import pymysql
import sys
import os
import glob
import json
import time
from urllib.parse import urlparse, parse_qs

def parse_jdbc_url(url):
    # jdbc:mysql://host:port/db?params
    # remove jdbc:mysql://
    if url.startswith("jdbc:mysql://"):
        url = url[13:]
    
    # split host:port and db
    if "/" in url:
        address, remainder = url.split("/", 1)
        if "?" in remainder:
            db, params = remainder.split("?", 1)
        else:
            db = remainder
            params = ""
    else:
        address = url
        db = ""
        params = ""
        
    if ":" in address:
        host, port = address.split(":")
        port = int(port)
    else:
        host = address
        port = 3306
        
    return host, port, db

def load_csv(jdbc_url, user, password, table, csv_dir, columns=None):
    host, port, db = parse_jdbc_url(jdbc_url)
    
    print(f"Connecting to MySQL {host}:{port}/{db} as {user}...")
    
    try:
        conn = pymysql.connect(
            host=host,
            port=port,
            user=user,
            password=password,
            database=db,
            local_infile=True,
            charset='utf8mb4',
            cursorclass=pymysql.cursors.DictCursor
        )
    except Exception as e:
        print(f"Connection failed: {e}")
        sys.exit(1)
        
    try:
        with conn.cursor() as cursor:
            # Optimization settings
            print("Setting session parameters for speed...")
            cursor.execute("SET NAMES utf8mb4")
            
            # 逐个尝试设置优化参数，避免因单个参数（如 SQL_LOG_BIN）权限不足导致整体失败
            opts = [
                ("SET FOREIGN_KEY_CHECKS = 0", "Foreign Key Checks Disabled"),
                ("SET UNIQUE_CHECKS = 0", "Unique Checks Disabled"),
                ("SET SQL_LOG_BIN = 0", "Binary Logging Disabled (Requires SUPER privilege)")
            ]
            
            for sql, desc in opts:
                try:
                    cursor.execute(sql)
                    print(f"  - {desc}: Success")
                except Exception as e:
                    # 如果是权限问题 (1227)，打印更友好的信息
                    if "1227" in str(e):
                        print(f"  - {desc}: Skipped (Insufficient privileges, but that's okay)")
                    else:
                        print(f"  - {desc}: Failed ({e})")

            # Truncate table
            print(f"Truncating table {table}...")
            cursor.execute(f"TRUNCATE TABLE `{table}`")
            
            # Find files
            files = glob.glob(os.path.join(csv_dir, "*"))
            if not files:
                print(f"No files found in {csv_dir}")
                return

            total_rows = 0
            start_time = time.time()
            
            for file_path in files:
                file_path = os.path.abspath(file_path).replace('\\', '/')
                print(f"Loading file: {file_path}")
                
                # Build SQL
                # Assuming DataX txtfilewriter defaults:
                # separator: ,
                # quoteChar: "
                # escapeChar: \
                # nullFormat: \N
                
                col_sql = ""
                if columns:
                    col_list = [f"`{c}`" for c in columns]
                    col_sql = "(" + ", ".join(col_list) + ")"
                
                sql = f"""
                    LOAD DATA LOCAL INFILE '{file_path}'
                    INTO TABLE `{table}`
                    CHARACTER SET utf8mb4
                    FIELDS TERMINATED BY ',' 
                    OPTIONALLY ENCLOSED BY '"' 
                    ESCAPED BY '\\\\'
                    LINES TERMINATED BY '\\n'
                    {col_sql}
                """
                
                cursor.execute(sql)
                rows = cursor.rowcount
                total_rows += rows
                print(f"  -> Loaded {rows} rows")
                
                # 显示 MySQL 警告（SHOW WARNINGS）的功能，用于排查导入差异
                try:
                    cursor.execute("SHOW WARNINGS")
                    warnings = cursor.fetchall()
                    if warnings:
                        print(f"  - MySQL Warnings ({len(warnings)}):")
                        # 最多显示前 5 条警告，避免日志过多
                        for i, warn in enumerate(warnings[:5]):
                            print(f"    - {warn.get('Level', 'Warning')}: {warn.get('Message', 'Unknown error')}")
                        if len(warnings) > 5:
                            print(f"    - ... and {len(warnings) - 5} more warnings")
                except Exception as warn_e:
                    print(f"  - Could not fetch warnings: {warn_e}")
                
            conn.commit()
            
            duration = time.time() - start_time
            print(f"Total loaded: {total_rows} rows in {duration:.2f}s ({total_rows/duration if duration > 0 else 0:.2f} rows/s)")
            
    except Exception as e:
        print(f"Error during load: {e}")
        sys.exit(1)
    finally:
        conn.close()

if __name__ == "__main__":
    if len(sys.argv) < 6:
        print("Usage: python LoadCsvToMysql.py <jdbc_url> <user> <password> <table> <csv_dir> [columns_json]")
        sys.exit(1)
        
    jdbc_url = sys.argv[1]
    user = sys.argv[2]
    password = sys.argv[3]
    table = sys.argv[4]
    csv_dir = sys.argv[5]
    
    columns = None
    if len(sys.argv) > 6:
        try:
            columns = json.loads(sys.argv[6])
        except:
            print("Warning: Could not parse columns JSON")
            
    load_csv(jdbc_url, user, password, table, csv_dir, columns)