import { ConflictException, Injectable, Logger, NotFoundException, ServiceUnavailableException } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { randomUUID } from 'node:crypto';
import { DataSource, In, Repository } from 'typeorm';
import { SyncLog, SyncState, Student, StudentDingMapping } from '../entities';
import { JinshujuMatchRule, type JinshujuFieldMapping } from '../entities/jinshuju-match-rule.entity';
import type { SyncPlatform, SyncStatus, SyncType } from '../entities/sync-log.entity';
import { AttendanceImportService } from '../attendance/attendance-import.service';
import { DingTalkService } from '../integration/dingtalk.service';
import { WeComService } from '../integration/wecom.service';
import { JinshujuService } from '../integration/jinshuju.service';
import { syncJinshujuStudents } from '../integration/jinshuju-student-sync';
import { ScheduleSyncService } from './schedule-sync.service';

@Injectable()
export class SyncService {
  private readonly logger = new Logger(SyncService.name);
  private static readonly LEASE_MS = 30 * 60 * 1000;

  constructor(
    @InjectRepository(SyncLog)
    private readonly syncLogRepo: Repository<SyncLog>,
    @InjectRepository(SyncState)
    private readonly syncStateRepo: Repository<SyncState>,
    @InjectRepository(StudentDingMapping)
    private readonly studentDingMappingRepo: Repository<StudentDingMapping>,
    @InjectRepository(JinshujuMatchRule)
    private readonly matchRuleRepo: Repository<JinshujuMatchRule>,
    private readonly dingTalkService: DingTalkService,
    private readonly weComService: WeComService,
    private readonly jinshujuService: JinshujuService,
    private readonly attendanceImportService: AttendanceImportService,
    private readonly scheduleSyncService: ScheduleSyncService,
    private readonly dataSource: DataSource,
  ) {}

  async syncDingTalkStudents(rootDeptId = 1): Promise<SyncLog> {
    return this.runSync('dingtalk_students', async () => {
      const result = await this.dingTalkService.syncAll(rootDeptId);
      return {
        recordsCount: result.created + result.updated,
        status: result.conflicts.length ? 'partial' : 'success',
        message: result.conflicts.length ? JSON.stringify(result.conflicts.slice(0, 20)) : undefined,
      };
    });
  }

  async syncDingTalkAttendance(): Promise<SyncLog> {
    return this.runSync('dingtalk_attendance', async (lastSyncAt) => {
      const endDate = new Date();
      const startDate = lastSyncAt ? new Date(lastSyncAt) : new Date(endDate);
      if (!lastSyncAt) startDate.setDate(startDate.getDate() - 7);

      const mappings = await this.studentDingMappingRepo.find();
      const userIds = [...new Set(mappings.map((mapping) => mapping.dingUserId).filter(Boolean))];
      if (userIds.length === 0) {
        throw new ServiceUnavailableException('没有可用于考勤导入的钉钉学生映射');
      }

      const result = await this.attendanceImportService.importFromDingTalk({
        startDate: startDate.toISOString().slice(0, 10),
        endDate: endDate.toISOString().slice(0, 10),
        userIds,
        autoMatch: true,
      });
      if (!result.success) {
        throw new ServiceUnavailableException(result.errors.join('；') || '钉钉考勤导入失败');
      }
      return { recordsCount: result.imported, status: 'success' };
    });
  }

  async syncWeCom(): Promise<SyncLog> {
    return this.runSync('wecom', async () => {
      const result = await this.weComService.syncAll();
      return { recordsCount: result.userCount, status: 'success' };
    });
  }
  async syncJinshuju(apiKey: string, apiSecret: string, formToken: string): Promise<SyncLog> {
    return this.runSync('jinshuju', async () => {
      const entries = await this.jinshujuService.fetchAllEntries(apiKey, apiSecret, formToken);
      const result = await this.dataSource.transaction((manager) =>
        syncJinshujuStudents(manager, entries),
      );
      return {
        recordsCount: result.matched + result.created,
        status: result.conflicts.length ? 'partial' : 'success',
        message: result.conflicts.length
          ? JSON.stringify(result.conflicts.slice(0, 20))
          : `匹配 ${result.matched} 人，新增 ${result.created} 人，跳过无姓名 ${result.skippedNoName} 条`,
      };
    });
  }

  /** Fetch Jinshuju entries and return with auto-suggested student matches (no writes). */
  getJinshujuFormFields(apiKey: string, apiSecret: string, formToken: string) {
    return this.jinshujuService.fetchFormFields(apiKey, apiSecret, formToken);
  }

  async previewJinshuju(apiKey: string, apiSecret: string, formToken: string, ruleId?: number) {
    const entries = await this.jinshujuService.fetchAllEntries(apiKey, apiSecret, formToken);
    const rule = ruleId ? await this.getMatchRule(ruleId, formToken) : null;
    const map = rule?.mappings ?? { name: 'field_1', phone: 'field_2' };

    const parsed = entries
      .map((e) => ({
        serialNumber: e.serial_number,
        name: this.extractField(e, map.name),
        phone: this.extractField(e, map.phone),
      }))
      .filter((p) => p.name);

    const phones = [...new Set(parsed.filter((p) => p.phone).map((p) => p.phone))];
    const names = [...new Set(parsed.map((p) => p.name))];

    const [phoneStudents, nameStudents] = await Promise.all([
      phones.length
        ? this.dataSource.getRepository(Student).find({ where: { phone: In(phones) } })
        : ([] as Student[]),
      names.length
        ? this.dataSource.getRepository(Student).find({ where: { name: In(names) } })
        : ([] as Student[]),
    ]);

    const studentByPhone = new Map(phoneStudents.map((s) => [s.phone, s]));
    const studentByName = new Map<string, Student[]>();
    for (const s of nameStudents) {
      const list = studentByName.get(s.name) || [];
      list.push(s);
      studentByName.set(s.name, list);
    }

    const allStudents = await this.dataSource.getRepository(Student).find({
      where: { status: 'active' },
      order: { name: 'ASC' },
      select: ['id', 'name', 'phone', 'studentNo'],
    });

    const rows = parsed.map((p) => {
      const phoneMatch = p.phone ? studentByPhone.get(p.phone) : undefined;
      const nameMatches = studentByName.get(p.name) || [];
      const suggested = phoneMatch ?? nameMatches[0] ?? null;
      return {
        serialNumber: p.serialNumber,
        name: p.name,
        phone: p.phone || null,
        suggestedStudent: suggested
          ? { id: suggested.id, name: suggested.name, phone: suggested.phone, studentNo: suggested.studentNo }
          : null,
      };
    });

    return { entries: rows, students: allStudents };
  }

  /** Apply user's matching decisions. */
  async applyJinshuju(
    apiKey: string,
    apiSecret: string,
    formToken: string,
    decisions: Array<{
      serialNumber: number;
      action: 'match' | 'create' | 'skip';
      matchStudentId?: number;
      createName?: string;
      createPhone?: string;
    }>,
    ruleId?: number,
  ): Promise<SyncLog> {
    return this.runSync('jinshuju', async () => {
      const rule = ruleId ? await this.getMatchRule(ruleId, formToken) : null;
      const map = rule?.mappings ?? { name: 'field_1', phone: 'field_2' };
      const entries = await this.jinshujuService.fetchAllEntries(apiKey, apiSecret, formToken);
      const entryMap = new Map(entries.map((entry) => [entry.serial_number, entry]));
      const decisionMap = new Map(decisions.map((decision) => [decision.serialNumber, decision]));

      let matched = 0;
      let created = 0;
      await this.dataSource.transaction(async (manager) => {
        const orgs = await manager.query(
          'SELECT id FROM organizations WHERE is_host = 1 AND status = ? LIMIT 1',
          ['active'],
        );
        const orgId: number | undefined = orgs[0]?.id;

        for (const [serial, entry] of entryMap) {
          const decision = decisionMap.get(serial);
          if (!decision || decision.action === 'skip') continue;

          const mappedValues = Object.fromEntries(
            Object.entries(map)
              .map(([studentField, fieldKey]) => [studentField, this.extractField(entry, fieldKey)])
              .filter(([, value]) => value),
          );

          if (decision.action === 'match' && decision.matchStudentId) {
            await manager.update(Student, decision.matchStudentId, mappedValues);
            matched++;
          } else if (decision.action === 'create') {
            const name = decision.createName || mappedValues.name;
            if (!name) continue;
            await manager.save(
              manager.create(Student, {
                ...mappedValues,
                name,
                phone: decision.createPhone || mappedValues.phone || undefined,
                organizationId: orgId,
              }),
            );
            created++;
          }
        }
      });

      return {
        recordsCount: matched + created,
        status: 'success',
        message: `匹配 ${matched} 人，新增 ${created} 人`,
      };
    });
  }

  async triggerSync(platform?: SyncPlatform, rootDeptId = 1): Promise<SyncLog[]> {
    if (platform === 'dingtalk_students') return [await this.syncDingTalkStudents(rootDeptId)];
    if (platform === 'dingtalk_attendance') return [await this.syncDingTalkAttendance()];
    if (platform === 'wecom') return [await this.syncWeCom()];
    return [
      await this.syncDingTalkStudents(rootDeptId),
      await this.syncDingTalkAttendance(),
      await this.syncWeCom(),
    ];
  }

  async getDingTalkOrgTree(rootDeptId = 1) {
    return this.dingTalkService.fetchOrgTree(rootDeptId);
  }

  async getDingTalkOrgTreeWithUsers(rootDeptId = 1) {
    return this.dingTalkService.fetchOrgTreeWithUsers(rootDeptId);
  }

  async getDingTalkAttendanceGroups() {
    return this.dingTalkService.queryAttendanceGroups();
  }

  async deleteAllDingTalkAttendanceGroups() {
    const groups = await this.dingTalkService.queryAttendanceGroups();
    const deleted: Array<{ groupId: number; groupName: string }> = [];
    const failed: Array<{ groupId: number; groupName: string; error: string }> = [];
    for (const group of groups) {
      try {
        await this.dingTalkService.deleteAttendanceGroup(group.group_id);
        deleted.push({ groupId: group.group_id, groupName: group.group_name });
      } catch (error: unknown) {
        failed.push({
          groupId: group.group_id,
          groupName: group.group_name,
          error: error instanceof Error ? error.message : String(error),
        });
      }
    }
    return { total: groups.length, deleted, failed };
  }

  async syncScheduleToDingTalk(
    dateFrom?: string,
    days = 30,
    attendanceMachineOnly = false,
  ) {
    return this.scheduleSyncService.syncAll(dateFrom, days, 'manager', attendanceMachineOnly);
  }

  async getScheduleSyncStatus(date?: string) {
    return this.scheduleSyncService.getStatus(date || new Date().toISOString().slice(0, 10));
  }

  async getLogs(platform?: SyncPlatform, limit = 50): Promise<SyncLog[]> {
    const where: Record<string, SyncPlatform> = {};
    if (platform) where.platform = platform;
    return this.syncLogRepo.find({ where, order: { createdAt: 'DESC' }, take: limit });
  }

  async getLastSync(platform: SyncPlatform | 'dingtalk'): Promise<SyncLog | null> {
    if (platform === 'dingtalk') {
      return this.syncLogRepo.findOne({
        where: [{ platform: 'dingtalk_students' }, { platform: 'dingtalk_attendance' }],
        order: { createdAt: 'DESC' },
      });
    }
    return this.syncLogRepo.findOne({ where: { platform }, order: { createdAt: 'DESC' } });
  }

  private async runSync(
    platform: SyncPlatform,
    operation: (lastSyncAt: Date | null) => Promise<{
      recordsCount: number;
      status: Extract<SyncStatus, 'success' | 'partial'>;
      message?: string;
    }>,
  ): Promise<SyncLog> {
    const runId = await this.acquireLease(platform);
    let log: SyncLog | undefined;
    try {
      const lastSyncAt = await this.getLastSyncAt(platform);
      log = await this.createSyncLog(platform, lastSyncAt ? 'incremental' : 'full', 'running');
      const result = await operation(lastSyncAt);
      await this.syncStateRepo.update({ platform }, { lastSyncAt: new Date() });
      await this.finishSyncLog(log, result.status, result.recordsCount, result.message);
      return log;
    } catch (error: unknown) {
      const message = error instanceof Error ? error.message : String(error);
      if (log) await this.finishSyncLog(log, 'failed', 0, message);
      this.logger.error(`${platform} sync failed: ${message}`, error instanceof Error ? error.stack : undefined);
      throw error;
    } finally {
      await this.releaseLease(platform, runId);
    }
  }

  private async acquireLease(platform: SyncPlatform): Promise<string> {
    await this.syncStateRepo
      .createQueryBuilder()
      .insert()
      .values({ platform, lastSyncAt: null, runId: null, runningSince: null })
      .orIgnore()
      .execute();

    const runId = randomUUID();
    const result = await this.syncStateRepo
      .createQueryBuilder()
      .update()
      .set({ runId, runningSince: new Date() })
      .where('platform = :platform', { platform })
      .andWhere('(running_since IS NULL OR running_since < :staleBefore)', {
        staleBefore: new Date(Date.now() - SyncService.LEASE_MS),
      })
      .execute();
    if (result.affected !== 1) throw new ConflictException(`${platform} 同步正在进行中`);
    return runId;
  }

  private async releaseLease(platform: SyncPlatform, runId: string): Promise<void> {
    await this.syncStateRepo
      .createQueryBuilder()
      .update()
      .set({ runId: null, runningSince: null })
      .where('platform = :platform AND run_id = :runId', { platform, runId })
      .execute();
  }

  private async getLastSyncAt(platform: SyncPlatform): Promise<Date | null> {
    const state = await this.syncStateRepo.findOne({ where: { platform } });
    return state?.lastSyncAt ?? null;
  }

  private async createSyncLog(
    platform: SyncPlatform,
    syncType: SyncType,
    status: SyncStatus,
  ): Promise<SyncLog> {
    return this.syncLogRepo.save(
      this.syncLogRepo.create({
        platform,
        syncType,
        status,
        recordsCount: 0,
        startedAt: new Date(),
      }),
    );
  }

  private async finishSyncLog(
    log: SyncLog,
    status: SyncStatus,
    recordsCount: number,
    errorMessage?: string,
  ): Promise<void> {
    log.status = status;
    log.recordsCount = recordsCount;
    log.finishedAt = new Date();
    log.errorMessage = errorMessage ?? null;
    await this.syncLogRepo.save(log);
  }

  // ── Match Rules CRUD ──

  async listMatchRules(): Promise<JinshujuMatchRule[]> {
    return this.matchRuleRepo.find({ order: { updatedAt: 'DESC' } });
  }

  async createMatchRule(dto: {
    name: string;
    formToken: string;
    mappings: JinshujuFieldMapping;
  }): Promise<JinshujuMatchRule> {
    this.validateMatchRule(dto.formToken, dto.mappings);
    return this.matchRuleRepo.save(
      this.matchRuleRepo.create({
        ...dto,
        name: dto.name.trim(),
        formToken: dto.formToken.trim(),
      }),
    );
  }

  async updateMatchRule(
    id: number,
    dto: { name?: string; mappings?: JinshujuFieldMapping },
  ): Promise<JinshujuMatchRule> {
    const rule = await this.matchRuleRepo.findOne({ where: { id } });
    if (!rule) throw new NotFoundException('规则不存在');
    const mappings = dto.mappings ?? rule.mappings;
    this.validateMatchRule(rule.formToken, mappings);
    await this.matchRuleRepo.update(id, {
      name: dto.name?.trim(),
      mappings,
    });
    return this.matchRuleRepo.findOneOrFail({ where: { id } });
  }

  async deleteMatchRule(id: number): Promise<void> {
    const result = await this.matchRuleRepo.delete(id);
    if (!result.affected) throw new NotFoundException('规则不存在');
  }

  private async getMatchRule(id: number, formToken: string): Promise<JinshujuMatchRule> {
    const rule = await this.matchRuleRepo.findOne({ where: { id } });
    if (!rule) throw new NotFoundException('规则不存在');
    if (rule.formToken !== formToken) {
      throw new ConflictException('匹配规则不属于当前表单');
    }
    return rule;
  }

  private validateMatchRule(formToken: string, mappings: JinshujuFieldMapping): void {
    if (!formToken.trim()) throw new ConflictException('表单 Token 不能为空');
    if (!mappings.name) throw new ConflictException('匹配规则必须映射姓名字段');
    const allowedStudentFields = new Set([
      'name',
      'studentNo',
      'phone',
      'idNumber',
      'gender',
      'ethnicity',
      'emergencyContact',
      'emergencyPhone',
    ]);
    for (const [studentField, fieldKey] of Object.entries(mappings)) {
      if (!allowedStudentFields.has(studentField)) {
        throw new ConflictException(`不允许映射学生字段：${studentField}`);
      }
      if (fieldKey && !/^field_\d+$/.test(fieldKey)) {
        throw new ConflictException(`无效的金数据字段：${fieldKey}`);
      }
    }
  }

  /** Extract value from a Jinshuju entry by field mapping. */
  private extractField(entry: Record<string, unknown>, fieldKey: string | undefined): string {
    if (!fieldKey) return '';
    const val = entry[fieldKey];
    return typeof val === 'string' ? val.trim() : '';
  }
}
