import { NextResponse } from "next/server";
import { createSupabaseRouteClient } from "@/lib/supabase/server";
import type {
  DocumentSearchFilters,
  DocumentSearchRequest,
  DocumentSearchResponse,
  DocumentSearchResult,
  DocumentSearchTimeRange,
} from "@/types/search";
import { buildSnippet } from "@/lib/search/snippet";

const MAX_LIMIT = 50;

const DEFAULT_FILTERS: DocumentSearchFilters = {
  titleOnly: false,
  exact: false,
  onlyCurrentPage: false,
  includeOcr: false,
  timeRange: "any",
  timeField: "updated",
};

const TIME_RANGE_TO_MS: Record<DocumentSearchTimeRange, number | null> = {
  any: null,
  "7d": 1000 * 60 * 60 * 24 * 7,
  "30d": 1000 * 60 * 60 * 24 * 30,
};

const TIME_FIELD_COLUMN = {
  updated: "updated_at",
  created: "created_at",
} as const;

const escapeLike = (value: string): string => value.replace(/[%_\\]/g, (match) => `\\${match}`);
interface DocumentRow {
  id: string;
  title: string | null;
  raw_text: string | null;
  updated_at: string | null;
  created_at: string | null;
}

const buildIsoBoundary = (value: string, isEnd = false): string | null => {
  if (!value) {
    return null;
  }
  const normalized = value.trim();
  if (!normalized) {
    return null;
  }
  const suffix = isEnd ? "T23:59:59.999Z" : "T00:00:00.000Z";
  const date = new Date(`${normalized}${suffix}`);
  if (Number.isNaN(date.getTime())) {
    return null;
  }
  return date.toISOString();
};

const mapDocumentToResult = (
  row: DocumentRow,
  keyword: string | null,
  forcedMatch?: DocumentSearchResult["matchField"],
): DocumentSearchResult => {
  const normalizedKeyword = keyword?.trim() ?? "";
  const normalizedTitle = row.title ?? "无标题";
  let matchField: DocumentSearchResult["matchField"] = "recent";
  if (forcedMatch) {
    matchField = forcedMatch;
  } else if (normalizedKeyword) {
    const matchesTitle = normalizedTitle.toLowerCase().includes(normalizedKeyword.toLowerCase());
    matchField = matchesTitle ? "title" : "content";
  }

  return {
    id: row.id,
    title: normalizedTitle,
    snippet: buildSnippet(row.raw_text, normalizedKeyword || null),
    updatedAt: row.updated_at,
    createdAt: row.created_at,
    matchField,
    hasOcr: Boolean(row.raw_text),
    publicPath: `/documents/${row.id}`,
    score: matchField === "title" ? 2 : 1,
  };
};

type RouteSupabaseClient = Awaited<ReturnType<typeof createSupabaseRouteClient>>;

const fetchRecentResults = async (
  supabase: RouteSupabaseClient,
  userId: string,
  workspaceId: string,
): Promise<DocumentSearchResult[]> => {
  const { data: recentRows, error: recentError } = await supabase
    .from("user_recent_pages")
    .select("document_id,last_accessed_at")
    .eq("user_id", userId)
    .eq("workspace_id", workspaceId)
    .order("last_accessed_at", { ascending: false })
    .limit(10);

  if (recentError || !recentRows || recentRows.length === 0) {
    return [];
  }

  const documentIds = recentRows.map((row) => row.document_id);

  const { data: docRows, error: docsError } = await supabase
    .from("documents")
    .select("id,title,updated_at,created_at,raw_text")
    .in("id", documentIds)
    .is("deleted_at", null);

  if (docsError || !docRows) {
    return [];
  }

  const docMap = new Map(docRows.map((row) => [row.id, row]));
  return recentRows
    .map((row) => docMap.get(row.document_id))
    .filter((row): row is DocumentRow => Boolean(row))
    .map((row) => mapDocumentToResult(row, null, "recent"));
};

const fetchOcrMatches = async (
  supabase: RouteSupabaseClient,
  workspaceId: string,
  likePattern: string,
  limit: number,
) => {
  const { data, error } = await supabase
    .from("media_assets")
    .select("document_id,ocr_text")
    .eq("workspace_id", workspaceId)
    .not("ocr_text", "is", null)
    .ilike("ocr_text", likePattern)
    .limit(limit);

  if (error || !data) {
    return [];
  }
  return data;
};

export async function POST(request: Request) {
  const supabase = await createSupabaseRouteClient();
  const {
    data: { session },
  } = await supabase.auth.getSession();

  if (!session) {
    return NextResponse.json({ error: "未登录" }, { status: 401 });
  }

  const payload = (await request.json()) as DocumentSearchRequest;
  const workspaceId = payload.workspaceId;

  if (!workspaceId) {
    return NextResponse.json({ error: "缺少 workspaceId" }, { status: 400 });
  }

  const filters: DocumentSearchFilters = {
    ...DEFAULT_FILTERS,
    ...payload.filters,
  };

  const { data: membership, error: membershipError } = await supabase
    .from("workspace_members")
    .select("workspace_id")
    .eq("workspace_id", workspaceId)
    .eq("user_id", session.user.id)
    .limit(1);

  if (membershipError) {
    return NextResponse.json({ error: membershipError.message }, { status: 500 });
  }

  if (!membership || membership.length === 0) {
    return NextResponse.json({ error: "无权访问该工作空间" }, { status: 403 });
  }

  if (filters.onlyCurrentPage && !payload.documentId) {
    filters.onlyCurrentPage = false;
  }

  const limit = Math.min(payload.limit ?? 30, MAX_LIMIT);
  const normalizedQuery = payload.query?.trim() ?? "";
  const likePattern = filters.exact ? normalizedQuery : `%${escapeLike(normalizedQuery)}%`;
  const timeColumn = TIME_FIELD_COLUMN[filters.timeField ?? "updated"];

  let builder = supabase
    .from("documents")
    .select("id,title,updated_at,created_at,raw_text,is_starred,access_scope")
    .eq("workspace_id", workspaceId)
    .is("deleted_at", null)
    .order(timeColumn, { ascending: false })
    .limit(limit);

  if (filters.onlyCurrentPage && payload.documentId) {
    builder = builder.eq("id", payload.documentId);
  }

  const customFrom = filters.customRange?.from ? buildIsoBoundary(filters.customRange.from, false) : null;
  const customTo = filters.customRange?.to ? buildIsoBoundary(filters.customRange.to, true) : null;

  if (customFrom) {
    builder = builder.gte(timeColumn, customFrom);
  }
  if (customTo) {
    builder = builder.lte(timeColumn, customTo);
  }

  if (!customFrom && !customTo) {
    const now = Date.now();
    const offset = TIME_RANGE_TO_MS[filters.timeRange];
    if (offset) {
      const from = new Date(now - offset).toISOString();
      builder = builder.gte(timeColumn, from);
    }
  }

  if (normalizedQuery) {
    if (filters.titleOnly) {
      builder = filters.exact ? builder.eq("title", normalizedQuery) : builder.ilike("title", likePattern);
    } else {
      const clauses = [
        `title.${filters.exact ? `eq.${normalizedQuery}` : `ilike.${likePattern}`}`,
      ];
      if (filters.includeOcr) {
        clauses.push(`raw_text.ilike.${likePattern}`);
      }
      builder = builder.or(clauses.join(","));
    }
  }

  const shouldSearchOcr = Boolean(filters.includeOcr && normalizedQuery);
  const [{ data, error }, recentResults, ocrMatches] = await Promise.all([
    builder,
    fetchRecentResults(supabase, session.user.id, workspaceId),
    shouldSearchOcr ? fetchOcrMatches(supabase, workspaceId, likePattern, limit) : Promise.resolve([]),
  ]);

  if (error) {
    return NextResponse.json({ error: error.message }, { status: 500 });
  }

  let results: DocumentSearchResult[] = (data ?? []).map((row) =>
    mapDocumentToResult(row, normalizedQuery || null),
  );

  if (ocrMatches.length > 0 && normalizedQuery) {
    const snippetMap = new Map<string, string>();
    ocrMatches.forEach((row: { document_id: string; ocr_text: string | null }) => {
      if (!row.ocr_text) return;
      if (!snippetMap.has(row.document_id)) {
        snippetMap.set(row.document_id, row.ocr_text);
      }
    });
    if (snippetMap.size > 0) {
      const resultMap = new Map(results.map((item) => [item.id, item]));
      const missingDocIds: string[] = [];
      snippetMap.forEach((text, docId) => {
        const snippet = buildSnippet(text, normalizedQuery || null);
        if (resultMap.has(docId)) {
          const existing = resultMap.get(docId)!;
          resultMap.set(docId, {
            ...existing,
            snippet: snippet || existing.snippet,
            hasOcr: true,
            matchField: "content",
          });
        } else {
          missingDocIds.push(docId);
        }
      });
      let extraResults: DocumentSearchResult[] = [];
      if (missingDocIds.length > 0) {
        const { data: extraDocs } = await supabase
          .from("documents")
          .select("id,title,updated_at,created_at,raw_text")
          .in("id", missingDocIds)
          .is("deleted_at", null);
        extraResults =
          extraDocs?.map((row) => {
            const snippetText = snippetMap.get(row.id) ?? row.raw_text ?? "";
            return {
              ...mapDocumentToResult(row, normalizedQuery || null, "content"),
              snippet: buildSnippet(snippetText, normalizedQuery || null),
              hasOcr: true,
            };
          }) ?? [];
      }
      results = [...resultMap.values(), ...extraResults];
    }
  }

  const response: DocumentSearchResponse = {
    results,
    recent: recentResults,
  };

  return NextResponse.json(response);
}