import {
  normalizeEmailAddress,
  type GooglePlaceCandidate,
} from "./lead-discovery-google";

export const LOCAL_BUSINESS_DATA_HOST = "local-business-data.p.rapidapi.com";
export const LOCAL_BUSINESS_DATA_SEARCH_ENDPOINT =
  `https://${LOCAL_BUSINESS_DATA_HOST}/search`;
export const LOCAL_BUSINESS_DATA_MAX_RESULTS = 500;

type CampaignLike = {
  categoryMode?: "preset" | "custom";
  category?: string | null;
  customSearchTerm?: string | null;
  postalCode: string;
  maxNewLeads: number;
};

type LocalBusinessDataError = {
  message?: string;
  code?: number;
};

type LocalBusinessDataBusiness = Record<string, unknown>;

export type LocalBusinessDataResponse = {
  status?: string;
  request_id?: string;
  error?: LocalBusinessDataError;
  data?: unknown;
};

function normalizeSearchTerm(value?: string | null) {
  return value?.trim() ?? "";
}

function clampSearchLimit(limit: number) {
  if (!Number.isFinite(limit)) {
    return 1;
  }

  return Math.min(Math.max(Math.floor(limit), 1), LOCAL_BUSINESS_DATA_MAX_RESULTS);
}

function stringValue(...values: unknown[]) {
  for (const value of values) {
    if (typeof value === "string" && value.trim().length > 0) {
      return value.trim();
    }
  }

  return null;
}

function numberValue(...values: unknown[]) {
  for (const value of values) {
    if (typeof value === "number" && Number.isFinite(value)) {
      return value;
    }
    if (typeof value === "string" && value.trim().length > 0) {
      const parsed = Number.parseFloat(value);
      if (Number.isFinite(parsed)) {
        return parsed;
      }
    }
  }

  return null;
}

function stringArrayValue(...values: unknown[]) {
  const result: string[] = [];

  for (const value of values) {
    if (typeof value === "string" && value.trim().length > 0) {
      result.push(value.trim());
      continue;
    }

    if (Array.isArray(value)) {
      for (const item of value) {
        if (typeof item === "string" && item.trim().length > 0) {
          result.push(item.trim());
        } else if (item && typeof item === "object") {
          const email = stringValue(
            (item as Record<string, unknown>).email,
            (item as Record<string, unknown>).value,
          );
          if (email) {
            result.push(email);
          }
        }
      }
    }
  }

  return [...new Set(result)];
}

function objectValue(value: unknown) {
  return value && typeof value === "object"
    ? (value as Record<string, unknown>)
    : null;
}

function normalizeWebsiteDomain(input?: string | null) {
  if (!input) {
    return null;
  }

  try {
    const url = new URL(input);
    return url.hostname.toLowerCase().replace(/^www\./, "");
  } catch {
    try {
      const url = new URL(`https://${input}`);
      return url.hostname.toLowerCase().replace(/^www\./, "");
    } catch {
      return null;
    }
  }
}

function normalizeWebsiteUrl(value?: string | null) {
  if (!value) {
    return null;
  }

  try {
    return new URL(value).toString();
  } catch {
    try {
      return new URL(`https://${value}`).toString();
    } catch {
      return null;
    }
  }
}

function extractBusinesses(data: unknown): LocalBusinessDataBusiness[] {
  if (Array.isArray(data)) {
    return data.filter(
      (item): item is LocalBusinessDataBusiness =>
        item !== null && typeof item === "object",
    );
  }

  if (data && typeof data === "object") {
    const record = data as Record<string, unknown>;
    for (const key of ["businesses", "results", "items"]) {
      const value = record[key];
      if (Array.isArray(value)) {
        return value.filter(
          (item): item is LocalBusinessDataBusiness =>
            item !== null && typeof item === "object",
        );
      }
    }
  }

  return [];
}

export function buildLocalBusinessSearchUrl({
  query,
  limit,
  language = "de",
  region = "de",
}: {
  query: string;
  limit: number;
  language?: string;
  region?: string;
}) {
  const url = new URL(LOCAL_BUSINESS_DATA_SEARCH_ENDPOINT);

  url.searchParams.set("query", query);
  url.searchParams.set("limit", String(clampSearchLimit(limit)));
  url.searchParams.set("language", language);
  url.searchParams.set("region", region);
  url.searchParams.set("extract_emails_and_contacts", "true");

  return url.toString();
}

export function getLocalBusinessSearchSpec(campaignLike: CampaignLike) {
  const category = normalizeSearchTerm(campaignLike.category);
  const baseTerm =
    campaignLike.categoryMode === "custom" || category === "Anderes"
      ? normalizeSearchTerm(campaignLike.customSearchTerm)
      : category;
  const query = `${baseTerm || "Unternehmen"} in ${campaignLike.postalCode} Deutschland`;
  const limit = clampSearchLimit(campaignLike.maxNewLeads);

  return {
    query,
    limit,
    url: buildLocalBusinessSearchUrl({ query, limit }),
  };
}

export function normalizeLocalBusinessSearchResponse(
  response: LocalBusinessDataResponse,
  fetchedAt: number,
): GooglePlaceCandidate[] {
  if (!response || response.status === "ERROR") {
    const code = response?.error?.code ?? "unknown";
    const message = response?.error?.message ?? "Unknown Local Business Data error.";
    throw new Error(`Local Business Data API error ${code}: ${message}`);
  }

  const businesses = extractBusinesses(response.data);

  return businesses.flatMap((business) => {
    const sourceBusinessId = stringValue(
      business.business_id,
      business.businessId,
      business.id,
    );
    const placeId = stringValue(
      business.place_id,
      business.google_place_id,
      business.google_id,
      business.googleId,
      sourceBusinessId,
    );
    const businessName = stringValue(
      business.name,
      business.business_name,
      business.title,
    );

    if (!placeId || !businessName) {
      return [];
    }

    const websiteUrl = normalizeWebsiteUrl(
      stringValue(business.website, business.site, business.url),
    );
    const emailsAndContacts = objectValue(business.emails_and_contacts);
    const directEmails = stringArrayValue(
      business.email,
      business.emails,
      business.contact_emails,
      business.contacts,
      emailsAndContacts?.emails,
    );
    const seenEmails = new Set<string>();
    const contactEmails = directEmails.flatMap((email) => {
      const normalizedEmail = normalizeEmailAddress(email);

      if (!normalizedEmail || seenEmails.has(normalizedEmail)) {
        return [];
      }

      seenEmails.add(normalizedEmail);

      return [
        {
          email: normalizedEmail,
          emailSource: "local_business_data",
          isBusinessContactAddress:
            normalizedEmail.split("@")[0]?.includes(".") === false,
        },
      ];
    });

    return [
      {
        placeId,
        sourceBusinessId: sourceBusinessId ?? placeId,
        businessName,
        address:
          stringValue(
            business.full_address,
            business.address,
            business.formatted_address,
          ) ?? "",
        websiteUrl,
        websiteDomain: normalizeWebsiteDomain(websiteUrl),
        phone:
          stringValue(
            business.phone_number,
            business.phone,
            business.telephone,
          ) ?? null,
        email: contactEmails[0]?.email ?? null,
        emailSource: contactEmails[0]?.emailSource ?? null,
        contactEmails,
        rating: numberValue(business.rating, business.google_rating),
        userRatingCount: numberValue(
          business.review_count,
          business.reviews_count,
          business.user_ratings_total,
        ),
        businessStatus:
          stringValue(business.business_status, business.status) ?? null,
        googleTypes: stringArrayValue(
          business.types,
          business.subtypes,
          business.category,
        ),
        googlePrimaryType:
          stringValue(business.type, business.primary_type, business.category) ??
          null,
        googleMapsUrl:
          stringValue(
            business.google_maps_url,
            business.google_maps_link,
            business.maps_url,
          ) ?? null,
        sourceProvider: "local_business_data",
        sourceFetchedAt: fetchedAt,
      },
    ];
  });
}