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

const ALLOWED_CREATE_COLUMNS = ['user_id', 'vacation_type_id', 'start_date', 'end_date', 'days_used', 'reason', 'status', 'reviewed_by', 'review_note'];
const ALLOWED_UPDATE_COLUMNS = ['vacation_type_id', 'start_date', 'end_date', 'days_used', 'reason'];

const vacationRequestModel = {
  async create(data, conn) {
    const db = conn || getPool();
    const filtered = {};
    for (const key of ALLOWED_CREATE_COLUMNS) {
      if (data[key] !== undefined) filtered[key] = data[key];
    }
    const columns = Object.keys(filtered);
    const placeholders = columns.map(() => '?').join(', ');
    const values = columns.map(c => filtered[c]);
    const [result] = await db.query(
      `INSERT INTO sp_vacation_requests (${columns.join(', ')}) VALUES (${placeholders})`,
      values
    );
    return result;
  },

  async getAll(filters = {}) {
    const db = getPool();
    let query = `
      SELECT
        vr.*,
        su.name as user_name,
        su.username,
        COALESCE(d.department_name, '미배정') as department_name,
        vt.type_name as vacation_type_name,
        vt.type_code,
        reviewer.name as reviewer_name
      FROM sp_vacation_requests vr
      INNER JOIN sso_users su ON vr.user_id = su.user_id
      LEFT JOIN departments d ON su.department_id = d.department_id
      INNER JOIN vacation_types vt ON vr.vacation_type_id = vt.id
      LEFT JOIN sso_users reviewer ON vr.reviewed_by = reviewer.user_id
      WHERE 1=1
    `;
    const params = [];

    if (filters.user_id) {
      query += ' AND vr.user_id = ?';
      params.push(filters.user_id);
    }
    if (filters.status) {
      query += ' AND vr.status = ?';
      params.push(filters.status);
    }
    if (filters.start_date) {
      query += ' AND vr.start_date >= ?';
      params.push(filters.start_date);
    }
    if (filters.end_date) {
      query += ' AND vr.end_date <= ?';
      params.push(filters.end_date);
    }
    if (filters.vacation_type_id) {
      query += ' AND vr.vacation_type_id = ?';
      params.push(filters.vacation_type_id);
    }
    if (filters.department_id) {
      query += ' AND su.department_id = ?';
      params.push(filters.department_id);
    }

    query += ' ORDER BY vr.created_at DESC';

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

  async getById(requestId) {
    const db = getPool();
    const [rows] = await db.query(`
      SELECT
        vr.*,
        su.name as user_name,
        su.username,
        COALESCE(d.department_name, '미배정') as department_name,
        vt.type_name as vacation_type_name,
        vt.type_code,
        reviewer.name as reviewer_name
      FROM sp_vacation_requests vr
      INNER JOIN sso_users su ON vr.user_id = su.user_id
      LEFT JOIN departments d ON su.department_id = d.department_id
      INNER JOIN vacation_types vt ON vr.vacation_type_id = vt.id
      LEFT JOIN sso_users reviewer ON vr.reviewed_by = reviewer.user_id
      WHERE vr.request_id = ?
    `, [requestId]);
    return rows;
  },

  async update(requestId, data) {
    const db = getPool();
    const filtered = {};
    for (const key of ALLOWED_UPDATE_COLUMNS) {
      if (data[key] !== undefined) filtered[key] = data[key];
    }
    const columns = Object.keys(filtered);
    if (columns.length === 0) return { affectedRows: 0 };
    const setClause = columns.map(c => `${c} = ?`).join(', ');
    const values = [...columns.map(c => filtered[c]), requestId];
    const [result] = await db.query(`UPDATE sp_vacation_requests SET ${setClause} WHERE request_id = ?`, values);
    return result;
  },

  async updateStatus(requestId, statusData, conn) {
    const db = conn || getPool();
    const [result] = await db.query(`
      UPDATE sp_vacation_requests
      SET status = ?, reviewed_by = ?, reviewed_at = NOW(), review_note = ?
      WHERE request_id = ?
    `, [statusData.status, statusData.reviewed_by, statusData.review_note || null, requestId]);
    return result;
  },

  async checkOverlap(userId, startDate, endDate, excludeRequestId = null) {
    const db = getPool();
    let query = `
      SELECT COUNT(*) as count FROM sp_vacation_requests
      WHERE user_id = ?
        AND status IN ('pending', 'approved')
        AND start_date <= ? AND end_date >= ?
    `;
    const params = [userId, endDate, startDate];

    if (excludeRequestId) {
      query += ' AND request_id != ?';
      params.push(excludeRequestId);
    }

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

  async getAllPending() {
    const db = getPool();
    const [rows] = await db.query(`
      SELECT
        vr.*,
        su.name as user_name,
        su.username,
        COALESCE(d.department_name, '미배정') as department_name,
        vt.type_name as vacation_type_name,
        vt.type_code
      FROM sp_vacation_requests vr
      INNER JOIN sso_users su ON vr.user_id = su.user_id
      LEFT JOIN departments d ON su.department_id = d.department_id
      INNER JOIN vacation_types vt ON vr.vacation_type_id = vt.id
      WHERE vr.status = 'pending'
      ORDER BY vr.created_at ASC
    `);
    return rows;
  },

  async runMigration() {
    const db = getPool();
    const fs = require('fs');
    const path = require('path');
    const migrationFiles = ['001_create_sp_tables.sql', '002_section_c_additions.sql'];
    for (const file of migrationFiles) {
      const sqlFile = path.join(__dirname, '..', 'db', 'migrations', file);
      if (!fs.existsSync(sqlFile)) continue;
      const sql = fs.readFileSync(sqlFile, 'utf8');
      const statements = sql.split(';').map(s => s.trim()).filter(s => s.length > 0);
      for (const stmt of statements) {
        try {
          await db.query(stmt);
        } catch (err) {
          if (err.code === 'ER_DUP_FIELDNAME' || err.code === 'ER_TABLE_EXISTS_ERROR') {
            // Already migrated
          } else {
            throw err;
          }
        }
      }
    }
    console.log('[tksupport] Migration completed');
  }
};

module.exports = vacationRequestModel;