#!/usr/bin/env python
"""
SQLite 到 MySQL 数据迁移脚本

用法:
    python scripts/migrate_sqlite_to_mysql.py [sqlite_db_path]

示例:
    python scripts/migrate_sqlite_to_mysql.py annotation_platform.db
"""
import sys
import os
import sqlite3

# 添加 backend 目录到路径
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))

import pymysql
from config import settings


def get_sqlite_connection(db_path: str):
    """获取 SQLite 连接"""
    conn = sqlite3.connect(db_path)
    conn.row_factory = sqlite3.Row
    return conn


def get_mysql_connection():
    """获取 MySQL 连接"""
    return pymysql.connect(
        host=settings.MYSQL_HOST,
        port=settings.MYSQL_PORT,
        user=settings.MYSQL_USER,
        password=settings.MYSQL_PASSWORD,
        database=settings.MYSQL_DATABASE,
        charset='utf8mb4',
        cursorclass=pymysql.cursors.DictCursor
    )


def migrate_table(sqlite_conn, mysql_conn, table_name: str, columns: list):
    """迁移单个表的数据"""
    sqlite_cursor = sqlite_conn.cursor()
    mysql_cursor = mysql_conn.cursor()
    
    # 查询 SQLite 数据
    sqlite_cursor.execute(f"SELECT * FROM {table_name}")
    rows = sqlite_cursor.fetchall()
    
    if not rows:
        print(f"  {table_name}: 无数据")
        return 0
    
    # 构建 INSERT 语句
    placeholders = ', '.join(['%s'] * len(columns))
    columns_str = ', '.join(columns)
    insert_sql = f"INSERT INTO {table_name} ({columns_str}) VALUES ({placeholders})"
    
    # 批量插入
    count = 0
    for row in rows:
        try:
            values = tuple(row[col] for col in columns)
            mysql_cursor.execute(insert_sql, values)
            count += 1
        except pymysql.err.IntegrityError as e:
            if e.args[0] == 1062:  # Duplicate entry
                print(f"  跳过重复记录: {row['id']}")
            else:
                raise
    
    mysql_conn.commit()
    print(f"  {table_name}: 迁移 {count} 条记录")
    return count


def main():
    # 获取 SQLite 数据库路径
    if len(sys.argv) > 1:
        sqlite_path = sys.argv[1]
    else:
        sqlite_path = os.path.join(os.path.dirname(__file__), '..', 'annotation_platform.db')
    
    if not os.path.exists(sqlite_path):
        print(f"错误: SQLite 数据库不存在: {sqlite_path}")
        sys.exit(1)
    
    print(f"源数据库: {sqlite_path}")
    print(f"目标数据库: {settings.MYSQL_HOST}:{settings.MYSQL_PORT}/{settings.MYSQL_DATABASE}")
    print()
    
    # 连接数据库
    sqlite_conn = get_sqlite_connection(sqlite_path)
    mysql_conn = get_mysql_connection()
    
    try:
        # 表结构和列定义
        tables = {
            'users': ['id', 'username', 'email', 'password_hash', 'role', 
                      'oauth_provider', 'oauth_id', 'created_at', 'updated_at'],
            'projects': ['id', 'name', 'description', 'config', 'created_at'],
            'tasks': ['id', 'project_id', 'name', 'data', 'status', 
                      'assigned_to', 'created_at'],
            'annotations': ['id', 'task_id', 'user_id', 'result', 
                           'created_at', 'updated_at'],
        }
        
        print("开始迁移...")
        total = 0
        
        # 按顺序迁移（考虑外键约束）
        for table_name in ['users', 'projects', 'tasks', 'annotations']:
            columns = tables[table_name]
            count = migrate_table(sqlite_conn, mysql_conn, table_name, columns)
            total += count
        
        print()
        print(f"迁移完成！共迁移 {total} 条记录")
        
    except Exception as e:
        print(f"迁移失败: {e}")
        mysql_conn.rollback()
        sys.exit(1)
    finally:
        sqlite_conn.close()
        mysql_conn.close()


if __name__ == '__main__':
    main()