from logging.config import fileConfig

import sys
from pathlib import Path

from sqlalchemy import engine_from_config, pool, text
from alembic import context

# 把项目根加入 pythonpath,让 alembic 能找到 src 包
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from src.db.base import Base  # noqa: E402
from src.db.models import *  # noqa: E402,F401,F403  # 导入所有模型确保注册
from src.core.config import settings  # noqa: E402

# this is the Alembic Config object
config = context.config

# 用 settings 的 DATABASE_URL,但转成 sync 驱动
DB_URL = settings.DATABASE_URL
if DB_URL.startswith("postgresql+asyncpg"):
    DB_URL = DB_URL.replace("postgresql+asyncpg", "postgresql+psycopg2", 1)
config.set_main_option("sqlalchemy.url", DB_URL)

# Interpret the config file for Python logging.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata


def _ensure_version_table(connection):
    """确保 alembic_version 表存在且 version_num 列足够长。

    Alembic 默认 version_num 是 String(32),但我们的迁移名较长(如
    0005_prediction_status_and_stats_provenance 有 41 个字符),会导致
    StringDataRightTruncation 错误。
    """
    result = connection.execute(text(
        "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'alembic_version')"
    ))
    if not result.scalar():
        connection.execute(text(
            "CREATE TABLE alembic_version (version_num VARCHAR(255) NOT NULL PRIMARY KEY)"
        ))
        connection.commit()


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode."""
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Run migrations in 'online' mode."""
    connectable = engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        _ensure_version_table(connection)
        context.configure(connection=connection, target_metadata=target_metadata)

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()