from __future__ import annotations

import re
from dataclasses import dataclass
from pathlib import Path


INVALID_PATH_CHARS_RE = re.compile(r'[<>:"/\\|?*\x00-\x1f]')
DEFAULT_WEB_PORT = 18080


def sanitize_path_component(value: str, fallback: str) -> str:
    cleaned = INVALID_PATH_CHARS_RE.sub("_", (value or "").strip()).rstrip(". ")
    return cleaned or fallback


def pick_first_artist_name(singers: str | None) -> str:
    for candidate in re.split(r"\s*(?:/|,|&|\|)\s*", singers or ""):
        if candidate.strip():
            return sanitize_path_component(candidate, "Unknown Artist")
    return "Unknown Artist"


def build_download_relative_dir(platform: str, singers: str | None) -> Path:
    return Path(sanitize_path_component(platform, "unknown")) / pick_first_artist_name(
        singers
    )


def parse_web_port(value: str | int | None, fallback: int = DEFAULT_WEB_PORT) -> int:
    try:
        parsed = int(value)  # type: ignore[arg-type]
    except (TypeError, ValueError):
        return fallback
    if 1 <= parsed <= 65535:
        return parsed
    return fallback


@dataclass
class CatalogSyncRuntimeConfig:
    root_dir: Path
    app_home: Path
    library_dir: Path
    db_path: Path
    env_file: Path
    input_dir: Path
    log_dir: Path
    python_bin: str
    venv_dir: Path
    web_host: str
    web_port: int
    download_layout: str

    @classmethod
    def from_mapping(cls, mapping: dict[str, str]) -> "CatalogSyncRuntimeConfig":
        root_dir = Path(mapping["ROOT_DIR"])
        app_home = Path(mapping.get("APP_HOME", root_dir / "catalogsync"))
        library_dir = Path(mapping.get("LIBRARY_DIR", root_dir / "library"))
        web_port = parse_web_port(mapping.get("WEB_PORT"), fallback=DEFAULT_WEB_PORT)
        return cls(
            root_dir=root_dir,
            app_home=app_home,
            library_dir=library_dir,
            db_path=Path(mapping.get("DB_PATH", app_home / "data" / "catalogsync.db")),
            env_file=Path(mapping.get("ENV_FILE", app_home / "config" / "catalogsync.env")),
            input_dir=Path(mapping.get("INPUT_DIR", app_home / "inputs")),
            log_dir=Path(mapping.get("LOG_DIR", app_home / "logs")),
            python_bin=mapping.get("PYTHON_BIN", "python3"),
            venv_dir=Path(mapping.get("VENV_DIR", app_home / "app" / ".venv")),
            web_host=mapping.get("WEB_HOST", "127.0.0.1"),
            web_port=web_port,
            download_layout=mapping.get("DOWNLOAD_LAYOUT", "platform_first_artist"),
        )

    def ensure_directories(self) -> None:
        for path in (
            self.root_dir,
            self.library_dir,
            self.app_home / "app",
            self.app_home / "bin",
            self.app_home / "config",
            self.db_path.parent,
            self.env_file.parent,
            self.input_dir,
            self.log_dir,
        ):
            path.mkdir(parents=True, exist_ok=True)