import re
from pathlib import Path
from typing import Any

import yaml
from pydantic import AliasChoices, BaseModel, Field, field_validator

IDENT_RE = re.compile(r"^[a-zA-Z_][a-zA-Z0-9_]*$")


class DatabaseConfig(BaseModel):
    host: str = "192.168.30.186"
    port: int = 5432
    name: str = "postgres"
    user: str = "postgres"
    password: str = ""
    table: str = "movie_files"
    # "schema" ist in YAML erlaubt; intern db_schema (Pydantic-Konflikt mit BaseModel.schema)
    db_schema: str = Field(
        default="public",
        validation_alias=AliasChoices("db_schema", "schema"),
    )
    ssl: bool = False

    @field_validator("table", "db_schema")
    @classmethod
    def validate_identifiers(cls, v: str) -> str:
        if not IDENT_RE.match(v):
            raise ValueError(f"Ungültiger Datenbank-Identifier: {v}")
        return v

    @property
    def qualified_table(self) -> str:
        return f'"{self.db_schema}"."{self.table}"'


class AppConfig(BaseModel):
    database: DatabaseConfig = Field(default_factory=DatabaseConfig)


def load_config(path: str | Path | None = None) -> tuple[AppConfig, Path]:
    config_path = Path(path or "/app/config/config.yaml")
    if not config_path.is_file():
        return AppConfig(), config_path

    with config_path.open(encoding="utf-8") as f:
        raw: dict[str, Any] = yaml.safe_load(f) or {}

    return AppConfig.model_validate(raw), config_path