with a bounded multi-step loop and returns a compact tool trace
+- [x] #2 Read-only transaction retrieval tool supports selected scope, bounded custom ranges, account/category/search filters, exact totals, sanitized rows, and hasMore
+- [x] #3 Spending summary and cashflow forecast tools compute deterministic aggregates without model-invented math
+- [x] #4 Frontend remains localStorage-backed, loads legacy chats, and renders compact tool traces under assistant answers
+- [x] #5 Focused Convex tests, build, and targeted lint verification pass or known blockers are documented
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Write failing Convex tests for read-only tool queries and traces
+2. Implement internal read-only savings agent tool queries
+3. Switch savingsChat.ask to AI SDK tool calling with bounded multi-step loop
+4. Update frontend chat messages and compact tool trace rendering
+5. Run focused tests, build, targeted lint, and record verification notes
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implementation complete pending user confirmation.
+
+Subagents:
+- Frontend UX worker updated src/pages/SavingsChatPage.tsx for legacy-safe localStorage message normalization and compact assistant tool traces.
+- QA explorer reviewed Convex test strategy and confirmed mock AI SDK approach for ask() coverage.
+
+Verification:
+- PASS npx vitest convex/savingsChat.test.ts --run (8 tests)
+- PASS npx eslint convex/savingsChat.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx
+- PASS npm run build
+- BLOCKED npm run lint on pre-existing unrelated files: convex/bank/comdirectProvider.ts, convex/bank/config.ts, src/components/import/TanAwaitDialog.tsx, layout/ui fast-refresh exports, SettingsPage.tsx, generated eslint-disable warnings, and existing React compiler warnings. No TASK-3 touched file appears in the full-lint error list.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-4 - Add-selection-total-to-transactions.md

@@ -0,0 +1,47 @@
+---
+id: TASK-4
+title: Add selection total to transactions
+status: Done
+assignee: []
+created_date: '2026-06-15 19:21'
+updated_date: '2026-06-15 19:54'
+labels: []
+dependencies: []
+priority: high
+ordinal: 4000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Add table selection controls on the transactions page so visible/filtered rows can be selected in bulk and the sum of selected transaction amounts is shown.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 A select-all control can select and clear all currently visible filtered transactions
+- [x] #2 Individual row selection continues to work alongside the select-all control
+- [x] #3 The UI displays the count and formatted euro total of selected transactions
+- [x] #4 Automated tests cover bulk selection and selected-total behavior
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Inspect current transaction table selection behavior
+2. Add failing coverage for select-all and selected sum
+3. Implement visible-row bulk selection and selected total UI
+4. Run focused tests/build and update acceptance criteria
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Added failing Vitest coverage for visible bulk selection and selected totals, then implemented transactionsSelection helpers and wired TransactionsPage header checkbox plus selected count/sum. Focused test and build pass. Global lint currently fails on pre-existing unrelated lint errors in Convex/generated/UI files.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-5 - Make-transaction-filters-combinable.md

@@ -0,0 +1,46 @@
+---
+id: TASK-5
+title: Make transaction filters combinable
+status: Done
+assignee: []
+created_date: '2026-06-15 19:32'
+updated_date: '2026-06-15 19:54'
+labels: []
+dependencies: []
+priority: high
+ordinal: 5000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Fix the transactions page so global timeframe, account, and month-basis filters are applied together with page-level filters like search, type, category, and pending-only.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Changing the date range filters the transactions list
+- [x] #2 Account, month basis, search, type, category, and pending-only filters combine instead of overriding each other
+- [x] #3 Automated tests cover combined transaction filtering
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Trace current filter data flow from shared controls to transactions query
+2. Add failing Convex test for combined date/account/category/search filtering
+3. Extend transactions list query args and wire TransactionsPage to shared filters
+4. Run focused tests, full tests/build, and update task notes
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Root cause: TransactionsPage did not pass global from/to/account/monthBasis filters into api.transactions.list, and transactions.list ignored date filters on the search-index path. Added red Convex tests covering combined filters and effective-month basis, then added basis/date filtering in the query and wired global filters from the page. Focused tests and build pass.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-6 - Add-transaction-filter-reset-button.md

@@ -0,0 +1,38 @@
+---
+id: TASK-6
+title: Add transaction filter reset button
+status: Done
+assignee: []
+created_date: '2026-06-15 19:35'
+updated_date: '2026-06-15 19:54'
+labels: []
+dependencies: []
+priority: medium
+ordinal: 6000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Add a reset button on the transactions page that clears the active filter combination and returns global plus page-level transaction filters to their defaults.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 A reset button is available on the transactions page filter bar
+- [x] #2 Clicking reset clears search, type, category, account, pending-only, and row selection
+- [x] #3 Clicking reset returns date range and month basis to their defaults
+- [x] #4 Automated tests cover the reset defaults
+<!-- AC:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Added a transactions toolbar reset button using shared reset defaults. The button clears global filters (current month, all accounts, no categories, effective month basis), clears page filters (search, type, pending-only), and clears row selection. Added Vitest coverage for reset defaults. Focused tests and build pass.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-7 - Add-all-read-only-savings-agent-insight-tools.md

@@ -0,0 +1,54 @@
+---
+id: TASK-7
+title: Add all read-only savings agent insight tools
+status: Done
+assignee: []
+created_date: '2026-06-15 19:39'
+updated_date: '2026-06-15 19:54'
+labels: []
+dependencies: []
+priority: high
+ordinal: 7000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Expand Talk to Savings with eight additional read-only AI SDK tools for accounts, categories, recurring transactions, anomalies, uncategorized transactions, period comparison, fixed-cost forecasting, and savings-rate explanations.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Agent registers all eight new read-only tools and returns compact trace summaries without raw/private fields
+- [x] #2 Metadata and data-quality tools return scoped, sanitized accounts, categories, and uncategorized transaction insight
+- [x] #3 Period, savings-rate, recurring, fixed-cost forecast, and anomaly tools compute deterministic aggregates
+- [x] #4 Convex tests cover each new tool and mocked ask() registration
+- [x] #5 Focused tests, targeted lint, build, and full lint status are documented
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add failing coverage for all eight read-only savings insight tools and ask() registry
+2. Implement scoped/sanitized internal Convex queries and deterministic finance helpers
+3. Register the tools in savingsChat.ask and add compact trace summaries
+4. Verify focused tests, targeted lint, build, and document full-lint blockers
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implemented eight new read-only tools in convex/savingsChat.ts: accounts, categories, recurring patterns, anomalies, uncategorized transactions, period comparison, fixed-cost forecast, and savings-rate explanation.
+Verification: npx vitest convex/savingsChat.test.ts --run --reporter=dot passed (17 tests).
+Verification: npx eslint convex/savingsChat.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx passed.
+Verification: npm run build passed with existing Vite chunk-size warning.
+Full npm run lint still fails on unrelated existing files: convex/bank/comdirectProvider.ts, convex/bank/config.ts, src/components/import/TanAwaitDialog.tsx, several react-refresh only-export-components files, and src/pages/SettingsPage.tsx; warnings also remain in generated Convex files and React Hook Form/TanStack Table locations.
+
+Hardened compare_periods snapshots to omit category IDs while keeping existing summarize_spending output compatible. Re-ran focused Vitest, targeted ESLint, and build successfully after this change.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Closed as Done after explicit user confirmation to mark all tasks done. Implementation and verification notes are already recorded on the task.
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-8 - Fix-savings-tool-category-matching.md

@@ -0,0 +1,47 @@
+---
+id: TASK-8
+title: Fix savings tool category matching
+status: In Progress
+assignee: []
+created_date: '2026-06-15 20:10'
+updated_date: '2026-06-15 20:19'
+labels: []
+dependencies: []
+priority: high
+ordinal: 8000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Make Talk to Savings read-only tools resolve user/model category names like Supermärkte or Lebensmittel und Supermarkt to existing categories such as Lebensmittel & Supermarkt, and surface diagnostics instead of misleading silent zero results.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Category filter aliases resolve ampersand/und, casing, punctuation, umlauts, and simple German plural/flexion variants
+- [x] #2 All savings tools that accept categoryNames use shared resolution diagnostics
+- [x] #3 Unknown or ambiguous category filters return diagnostics and compact trace summaries instead of silently confident zero results
+- [x] #4 Regression tests cover Lebensmittel und Supermarkt, Supermärkte, unknown diagnostics, and trace summaries
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add failing Convex regression tests for tolerant categoryNames and diagnostics
+2. Implement shared category-name normalization and resolver in convex/savingsChat.ts
+3. Thread diagnostics through every categoryNames-aware tool output and compact traces
+4. Update tool/prompt guidance to avoid confident zero answers on unresolved filters
+5. Run focused Vitest, targeted ESLint, and production build
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implemented shared tolerant category resolver for savings tools and added diagnostics to categoryNames-aware outputs.
+Verification passed: npx vitest convex/savingsChat.test.ts --run (20 tests), npx eslint convex/savingsChat.ts convex/savingsChat.test.ts, npm run build (with existing Vite chunk-size warning).
+
+Added an additional regression test to preserve the virtual Ohne Kategorie filter while moving categoryNames to resolver-based category IDs. Re-ran focused Vitest, targeted ESLint, and build successfully after this adjustment.
+
+Addressed QA review findings: added ASCII transliteration coverage for Supermaerkte, explicit ambiguous category filter coverage, and multi-diagnostic compact trace summaries. Final verification passed: npx vitest convex/savingsChat.test.ts --run (22 tests), npx eslint convex/savingsChat.ts convex/savingsChat.test.ts, npm run build (with existing Vite chunk-size warning).
+<!-- SECTION:NOTES:END -->

backlog/tasks/task-9 - Add-Convex-synced-savings-chat-history.md

@@ -0,0 +1,72 @@
+---
+id: TASK-9
+title: Add Convex-synced savings chat history
+status: Done
+assignee: []
+created_date: '2026-06-16 07:58'
+updated_date: '2026-06-16 08:23'
+labels: []
+dependencies: []
+priority: high
+ordinal: 9000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Persist savings chat sessions and messages in Convex per authenticated user so chat history syncs across devices, with automatic one-time import of existing localStorage chats.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Chat sessions and messages are stored in Convex per authenticated user and synchronize across devices
+- [x] #2 Existing localStorage savings chats are imported once, deduplicated by legacy local id, and old local data is not deleted
+- [x] #3 Sending a chat message stores both user and assistant messages, including assistant tool traces
+- [x] #4 Deleting a chat hides it account-wide and unauthorized users cannot read or mutate another user's chats
+- [x] #5 Focused Convex tests, focused ESLint, and build verification are run and recorded
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add failing Convex tests for user-scoped chat history, legacy import, sendMessage persistence, and deletion
+2. Add chatSessions/chatMessages schema tables
+3. Implement savingsChatHistory queries and mutations
+4. Refactor savingsChat AI generation helper and add sendMessage action
+5. Move SavingsChatPage to Convex-backed state and automatic legacy import
+6. Run focused tests, focused lint, build, and record verification notes
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implementation completed on branch codex/convex-chat-history-sync.
+
+Verification:
+- RED verified first: npx vitest convex/savingsChat.test.ts --run failed with 3 missing chat-history/sendMessage tests.
+- PASS npx vitest convex/savingsChat.test.ts --run (25 tests).
+- PASS npx eslint convex/schema.ts convex/savingsChat.ts convex/savingsChatHistory.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx src/components/chat/ChatHistory.tsx.
+- PASS npm run build (Vite chunk-size warning remains).
+- FULL LINT npm run lint still fails on pre-existing unrelated files: convex/bank/comdirectProvider.ts, convex/bank/config.ts, src/components/import/TanAwaitDialog.tsx, layout/ui fast-refresh exports, src/main.tsx, src/pages/SettingsPage.tsx, plus existing React Compiler warnings. No changed feature file appears in the full-lint error list.
+
+Notes:
+- Ran npx convex codegen; first sandboxed attempt failed on DNS/fetch to Sentry, rerun outside sandbox succeeded and updated convex/_generated/api.d.ts.
+- Backlog task remains In Progress pending explicit user confirmation after manual testing.
+
+Review follow-up:
+- Addressed code-review finding: legacy import marker is now scoped by current Convex user id instead of only browser-global.
+- Addressed code-review finding: sendMessage now persists an assistant failure message if AI generation fails after saving the user message.
+- Added regression coverage for unauthorized listMessages, unauthorized sendMessage, and failed-generation persistence.
+
+Final verification after review fixes:
+- PASS npx vitest convex/savingsChat.test.ts --run (26 tests).
+- PASS npx eslint convex/schema.ts convex/savingsChat.ts convex/savingsChatHistory.ts convex/savingsChat.test.ts src/pages/SavingsChatPage.tsx src/components/chat/ChatHistory.tsx.
+- PASS npm run build (Vite chunk-size warning remains).
+- FULL LINT npm run lint still fails only on pre-existing unrelated files and generated-file warnings; no changed feature file is in the full-lint error list.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Shipped Convex-backed savings chat history sync with user-scoped sessions/messages, automatic per-user legacy localStorage import, server-persisted sendMessage flow, account-wide delete behavior, authorization coverage, and focused verification. Full lint still has unrelated pre-existing failures documented in notes.
+<!-- SECTION:FINAL_SUMMARY:END -->

convex/_generated/api.d.ts

@@ -35,6 +35,7 @@ import type * as lib_month from "../lib/month.js";
 import type * as lib_seedCategories from "../lib/seedCategories.js";
 import type * as loans from "../loans.js";
 import type * as savingsChat from "../savingsChat.js";
+import type * as savingsChatHistory from "../savingsChatHistory.js";
 import type * as settings from "../settings.js";
 import type * as transactions from "../transactions.js";
 import type * as users from "../users.js";
@@ -73,6 +74,7 @@ declare const fullApi: ApiFromModules<{
   "lib/seedCategories": typeof lib_seedCategories;
   loans: typeof loans;
   savingsChat: typeof savingsChat;
+  savingsChatHistory: typeof savingsChatHistory;
   settings: typeof settings;
   transactions: typeof transactions;
   users: typeof users;

convex/savingsChatHistory.ts

@@ -0,0 +1,266 @@
+import { paginationOptsValidator, paginationResultValidator } from "convex/server";
+import { v } from "convex/values";
+import { internalMutation, internalQuery, mutation, query } from "./_generated/server";
+import type { Id } from "./_generated/dataModel";
+import type { MutationCtx, QueryCtx } from "./_generated/server";
+import { assertOwned, requireUserId } from "./lib/helpers";
+
+const initialAssistantMessage =
+  "Frag mich zu deinen Umsätzen – ich werte sie im aktuellen Zeitraum aus.";
+
+const toolTraceValidator = v.object({
+  name: v.string(),
+  inputSummary: v.string(),
+  resultSummary: v.string(),
+});
+
+const chatRoleValidator = v.union(v.literal("user"), v.literal("assistant"));
+
+const importMessageValidator = v.object({
+  role: chatRoleValidator,
+  content: v.string(),
+  toolTrace: v.optional(v.array(toolTraceValidator)),
+});
+
+const sessionValidator = v.object({
+  _id: v.id("chatSessions"),
+  _creationTime: v.number(),
+  userId: v.id("users"),
+  title: v.string(),
+  createdAt: v.number(),
+  updatedAt: v.number(),
+  messageCount: v.number(),
+  legacyLocalId: v.optional(v.string()),
+  isDeleted: v.boolean(),
+});
+
+const messageValidator = v.object({
+  _id: v.id("chatMessages"),
+  _creationTime: v.number(),
+  userId: v.id("users"),
+  sessionId: v.id("chatSessions"),
+  role: chatRoleValidator,
+  content: v.string(),
+  createdAt: v.number(),
+  toolTrace: v.optional(v.array(toolTraceValidator)),
+});
+
+const promptMessageValidator = v.object({
+  role: chatRoleValidator,
+  content: v.string(),
+});
+
+function normalizeTitle(title: string | undefined) {
+  const trimmed = title?.trim();
+  return trimmed ? trimmed : "Neuer Chat";
+}
+
+function titleFromContent(content: string) {
+  const trimmed = content.trim();
+  if (!trimmed) return "Neuer Chat";
+  return trimmed.length > 44 ? `${trimmed.slice(0, 44)}…` : trimmed;
+}
+
+async function requireOwnedSession(
+  ctx: QueryCtx | MutationCtx,
+  sessionId: Id<"chatSessions">,
+  userId: Id<"users">,
+) {
+  const session = await assertOwned(await ctx.db.get(sessionId), userId, "Chat");
+  if (session.isDeleted) throw new Error("Chat nicht gefunden");
+  return session;
+}
+
+export const listSessions = query({
+  args: { paginationOpts: paginationOptsValidator },
+  returns: paginationResultValidator(sessionValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    return await ctx.db
+      .query("chatSessions")
+      .withIndex("by_user_deleted_updated", (index) =>
+        index.eq("userId", userId).eq("isDeleted", false),
+      )
+      .order("desc")
+      .paginate(args.paginationOpts);
+  },
+});
+
+export const listMessages = query({
+  args: {
+    sessionId: v.id("chatSessions"),
+    paginationOpts: paginationOptsValidator,
+  },
+  returns: paginationResultValidator(messageValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    return await ctx.db
+      .query("chatMessages")
+      .withIndex("by_user_session_created", (index) =>
+        index.eq("userId", userId).eq("sessionId", args.sessionId),
+      )
+      .order("desc")
+      .paginate(args.paginationOpts);
+  },
+});
+
+export const createSession = mutation({
+  args: { title: v.optional(v.string()) },
+  returns: v.object({ sessionId: v.id("chatSessions") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const now = Date.now();
+    const sessionId = await ctx.db.insert("chatSessions", {
+      userId,
+      title: normalizeTitle(args.title),
+      createdAt: now,
+      updatedAt: now,
+      messageCount: 1,
+      isDeleted: false,
+    });
+    await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId,
+      role: "assistant",
+      content: initialAssistantMessage,
+      createdAt: now,
+    });
+    return { sessionId };
+  },
+});
+
+export const deleteSession = mutation({
+  args: { sessionId: v.id("chatSessions") },
+  returns: v.null(),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    await ctx.db.patch(args.sessionId, {
+      isDeleted: true,
+      updatedAt: Date.now(),
+    });
+    return null;
+  },
+});
+
+export const importLocalSession = mutation({
+  args: {
+    legacyLocalId: v.string(),
+    title: v.string(),
+    createdAt: v.number(),
+    updatedAt: v.number(),
+    messages: v.array(importMessageValidator),
+  },
+  returns: v.object({ sessionId: v.id("chatSessions") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const existing = await ctx.db
+      .query("chatSessions")
+      .withIndex("by_user_legacyLocalId", (index) =>
+        index.eq("userId", userId).eq("legacyLocalId", args.legacyLocalId),
+      )
+      .unique();
+    if (existing) return { sessionId: existing._id };
+
+    const sessionId = await ctx.db.insert("chatSessions", {
+      userId,
+      title: normalizeTitle(args.title),
+      createdAt: args.createdAt,
+      updatedAt: args.updatedAt,
+      messageCount: args.messages.length,
+      legacyLocalId: args.legacyLocalId,
+      isDeleted: false,
+    });
+
+    for (const [index, message] of args.messages.entries()) {
+      await ctx.db.insert("chatMessages", {
+        userId,
+        sessionId,
+        role: message.role,
+        content: message.content,
+        createdAt: args.createdAt + index,
+        ...(message.toolTrace ? { toolTrace: message.toolTrace } : {}),
+      });
+    }
+
+    return { sessionId };
+  },
+});
+
+export const appendUserMessage = internalMutation({
+  args: {
+    sessionId: v.id("chatSessions"),
+    content: v.string(),
+  },
+  returns: v.object({ messageId: v.id("chatMessages") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const session = await requireOwnedSession(ctx, args.sessionId, userId);
+    const now = Date.now();
+    const messageId = await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId: args.sessionId,
+      role: "user",
+      content: args.content,
+      createdAt: now,
+    });
+    await ctx.db.patch(args.sessionId, {
+      title: session.title === "Neuer Chat" ? titleFromContent(args.content) : session.title,
+      updatedAt: now,
+      messageCount: session.messageCount + 1,
+    });
+    return { messageId };
+  },
+});
+
+export const appendAssistantMessage = internalMutation({
+  args: {
+    sessionId: v.id("chatSessions"),
+    content: v.string(),
+    toolTrace: v.optional(v.array(toolTraceValidator)),
+  },
+  returns: v.object({ messageId: v.id("chatMessages") }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const session = await requireOwnedSession(ctx, args.sessionId, userId);
+    const now = Date.now();
+    const messageId = await ctx.db.insert("chatMessages", {
+      userId,
+      sessionId: args.sessionId,
+      role: "assistant",
+      content: args.content,
+      createdAt: now,
+      ...(args.toolTrace ? { toolTrace: args.toolTrace } : {}),
+    });
+    await ctx.db.patch(args.sessionId, {
+      updatedAt: now,
+      messageCount: session.messageCount + 1,
+    });
+    return { messageId };
+  },
+});
+
+export const getRecentMessagesForPrompt = internalQuery({
+  args: {
+    sessionId: v.id("chatSessions"),
+    limit: v.number(),
+  },
+  returns: v.array(promptMessageValidator),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await requireOwnedSession(ctx, args.sessionId, userId);
+    const limit = Math.max(1, Math.min(50, Math.floor(args.limit)));
+    const messages = await ctx.db
+      .query("chatMessages")
+      .withIndex("by_user_session_created", (index) =>
+        index.eq("userId", userId).eq("sessionId", args.sessionId),
+      )
+      .order("desc")
+      .take(limit);
+    return messages.reverse().map((message) => ({
+      role: message.role,
+      content: message.content,
+    }));
+  },
+});

convex/schema.ts

@@ -9,6 +9,12 @@ const loanStatus = v.union(
   v.literal("abbezahlt"),
   v.literal("pausiert"),
 );
+const chatRole = v.union(v.literal("user"), v.literal("assistant"));
+const chatToolTrace = v.object({
+  name: v.string(),
+  inputSummary: v.string(),
+  resultSummary: v.string(),
+});
 
 export default defineSchema({
   ...authTables,
@@ -175,4 +181,25 @@ export default defineSchema({
     isDecoupled: v.optional(v.boolean()),
     submittedTan: v.optional(v.string()),
   }).index("by_user", ["userId"]),
+
+  chatSessions: defineTable({
+    userId: v.id("users"),
+    title: v.string(),
+    createdAt: v.number(),
+    updatedAt: v.number(),
+    messageCount: v.number(),
+    legacyLocalId: v.optional(v.string()),
+    isDeleted: v.boolean(),
+  })
+    .index("by_user_deleted_updated", ["userId", "isDeleted", "updatedAt"])
+    .index("by_user_legacyLocalId", ["userId", "legacyLocalId"]),
+
+  chatMessages: defineTable({
+    userId: v.id("users"),
+    sessionId: v.id("chatSessions"),
+    role: chatRole,
+    content: v.string(),
+    createdAt: v.number(),
+    toolTrace: v.optional(v.array(chatToolTrace)),
+  }).index("by_user_session_created", ["userId", "sessionId", "createdAt"]),
 });

convex/transactions.test.ts

@@ -0,0 +1,189 @@
+/// <reference types="vite/client" />
+
+import { convexTest } from "convex-test";
+import { describe, expect, test } from "vitest";
+import { api } from "./_generated/api";
+import type { Id } from "./_generated/dataModel";
+import schema from "./schema";
+
+const modules = import.meta.glob("./**/*.ts");
+delete modules["./transactions.test.ts"];
+
+describe("transactions.list", () => {
+  test("combines search, date range, account, category, and type filters", async () => {
+    const t = convexTest(schema, modules);
+
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", {
+        name: "Filter User",
+        email: "filter@example.com",
+      });
+      const giroAccountId = await ctx.db.insert("accounts", {
+        userId,
+        name: "Girokonto",
+        type: "checking",
+        openingBalance: 0,
+        currency: "EUR",
+        isArchived: false,
+      });
+      const otherAccountId = await ctx.db.insert("accounts", {
+        userId,
+        name: "Depot",
+        type: "investment",
+        openingBalance: 0,
+        currency: "EUR",
+        isArchived: false,
+      });
+      const groceryCategoryId = await ctx.db.insert("categories", {
+        userId,
+        name: "Lebensmittel & Supermarkt",
+        kind: "ausgabe",
+        block: "variabel",
+        color: "#ef4444",
+        sortOrder: 1,
+        isSystem: false,
+      });
+      const restaurantCategoryId = await ctx.db.insert("categories", {
+        userId,
+        name: "Restaurant",
+        kind: "ausgabe",
+        block: "variabel",
+        color: "#f97316",
+        sortOrder: 2,
+        isSystem: false,
+      });
+
+      const matchingId = await ctx.db.insert("transactions", {
+        userId,
+        accountId: giroAccountId,
+        categoryId: groceryCategoryId,
+        bookingDate: "2026-06-15",
+        description: "LIDL SAGT DANKE",
+        amount: -18.37,
+        isPending: false,
+        effectiveMonth: "2026-06",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId: giroAccountId,
+        categoryId: groceryCategoryId,
+        bookingDate: "2026-05-29",
+        description: "LIDL OLD MONTH",
+        amount: -21.92,
+        isPending: false,
+        effectiveMonth: "2026-05",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId: otherAccountId,
+        categoryId: groceryCategoryId,
+        bookingDate: "2026-06-16",
+        description: "LIDL OTHER ACCOUNT",
+        amount: -99,
+        isPending: false,
+        effectiveMonth: "2026-06",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId: giroAccountId,
+        categoryId: restaurantCategoryId,
+        bookingDate: "2026-06-17",
+        description: "LIDL RESTAURANT",
+        amount: -12,
+        isPending: false,
+        effectiveMonth: "2026-06",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId: giroAccountId,
+        categoryId: groceryCategoryId,
+        bookingDate: "2026-06-18",
+        description: "LIDL REFUND",
+        amount: 5,
+        isPending: false,
+        effectiveMonth: "2026-06",
+      });
+
+      return { userId, giroAccountId, groceryCategoryId, matchingId };
+    });
+
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|test-session`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+
+    const result = await asUser.query(api.transactions.list, {
+      paginationOpts: { cursor: null, numItems: 20 },
+      search: "LIDL",
+      from: "2026-06-01",
+      to: "2026-06-30",
+      accountId: seeded.giroAccountId as Id<"accounts">,
+      categoryIds: [seeded.groceryCategoryId as Id<"categories">],
+      type: "ausgabe",
+      basis: "booking",
+    });
+
+    expect(result.page.map((tx) => tx._id)).toEqual([seeded.matchingId]);
+  });
+
+  test("filters by effective month when the global basis is assignment month", async () => {
+    const t = convexTest(schema, modules);
+
+    const seeded = await t.run(async (ctx) => {
+      const userId = await ctx.db.insert("users", {
+        name: "Basis User",
+        email: "basis@example.com",
+      });
+      const accountId = await ctx.db.insert("accounts", {
+        userId,
+        name: "Girokonto",
+        type: "checking",
+        openingBalance: 0,
+        currency: "EUR",
+        isArchived: false,
+      });
+      const shiftedId = await ctx.db.insert("transactions", {
+        userId,
+        accountId,
+        bookingDate: "2026-05-29",
+        description: "Salary shifted into June",
+        amount: 2500,
+        isPending: false,
+        assignedMonth: "2026-06",
+        effectiveMonth: "2026-06",
+      });
+      await ctx.db.insert("transactions", {
+        userId,
+        accountId,
+        bookingDate: "2026-05-20",
+        description: "May only",
+        amount: -15,
+        isPending: false,
+        effectiveMonth: "2026-05",
+      });
+
+      return { userId, shiftedId };
+    });
+
+    const asUser = t.withIdentity({
+      subject: `${seeded.userId}|test-session`,
+      tokenIdentifier: `test:${seeded.userId}`,
+    });
+
+    const effectiveResult = await asUser.query(api.transactions.list, {
+      paginationOpts: { cursor: null, numItems: 20 },
+      from: "2026-06-01",
+      to: "2026-06-30",
+      basis: "effective",
+    });
+    const bookingResult = await asUser.query(api.transactions.list, {
+      paginationOpts: { cursor: null, numItems: 20 },
+      from: "2026-06-01",
+      to: "2026-06-30",
+      basis: "booking",
+    });
+
+    expect(effectiveResult.page.map((tx) => tx._id)).toEqual([seeded.shiftedId]);
+    expect(bookingResult.page).toEqual([]);
+  });
+});

convex/transactions.ts

@@ -41,6 +41,7 @@ export const list = query({
     categoryIds: v.optional(v.array(v.id("categories"))),
     withoutCategory: v.optional(v.boolean()),
     accountId: v.optional(v.id("accounts")),
+    basis: v.optional(v.union(v.literal("effective"), v.literal("booking"))),
     type: v.optional(v.union(v.literal("einnahme"), v.literal("ausgabe"))),
     pendingOnly: v.optional(v.boolean()),
   },
@@ -51,6 +52,9 @@ export const list = query({
   }),
   handler: async (ctx, args) => {
     const userId = await requireUserId(ctx);
+    const basis = args.basis ?? "booking";
+    const fromMonth = args.from?.slice(0, 7);
+    const toMonth = args.to?.slice(0, 7);
 
     let q;
     if (args.search) {
@@ -60,21 +64,77 @@ export const list = query({
           sq.search("description", args.search!).eq("userId", userId),
         );
     } else {
-      q = ctx.db
-        .query("transactions")
-        .withIndex("by_user_booking", (iq) => {
-          if (args.from && args.to) {
-            return iq.eq("userId", userId).gte("bookingDate", args.from).lte("bookingDate", args.to);
-          }
-          if (args.from) {
-            return iq.eq("userId", userId).gte("bookingDate", args.from);
-          }
-          if (args.to) {
-            return iq.eq("userId", userId).lte("bookingDate", args.to);
-          }
-          return iq.eq("userId", userId);
-        })
-        .order("desc");
+      if (basis === "effective") {
+        q = ctx.db
+          .query("transactions")
+          .withIndex("by_user_effmonth", (iq) => {
+            if (fromMonth && toMonth) {
+              return iq.eq("userId", userId).gte("effectiveMonth", fromMonth).lte("effectiveMonth", toMonth);
+            }
+            if (fromMonth) {
+              return iq.eq("userId", userId).gte("effectiveMonth", fromMonth);
+            }
+            if (toMonth) {
+              return iq.eq("userId", userId).lte("effectiveMonth", toMonth);
+            }
+            return iq.eq("userId", userId);
+          })
+          .order("desc");
+      } else {
+        q = ctx.db
+          .query("transactions")
+          .withIndex("by_user_booking", (iq) => {
+            if (args.from && args.to) {
+              return iq.eq("userId", userId).gte("bookingDate", args.from).lte("bookingDate", args.to);
+            }
+            if (args.from) {
+              return iq.eq("userId", userId).gte("bookingDate", args.from);
+            }
+            if (args.to) {
+              return iq.eq("userId", userId).lte("bookingDate", args.to);
+            }
+            return iq.eq("userId", userId);
+          })
+          .order("desc");
+      }
+    }
+
+    if (args.search) {
+      if (basis === "effective") {
+        if (fromMonth) {
+          const fallbackFrom = `${fromMonth}-01`;
+          q = q.filter((f) =>
+            f.or(
+              f.gte(f.field("effectiveMonth"), fromMonth),
+              f.and(
+                f.eq(f.field("effectiveMonth"), undefined),
+                f.gte(f.field("bookingDate"), fallbackFrom),
+              ),
+            ),
+          );
+        }
+        if (toMonth) {
+          const fallbackTo = `${toMonth}-31`;
+          q = q.filter((f) =>
+            f.or(
+              f.lte(f.field("effectiveMonth"), toMonth),
+              f.and(
+                f.eq(f.field("effectiveMonth"), undefined),
+                f.lte(f.field("bookingDate"), fallbackTo),
+              ),
+            ),
+          );
+        }
+      } else {
+        if (args.from) {
+          const from = args.from;
+          q = q.filter((f) => f.gte(f.field("bookingDate"), from));
+        }
+        if (args.to) {
+          const to = args.to;
+          q = q.filter((f) => f.lte(f.field("bookingDate"), to));
+        }
+      }
     }
 
     if (args.pendingOnly) {

pnpm-lock.yaml

@@ -158,7 +158,7 @@ importers:
         version: 7.1.1(eslint@10.5.0(jiti@2.7.0))
       eslint-plugin-react-refresh:
         specifier: ^0.5.2
-        version: 0.5.2(eslint@10.5.0(jiti@2.7.0))
+        version: 0.5.3(eslint@10.5.0(jiti@2.7.0))
       globals:
         specifier: ^17.6.0
         version: 17.6.0
@@ -1655,8 +1655,8 @@ packages:
     peerDependencies:
       eslint: ^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0 || ^7.0.0 || ^8.0.0-0 || ^9.0.0 || ^10.0.0
 
-  eslint-plugin-react-refresh@0.5.2:
-    resolution: {integrity: sha512-hmgTH57GfzoTFjVN0yBwTggnsVUF2tcqi7RJZHqi9lIezSs4eFyAMktA68YD4r5kNw1mxyY4dmkyoFDb3FIqrA==}
+  eslint-plugin-react-refresh@0.5.3:
+    resolution: {integrity: sha512-5EMmLCV98Pi4o/f/3DP/v/tNqLHMIc9I8LKClNDWhZ9JTho89/kQcitCXQBMG7sAfVRK0Ie3T2EDOzp1YXYiVA==}
     peerDependencies:
       eslint: ^9 || ^10
 
@@ -3828,7 +3828,7 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  eslint-plugin-react-refresh@0.5.2(eslint@10.5.0(jiti@2.7.0)):
+  eslint-plugin-react-refresh@0.5.3(eslint@10.5.0(jiti@2.7.0)):
     dependencies:
       eslint: 10.5.0(jiti@2.7.0)
 

pnpm-workspace.yaml

@@ -1,2 +1,11 @@
 allowBuilds:
   esbuild: true
+minimumReleaseAgeExclude:
+  - '@vitest/expect@4.1.9'
+  - '@vitest/mocker@4.1.9'
+  - '@vitest/pretty-format@4.1.9'
+  - '@vitest/runner@4.1.9'
+  - '@vitest/snapshot@4.1.9'
+  - '@vitest/spy@4.1.9'
+  - '@vitest/utils@4.1.9'
+  - vitest@4.1.9

src/lib/transactionFilterReset.ts

@@ -0,0 +1,29 @@
+export const DEFAULT_TRANSACTION_FILTER_RESET = {
+  global: {
+    preset: "current-month",
+    accountId: undefined,
+    categoryIds: [],
+    monthBasis: "effective",
+  },
+  page: {
+    search: "",
+    type: "all",
+    pendingOnly: false,
+    rowSelection: {},
+  },
+} as const;
+
+export type TransactionFilterResetState = typeof DEFAULT_TRANSACTION_FILTER_RESET;
+
+export function getResetTransactionFilterState(): TransactionFilterResetState {
+  return {
+    global: {
+      ...DEFAULT_TRANSACTION_FILTER_RESET.global,
+      categoryIds: [...DEFAULT_TRANSACTION_FILTER_RESET.global.categoryIds],
+    },
+    page: {
+      ...DEFAULT_TRANSACTION_FILTER_RESET.page,
+      rowSelection: { ...DEFAULT_TRANSACTION_FILTER_RESET.page.rowSelection },
+    },
+  };
+}

src/pages/SavingsChatPage.tsx

@@ -1,7 +1,8 @@
-import { type FormEvent, useEffect, useRef, useState } from "react";
-import { useAction, useQuery } from "convex/react";
+import { type FormEvent, useEffect, useMemo, useRef, useState } from "react";
+import { useAction, useMutation, usePaginatedQuery, useQuery } from "convex/react";
 import { MessageCircle, Send, Loader2 } from "lucide-react";
 import { api } from "../../convex/_generated/api";
+import type { Id } from "../../convex/_generated/dataModel";
 import { useAccountFilterId } from "@/components/layout/AccountFilter";
 import { useFilters } from "@/context/FilterContext";
 import { Button } from "@/components/ui/button";
@@ -11,67 +12,157 @@ import { Separator } from "@/components/ui/separator";
 import { ChatHistory, type ChatHistoryItem } from "@/components/chat/ChatHistory";
 import { toast } from "sonner";
 
-type ChatMessage = { role: "user" | "assistant"; content: string };
-type ChatSession = {
+type ToolTrace = {
+  name: string;
+  inputSummary: string;
+  resultSummary: string;
+};
+type UserChatMessage = { role: "user"; content: string };
+type AssistantChatMessage = {
+  role: "assistant";
+  content: string;
+  toolTrace?: ToolTrace[];
+};
+type ChatMessage = UserChatMessage | AssistantChatMessage;
+type LegacyChatSession = {
   id: string;
   title: string;
   createdAt: number;
   updatedAt: number;
   messages: ChatMessage[];
 };
+type DisplayChatMessage = ChatMessage & { _id: string };
 
 const STORAGE_KEY = "savings-chat-sessions";
+const IMPORTED_KEY = "savings-chat-sessions-imported-v1";
 const initialAssistantMessage: ChatMessage = {
   role: "assistant",
   content: "Frag mich zu deinen Umsätzen – ich werte sie im aktuellen Zeitraum aus.",
 };
-const fallbackMessages = [initialAssistantMessage];
+const fallbackMessages: DisplayChatMessage[] = [{ ...initialAssistantMessage, _id: "fallback-0" }];
 
-function createSession(): ChatSession {
-  const now = Date.now();
-  const randomId =
-    typeof crypto !== "undefined" && "randomUUID" in crypto
-      ? crypto.randomUUID()
-      : `${now}-${Math.random().toString(36).slice(2)}`;
+function normalizeToolTrace(value: unknown): ToolTrace[] | undefined {
+  if (!Array.isArray(value)) return undefined;
+  const trace = value.flatMap((item) => {
+    if (!item || typeof item !== "object") return [];
+    const candidate = item as Record<string, unknown>;
+    if (
+      typeof candidate.name !== "string" ||
+      typeof candidate.inputSummary !== "string" ||
+      typeof candidate.resultSummary !== "string"
+    ) {
+      return [];
+    }
+
+    return [
+      {
+        name: candidate.name,
+        inputSummary: candidate.inputSummary,
+        resultSummary: candidate.resultSummary,
+      },
+    ];
+  });
+
+  return trace.length > 0 ? trace : undefined;
+}
+
+function normalizeMessage(value: unknown): ChatMessage | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (typeof candidate.content !== "string") return null;
+  if (candidate.role === "user") {
+    return { role: "user", content: candidate.content };
+  }
+  if (candidate.role === "assistant") {
+    const toolTrace = normalizeToolTrace(candidate.toolTrace);
+    return toolTrace
+      ? { role: "assistant", content: candidate.content, toolTrace }
+      : { role: "assistant", content: candidate.content };
+  }
+
+  return null;
+}
+
+function isChatMessage(value: ChatMessage | null): value is ChatMessage {
+  return value !== null;
+}
+
+function normalizeSession(value: unknown): LegacyChatSession | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.id !== "string" ||
+    typeof candidate.title !== "string" ||
+    typeof candidate.createdAt !== "number" ||
+    typeof candidate.updatedAt !== "number" ||
+    !Array.isArray(candidate.messages)
+  ) {
+    return null;
+  }
+
+  const messages = candidate.messages.map(normalizeMessage);
+  if (!messages.every(isChatMessage)) return null;
 
   return {
-    id: randomId,
-    title: "Neuer Chat",
-    createdAt: now,
-    updatedAt: now,
-    messages: [initialAssistantMessage],
+    id: candidate.id,
+    title: candidate.title,
+    createdAt: candidate.createdAt,
+    updatedAt: candidate.updatedAt,
+    messages,
   };
 }
 
-function loadSessions(): ChatSession[] {
+function loadLegacySessions(): LegacyChatSession[] {
   try {
     const raw = localStorage.getItem(STORAGE_KEY);
-    if (!raw) return [createSession()];
-    const parsed = JSON.parse(raw) as ChatSession[];
-    if (!Array.isArray(parsed) || parsed.length === 0) return [createSession()];
-    return parsed;
+    if (!raw) return [];
+    const parsed: unknown = JSON.parse(raw);
+    if (!Array.isArray(parsed)) return [];
+    return parsed
+      .map(normalizeSession)
+      .filter((session): session is LegacyChatSession => session !== null)
+      .filter((session) => session.messages.some((message) => message.role === "user"));
   } catch {
-    return [createSession()];
+    return [];
   }
 }
 
-function titleFromMessages(messages: ChatMessage[]) {
-  const firstUserMessage = messages.find((message) => message.role === "user")?.content.trim();
-  if (!firstUserMessage) return "Neuer Chat";
-  return firstUserMessage.length > 44 ? `${firstUserMessage.slice(0, 44)}…` : firstUserMessage;
-}
-
 export function SavingsChatPage() {
   const { from, to, monthBasis } = useFilters();
   const accountId = useAccountFilterId();
 
   const [draft, setDraft] = useState("");
-  const [sessions, setSessions] = useState<ChatSession[]>(loadSessions);
-  const [activeSessionId, setActiveSessionId] = useState(() => sessions[0]?.id ?? "");
+  const [selectedSessionId, setSelectedSessionId] = useState<Id<"chatSessions"> | undefined>();
   const [isSubmitting, setIsSubmitting] = useState(false);
+  const [legacyImportResult, setLegacyImportResult] = useState<{
+    key: string;
+    importedCount: number;
+  } | null>(null);
+  const legacyImportStartedRef = useRef<string | undefined>(undefined);
+  const createInitialStartedRef = useRef(false);
   const listRef = useRef<HTMLDivElement | null>(null);
-  const activeSession = sessions.find((session) => session.id === activeSessionId) ?? sessions[0];
-  const messages = activeSession?.messages ?? fallbackMessages;
+
+  const sessionsQuery = usePaginatedQuery(
+    api.savingsChatHistory.listSessions,
+    {},
+    { initialNumItems: 50 },
+  );
+  const sessions = sessionsQuery.results;
+  const activeSessionId =
+    selectedSessionId && sessions.some((session) => session._id === selectedSessionId)
+      ? selectedSessionId
+      : sessions[0]?._id;
+  const activeSession = sessions.find((session) => session._id === activeSessionId);
+  const messagesQuery = usePaginatedQuery(
+    api.savingsChatHistory.listMessages,
+    activeSessionId ? { sessionId: activeSessionId } : "skip",
+    { initialNumItems: 100 },
+  );
+  const messages = useMemo(
+    () => [...messagesQuery.results].reverse() as DisplayChatMessage[],
+    [messagesQuery.results],
+  );
+  const displayMessages = activeSessionId && messages.length > 0 ? messages : fallbackMessages;
 
   const context = useQuery(api.savingsChat.getContext, {
     from,
@@ -79,9 +170,23 @@ export function SavingsChatPage() {
     accountId,
     basis: monthBasis,
   });
-  const ask = useAction(api.savingsChat.ask);
+  const currentUser = useQuery(api.users.currentUser);
+  const createSession = useMutation(api.savingsChatHistory.createSession);
+  const deleteSession = useMutation(api.savingsChatHistory.deleteSession);
+  const importLocalSession = useMutation(api.savingsChatHistory.importLocalSession);
+  const sendMessage = useAction(api.savingsChat.sendMessage);
+  const importMarkerKey = currentUser ? `${IMPORTED_KEY}:${currentUser._id}` : undefined;
+  const legacyImportComplete = Boolean(
+    importMarkerKey &&
+      (legacyImportResult?.key === importMarkerKey ||
+        localStorage.getItem(importMarkerKey) === "true"),
+  );
+  const legacyImportedCount =
+    legacyImportResult && legacyImportResult.key === importMarkerKey
+      ? legacyImportResult.importedCount
+      : 0;
 
-  const buttonDisabled = isSubmitting || draft.trim().length === 0;
+  const buttonDisabled = isSubmitting || draft.trim().length === 0 || !activeSessionId;
 
   const formatAmount = (amount: number) =>
     new Intl.NumberFormat("de-DE", {
@@ -98,85 +203,120 @@ export function SavingsChatPage() {
 
   useEffect(() => {
     listRef.current?.lastElementChild?.scrollIntoView({ behavior: "smooth" });
-  }, [messages]);
+  }, [displayMessages.length, activeSessionId]);
 
   useEffect(() => {
-    localStorage.setItem(STORAGE_KEY, JSON.stringify(sessions));
-  }, [sessions]);
+    if (!importMarkerKey || legacyImportComplete || legacyImportStartedRef.current === importMarkerKey) return;
+    legacyImportStartedRef.current = importMarkerKey;
+    const legacySessions = loadLegacySessions();
+    if (legacySessions.length === 0) {
+      localStorage.setItem(importMarkerKey, "true");
+      void Promise.resolve().then(() =>
+        setLegacyImportResult({ key: importMarkerKey, importedCount: 0 }),
+      );
+      return;
+    }
 
-  const updateSession = (id: string, nextMessages: ChatMessage[]) => {
-    const now = Date.now();
-    setSessions((prev) =>
-      prev.map((session) =>
-        session.id === id
-          ? {
-              ...session,
-              title: titleFromMessages(nextMessages),
-              updatedAt: now,
-              messages: nextMessages,
-            }
-          : session,
+    let importedCount = 0;
+    void Promise.all(
+      legacySessions.map((session) =>
+        importLocalSession({
+          legacyLocalId: session.id,
+          title: session.title,
+          createdAt: session.createdAt,
+          updatedAt: session.updatedAt,
+          messages: session.messages,
+        }),
       ),
-    );
-  };
+    )
+      .then(() => {
+        importedCount = legacySessions.length;
+        localStorage.setItem(importMarkerKey, "true");
+      })
+      .catch((error) => {
+        console.error(error);
+        toast.error("Lokale Chat-Historie konnte nicht importiert werden.");
+      })
+      .finally(() => {
+        setLegacyImportResult({ key: importMarkerKey, importedCount });
+      });
+  }, [importLocalSession, importMarkerKey, legacyImportComplete]);
+
+  useEffect(() => {
+    if (
+      !legacyImportComplete ||
+      legacyImportedCount > 0 ||
+      sessionsQuery.status === "LoadingFirstPage" ||
+      sessions.length > 0 ||
+      createInitialStartedRef.current
+    ) {
+      return;
+    }
+
+    createInitialStartedRef.current = true;
+    void createSession({ title: "Neuer Chat" })
+      .then((session) => setSelectedSessionId(session.sessionId))
+      .catch((error) => {
+        console.error(error);
+        toast.error("Neuer Chat konnte nicht erstellt werden.");
+      });
+  }, [createSession, legacyImportComplete, legacyImportedCount, sessions.length, sessionsQuery.status]);
 
   const createNewChat = () => {
-    const session = createSession();
-    setSessions((prev) => [session, ...prev]);
-    setActiveSessionId(session.id);
     setDraft("");
+    void createSession({ title: "Neuer Chat" })
+      .then((session) => setSelectedSessionId(session.sessionId))
+      .catch((error) => {
+        console.error(error);
+        toast.error("Neuer Chat konnte nicht erstellt werden.");
+      });
   };
 
   const deleteChat = (id: string) => {
-    const remaining = sessions.filter((session) => session.id !== id);
-    const nextSessions = remaining.length > 0 ? remaining : [createSession()];
-    setSessions(nextSessions);
-    if (id === activeSessionId) setActiveSessionId(nextSessions[0].id);
+    void deleteSession({ sessionId: id as Id<"chatSessions"> })
+      .then(() => {
+        if (id === activeSessionId) {
+          const nextSession = sessions.find((session) => session._id !== id);
+          setSelectedSessionId(nextSession?._id);
+        }
+      })
+      .catch((error) => {
+        console.error(error);
+        toast.error("Chat konnte nicht gelöscht werden.");
+      });
   };
 
-  const historyItems: ChatHistoryItem[] = sessions
-    .map((session) => ({
-      id: session.id,
-      title: session.title,
-      updatedAt: session.updatedAt,
-      messageCount: session.messages.length,
-    }))
-    .sort((a, b) => b.updatedAt - a.updatedAt);
+  const historyItems: ChatHistoryItem[] = useMemo(
+    () =>
+      sessions.map((session) => ({
+        id: session._id,
+        title: session.title,
+        updatedAt: session.updatedAt,
+        messageCount: session.messageCount,
+      })),
+    [sessions],
+  );
 
   const submit = async (event: FormEvent) => {
     event.preventDefault();
     const content = draft.trim();
-    if (!content || isSubmitting) return;
+    if (!content || isSubmitting || !activeSessionId) return;
 
-    const submittedSessionId = activeSessionId;
-    const typedNextMessages: ChatMessage[] = [...messages, { role: "user", content }];
-    updateSession(submittedSessionId, typedNextMessages);
     setDraft("");
     setIsSubmitting(true);
 
     try {
-      const response = await ask({
-        messages: typedNextMessages,
+      await sendMessage({
+        sessionId: activeSessionId,
+        content,
         from,
         to,
         accountId,
         basis: monthBasis,
       });
-
-      updateSession(submittedSessionId, [
-        ...typedNextMessages,
-        { role: "assistant", content: response.answer },
-      ]);
     } catch (error) {
       console.error(error);
       toast.error("Antwort konnte nicht geladen werden.");
-      updateSession(submittedSessionId, [
-        ...typedNextMessages,
-        {
-          role: "assistant",
-          content: "Ich konnte gerade keine Antwort erzeugen. Bitte später erneut versuchen.",
-        },
-      ]);
     } finally {
       setIsSubmitting(false);
     }
@@ -186,8 +326,8 @@ export function SavingsChatPage() {
     <div className="grid gap-4 xl:grid-cols-[280px_minmax(0,1fr)]">
       <ChatHistory
         items={historyItems}
-        activeId={activeSessionId}
-        onSelect={setActiveSessionId}
+        activeId={activeSessionId ?? ""}
+        onSelect={(id) => setSelectedSessionId(id as Id<"chatSessions">)}
         onCreate={createNewChat}
         onDelete={deleteChat}
       />
@@ -198,67 +338,80 @@ export function SavingsChatPage() {
           <h1 className="text-lg font-semibold">Talk to your savings account</h1>
         </div>
 
-      <Card>
-        <CardHeader>
-          <CardTitle>Kontext der Auswertung</CardTitle>
-        </CardHeader>
-        <CardContent className="space-y-1 text-sm">
-          <p>Zeitraum: {from} bis {to}</p>
-          <p>Basis: {monthBasis === "effective" ? "Effektiv" : "Buchungstag"}</p>
-          <p>
-            Konto: {context?.accountName ?? "Alle Konten"} (Basis-Saldo{" "}
-            {context ? formatAmount(context.totals.balance) : "—"})
-          </p>
-          <p>
-            {context ? getContextSummary() : "Lade Kontext…"}
-          </p>
-        </CardContent>
-      </Card>
+        <Card>
+          <CardHeader>
+            <CardTitle>Kontext der Auswertung</CardTitle>
+          </CardHeader>
+          <CardContent className="space-y-1 text-sm">
+            <p>Zeitraum: {from} bis {to}</p>
+            <p>Basis: {monthBasis === "effective" ? "Effektiv" : "Buchungstag"}</p>
+            <p>
+              Konto: {context?.accountName ?? "Alle Konten"} (Basis-Saldo{" "}
+              {context ? formatAmount(context.totals.balance) : "—"})
+            </p>
+            <p>{context ? getContextSummary() : "Lade Kontext…"}</p>
+          </CardContent>
+        </Card>
 
-      <Card>
-        <CardContent className="p-4">
-          <div className="h-[52vh] overflow-y-auto" ref={listRef}>
-            <div className="space-y-3">
-              {messages.map((message, index) => (
-                <div
-                  key={`${message.role}-${index}`}
-                  className={`rounded-lg border p-3 ${
-                    message.role === "user" ? "bg-muted/50" : "bg-background"
-                  }`}
-                >
-                  <p className="text-xs uppercase text-muted-foreground">{message.role}</p>
-                  <p className="whitespace-pre-wrap text-sm">{message.content}</p>
-                </div>
-              ))}
-              {isSubmitting && (
-                <div className="flex items-center gap-2 text-sm text-muted-foreground">
-                  <Loader2 className="h-4 w-4 animate-spin" />
-                  Denk mit der KI nach…
-                </div>
-              )}
+        <Card>
+          <CardContent className="p-4">
+            <div className="h-[52vh] overflow-y-auto" ref={listRef}>
+              <div className="space-y-3">
+                {displayMessages.map((message) => (
+                  <div
+                    key={message._id}
+                    className={`rounded-lg border p-3 ${
+                      message.role === "user" ? "bg-muted/50" : "bg-background"
+                    }`}
+                  >
+                    <p className="text-xs uppercase text-muted-foreground">{message.role}</p>
+                    <p className="whitespace-pre-wrap text-sm">{message.content}</p>
+                    {message.role === "assistant" && message.toolTrace && message.toolTrace.length > 0 && (
+                      <div className="mt-3 rounded-md border bg-muted/30 p-2">
+                        <p className="text-xs font-medium text-muted-foreground">
+                          Verwendete Werkzeuge
+                        </p>
+                        <div className="mt-2 space-y-2">
+                          {message.toolTrace.map((tool, toolIndex) => (
+                            <div key={`${tool.name}-${toolIndex}`} className="text-xs">
+                              <p className="font-medium">{tool.name}</p>
+                              <p className="text-muted-foreground">{tool.resultSummary}</p>
+                            </div>
+                          ))}
+                        </div>
+                      </div>
+                    )}
+                  </div>
+                ))}
+                {isSubmitting && (
+                  <div className="flex items-center gap-2 text-sm text-muted-foreground">
+                    <Loader2 className="h-4 w-4 animate-spin" />
+                    Denk mit der KI nach…
+                  </div>
+                )}
+              </div>
             </div>
-          </div>
-        </CardContent>
-      </Card>
+          </CardContent>
+        </Card>
 
-      <form className="flex gap-2" onSubmit={submit}>
-        <Input
-          value={draft}
-          onChange={(event) => setDraft(event.target.value)}
-          placeholder="Welche Auswertung soll ich machen?"
-          disabled={isSubmitting}
-          autoFocus
-        />
-        <Button type="submit" disabled={buttonDisabled}>
-          <Send className="h-4 w-4" />
-          Senden
-        </Button>
-      </form>
+        <form className="flex gap-2" onSubmit={submit}>
+          <Input
+            value={draft}
+            onChange={(event) => setDraft(event.target.value)}
+            placeholder={activeSession ? "Welche Auswertung soll ich machen?" : "Chat wird vorbereitet…"}
+            disabled={isSubmitting || !activeSessionId}
+            autoFocus
+          />
+          <Button type="submit" disabled={buttonDisabled}>
+            <Send className="h-4 w-4" />
+            Senden
+          </Button>
+        </form>
 
-      <Separator />
-      <p className="text-xs text-muted-foreground">
-        Antwortmodell: {context ? "Server-seitig bereit" : "…"}
-      </p>
+        <Separator />
+        <p className="text-xs text-muted-foreground">
+          Antwortmodell: {context ? "Server-seitig bereit" : "…"}
+        </p>
       </div>
     </div>
   );

src/pages/TransactionsPage.tsx

@@ -1,4 +1,12 @@
-import { memo, useCallback, useEffect, useMemo, useRef, useState } from "react";
+import {
+  memo,
+  useCallback,
+  useEffect,
+  useMemo,
+  useRef,
+  useState,
+  type ChangeEventHandler,
+} from "react";
 import { useMutation, usePaginatedQuery, useQuery } from "convex/react";
 import {
   flexRender,
@@ -10,6 +18,7 @@ import { useVirtualizer } from "@tanstack/react-virtual";
 import { api } from "../../convex/_generated/api";
 import type { Doc, Id } from "../../convex/_generated/dataModel";
 import { useFilters } from "@/context/FilterContext";
+import { useAccountFilterId } from "@/components/layout/AccountFilter";
 import { CategoryFilter } from "@/components/layout/CategoryFilter";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -20,20 +29,50 @@ import { amountClass, formatAmount, formatDate, formatMonth } from "@/lib/format
 import { TransactionFormDialog } from "@/components/transactions/TransactionFormDialog";
 import { AssignMonthDialog } from "@/components/transactions/AssignMonthDialog";
 import { toast } from "sonner";
+import {
+  getVisibleSelectionState,
+  selectedTransactionsTotal,
+  toggleVisibleSelection,
+} from "./transactionsSelection";
+import { getResetTransactionFilterState } from "@/lib/transactionFilterReset";
+import { RotateCcw } from "lucide-react";
 
 type Tx = Doc<"transactions">;
 type Category = Doc<"categories">;
+const EMPTY_TRANSACTIONS: Tx[] = [];
 
 /* ── Memoized cell components ────────────────────────────────────── */
 
 const RowCheckbox = memo(function RowCheckbox({
   checked,
+  indeterminate = false,
+  disabled = false,
+  ariaLabel,
   onToggle,
 }: {
   checked: boolean;
-  onToggle: (e?: unknown) => void;
+  indeterminate?: boolean;
+  disabled?: boolean;
+  ariaLabel: string;
+  onToggle: ChangeEventHandler<HTMLInputElement>;
 }) {
-  return <input type="checkbox" checked={checked} onChange={onToggle} />;
+  const ref = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    if (ref.current) ref.current.indeterminate = indeterminate;
+  }, [indeterminate]);
+
+  return (
+    <input
+      ref={ref}
+      type="checkbox"
+      checked={checked}
+      disabled={disabled}
+      aria-label={ariaLabel}
+      onChange={onToggle}
+      className="h-4 w-4 rounded border-border accent-primary"
+    />
+  );
 });
 
 const AccountCell = memo(function AccountCell({ name }: { name: string | undefined }) {
@@ -152,7 +191,17 @@ export function TransactionsPage() {
   const [assignTx, setAssignTx] = useState<Tx | null>(null);
   const [createOpen, setCreateOpen] = useState(false);
 
-  const { categoryIds } = useFilters();
+  const {
+    categoryIds,
+    from,
+    to,
+    monthBasis,
+    setPreset,
+    setAccountId,
+    setCategoryIds,
+    setMonthBasis,
+  } = useFilters();
+  const accountId = useAccountFilterId();
 
   const categories = useQuery(api.categories.list);
   const accounts = useQuery(api.accounts.list);
@@ -164,6 +213,10 @@ export function TransactionsPage() {
     api.transactions.list,
     {
       search: search || undefined,
+      from,
+      to,
+      accountId,
+      basis: monthBasis,
       type: type === "all" ? undefined : type,
       pendingOnly: pendingOnly || undefined,
       categoryIds:
@@ -183,6 +236,15 @@ export function TransactionsPage() {
     () => new Map(accounts?.map((a) => [a._id, a.name])),
     [accounts],
   );
+  const visibleTransactions = results ?? EMPTY_TRANSACTIONS;
+  const visibleSelectionState = useMemo(
+    () => getVisibleSelectionState(visibleTransactions, rowSelection),
+    [visibleTransactions, rowSelection],
+  );
+  const selectedTotal = useMemo(
+    () => selectedTransactionsTotal(visibleTransactions, rowSelection),
+    [visibleTransactions, rowSelection],
+  );
 
   const handleUpdateCategory = useCallback(
     (id: Id<"transactions">, categoryId: Id<"categories">) => {
@@ -201,21 +263,59 @@ export function TransactionsPage() {
     },
     [removeTx],
   );
+  const handleToggleAllVisible = useCallback(
+    (checked: boolean) => {
+      setRowSelection((selection) =>
+        toggleVisibleSelection(selection, visibleTransactions, checked),
+      );
+    },
+    [visibleTransactions],
+  );
+  const handleResetFilters = useCallback(() => {
+    const reset = getResetTransactionFilterState();
+
+    setPreset(reset.global.preset);
+    setAccountId(reset.global.accountId);
+    setCategoryIds([...reset.global.categoryIds]);
+    setMonthBasis(reset.global.monthBasis);
+    setSearch(reset.page.search);
+    setType(reset.page.type);
+    setPendingOnly(reset.page.pendingOnly);
+    setRowSelection(reset.page.rowSelection);
+  }, [setAccountId, setCategoryIds, setMonthBasis, setPreset]);
 
   const selectedIds = useMemo(
-    () => Object.keys(rowSelection).filter((k) => rowSelection[k]) as Id<"transactions">[],
-    [rowSelection],
+    () =>
+      visibleTransactions
+        .filter((tx) => rowSelection[tx._id])
+        .map((tx) => tx._id),
+    [visibleTransactions, rowSelection],
   );
 
   const columns = useMemo<ColumnDef<Tx>[]>(
     () => [
       {
         id: "select",
-        header: () => null,
+        header: () => (
+          <RowCheckbox
+            checked={visibleSelectionState.allSelected}
+            indeterminate={
+              visibleSelectionState.someSelected && !visibleSelectionState.allSelected
+            }
+            disabled={visibleTransactions.length === 0}
+            ariaLabel={
+              visibleSelectionState.allSelected
+                ? "Alle sichtbaren Transaktionen abwählen"
+                : "Alle sichtbaren Transaktionen auswählen"
+            }
+            onToggle={(event) => handleToggleAllVisible(event.target.checked)}
+          />
+        ),
         cell: ({ row }) => (
           <RowCheckbox
             checked={row.getIsSelected()}
-            onToggle={row.getToggleSelectedHandler()}
+            ariaLabel="Transaktion auswählen"
+            onToggle={(event) => row.getToggleSelectedHandler()(event)}
           />
         ),
       },
@@ -288,11 +388,14 @@ export function TransactionsPage() {
       handleEdit,
       handleAssign,
       handleRemove,
+      visibleSelectionState,
+      visibleTransactions.length,
+      handleToggleAllVisible,
     ],
   );
 
   const table = useReactTable({
-    data: results ?? [],
+    data: visibleTransactions,
     columns,
     state: { rowSelection },
     onRowSelectionChange: setRowSelection,
@@ -354,7 +457,22 @@ export function TransactionsPage() {
           />
           Nur offene
         </label>
+        <Button variant="outline" onClick={handleResetFilters}>
+          <RotateCcw className="h-4 w-4" />
+          Zurücksetzen
+        </Button>
         <Button onClick={() => setCreateOpen(true)}>Neu</Button>
+        {visibleSelectionState.someSelected && (
+          <div className="flex h-9 items-center gap-2 rounded-md border bg-muted/40 px-3 text-sm">
+            <span className="font-medium">
+              {visibleSelectionState.selectedCount} ausgewählt
+            </span>
+            <span className="text-muted-foreground">Summe</span>
+            <span className={`font-semibold tabular-nums ${amountClass(selectedTotal)}`}>
+              {formatAmount(selectedTotal)}
+            </span>
+          </div>
+        )}
         {selectedIds.length > 0 && categories && (
           <Select
             onValueChange={async (categoryId) => {

src/pages/transactionFilterReset.test.ts

@@ -0,0 +1,25 @@
+import { describe, expect, test } from "vitest";
+import {
+  DEFAULT_TRANSACTION_FILTER_RESET,
+  getResetTransactionFilterState,
+} from "@/lib/transactionFilterReset";
+
+describe("transaction filter reset defaults", () => {
+  test("resets global and page-level transaction filters", () => {
+    expect(getResetTransactionFilterState()).toEqual({
+      global: {
+        preset: "current-month",
+        accountId: undefined,
+        categoryIds: [],
+        monthBasis: "effective",
+      },
+      page: {
+        search: "",
+        type: "all",
+        pendingOnly: false,
+        rowSelection: {},
+      },
+    });
+    expect(DEFAULT_TRANSACTION_FILTER_RESET.page.rowSelection).toEqual({});
+  });
+});

src/pages/transactionsSelection.test.ts

@@ -0,0 +1,48 @@
+import { describe, expect, test } from "vitest";
+import {
+  getVisibleSelectionState,
+  selectedTransactionsTotal,
+  toggleVisibleSelection,
+} from "./transactionsSelection";
+
+const visibleTransactions = [
+  { _id: "tx-1", amount: -55.68 },
+  { _id: "tx-2", amount: -26.75 },
+  { _id: "tx-3", amount: 12 },
+];
+
+describe("transactions selection helpers", () => {
+  test("selects and clears all visible transactions without changing hidden selections", () => {
+    expect(
+      toggleVisibleSelection(
+        { "hidden-tx": true, "tx-1": true },
+        visibleTransactions,
+        true,
+      ),
+    ).toEqual({
+      "hidden-tx": true,
+      "tx-1": true,
+      "tx-2": true,
+      "tx-3": true,
+    });
+
+    expect(
+      toggleVisibleSelection(
+        { "hidden-tx": true, "tx-1": true, "tx-2": true, "tx-3": true },
+        visibleTransactions,
+        false,
+      ),
+    ).toEqual({ "hidden-tx": true });
+  });
+
+  test("computes selected count, all-selected state, and signed total from visible transactions", () => {
+    const selection = { "hidden-tx": true, "tx-1": true, "tx-3": true };
+
+    expect(getVisibleSelectionState(visibleTransactions, selection)).toEqual({
+      allSelected: false,
+      someSelected: true,
+      selectedCount: 2,
+    });
+    expect(selectedTransactionsTotal(visibleTransactions, selection)).toBe(-43.68);
+  });
+});

src/pages/transactionsSelection.ts

@@ -0,0 +1,49 @@
+export type TransactionSelection = Record<string, boolean>;
+
+export type SelectableTransaction = {
+  _id: string;
+  amount: number;
+};
+
+export function toggleVisibleSelection(
+  selection: TransactionSelection,
+  visibleTransactions: SelectableTransaction[],
+  selectAll: boolean,
+): TransactionSelection {
+  const next = { ...selection };
+
+  for (const tx of visibleTransactions) {
+    if (selectAll) {
+      next[tx._id] = true;
+    } else {
+      delete next[tx._id];
+    }
+  }
+
+  return next;
+}
+
+export function getVisibleSelectionState(
+  visibleTransactions: SelectableTransaction[],
+  selection: TransactionSelection,
+) {
+  const selectedCount = visibleTransactions.filter((tx) => selection[tx._id]).length;
+
+  return {
+    allSelected: visibleTransactions.length > 0 && selectedCount === visibleTransactions.length,
+    someSelected: selectedCount > 0,
+    selectedCount,
+  };
+}
+
+export function selectedTransactionsTotal(
+  visibleTransactions: SelectableTransaction[],
+  selection: TransactionSelection,
+): number {
+  const total = visibleTransactions.reduce(
+    (sum, tx) => (selection[tx._id] ? sum + tx.amount : sum),
+    0,
+  );
+
+  return Math.round(total * 100) / 100;
+}