const { getPool } = require('../middleware/auth');

const vacationBalanceModel = {
  async getByUserAndYear(userId, year) {
    const db = getPool();
    const [rows] = await db.query(`
      SELECT
        vb.*,
        vb.balance_type,
        vb.expires_at,
        vt.type_name,
        vt.type_code,
        vt.priority,
        vt.is_special,
        (vb.total_days - vb.used_days) as remaining_days
      FROM sp_vacation_balances vb
      INNER JOIN vacation_types vt ON vb.vacation_type_id = vt.id
      WHERE vb.user_id = ? AND (vb.year = ? OR (vb.balance_type = 'LONG_SERVICE' AND vb.expires_at IS NULL))
      ORDER BY vt.priority ASC, vt.type_name ASC
    `, [userId, year]);
    return rows;
  },

  async getAllByYear(year) {
    const db = getPool();
    const [rows] = await db.query(`
      SELECT
        vb.*,
        vb.balance_type,
        su.name as user_name,
        su.username,
        su.hire_date,
        su.department_id,
        COALESCE(d.department_name, '미배정') as department_name,
        vt.type_name,
        vt.type_code,
        vt.priority,
        (vb.total_days - vb.used_days) as remaining_days
      FROM sp_vacation_balances vb
      INNER JOIN sso_users su ON vb.user_id = su.user_id
      INNER JOIN vacation_types vt ON vb.vacation_type_id = vt.id
      LEFT JOIN departments d ON su.department_id = d.department_id
      WHERE (vb.year = ? OR (vb.balance_type = 'LONG_SERVICE' AND vb.expires_at IS NULL)) AND su.is_active = 1
      ORDER BY su.name ASC, vt.priority ASC
    `, [year]);
    return rows;
  },

  async allocate(data) {
    const db = getPool();
    const balanceType = data.balance_type || 'AUTO';
    const expiresAt = data.expires_at || null;
    const [result] = await db.query(`
      INSERT INTO sp_vacation_balances (user_id, vacation_type_id, year, total_days, used_days, notes, created_by, balance_type, expires_at)
      VALUES (?, ?, ?, ?, 0, ?, ?, ?, ?)
      ON DUPLICATE KEY UPDATE
        total_days = VALUES(total_days),
        notes = VALUES(notes),
        updated_at = NOW()
    `, [data.user_id, data.vacation_type_id, data.year, data.total_days, data.notes || null, data.created_by, balanceType, expiresAt]);
    return result;
  },

  async deductDays(userId, vacationTypeId, year, daysToDeduct, conn) {
    const db = conn || getPool();
    const [result] = await db.query(`
      UPDATE sp_vacation_balances
      SET used_days = used_days + ?, updated_at = NOW()
      WHERE user_id = ? AND vacation_type_id = ? AND year = ?
    `, [daysToDeduct, userId, vacationTypeId, year]);
    return result;
  },

  async restoreDays(userId, vacationTypeId, year, daysToRestore, conn) {
    const db = conn || getPool();
    const [result] = await db.query(`
      UPDATE sp_vacation_balances
      SET used_days = GREATEST(0, used_days - ?), updated_at = NOW()
      WHERE user_id = ? AND vacation_type_id = ? AND year = ?
    `, [daysToRestore, userId, vacationTypeId, year]);
    return result;
  },

  calculateAnnualLeaveDays(hireDate, targetYear) {
    const hire = new Date(hireDate);
    const targetDate = new Date(targetYear, 0, 1);
    const monthsDiff = (targetDate.getFullYear() - hire.getFullYear()) * 12
                     + (targetDate.getMonth() - hire.getMonth());
    if (monthsDiff < 12) {
      return Math.floor(monthsDiff);
    }
    const yearsWorked = Math.floor(monthsDiff / 12);
    const additionalDays = Math.floor((yearsWorked - 1) / 2);
    return Math.min(15 + additionalDays, 25);
  },

  async getUserHireDate(userId) {
    const db = getPool();
    const [rows] = await db.query('SELECT hire_date FROM sso_users WHERE user_id = ?', [userId]);
    return rows.length > 0 ? rows[0].hire_date : null;
  }
};

module.exports = vacationBalanceModel;
