#!/usr/bin/env python3
"""
将 mysqldump 备份中的数据合并导入 MySQL，跳过已存在行（INSERT IGNORE）。

适用场景：目标库已有部分数据，需要从备份补全而不产生主键/唯一键重复。

默认连接 Dev 165 / aidopdev（与 Database.json 开发库一致）。
不会执行 DROP TABLE / CREATE TABLE / CREATE DATABASE，不覆盖表结构。

用法示例：
  python doc/db/import_sql_dump_merge.py --dry-run
  python doc/db/import_sql_dump_merge.py
  python doc/db/import_sql_dump_merge.py --skip-tables abpauditlogs,abpauditlogactions
"""

from __future__ import annotations

import argparse
import re
import sys
import time
from collections import defaultdict
from pathlib import Path

import pymysql

DEFAULT_SOURCE = (
    Path(__file__).resolve().parents[4]
    / "阿里云数据库备份"
    / "aidopdev_20260608_053527.sql"
    / "aidopdev_20260608_053527.sql"
)

DEFAULT_DB = dict(
    host="123.60.180.165",
    port=3306,
    user="aidopremote",
    password="1234567890aiDOP#",
    database="aidopdev",
    charset="utf8mb4",
)

SKIP_PREFIXES = (
    "DROP TABLE",
    "DROP DATABASE",
    "CREATE DATABASE",
    "CREATE TABLE",
    "ALTER TABLE",
    "LOCK TABLES",
    "UNLOCK TABLES",
    "/*!40000 ALTER TABLE",
    "/*!40101 SET @saved_cs_client",
)

SAFE_PREFIXES = (
    "SET NAMES",
    "SET TIME_ZONE",
    "SET @OLD_",
    "SET SQL_MODE",
    "SET FOREIGN_KEY_CHECKS",
    "SET UNIQUE_CHECKS",
    "SET CHARACTER_SET_CLIENT",
    "SET CHARACTER_SET_RESULTS",
    "SET COLLATION_CONNECTION",
    "SET SQL_NOTES",
    "/*!40101 SET @OLD_",
    "/*!40103 SET @OLD_",
    "/*!40014 SET @OLD_",
    "/*!40111 SET @OLD_",
    "/*!50503 SET NAMES",
)

INSERT_RE = re.compile(
    r"^INSERT\s+(?:IGNORE\s+)?INTO\s+[`]?([^`\s(]+)[`]?",
    re.IGNORECASE,
)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Merge mysqldump data into MySQL with INSERT IGNORE")
    parser.add_argument(
        "--source",
        type=Path,
        default=DEFAULT_SOURCE,
        help=f"SQL dump file path (default: {DEFAULT_SOURCE})",
    )
    parser.add_argument("--host", default=DEFAULT_DB["host"])
    parser.add_argument("--port", type=int, default=DEFAULT_DB["port"])
    parser.add_argument("--user", default=DEFAULT_DB["user"])
    parser.add_argument("--password", default=DEFAULT_DB["password"])
    parser.add_argument("--database", default=DEFAULT_DB["database"])
    parser.add_argument("--dry-run", action="store_true", help="Only scan and report, do not execute")
    parser.add_argument(
        "--only-tables",
        default="",
        help="Comma-separated table allowlist (lowercase). Empty = all tables with INSERT",
    )
    parser.add_argument(
        "--skip-tables",
        default="",
        help="Comma-separated tables to skip (lowercase)",
    )
    parser.add_argument(
        "--batch-commit",
        type=int,
        default=1,
        help="Commit every N INSERT statements (default 1)",
    )
    return parser.parse_args()


def normalize_table(name: str) -> str:
    return name.strip("`").lower()


def should_skip_statement(stmt: str) -> bool:
    upper = stmt.lstrip().upper()
    if upper.startswith("USE "):
        return True
    return any(upper.startswith(prefix.upper()) for prefix in SKIP_PREFIXES)


def is_safe_session(stmt: str) -> bool:
    stripped = stmt.lstrip()
    return any(stripped.startswith(prefix) for prefix in SAFE_PREFIXES)


def to_insert_ignore(stmt: str) -> str:
    if re.match(r"^INSERT\s+IGNORE\s+INTO", stmt, re.IGNORECASE):
        return stmt
    return re.sub(r"^INSERT\s+INTO", "INSERT IGNORE INTO", stmt, count=1, flags=re.IGNORECASE)


def rewrite_insert_table(stmt: str, actual_table: str) -> str:
    sql = to_insert_ignore(stmt)
    return re.sub(
        r"^(INSERT\s+(?:IGNORE\s+)?INTO\s+)[`']?[^`'\s(]+[`']?",
        rf"\1`{actual_table}`",
        sql,
        count=1,
        flags=re.IGNORECASE,
    )


def iter_statements(path: Path):
    buffer: list[str] = []
    for line in path.open("r", encoding="utf-8", errors="replace"):
        buffer.append(line)
        if not line.rstrip().endswith(";"):
            continue
        stmt = "".join(buffer).strip()
        buffer.clear()
        if stmt:
            yield stmt
    if buffer:
        tail = "".join(buffer).strip()
        if tail:
            yield tail


def is_values_only_insert(stmt: str) -> bool:
    """Only import mysqldump data rows; skip procedure fragments with column lists."""
    stripped = stmt.lstrip()
    return bool(
        re.match(
            r"^INSERT\s+(?:IGNORE\s+)?INTO\s+[`']?[^`'\s(]+[`']?\s+VALUES\s",
            stripped,
            re.IGNORECASE,
        )
    )


def extract_insert_table(stmt: str) -> str | None:
    match = INSERT_RE.match(stmt.strip())
    return normalize_table(match.group(1)) if match else None


def connect_db(args: argparse.Namespace):
    return pymysql.connect(
        host=args.host,
        port=args.port,
        user=args.user,
        password=args.password,
        database=args.database,
        charset="utf8mb4",
        autocommit=False,
        connect_timeout=30,
        read_timeout=600,
        write_timeout=600,
    )


def load_target_tables(conn) -> dict[str, str]:
    """Return lowercase table name -> actual TABLE_NAME on server."""
    with conn.cursor() as cur:
        cur.execute(
            "SELECT TABLE_NAME FROM information_schema.TABLES "
            "WHERE TABLE_SCHEMA = DATABASE()"
        )
        mapping: dict[str, str] = {}
        for row in cur.fetchall():
            actual = row[0]
            mapping[normalize_table(actual)] = actual
        return mapping


def main() -> int:
    args = parse_args()
    source: Path = args.source
    if not source.is_file():
        print(f"[ERROR] Source file not found: {source}", file=sys.stderr)
        return 1

    only_tables = {t.strip().lower() for t in args.only_tables.split(",") if t.strip()}
    skip_tables = {t.strip().lower() for t in args.skip_tables.split(",") if t.strip()}

    stats = defaultdict(int)
    table_rows_attempted = defaultdict(int)
    errors: list[str] = []
    warnings: list[str] = []

    print(f"Source: {source}")
    print(f"Target: {args.user}@{args.host}:{args.port}/{args.database}")
    print(f"Mode: {'DRY-RUN' if args.dry_run else 'EXECUTE'}")
    if only_tables:
        print(f"Only tables: {', '.join(sorted(only_tables))}")
    if skip_tables:
        print(f"Skip tables: {', '.join(sorted(skip_tables))}")

    conn = None
    target_tables: dict[str, str] = {}
    if not args.dry_run:
        conn = connect_db(args)
        target_tables = load_target_tables(conn)
        print(f"Target tables in database: {len(target_tables)}")

    started = time.time()
    pending_since_commit = 0

    try:
        for stmt in iter_statements(source):
            if should_skip_statement(stmt):
                stats["skipped_ddl"] += 1
                continue

            table = extract_insert_table(stmt)
            if table:
                if not is_values_only_insert(stmt):
                    stats["skipped_non_values_insert"] += 1
                    continue
                if only_tables and table not in only_tables:
                    stats["skipped_filter"] += 1
                    continue
                if table in skip_tables:
                    stats["skipped_filter"] += 1
                    continue
                if not args.dry_run and table not in target_tables:
                    stats["skipped_missing_table"] += 1
                    warnings.append(f"missing table on target: {table}")
                    continue

                stats["insert_statements"] += 1
                table_rows_attempted[table] += 1
                if args.dry_run:
                    continue

                sql = rewrite_insert_table(stmt, target_tables[table])
                try:
                    with conn.cursor() as cur:
                        affected = cur.execute(sql)
                    stats["insert_executed"] += 1
                    stats["rows_affected"] += max(affected, 0)
                    pending_since_commit += 1
                    if pending_since_commit >= args.batch_commit:
                        conn.commit()
                        pending_since_commit = 0
                except Exception as exc:  # noqa: BLE001
                    conn.rollback()
                    pending_since_commit = 0
                    stats["insert_failed"] += 1
                    errors.append(f"{table}: {exc}")
                continue

            if is_safe_session(stmt):
                if args.dry_run:
                    stats["session_setup"] += 1
                    continue
                try:
                    with conn.cursor() as cur:
                        cur.execute(stmt)
                    stats["session_setup"] += 1
                except Exception:
                    stats["session_setup_ignored"] += 1
                continue

            stats["skipped_other"] += 1

        if conn and pending_since_commit:
            conn.commit()
    finally:
        if conn:
            conn.close()

    elapsed = time.time() - started
    print("\n=== Summary ===")
    print(f"Elapsed: {elapsed:.1f}s")
    for key in sorted(stats):
        print(f"  {key}: {stats[key]}")
    if table_rows_attempted:
        print("\nINSERT statements by table (top 20):")
        for table, count in sorted(table_rows_attempted.items(), key=lambda x: (-x[1], x[0]))[:20]:
            print(f"  {table}: {count}")
        if len(table_rows_attempted) > 20:
            print(f"  ... and {len(table_rows_attempted) - 20} more tables")

    if warnings:
        print(f"\nWarnings ({len(warnings)}):")
        for msg in warnings[:30]:
            print(f"  - {msg}")
        if len(warnings) > 30:
            print(f"  ... and {len(warnings) - 30} more")

    if errors:
        print(f"\nErrors ({len(errors)}):")
        for msg in errors[:30]:
            print(f"  - {msg}")
        if len(errors) > 30:
            print(f"  ... and {len(errors) - 30} more")
        return 2

    return 0


if __name__ == "__main__":
    raise SystemExit(main())