import contextlib
import os
import platform
import shlex
import shutil
import subprocess
import sys
from pathlib import Path

from tortoise import Tortoise, generate_schema_for_client
from tortoise.exceptions import DBConnectionError, OperationalError

if sys.version_info >= (3, 11):
    from contextlib import chdir
else:

    class chdir(contextlib.AbstractContextManager):  # Copied from source code of Python3.13
        """Non thread-safe context manager to change the current working directory."""

        def __init__(self, path):
            self.path = path
            self._old_cwd = []

        def __enter__(self):
            self._old_cwd.append(os.getcwd())
            os.chdir(self.path)

        def __exit__(self, *excinfo):
            os.chdir(self._old_cwd.pop())


async def drop_db(tortoise_orm) -> None:
    # Placing init outside the try-block(suppress) since it doesn't
    # establish connections to the DB eagerly.
    await Tortoise.init(config=tortoise_orm)
    with contextlib.suppress(DBConnectionError, OperationalError):
        await Tortoise._drop_databases()


async def init_db(tortoise_orm, generate_schemas=True) -> None:
    await drop_db(tortoise_orm)
    await Tortoise.init(config=tortoise_orm, _create_db=True)
    if generate_schemas:
        await generate_schema_for_client(Tortoise.get_connection("default"), safe=True)


def copy_files(*src_files: Path, target_dir: Path) -> None:
    for src in src_files:
        shutil.copy(src, target_dir)


class Dialect:
    test_db_url: str

    @classmethod
    def load_env(cls) -> None:
        if getattr(cls, "test_db_url", None) is None:
            cls.test_db_url = os.getenv("TEST_DB", "")

    @classmethod
    def is_postgres(cls) -> bool:
        cls.load_env()
        return "postgres" in cls.test_db_url

    @classmethod
    def is_mysql(cls) -> bool:
        cls.load_env()
        return "mysql" in cls.test_db_url

    @classmethod
    def is_sqlite(cls) -> bool:
        cls.load_env()
        return not cls.test_db_url or "sqlite" in cls.test_db_url


WINDOWS = platform.system() == "Windows"


def run_shell(command: str, capture_output=True, **kw) -> str:
    if WINDOWS and command.startswith("aerich "):
        command = "python -m " + command
    r = subprocess.run(shlex.split(command), capture_output=capture_output)
    if r.returncode != 0 and r.stderr:
        return r.stderr.decode()
    if not r.stdout:
        return ""
    return r.stdout.decode()