import pymysql
import re
from config.db_config import *
from connectors.clickhouse_connector import ClickHouseConnector


def get_mysql_table_structure(config, table):
    """获取MySQL表结构信息"""
    conn = pymysql.connect(host=config["host"],
                           port=config["port"],
                           user=config["user"],
                           password=config["password"],
                           database=config["database"])

    # 获取字段信息
    with conn.cursor() as cursor:
        cursor.execute(f"""
            SELECT column_name, data_type, column_type, is_nullable, column_default
            FROM information_schema.columns
            WHERE table_schema = '{config["database"]}' AND table_name = '{table}'
        """)
        columns = cursor.fetchall()

    # 获取索引信息
    with conn.cursor() as cursor:
        cursor.execute(f"""
            SELECT index_name, column_name, non_unique
            FROM information_schema.statistics
            WHERE table_schema = '{config["database"]}' AND table_name = '{table}'
        """)
        indexes = cursor.fetchall()

    # 获取主键信息
    with conn.cursor() as cursor:
        cursor.execute(f"""
            SELECT column_name
            FROM information_schema.key_column_usage
            WHERE table_schema = '{config["database"]}' 
            AND table_name = '{table}'
            AND constraint_name = 'PRIMARY'
        """)
        primary_keys = [row[0] for row in cursor.fetchall()]

    conn.close()
    return columns, indexes, primary_keys


def convert_to_clickhouse_type(mysql_type):
    """将MySQL类型转换为ClickHouse类型，并处理无符号类型"""
    # 去除unsigned标记并转换为小写
    type_str = re.sub(r'\sunsigned', '', mysql_type, flags=re.IGNORECASE).lower()

    # 类型映射
    type_map = {
        'tinyint': 'Int8',
        'smallint': 'Int16',
        'mediumint': 'Int32',
        'int': 'Int32',
        'bigint': 'Int64',
        'float': 'Float32',
        'double': 'Float64',
        'decimal': 'Decimal',
        'char': 'String',
        'varchar': 'String',
        'text': 'String',
        'longtext': 'String',
        'date': 'Date',
        'datetime': 'DateTime',
        'timestamp': 'DateTime',
        'enum': 'String'
    }

    # 处理特殊类型
    if 'tinyint(1)' in type_str:
        return 'Int8'  # 处理MySQL的布尔类型

    # 匹配数字精度
    match = re.match(r'(\w+)(\(\d+,\d+\))?', type_str)
    if match:
        base_type = match.group(1)
        precision = match.group(2) or ''
        return type_map.get(base_type, 'String') + precision

    return type_map.get(type_str, 'String')


def generate_clickhouse_ddl(table_name, columns, indexes, primary_keys):
    """生成ClickHouse建表语句"""
    # 处理字段定义
    column_defs = []
    for col in columns:
        name, data_type, column_type, is_nullable, default = col
        ch_type = convert_to_clickhouse_type(column_type)
        # 修正浮点型定义
        if 'Float64' in ch_type and '(' in ch_type:
            ch_type = 'Float64'
        nullable = 'Nullable(' + ch_type + ')' if is_nullable == 'YES' else ch_type
        column_defs.append(f'    {name} {nullable}')

    # 处理主键
    order_by = 'ORDER BY (' + ', '.join(primary_keys) + ')' if primary_keys else ''

    # 处理索引（新增分组逻辑）
    index_groups = {}
    for idx in indexes:
        index_name, column_name, non_unique = idx
        if index_name == 'PRIMARY':
            continue
        if index_name not in index_groups:
            index_groups[index_name] = {
                'non_unique': non_unique,
                'columns': []
            }
        index_groups[index_name]['columns'].append(column_name)

    index_defs = []
    for index_name, info in index_groups.items():
        columns = info['columns']
        # 修正索引语法（ClickHouse不支持UNIQUE KEY）
        index_type = 'minmax'  # 默认索引类型
        # 统一使用INDEX语法，ClickHouse 24.8+ 的MergeTree引擎不支持UNIQUE约束
        index_defs.append(
            f'    INDEX {index_name} ({", ".join(columns)}) TYPE {index_type} GRANULARITY 3'
        )

    # 组合DDL语句
    ddl = f'CREATE TABLE {table_name} (\n'
    ddl += ',\n'.join(column_defs)
    if index_defs:
        ddl += ',\n' + ',\n'.join(index_defs)
    ddl += '\n) ENGINE = ReplacingMergeTree()\n'
    ddl += order_by
    ddl += '\nSETTINGS index_granularity = 8192;'

    return ddl


# 创建ClickHouse表
def create_ch_table(table):
    ch_conn = ClickHouseConnector(CH_CONFIG)
    """创建ClickHouse表"""
    with open("schemas/" + table + ".sql", 'r', encoding='utf-8') as f:
        create_sql = f.read()

    client = ch_conn.connect()
    client.execute("DROP TABLE IF EXISTS " + table)  # 删除表（如果存在）
    client.execute(create_sql)  # 创建新表
    ch_conn.disconnect()


if __name__ == '__main__':
    # 输出配置信息
    print_config()

    # tables=['t_station','t_equipment','t_equipment_charge_order']
    tables = ['t_station', 't_equipment', 't_equipment_charge_order']
    for table in tables:
        # 获取表结构
        columns, indexes, primary_keys = get_mysql_table_structure(MYSQL_CONFIG, table)

        # 生成ClickHouse DDL
        ddl = generate_clickhouse_ddl(table, columns, indexes, primary_keys)
        # 保存到文件中 schemas/t_station.sql
        with open(f'schemas/{table}.sql', 'w', encoding='utf-8') as f:
            f.write(ddl)
        # print(f'✅ DDL语句已保存至：schemas/{table}.sql')

        # 创建ClickHouse表
        create_ch_table(table)
        print(f'✅ ClickHouse表{table}已创建')