/**
 * Vacation Model
 *
 * vacation_types + vacation_balance_details CRUD (MariaDB)
 * System 1과 같은 DB를 공유
 */

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

/* ===== Vacation Types (휴가 유형) ===== */

async function getVacationTypes() {
  const db = getPool();
  const [rows] = await db.query(
    'SELECT * FROM vacation_types WHERE is_active = TRUE ORDER BY priority ASC, id ASC'
  );
  return rows;
}

async function getAllVacationTypes() {
  const db = getPool();
  const [rows] = await db.query(
    'SELECT * FROM vacation_types ORDER BY priority ASC, id ASC'
  );
  return rows;
}

async function getVacationTypeById(id) {
  const db = getPool();
  const [rows] = await db.query('SELECT * FROM vacation_types WHERE id = ?', [id]);
  return rows[0] || null;
}

async function createVacationType({ type_code, type_name, deduct_days, is_special, priority, description }) {
  const db = getPool();
  const [result] = await db.query(
    `INSERT INTO vacation_types (type_code, type_name, deduct_days, is_special, priority, description, is_system)
     VALUES (?, ?, ?, ?, ?, ?, FALSE)`,
    [type_code, type_name, deduct_days ?? 1.0, is_special ? 1 : 0, priority ?? 99, description || null]
  );
  return getVacationTypeById(result.insertId);
}

async function updateVacationType(id, data) {
  const db = getPool();
  const fields = [];
  const values = [];
  if (data.type_code !== undefined) { fields.push('type_code = ?'); values.push(data.type_code); }
  if (data.type_name !== undefined) { fields.push('type_name = ?'); values.push(data.type_name); }
  if (data.deduct_days !== undefined) { fields.push('deduct_days = ?'); values.push(data.deduct_days); }
  if (data.is_special !== undefined) { fields.push('is_special = ?'); values.push(data.is_special ? 1 : 0); }
  if (data.priority !== undefined) { fields.push('priority = ?'); values.push(data.priority); }
  if (data.description !== undefined) { fields.push('description = ?'); values.push(data.description || null); }
  if (data.is_active !== undefined) { fields.push('is_active = ?'); values.push(data.is_active ? 1 : 0); }
  if (fields.length === 0) return getVacationTypeById(id);
  values.push(id);
  await db.query(`UPDATE vacation_types SET ${fields.join(', ')} WHERE id = ?`, values);
  return getVacationTypeById(id);
}

async function deleteVacationType(id) {
  const db = getPool();
  // 시스템 유형은 비활성화만
  const type = await getVacationTypeById(id);
  if (type && type.is_system) {
    await db.query('UPDATE vacation_types SET is_active = FALSE WHERE id = ?', [id]);
  } else {
    await db.query('UPDATE vacation_types SET is_active = FALSE WHERE id = ?', [id]);
  }
}

async function updatePriorities(items) {
  const db = getPool();
  for (const { id, priority } of items) {
    await db.query('UPDATE vacation_types SET priority = ? WHERE id = ?', [priority, id]);
  }
}

/* ===== Vacation Balances (연차 배정) ===== */

async function getBalancesByYear(year) {
  const db = getPool();
  const [rows] = await db.query(
    `SELECT vbd.*, vt.type_code, vt.type_name, vt.deduct_days, vt.priority,
            w.worker_name, w.hire_date
     FROM vacation_balance_details vbd
     JOIN vacation_types vt ON vbd.vacation_type_id = vt.id
     JOIN workers w ON vbd.worker_id = w.worker_id
     WHERE vbd.year = ?
     ORDER BY w.worker_name ASC, vt.priority ASC`,
    [year]
  );
  return rows;
}

async function getBalancesByWorkerYear(workerId, year) {
  const db = getPool();
  const [rows] = await db.query(
    `SELECT vbd.*, vt.type_code, vt.type_name, vt.deduct_days, vt.priority
     FROM vacation_balance_details vbd
     JOIN vacation_types vt ON vbd.vacation_type_id = vt.id
     WHERE vbd.worker_id = ? AND vbd.year = ?
     ORDER BY vt.priority ASC`,
    [workerId, year]
  );
  return rows;
}

async function getBalanceById(id) {
  const db = getPool();
  const [rows] = await db.query(
    `SELECT vbd.*, vt.type_code, vt.type_name
     FROM vacation_balance_details vbd
     JOIN vacation_types vt ON vbd.vacation_type_id = vt.id
     WHERE vbd.id = ?`,
    [id]
  );
  return rows[0] || null;
}

async function createBalance({ worker_id, vacation_type_id, year, total_days, used_days, notes, created_by }) {
  const db = getPool();
  const [result] = await db.query(
    `INSERT INTO vacation_balance_details (worker_id, vacation_type_id, year, total_days, used_days, notes, created_by)
     VALUES (?, ?, ?, ?, ?, ?, ?)
     ON DUPLICATE KEY UPDATE total_days = VALUES(total_days), used_days = VALUES(used_days), notes = VALUES(notes)`,
    [worker_id, vacation_type_id, year, total_days ?? 0, used_days ?? 0, notes || null, created_by]
  );
  return result.insertId ? getBalanceById(result.insertId) : null;
}

async function updateBalance(id, data) {
  const db = getPool();
  const fields = [];
  const values = [];
  if (data.total_days !== undefined) { fields.push('total_days = ?'); values.push(data.total_days); }
  if (data.used_days !== undefined) { fields.push('used_days = ?'); values.push(data.used_days); }
  if (data.notes !== undefined) { fields.push('notes = ?'); values.push(data.notes || null); }
  if (fields.length === 0) return getBalanceById(id);
  values.push(id);
  await db.query(`UPDATE vacation_balance_details SET ${fields.join(', ')} WHERE id = ?`, values);
  return getBalanceById(id);
}

async function deleteBalance(id) {
  const db = getPool();
  await db.query('DELETE FROM vacation_balance_details WHERE id = ?', [id]);
}

async function bulkUpsertBalances(balances) {
  const db = getPool();
  let count = 0;
  for (const b of balances) {
    await db.query(
      `INSERT INTO vacation_balance_details (worker_id, vacation_type_id, year, total_days, used_days, notes, created_by)
       VALUES (?, ?, ?, ?, ?, ?, ?)
       ON DUPLICATE KEY UPDATE total_days = VALUES(total_days), notes = VALUES(notes)`,
      [b.worker_id, b.vacation_type_id, b.year, b.total_days ?? 0, b.used_days ?? 0, b.notes || null, b.created_by]
    );
    count++;
  }
  return count;
}

/* ===== 연차 자동 계산 (근로기준법) ===== */

function calculateAnnualDays(hireDate, targetYear) {
  if (!hireDate) return 0;
  const hire = new Date(hireDate);
  const yearStart = new Date(targetYear, 0, 1);
  const monthsDiff = (yearStart.getFullYear() - hire.getFullYear()) * 12 + (yearStart.getMonth() - hire.getMonth());

  if (monthsDiff < 0) return 0;
  if (monthsDiff < 12) {
    // 1년 미만: 근무 개월 수
    return Math.max(0, Math.floor(monthsDiff));
  }
  // 1년 이상: 15일 + 2년마다 1일 추가 (최대 25일)
  const yearsWorked = Math.floor(monthsDiff / 12);
  const additional = Math.floor((yearsWorked - 1) / 2);
  return Math.min(15 + additional, 25);
}

async function autoCalculateForAllWorkers(year, createdBy) {
  const db = getPool();
  const [workers] = await db.query(
    'SELECT worker_id, worker_name, hire_date FROM workers WHERE status != ? ORDER BY worker_name',
    ['inactive']
  );
  // 연차 유형 (ANNUAL_FULL) 찾기
  const [types] = await db.query(
    "SELECT id FROM vacation_types WHERE type_code = 'ANNUAL_FULL' AND is_active = TRUE LIMIT 1"
  );
  if (!types.length) return { count: 0, results: [] };
  const annualTypeId = types[0].id;

  const results = [];
  for (const w of workers) {
    const days = calculateAnnualDays(w.hire_date, year);
    if (days > 0) {
      await db.query(
        `INSERT INTO vacation_balance_details (worker_id, vacation_type_id, year, total_days, used_days, notes, created_by)
         VALUES (?, ?, ?, ?, 0, ?, ?)
         ON DUPLICATE KEY UPDATE total_days = VALUES(total_days), notes = VALUES(notes)`,
        [w.worker_id, annualTypeId, year, days, `자동계산 (입사: ${w.hire_date ? w.hire_date.toISOString().substring(0,10) : ''})`, createdBy]
      );
      results.push({ worker_id: w.worker_id, worker_name: w.worker_name, days, hire_date: w.hire_date });
    }
  }
  return { count: results.length, results };
}

module.exports = {
  getVacationTypes, getAllVacationTypes, getVacationTypeById,
  createVacationType, updateVacationType, deleteVacationType, updatePriorities,
  getBalancesByYear, getBalancesByWorkerYear, getBalanceById,
  createBalance, updateBalance, deleteBalance, bulkUpsertBalances,
  calculateAnnualDays, autoCalculateForAllWorkers
};