// models/monthlyComparisonModel.js — 월간 비교·확인·정산
const { getDb } = require('../dbPool');

const MonthlyComparisonModel = {
  // 0. 해당 월의 회사 휴무일 조회
  async getCompanyHolidays(year, month) {
    const db = await getDb();
    const [rows] = await db.query(
      `SELECT holiday_date, holiday_name FROM company_holidays
       WHERE YEAR(holiday_date) = ? AND MONTH(holiday_date) = ?`,
      [year, month]
    );
    const dateSet = new Set();
    const nameMap = {};
    rows.forEach(r => {
      const d = r.holiday_date instanceof Date
        ? r.holiday_date.toISOString().split('T')[0]
        : String(r.holiday_date).split('T')[0];
      dateSet.add(d);
      nameMap[d] = r.holiday_name;
    });
    return { dateSet, nameMap };
  },

  // 1. 작업보고서 일별 합산
  async getWorkReports(userId, year, month) {
    const db = await getDb();
    const [rows] = await db.query(`
      SELECT
        dwr.report_date,
        SUM(dwr.work_hours) AS total_hours,
        GROUP_CONCAT(DISTINCT p.project_name SEPARATOR ', ') AS project_names,
        GROUP_CONCAT(DISTINCT wt.name SEPARATOR ', ') AS work_type_names
      FROM daily_work_reports dwr
      LEFT JOIN projects p ON dwr.project_id = p.project_id
      LEFT JOIN work_types wt ON dwr.work_type_id = wt.id
      WHERE dwr.user_id = ?
        AND YEAR(dwr.report_date) = ?
        AND MONTH(dwr.report_date) = ?
      GROUP BY dwr.report_date
      ORDER BY dwr.report_date
    `, [userId, year, month]);
    return rows;
  },

  // 2. 근태관리 일별 기록
  async getAttendanceRecords(userId, year, month) {
    const db = await getDb();
    const [rows] = await db.query(`
      SELECT
        dar.record_date,
        dar.total_work_hours,
        dar.attendance_type_id,
        dar.vacation_type_id,
        dar.status,
        dar.is_present,
        dar.notes,
        wat.type_name AS attendance_type_name,
        vt.type_name AS vacation_type_name,
        vt.deduct_days AS vacation_days
      FROM daily_attendance_records dar
      LEFT JOIN work_attendance_types wat ON dar.attendance_type_id = wat.id
      LEFT JOIN vacation_types vt ON dar.vacation_type_id = vt.id
      WHERE dar.user_id = ?
        AND YEAR(dar.record_date) = ?
        AND MONTH(dar.record_date) = ?
      ORDER BY dar.record_date
    `, [userId, year, month]);
    return rows;
  },

  // 3. 확인 상태 조회
  async getConfirmation(userId, year, month) {
    const db = await getDb();
    const [rows] = await db.query(
      'SELECT * FROM monthly_work_confirmations WHERE user_id = ? AND year = ? AND month = ?',
      [userId, year, month]
    );
    return rows[0] || null;
  },

  // 4. 확인 UPSERT + 반려 시 알림 (단일 트랜잭션)
  async upsertConfirmation(data, notificationData) {
    const db = await getDb();
    const conn = await db.getConnection();
    try {
      await conn.beginTransaction();

      // 기존 상태 체크 + 전환 검증
      const [existing] = await conn.query(
        'SELECT id, status FROM monthly_work_confirmations WHERE user_id = ? AND year = ? AND month = ?',
        [data.user_id, data.year, data.month]
      );
      const currentStatus = existing.length > 0 ? existing[0].status : null;

      if (currentStatus === 'confirmed') {
        await conn.rollback();
        return { error: '이미 확인된 내역은 변경할 수 없습니다.' };
      }

      // 작업자 확인: review_sent 또는 rejected 상태에서만 가능
      if (data.status === 'confirmed' && currentStatus && currentStatus !== 'review_sent' && currentStatus !== 'rejected') {
        await conn.rollback();
        return { error: '관리자 확인요청 후에 확인할 수 있습니다.' };
      }

      // 작업자 수정요청: review_sent 상태에서만 가능
      if (data.status === 'change_request' && currentStatus !== 'review_sent') {
        await conn.rollback();
        return { error: '확인요청 상태에서만 수정요청이 가능합니다.' };
      }

      // UPSERT
      const [result] = await conn.query(`
        INSERT INTO monthly_work_confirmations
          (user_id, year, month, status, total_work_days, total_work_hours,
           total_overtime_hours, vacation_days, mismatch_count, reject_reason,
           confirmed_at, rejected_at, change_details)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
        ON DUPLICATE KEY UPDATE
          status = VALUES(status),
          total_work_days = VALUES(total_work_days),
          total_work_hours = VALUES(total_work_hours),
          total_overtime_hours = VALUES(total_overtime_hours),
          vacation_days = VALUES(vacation_days),
          mismatch_count = VALUES(mismatch_count),
          reject_reason = VALUES(reject_reason),
          confirmed_at = VALUES(confirmed_at),
          rejected_at = VALUES(rejected_at),
          change_details = VALUES(change_details)
      `, [
        data.user_id, data.year, data.month, data.status,
        data.total_work_days || 0, data.total_work_hours || 0,
        data.total_overtime_hours || 0, data.vacation_days || 0,
        data.mismatch_count || 0, data.reject_reason || null,
        data.status === 'confirmed' ? new Date() : null,
        data.status === 'rejected' ? new Date() : null,
        data.change_details || null
      ]);

      const confirmationId = result.insertId || (existing.length > 0 ? existing[0].id : null);

      // 알림 생성 (반려 또는 수정요청)
      if (notificationData && confirmationId) {
        const { recipients, title, message, linkUrl, createdBy } = notificationData;
        for (const recipientId of recipients) {
          await conn.query(`
            INSERT INTO notifications
              (user_id, type, title, message, link_url, reference_type, reference_id, is_read, created_by)
            VALUES (?, 'system', ?, ?, ?, 'monthly_work_confirmation', ?, 0, ?)
          `, [recipientId, title, message, linkUrl, confirmationId, createdBy]);
        }
      }

      await conn.commit();
      return { id: confirmationId, status: data.status };
    } catch (err) {
      await conn.rollback();
      throw err;
    } finally {
      conn.release();
    }
  },

  // 관리자: 확인요청 발송 (pending → review_sent)
  async bulkReviewSend(year, month, userIds, reviewedBy) {
    const db = await getDb();
    const conn = await db.getConnection();
    try {
      await conn.beginTransaction();

      // 대상 작업자 결정 (userIds 있으면 단건, 없으면 pending 전체)
      let targetIds = userIds || [];
      if (!targetIds.length) {
        const [pendingRows] = await conn.query(
          `SELECT DISTINCT w.user_id FROM workers w
           LEFT JOIN monthly_work_confirmations mwc ON w.user_id = mwc.user_id AND mwc.year = ? AND mwc.month = ?
           WHERE w.status = 'active' AND w.user_id IS NOT NULL
             AND (mwc.status IS NULL OR mwc.status = 'pending')`,
          [year, month]
        );
        targetIds = pendingRows.map(r => r.user_id);
      }

      if (!targetIds.length) {
        await conn.rollback();
        return { count: 0, message: '대상 작업자가 없습니다.' };
      }

      // 상태 전환 + 알림 생성
      for (const uid of targetIds) {
        await conn.query(
          `INSERT INTO monthly_work_confirmations (user_id, year, month, status, reviewed_by, reviewed_at)
           VALUES (?, ?, ?, 'review_sent', ?, NOW())
           ON DUPLICATE KEY UPDATE status = 'review_sent', reviewed_by = ?, reviewed_at = NOW()`,
          [uid, year, month, reviewedBy, reviewedBy]
        );
        await conn.query(
          `INSERT INTO notifications (user_id, type, title, message, link_url, reference_type, is_read, created_by)
           VALUES (?, 'system', '월간 근무 확인 요청', ?, '/pages/attendance/my-monthly-confirm.html?year=${year}&month=${month}', 'monthly_work_confirmation', 0, ?)`,
          [uid, `${year}년 ${month}월 근무 내역을 확인해주세요.`, reviewedBy]
        );
      }

      await conn.commit();
      return { count: targetIds.length };
    } catch (err) {
      await conn.rollback();
      throw err;
    } finally {
      conn.release();
    }
  },

  // 관리자: 수정요청 응답 (change_request → review_sent 또는 rejected)
  async reviewRespond(userId, year, month, action, rejectReason, respondedBy) {
    const db = await getDb();
    const conn = await db.getConnection();
    try {
      await conn.beginTransaction();

      const [existing] = await conn.query(
        'SELECT id, status FROM monthly_work_confirmations WHERE user_id = ? AND year = ? AND month = ?',
        [userId, year, month]
      );
      if (!existing.length || existing[0].status !== 'change_request') {
        await conn.rollback();
        return { error: '수정요청 상태가 아닙니다.' };
      }

      var newStatus = action === 'approve' ? 'review_sent' : 'rejected';
      await conn.query(
        `UPDATE monthly_work_confirmations SET status = ?, reviewed_by = ?, reviewed_at = NOW(),
         reject_reason = ?, change_details = NULL WHERE id = ?`,
        [newStatus, respondedBy, action === 'reject' ? rejectReason : null, existing[0].id]
      );

      // 작업자에게 알림
      var title = action === 'approve' ? '수정요청 승인' : '수정요청 거부';
      var message = action === 'approve'
        ? `${year}년 ${month}월 근무 수정이 반영되었습니다. 다시 확인해주세요.`
        : `${year}년 ${month}월 근무 수정요청이 거부되었습니다. 사유: ${rejectReason || '-'}`;
      await conn.query(
        `INSERT INTO notifications (user_id, type, title, message, link_url, reference_type, reference_id, is_read, created_by)
         VALUES (?, 'system', ?, ?, ?, 'monthly_work_confirmation', ?, 0, ?)`,
        [userId, title, message, '/pages/attendance/my-monthly-confirm.html?year=' + year + '&month=' + month, existing[0].id, respondedBy]
      );

      await conn.commit();
      return { status: newStatus };
    } catch (err) {
      await conn.rollback();
      throw err;
    } finally {
      conn.release();
    }
  },

  // 5. 전체 작업자 확인 현황 (실제 근태 데이터 집계 포함)
  async getAllStatus(year, month, departmentId) {
    const db = await getDb();
    let sql = `
      SELECT
        w.user_id, w.worker_name, w.job_type,
        COALESCE(d.department_name, '미배정') AS department_name,
        COALESCE(mwc.status, 'pending') AS status,
        mwc.confirmed_at, mwc.rejected_at, mwc.reject_reason,
        mwc.change_details, COALESCE(mwc.admin_checked, 0) AS admin_checked,
        COALESCE(att.work_days, 0) AS total_work_days,
        COALESCE(att.work_hours, 0) AS total_work_hours,
        COALESCE(att.overtime_hours, 0) AS total_overtime_hours,
        COALESCE(att.vac_days, 0) AS vacation_days
      FROM workers w
      LEFT JOIN departments d ON w.department_id = d.department_id
      LEFT JOIN monthly_work_confirmations mwc
        ON w.user_id = mwc.user_id AND mwc.year = ? AND mwc.month = ?
      LEFT JOIN (
        SELECT dar.user_id,
          COUNT(CASE WHEN dar.total_work_hours > 0 THEN 1 END) AS work_days,
          COALESCE(SUM(dar.total_work_hours), 0) AS work_hours,
          COALESCE(SUM(CASE WHEN dar.total_work_hours > 8 THEN dar.total_work_hours - 8 ELSE 0 END), 0) AS overtime_hours,
          COALESCE(SUM(CASE WHEN vt.deduct_days IS NOT NULL THEN vt.deduct_days ELSE 0 END), 0) AS vac_days
        FROM daily_attendance_records dar
        LEFT JOIN vacation_types vt ON dar.vacation_type_id = vt.id
        WHERE YEAR(dar.record_date) = ? AND MONTH(dar.record_date) = ?
        GROUP BY dar.user_id
      ) att ON w.user_id = att.user_id
      WHERE w.status = 'active' AND w.user_id IS NOT NULL
    `;
    const params = [year, month, year, month];
    if (departmentId) {
      sql += ' AND w.department_id = ?';
      params.push(departmentId);
    }
    sql += ' ORDER BY d.department_name, w.worker_name';

    const [rows] = await db.query(sql, params);
    return rows;
  },

  // 5b. 관리자 개별 검토 태깅
  async adminCheck(userId, year, month, checked, checkedBy) {
    const db = await getDb();
    await db.query(`
      INSERT INTO monthly_work_confirmations (user_id, year, month, status, admin_checked)
      VALUES (?, ?, ?, 'pending', ?)
      ON DUPLICATE KEY UPDATE admin_checked = ?
    `, [userId, year, month, checked ? 1 : 0, checked ? 1 : 0]);
    return { admin_checked: checked };
  },

  // 6. 지원팀 사용자 목록 (알림 수신자)
  async getSupportTeamUsers() {
    const db = await getDb();
    const [rows] = await db.query(
      "SELECT user_id FROM sso_users WHERE role IN ('support_team', 'admin', 'system') AND is_active = 1"
    );
    return rows.map(r => r.user_id);
  },

  // 7. 출근부 엑셀용 — 작업자 목록 + 일별 근태 + 연차잔액
  async getExportData(year, month, departmentId) {
    const db = await getDb();

    // (a) 해당 부서 활성 작업자 (worker_id 순)
    let workerSql = `
      SELECT w.user_id, w.worker_id, w.worker_name, w.job_type,
             COALESCE(d.department_name, '미배정') AS department_name
      FROM workers w
      LEFT JOIN departments d ON w.department_id = d.department_id
      WHERE w.status = 'active'
    `;
    const workerParams = [];
    if (departmentId) { workerSql += ' AND w.department_id = ?'; workerParams.push(departmentId); }
    workerSql += ' ORDER BY w.worker_id';
    const [workers] = await db.query(workerSql, workerParams);

    if (workers.length === 0) return { workers: [], attendance: [], vacations: [] };

    const userIds = workers.map(w => w.user_id);
    const placeholders = userIds.map(() => '?').join(',');

    // (b) 일별 근태 기록
    const [attendance] = await db.query(`
      SELECT dar.user_id, dar.record_date,
             dar.total_work_hours,
             dar.attendance_type_id,
             dar.vacation_type_id,
             vt.type_code AS vacation_type_code,
             vt.type_name AS vacation_type_name,
             vt.deduct_days
      FROM daily_attendance_records dar
      LEFT JOIN vacation_types vt ON dar.vacation_type_id = vt.id
      WHERE dar.user_id IN (${placeholders})
        AND YEAR(dar.record_date) = ? AND MONTH(dar.record_date) = ?
      ORDER BY dar.user_id, dar.record_date
    `, [...userIds, year, month]);

    // (c) 연차 잔액 (sp_vacation_balances)
    const [vacations] = await db.query(`
      SELECT svb.user_id,
             SUM(svb.total_days) AS total_days,
             SUM(svb.used_days) AS used_days,
             SUM(svb.total_days - svb.used_days) AS remaining_days
      FROM sp_vacation_balances svb
      WHERE svb.user_id IN (${placeholders}) AND svb.year = ?
      GROUP BY svb.user_id
    `, [...userIds, year]);

    return { workers, attendance, vacations };
  },

  // 8. 작업자 정보
  async getWorkerInfo(userId) {
    const db = await getDb();
    const [rows] = await db.query(`
      SELECT w.user_id, w.worker_name, w.job_type,
             COALESCE(d.department_name, '미배정') AS department_name
      FROM workers w
      LEFT JOIN departments d ON w.department_id = d.department_id
      WHERE w.user_id = ?
    `, [userId]);
    return rows[0] || null;
  }
};

module.exports = MonthlyComparisonModel;