"""
migrate_sqlite_to_pg.py — 将SQLite数据迁移到PostgreSQL

用法：
  python3 backend/migrate_sqlite_to_pg.py

迁移顺序：
1. 创建PG schema + 分区
2. 迁移 rate_snapshots
3. 迁移 agg_trades（按月表）
4. 迁移 agg_trades_meta
5. 校验计数
"""

import os
import sqlite3
import time
import logging

import psycopg2
import psycopg2.extras

from db import get_sync_conn, init_schema, ensure_partitions

logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
logger = logging.getLogger("migrate")

SQLITE_PATH = os.path.join(os.path.dirname(__file__), "..", "arb.db")


def migrate_rate_snapshots(sqlite_conn, pg_conn):
    logger.info("=== 迁移 rate_snapshots ===")
    rows = sqlite_conn.execute("SELECT ts, btc_rate, eth_rate, btc_price, eth_price, btc_index_price, eth_index_price FROM rate_snapshots ORDER BY ts").fetchall()
    logger.info(f"  SQLite: {len(rows)} 条")

    if not rows:
        return

    values = [(r["ts"], r["btc_rate"], r["eth_rate"], r["btc_price"], r["eth_price"],
               r["btc_index_price"], r["eth_index_price"]) for r in rows]

    with pg_conn.cursor() as cur:
        psycopg2.extras.execute_values(
            cur,
            "INSERT INTO rate_snapshots (ts, btc_rate, eth_rate, btc_price, eth_price, btc_index_price, eth_index_price) VALUES %s ON CONFLICT DO NOTHING",
            values,
            template="(%s, %s, %s, %s, %s, %s, %s)",
            page_size=5000,
        )
        pg_conn.commit()
        logger.info(f"  PG: {cur.rowcount} 条写入")


def migrate_agg_trades(sqlite_conn, pg_conn):
    logger.info("=== 迁移 agg_trades ===")

    # 确保PG分区存在
    ensure_partitions()

    # 找所有SQLite月表
    tables = sqlite_conn.execute(
        "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'agg_trades_2%' ORDER BY name"
    ).fetchall()

    total = 0
    for t in tables:
        tname = t["name"]
        count = sqlite_conn.execute(f"SELECT COUNT(*) as c FROM {tname}").fetchone()["c"]
        logger.info(f"  {tname}: {count:,} 条")

        if count == 0:
            continue

        # 确保对应PG分区存在
        month = tname.replace("agg_trades_", "")
        import datetime
        year = int(month[:4])
        mon = int(month[4:])
        start = datetime.datetime(year, mon, 1)
        if mon == 12:
            end = datetime.datetime(year + 1, 1, 1)
        else:
            end = datetime.datetime(year, mon + 1, 1)
        start_ms = int(start.timestamp() * 1000)
        end_ms = int(end.timestamp() * 1000)

        with pg_conn.cursor() as cur:
            try:
                cur.execute(f"""
                    CREATE TABLE IF NOT EXISTS {tname}
                    PARTITION OF agg_trades
                    FOR VALUES FROM ({start_ms}) TO ({end_ms})
                """)
                pg_conn.commit()
            except Exception:
                pg_conn.rollback()

        # 分批读取+写入
        offset = 0
        batch_size = 10000
        batch_total = 0

        while True:
            rows = sqlite_conn.execute(
                f"SELECT agg_id, symbol, price, qty, time_ms, is_buyer_maker FROM {tname} "
                f"ORDER BY agg_id LIMIT {batch_size} OFFSET {offset}"
            ).fetchall()

            if not rows:
                break

            values = [(r["agg_id"], r["symbol"], r["price"], r["qty"], r["time_ms"], r["is_buyer_maker"]) for r in rows]

            with pg_conn.cursor() as cur:
                psycopg2.extras.execute_values(
                    cur,
                    "INSERT INTO agg_trades (agg_id, symbol, price, qty, time_ms, is_buyer_maker) VALUES %s "
                    "ON CONFLICT (time_ms, symbol, agg_id) DO NOTHING",
                    values,
                    template="(%s, %s, %s, %s, %s, %s)",
                    page_size=5000,
                )
                batch_total += cur.rowcount
                pg_conn.commit()

            offset += batch_size

            if offset % 100000 == 0:
                logger.info(f"    {tname}: {offset:,}/{count:,} ({offset/count*100:.0f}%)")

        total += batch_total
        logger.info(f"    {tname}: 完成，写入 {batch_total:,} 条")

    logger.info(f"  agg_trades 总计: {total:,} 条")


def migrate_meta(sqlite_conn, pg_conn):
    logger.info("=== 迁移 agg_trades_meta ===")
    try:
        rows = sqlite_conn.execute("SELECT * FROM agg_trades_meta").fetchall()
    except Exception:
        rows = []
    
    for r in rows:
        with pg_conn.cursor() as cur:
            cur.execute("""
                INSERT INTO agg_trades_meta (symbol, last_agg_id, last_time_ms, earliest_agg_id, earliest_time_ms, updated_at)
                VALUES (%s, %s, %s, %s, %s, %s)
                ON CONFLICT(symbol) DO UPDATE SET
                    last_agg_id = EXCLUDED.last_agg_id,
                    last_time_ms = EXCLUDED.last_time_ms,
                    earliest_agg_id = EXCLUDED.earliest_agg_id,
                    earliest_time_ms = EXCLUDED.earliest_time_ms
            """, (
                r["symbol"],
                r["last_agg_id"],
                r.get("last_time_ms"),
                r.get("earliest_agg_id"),
                r.get("earliest_time_ms"),
                r.get("updated_at"),
            ))
            pg_conn.commit()
    logger.info(f"  {len(rows)} 条 meta 迁移完成")


def verify(sqlite_conn, pg_conn):
    logger.info("=== 校验 ===")

    # rate_snapshots
    sq_count = sqlite_conn.execute("SELECT COUNT(*) as c FROM rate_snapshots").fetchone()["c"]
    with pg_conn.cursor() as cur:
        cur.execute("SELECT COUNT(*) FROM rate_snapshots")
        pg_count = cur.fetchone()[0]
    logger.info(f"  rate_snapshots: SQLite={sq_count:,}, PG={pg_count:,} {'✅' if pg_count >= sq_count else '⚠️'}")

    # agg_trades
    tables = sqlite_conn.execute(
        "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'agg_trades_2%'"
    ).fetchall()
    sq_total = 0
    for t in tables:
        c = sqlite_conn.execute(f"SELECT COUNT(*) as c FROM {t['name']}").fetchone()["c"]
        sq_total += c

    with pg_conn.cursor() as cur:
        cur.execute("SELECT COUNT(*) FROM agg_trades")
        pg_total = cur.fetchone()[0]
    logger.info(f"  agg_trades: SQLite={sq_total:,}, PG={pg_total:,} {'✅' if pg_total >= sq_total else '⚠️'}")


def main():
    logger.info("开始 SQLite → PostgreSQL 迁移")
    start = time.time()

    # 初始化PG
    init_schema()

    # 打开SQLite
    sqlite_conn = sqlite3.connect(SQLITE_PATH)
    sqlite_conn.row_factory = sqlite3.Row

    # 获取PG连接
    with get_sync_conn() as pg_conn:
        migrate_rate_snapshots(sqlite_conn, pg_conn)
        migrate_agg_trades(sqlite_conn, pg_conn)
        migrate_meta(sqlite_conn, pg_conn)
        verify(sqlite_conn, pg_conn)

    sqlite_conn.close()
    elapsed = time.time() - start
    logger.info(f"=== 迁移完成，耗时 {elapsed:.0f}秒 ===")


if __name__ == "__main__":
    main()