const sqlite3 = require('sqlite3').verbose();
const path = require('path');
const fs = require('fs');

const dbPath = path.resolve(__dirname, '../database.sqlite');
const db = new sqlite3.Database(dbPath);

// Promisify query method
const query = (sql, params = []) => {
    return new Promise((resolve, reject) => {
        // Handle SELECT vs INSERT/UPDATE/DELETE
        const trimmedSql = sql.trim().toUpperCase();
        if (trimmedSql.startsWith('SELECT') || trimmedSql.startsWith('PRAGMA')) {
            db.all(sql, params, (err, rows) => {
                if (err) {
                    console.error('Database query error:', err);
                    reject(err);
                } else {
                    resolve(rows);
                }
            });
        } else {
            db.run(sql, params, function(err) {
                if (err) {
                    console.error('Database execution error:', err);
                    reject(err);
                } else {
                    // Normalize result to look like MySQL result
                    // this.lastID, this.changes
                    resolve({
                        insertId: this.lastID,
                        affectedRows: this.changes,
                        warningStatus: 0
                    });
                }
            });
        }
    });
};

// Mock Pool object for compatibility
const pool = {
    query: query,
    execute: (sql, params) => query(sql, params).then(res => [res]), // Wrap in array for mysql2 compatibility
    getConnection: () => Promise.resolve({
        release: () => {},
        query: query,
        execute: (sql, params) => query(sql, params).then(res => [res]),
        beginTransaction: () => query('BEGIN TRANSACTION'),
        commit: () => query('COMMIT'),
        rollback: () => query('ROLLBACK')
    })
};

const testConnection = async () => {
    try {
        await query('SELECT 1');
        console.log('SQLite 数据库连接成功');
        return true;
    } catch (error) {
        console.error('SQLite 数据库连接失败:', error.message);
        return false;
    }
};

module.exports = {
    pool,
    query,
    testConnection
};