import { BadRequestException, Injectable } from "@nestjs/common";
import { Types } from "mongoose";
import { ClaimCaseDbService } from "src/claim-request-management/entites/db-service/claim-case.db.service";
import {
  blameCaseStatusToReportBucket,
  claimCaseStatusToReportBucket,
  initialBlameExpertReportBuckets,
  initialClaimExpertReportBuckets,
} from "src/helpers/expert-panel-status-report";
import {
  blameCaseTouchesClient,
  claimCaseTouchesClient,
  requireActorClientKey,
} from "src/helpers/tenant-scope";
import { BlameRequestDbService } from "src/request-management/entities/db-service/blame-request.db.service";
import { DamageExpertDbService } from "src/users/entities/db-service/damage-expert.db.service";
import { ExpertDbService } from "src/users/entities/db-service/expert.db.service";
import { ExpertFileActivityDbService } from "src/users/entities/db-service/expert-file-activity.db.service";
import { ExpertFileActivityType } from "src/users/entities/schema/expert-file-activity.schema";
import {
  InsurerExpertWorkLogPerMonthRowDtoRs,
  InsurerExpertWorkLogResponseDtoRs,
  InsurerExpertWorkLogEntryDtoRs,
  InsurerPerMonthReportRowDtoRs,
  InsurerRequestsSummaryDtoRs,
} from "./dto/reports.dto";

type NormalizedActivity = {
  expertId: string;
  fileId: string;
  eventType: ExpertFileActivityType;
  occurredAt: Date;
};

@Injectable()
export class ReportsService {
  constructor(
    private readonly blameRequestDbService: BlameRequestDbService,
    private readonly claimCaseDbService: ClaimCaseDbService,
    private readonly expertDbService: ExpertDbService,
    private readonly damageExpertDbService: DamageExpertDbService,
    private readonly expertFileActivityDbService: ExpertFileActivityDbService,
  ) {}

  private parseDateRange(from?: string, to?: string) {
    const fromDate = from ? new Date(from) : undefined;
    const toDate = to ? new Date(to) : undefined;

    if (fromDate && Number.isNaN(fromDate.getTime())) {
      throw new BadRequestException("Invalid 'from' date");
    }
    if (toDate && Number.isNaN(toDate.getTime())) {
      throw new BadRequestException("Invalid 'to' date");
    }
    if (fromDate && toDate && fromDate > toDate) {
      throw new BadRequestException("'from' must be before or equal to 'to'");
    }
    return { fromDate, toDate };
  }

  private isInDateRange(
    value: unknown,
    fromDate?: Date,
    toDate?: Date,
  ): boolean {
    if (!fromDate && !toDate) return true;
    if (!value) return false;
    const d = new Date(value as string | Date);
    if (Number.isNaN(d.getTime())) return false;
    if (fromDate && d < fromDate) return false;
    if (toDate && d > toDate) return false;
    return true;
  }

  private publicIdKey(doc: Record<string, unknown>): string {
    return String(doc.publicId ?? doc._id ?? "");
  }

  private buildClaimBucketsForInsurer(
    rows: Record<string, unknown>[],
    clientKey: string,
    dateFrom?: Date,
    dateTo?: Date,
  ): Record<string, number> {
    const buckets = initialClaimExpertReportBuckets();
    for (const doc of rows) {
      if (!claimCaseTouchesClient(doc, clientKey)) continue;
      if (!this.isInDateRange(doc.createdAt, dateFrom, dateTo)) continue;
      const st = String(doc.status ?? "");
      const key = claimCaseStatusToReportBucket(st);
      buckets.all++;
      buckets[key] = (buckets[key] ?? 0) + 1;
    }
    return buckets;
  }

  private buildBlameBucketsForInsurer(
    rows: Record<string, unknown>[],
    clientKey: string,
    dateFrom?: Date,
    dateTo?: Date,
  ): Record<string, number> {
    const buckets = initialBlameExpertReportBuckets();
    for (const doc of rows) {
      if (!blameCaseTouchesClient(doc, clientKey)) continue;
      if (!this.isInDateRange(doc.createdAt, dateFrom, dateTo)) continue;
      const st = String(doc.status ?? "");
      const key = blameCaseStatusToReportBucket(st);
      buckets.all++;
      buckets[key] = (buckets[key] ?? 0) + 1;
    }
    return buckets;
  }

  /**
   * One insurer “file” per `publicId`, aligned with `ExpertInsurerService.retrieveAllFilesOfClient`.
   */
  private countUnifiedByPublicId(
    blameRows: Record<string, unknown>[],
    claimRows: Record<string, unknown>[],
    clientKey: string,
    dateFrom?: Date,
    dateTo?: Date,
  ): number {
    const keys = new Set<string>();
    for (const doc of blameRows) {
      if (!blameCaseTouchesClient(doc, clientKey)) continue;
      if (!this.isInDateRange(doc.createdAt, dateFrom, dateTo)) continue;
      const k = this.publicIdKey(doc);
      if (k) keys.add(k);
    }
    for (const doc of claimRows) {
      if (!claimCaseTouchesClient(doc, clientKey)) continue;
      if (!this.isInDateRange(doc.createdAt, dateFrom, dateTo)) continue;
      const k = this.publicIdKey(doc);
      if (k) keys.add(k);
    }
    return keys.size;
  }

  private buildInsurerSummary(
    blames: Record<string, unknown>[],
    claims: Record<string, unknown>[],
    clientKey: string,
    dateFrom?: Date,
    dateTo?: Date,
  ): InsurerRequestsSummaryDtoRs {
    const claim = this.buildClaimBucketsForInsurer(
      claims,
      clientKey,
      dateFrom,
      dateTo,
    );
    const blame = this.buildBlameBucketsForInsurer(
      blames,
      clientKey,
      dateFrom,
      dateTo,
    );
    const unifiedTotal = this.countUnifiedByPublicId(
      blames,
      claims,
      clientKey,
      dateFrom,
      dateTo,
    );
    return new InsurerRequestsSummaryDtoRs(claim, blame, unifiedTotal);
  }

  async getInsurerRequestsSummary(actor: {
    clientKey?: string;
  }): Promise<InsurerRequestsSummaryDtoRs> {
    const clientKey = requireActorClientKey(actor);
    const [blames, claims] = await Promise.all([
      this.blameRequestDbService.find({}, { lean: true }),
      this.claimCaseDbService.find({}, { lean: true }),
    ]);
    return this.buildInsurerSummary(
      blames as Record<string, unknown>[],
      claims as Record<string, unknown>[],
      clientKey,
    );
  }

  async getInsurerRequestsSummaryPerMonth(actor: {
    clientKey?: string;
  }): Promise<InsurerPerMonthReportRowDtoRs[]> {
    const clientKey = requireActorClientKey(actor);
    const [blames, claims] = await Promise.all([
      this.blameRequestDbService.find({}, { lean: true }),
      this.claimCaseDbService.find({}, { lean: true }),
    ]);
    const blameRows = blames as Record<string, unknown>[];
    const claimRows = claims as Record<string, unknown>[];

    const result: InsurerPerMonthReportRowDtoRs[] = [];
    const now = new Date();

    for (let i = 0; i < 5; i++) {
      const monthStart = new Date(now.getFullYear(), now.getMonth() - i, 1);
      const monthEnd = new Date(
        now.getFullYear(),
        now.getMonth() - i + 1,
        0,
        23,
        59,
        59,
      );
      const label = monthStart.toLocaleDateString("fa-IR", {
        month: "long",
        year: "numeric",
      });

      const data = this.buildInsurerSummary(
        blameRows,
        claimRows,
        clientKey,
        monthStart,
        monthEnd,
      );

      result.unshift(
        new InsurerPerMonthReportRowDtoRs(monthStart, monthEnd, label, data),
      );
    }
    return result;
  }

  async getInsurerRequestsSummaryByDateRange(
    actor: { clientKey?: string },
    from?: string,
    to?: string,
  ): Promise<InsurerRequestsSummaryDtoRs> {
    const clientKey = requireActorClientKey(actor);
    const { fromDate, toDate } = this.parseDateRange(from, to);

    const [blames, claims] = await Promise.all([
      this.blameRequestDbService.find({}, { lean: true }),
      this.claimCaseDbService.find({}, { lean: true }),
    ]);
    return this.buildInsurerSummary(
      blames as Record<string, unknown>[],
      claims as Record<string, unknown>[],
      clientKey,
      fromDate,
      toDate,
    );
  }

  /** Same replay rules as `ExpertInsurerService.buildExpertActivityStatsMap`. */
  private replayExpertFileStates(
    events: NormalizedActivity[],
    cutoff: Date,
  ): Map<string, { checked: boolean; handled: boolean }> {
    const stateByKey = new Map<string, { checked: boolean; handled: boolean }>();
    const filtered = events.filter((e) => e.occurredAt <= cutoff);
    filtered.sort((a, b) => {
      const t = a.occurredAt.getTime() - b.occurredAt.getTime();
      if (t !== 0) return t;
      return `${a.expertId}:${a.fileId}`.localeCompare(`${b.expertId}:${b.fileId}`);
    });
    for (const e of filtered) {
      const key = `${e.expertId}:${e.fileId}`;
      const prev = stateByKey.get(key) ?? { checked: false, handled: false };
      if (e.eventType === ExpertFileActivityType.CHECKED) {
        if (!prev.handled) prev.checked = true;
      } else if (e.eventType === ExpertFileActivityType.UNCHECKED) {
        prev.checked = false;
      } else if (e.eventType === ExpertFileActivityType.HANDLED) {
        prev.handled = true;
        prev.checked = false;
      }
      stateByKey.set(key, prev);
    }
    return stateByKey;
  }

  private snapshotCountsForExpert(
    stateByKey: Map<string, { checked: boolean; handled: boolean }>,
    expertId: string,
  ): { totalHandled: number; currentlyChecking: number } {
    let totalHandled = 0;
    let currentlyChecking = 0;
    const prefix = `${expertId}:`;
    for (const [key, st] of stateByKey.entries()) {
      if (!key.startsWith(prefix)) continue;
      if (st.handled) totalHandled++;
      else if (st.checked) currentlyChecking++;
    }
    return { totalHandled, currentlyChecking };
  }

  private distinctFilesWithCheckInWindow(
    events: NormalizedActivity[],
    expertId: string,
    from: Date,
    to: Date,
  ): number {
    const files = new Set<string>();
    for (const e of events) {
      if (e.expertId !== expertId) continue;
      if (e.eventType !== ExpertFileActivityType.CHECKED) continue;
      if (e.occurredAt < from || e.occurredAt > to) continue;
      files.add(e.fileId);
    }
    return files.size;
  }

  private async loadTenantExpertsAndActivities(clientKey: string): Promise<{
    events: NormalizedActivity[];
    expertRows: Array<{
      id: string;
      fullName: string;
      kind: "expert" | "damage_expert";
    }>;
  }> {
    const tenantOid = new Types.ObjectId(clientKey);
    const tenantStr = String(tenantOid);

    /**
     * `clientKey` is sometimes stored as ObjectId, sometimes as string — match both.
     * Activity is loaded for the whole tenant so claim (V2) damage experts still appear
     * even if a roster row was missed by shape mismatches; we then merge `_id` lookups.
     */
    const [blamePanelExperts, damageExperts, rawEvents] = await Promise.all([
      this.expertDbService.findAll({
        $or: [{ clientKey: tenantStr }, { clientKey: tenantOid }],
      } as never),
      this.damageExpertDbService.findAll({
        $or: [{ clientKey: tenantOid }, { clientKey: tenantStr }],
      } as never),
      this.expertFileActivityDbService.findByTenant(tenantOid),
    ]);

    const expertRows: Array<{
      id: string;
      fullName: string;
      kind: "expert" | "damage_expert";
    }> = [];
    const seenIds = new Set<string>();

    const pushRow = (id: string, fullName: string, kind: "expert" | "damage_expert") => {
      if (seenIds.has(id)) return;
      seenIds.add(id);
      expertRows.push({ id, fullName, kind });
    };

    for (const e of blamePanelExperts) {
      const fullName =
        `${(e as any).firstName ?? ""} ${(e as any).lastName ?? ""}`.trim() ||
        (e as any).email ||
        String((e as any)._id);
      pushRow(String((e as any)._id), fullName, "expert");
    }
    for (const e of damageExperts) {
      const fullName =
        `${(e as any).firstName ?? ""} ${(e as any).lastName ?? ""}`.trim() ||
        (e as any).email ||
        String((e as any)._id);
      pushRow(String((e as any)._id), fullName, "damage_expert");
    }

    const activityExpertIds = [
      ...new Set(
        rawEvents
          .map((row) => String(row.expertId))
          .filter((id) => Types.ObjectId.isValid(id)),
      ),
    ].filter((id) => !seenIds.has(id));

    if (activityExpertIds.length > 0) {
      const oids = activityExpertIds.map((id) => new Types.ObjectId(id));
      const [extraDamages, extraExperts] = await Promise.all([
        this.damageExpertDbService.findAll({ _id: { $in: oids } } as never),
        this.expertDbService.findAll({ _id: { $in: oids } } as never),
      ]);
      for (const d of extraDamages) {
        const id = String((d as any)._id);
        if (seenIds.has(id)) continue;
        const fullName =
          `${(d as any).firstName ?? ""} ${(d as any).lastName ?? ""}`.trim() ||
          (d as any).email ||
          id;
        pushRow(id, fullName, "damage_expert");
      }
      for (const x of extraExperts) {
        const id = String((x as any)._id);
        if (seenIds.has(id)) continue;
        const fullName =
          `${(x as any).firstName ?? ""} ${(x as any).lastName ?? ""}`.trim() ||
          (x as any).email ||
          id;
        pushRow(id, fullName, "expert");
      }
    }

    const events: NormalizedActivity[] = rawEvents.map((row) => ({
      expertId: String(row.expertId),
      fileId: String(row.fileId),
      eventType: row.eventType,
      occurredAt:
        row.occurredAt instanceof Date
          ? row.occurredAt
          : new Date(row.occurredAt as string | Date),
    }));

    return { events, expertRows };
  }

  private buildWorkLogEntries(
    expertRows: Array<{
      id: string;
      fullName: string;
      kind: "expert" | "damage_expert";
    }>,
    events: NormalizedActivity[],
    cutoff: Date,
    checkedWindow: { from: Date; to: Date },
  ): InsurerExpertWorkLogEntryDtoRs[] {
    const state = this.replayExpertFileStates(events, cutoff);
    return expertRows.map((row) => {
      const snap = this.snapshotCountsForExpert(state, row.id);
      return new InsurerExpertWorkLogEntryDtoRs(
        row.id,
        row.fullName,
        row.kind,
        snap.totalHandled,
        snap.currentlyChecking,
        this.distinctFilesWithCheckInWindow(
          events,
          row.id,
          checkedWindow.from,
          checkedWindow.to,
        ),
      );
    });
  }

  async getInsurerExpertWorkLog(actor: {
    clientKey?: string;
  }): Promise<InsurerExpertWorkLogResponseDtoRs> {
    const clientKey = requireActorClientKey(actor);
    const { events, expertRows } =
      await this.loadTenantExpertsAndActivities(clientKey);
    const now = new Date();
    const epoch = new Date(0);
    const entries = this.buildWorkLogEntries(expertRows, events, now, {
      from: epoch,
      to: now,
    });
    return new InsurerExpertWorkLogResponseDtoRs(entries);
  }

  async getInsurerExpertWorkLogPerMonth(actor: {
    clientKey?: string;
  }): Promise<InsurerExpertWorkLogPerMonthRowDtoRs[]> {
    const clientKey = requireActorClientKey(actor);
    const { events, expertRows } =
      await this.loadTenantExpertsAndActivities(clientKey);
    const result: InsurerExpertWorkLogPerMonthRowDtoRs[] = [];
    const now = new Date();

    for (let i = 0; i < 5; i++) {
      const monthStart = new Date(now.getFullYear(), now.getMonth() - i, 1);
      const monthEnd = new Date(
        now.getFullYear(),
        now.getMonth() - i + 1,
        0,
        23,
        59,
        59,
      );
      const label = monthStart.toLocaleDateString("fa-IR", {
        month: "long",
        year: "numeric",
      });

      const experts = this.buildWorkLogEntries(
        expertRows,
        events,
        monthEnd,
        { from: monthStart, to: monthEnd },
      );

      result.unshift(
        new InsurerExpertWorkLogPerMonthRowDtoRs(
          monthStart,
          monthEnd,
          label,
          experts,
        ),
      );
    }
    return result;
  }
}