#!/usr/bin/env python3
import argparse
import re
import sys
from pathlib import Path

import pymysql


def parse_env_file(env_path: Path):
    data = {}
    for raw in env_path.read_text(encoding='utf-8').splitlines():
        line = raw.strip()
        if not line or line.startswith('#'):
            continue
        if '=' not in line:
            continue
        k, v = line.split('=', 1)
        data[k.strip()] = v.strip()
    return data


def split_sql_statements(sql_text: str):
    statements = []
    buf = []
    in_single = False
    in_double = False
    in_line_comment = False
    in_block_comment = False

    i = 0
    while i < len(sql_text):
        ch = sql_text[i]
        nxt = sql_text[i + 1] if i + 1 < len(sql_text) else ''

        if in_line_comment:
            if ch == '\n':
                in_line_comment = False
                buf.append(ch)
            i += 1
            continue

        if in_block_comment:
            if ch == '*' and nxt == '/':
                in_block_comment = False
                i += 2
            else:
                i += 1
            continue

        if not in_single and not in_double:
            if ch == '-' and nxt == '-':
                in_line_comment = True
                i += 2
                continue
            if ch == '#':
                in_line_comment = True
                i += 1
                continue
            if ch == '/' and nxt == '*':
                in_block_comment = True
                i += 2
                continue

        if ch == "'" and not in_double:
            in_single = not in_single
            buf.append(ch)
            i += 1
            continue

        if ch == '"' and not in_single:
            in_double = not in_double
            buf.append(ch)
            i += 1
            continue

        if ch == ';' and not in_single and not in_double:
            stmt = ''.join(buf).strip()
            if stmt:
                statements.append(stmt)
            buf = []
            i += 1
            continue

        buf.append(ch)
        i += 1

    tail = ''.join(buf).strip()
    if tail:
        statements.append(tail)
    return statements


def main():
    parser = argparse.ArgumentParser(description='Run SQL migration from file')
    parser.add_argument('--env', default='backend/.env', help='Path to .env file')
    parser.add_argument('--sql', required=True, help='Path to SQL file')
    args = parser.parse_args()

    env = parse_env_file(Path(args.env))
    sql_path = Path(args.sql)
    if not sql_path.exists():
        print(f'[ERROR] SQL file not found: {sql_path}')
        return 1

    sql_text = sql_path.read_text(encoding='utf-8')
    statements = split_sql_statements(sql_text)
    if not statements:
        print('[ERROR] No SQL statements found')
        return 1

    conn = pymysql.connect(
        host=env.get('DB_HOST', '127.0.0.1'),
        port=int(env.get('DB_PORT', '3306')),
        user=env.get('DB_USER', 'root'),
        password=env.get('DB_PASSWORD', ''),
        database=env.get('DB_NAME', ''),
        charset='utf8mb4',
        cursorclass=pymysql.cursors.DictCursor,
        autocommit=False,
    )

    # duplicate column/index tolerated for idempotency rerun
    tolerated_errnos = {1060, 1061, 1831}

    try:
        with conn.cursor() as cur:
            print(f'[INFO] Running {len(statements)} statements from {sql_path}')
            for idx, stmt in enumerate(statements, start=1):
                normalized = re.sub(r'\s+', ' ', stmt).strip()
                head = normalized[:120]
                try:
                    cur.execute(stmt)
                    print(f'[OK] {idx:03d}: {head}')
                except pymysql.MySQLError as e:
                    if e.args and e.args[0] in tolerated_errnos:
                        print(f'[SKIP] {idx:03d}: errno={e.args[0]} {e.args[1]} | {head}')
                        continue
                    conn.rollback()
                    print(f'[FAIL] {idx:03d}: errno={e.args[0] if e.args else "?"} {e}')
                    print(f'[STMT] {head}')
                    return 2

            conn.commit()
            print('[INFO] Migration committed successfully')

            checks = [
                "SELECT COUNT(*) AS cnt FROM menus",
                "SELECT COUNT(*) AS cnt FROM role_menu_permissions",
                "SELECT COUNT(*) AS cnt FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='menus' AND COLUMN_NAME IN ('menu_level','tree_path','is_visible')",
                "SELECT COUNT(*) AS cnt FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='role_menu_permissions' AND COLUMN_NAME IN ('granted_by','granted_at')",
            ]
            for q in checks:
                cur.execute(q)
                row = cur.fetchone()
                print(f'[CHECK] {q} => {row}')

    finally:
        conn.close()

    return 0


if __name__ == '__main__':
    sys.exit(main())