"""Database dialect guard helpers for app startup."""

from __future__ import annotations

import os

from ..config import settings
from ..logging import get_logger

logger = get_logger(__name__)


def is_missing_table_error(exc: Exception) -> bool:
    text = str(exc).lower()
    return (
        "no such table" in text
        or "undefined table" in text
        or "relation" in text and "does not exist" in text
    )


def normalize_dialect(value: str) -> str:
    raw = str(value or "").strip().lower()
    if not raw:
        return ""
    if raw.startswith("postgres"):
        return "postgresql"
    if raw.startswith("mysql"):
        return "mysql"
    if "+" in raw:
        raw = raw.split("+", 1)[0]
    if ":" in raw:
        raw = raw.split(":", 1)[0]
    return raw


def mask_db_url(url: str) -> str:
    value = str(url or "").strip()
    if "@" not in value:
        return value
    prefix, suffix = value.split("@", 1)
    if "://" not in prefix:
        return f"***@{suffix}"
    scheme, creds = prefix.split("://", 1)
    user = creds.split(":", 1)[0] if ":" in creds else creds
    return f"{scheme}://{user}:***@{suffix}"


def check_database_dialect_guard(sync_conn) -> None:
    configured = normalize_dialect(settings.database_url)
    actual = normalize_dialect(sync_conn.dialect.name)
    expected = normalize_dialect(os.getenv("PMFLOW_EXPECTED_DB_DIALECT", "postgresql")) or "postgresql"

    env_urls = [
        os.getenv("DATABASE_URL", ""),
        os.getenv("SQLALCHEMY_DATABASE_URL", ""),
        os.getenv("SYNC_DATABASE_URL", ""),
    ]
    configured_families = {normalize_dialect(item) for item in env_urls if str(item or "").strip()}
    configured_families.discard("")

    logger.info(
        "database_dialect_guard",
        configured=configured,
        actual=actual,
        expected=expected or "unset",
        database_url=mask_db_url(settings.database_url),
    )
    print(
        "[DB-Guard] "
        f"configured={configured}, actual={actual}, expected={expected or 'unset'}, "
        f"url={mask_db_url(settings.database_url)}"
    )
    if configured != "postgresql":
        raise RuntimeError(f"DATABASE_URL 必须为 PostgreSQL，当前 configured={configured or 'unset'}。")
    if actual != "postgresql":
        raise RuntimeError(f"运行时数据库必须为 PostgreSQL，当前 actual={actual or 'unset'}。")
    if configured and actual and configured != actual:
        raise RuntimeError(
            f"数据库方言不一致: configured={configured}, actual={actual}。"
            "请确保同一服务只连接单一数据库方言。"
        )
    if expected and actual and expected != actual:
        raise RuntimeError(
            f"数据库方言与 PMFLOW_EXPECTED_DB_DIALECT 不一致: expected={expected}, actual={actual}。"
        )
    if len(configured_families) > 1:
        raise RuntimeError(
            f"检测到多种数据库方言配置: {sorted(configured_families)}。"
            "禁止同一服务混用多数据库方言。"
        )