const Database = require('better-sqlite3');
const path = require('path');
const logger = require('./utils/logger');

const db = new Database(path.join(__dirname, '..', 'data.db'));

// 启用 WAL 模式和外键约束
db.pragma('journal_mode = WAL');
db.pragma('foreign_keys = ON');

/**
 * 创建表结构
 */
function createTables() {
  db.exec(`
    CREATE TABLE IF NOT EXISTS users (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      username TEXT UNIQUE NOT NULL,
      password TEXT NOT NULL,
      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
    );

    CREATE TABLE IF NOT EXISTS records (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      user_id INTEGER NOT NULL,
      type TEXT NOT NULL CHECK(type IN ('income', 'expense')),
      category TEXT NOT NULL,
      amount REAL NOT NULL,
      quantity INTEGER,
      unit_price REAL,
      boss TEXT,
      partner TEXT,
      source TEXT,
      destination TEXT,
      note TEXT,
      created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
      FOREIGN KEY (user_id) REFERENCES users(id)
    );

    CREATE INDEX IF NOT EXISTS idx_records_user_id ON records(user_id);
    CREATE INDEX IF NOT EXISTS idx_records_category ON records(category);
    CREATE INDEX IF NOT EXISTS idx_records_created_at ON records(created_at);
    CREATE INDEX IF NOT EXISTS idx_records_type ON records(type);
    CREATE INDEX IF NOT EXISTS idx_records_boss ON records(boss);
    CREATE INDEX IF NOT EXISTS idx_records_partner ON records(partner);
    CREATE INDEX IF NOT EXISTS idx_records_source ON records(source);
    CREATE INDEX IF NOT EXISTS idx_records_user_date ON records(user_id, created_at);
    CREATE INDEX IF NOT EXISTS idx_records_user_category ON records(user_id, category, created_at);
    CREATE INDEX IF NOT EXISTS idx_records_destination ON records(destination);
  `);
  logger.debug('表结构创建完成');
}

/**
 * 迁移：去掉 category 的 CHECK 约束
 */
function migrateRemoveCategoryCheck() {
  try {
    const tableInfo = db.prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='records'").get();
    if (tableInfo && tableInfo.sql.includes("CHECK(category IN")) {
      logger.info('执行迁移：移除 category CHECK 约束');
      db.exec(`
        CREATE TABLE records_new (
          id INTEGER PRIMARY KEY AUTOINCREMENT,
          user_id INTEGER NOT NULL,
          type TEXT NOT NULL CHECK(type IN ('income', 'expense')),
          category TEXT NOT NULL,
          amount REAL NOT NULL,
          quantity INTEGER,
          unit_price REAL,
          boss TEXT,
          partner TEXT,
          source TEXT,
          destination TEXT,
          note TEXT,
          created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
          FOREIGN KEY (user_id) REFERENCES users(id)
        );
        INSERT INTO records_new SELECT * FROM records;
        DROP TABLE records;
        ALTER TABLE records_new RENAME TO records;
      `);
      logger.info('迁移完成：category CHECK 约束已移除');
    }
  } catch (e) {
    logger.warn('迁移跳过 (category):', e.message);
  }
}

/**
 * 迁移：添加 rebate 列
 */
function migrateAddRebateColumn() {
  try {
    const cols = db.prepare("PRAGMA table_info(records)").all();
    if (!cols.find(c => c.name === 'rebate')) {
      logger.info('执行迁移：添加 rebate 列');
      db.exec("ALTER TABLE records ADD COLUMN rebate REAL");
      logger.info('迁移完成：rebate 列已添加');
    }
  } catch (e) {
    logger.warn('迁移跳过 (rebate):', e.message);
  }
}

/**
 * 初始化默认用户
 */
function initDefaultUser() {
  if (process.env.NODE_ENV === 'production') {
    logger.info('生产环境跳过默认用户初始化');
    return;
  }

  const existingUser = db.prepare('SELECT id FROM users WHERE username = ?').get('lizhilun');
  if (!existingUser) {
    const bcrypt = require('bcryptjs');
    const hash = bcrypt.hashSync('lizhilun', 10);
    db.prepare('INSERT INTO users (username, password) VALUES (?, ?)').run('lizhilun', hash);
    logger.info('开发默认用户 lizhilun 已创建');
  }
}

// 执行初始化
createTables();
migrateRemoveCategoryCheck();
migrateAddRebateColumn();
initDefaultUser();

module.exports = db;