"""Shared configuration loader — reads build config from pyproject.toml."""

import re
from pathlib import Path
from typing import NamedTuple

import tomllib


class BuildConfig(NamedTuple):
    """Build configuration extracted from pyproject.toml."""

    alfred_version: str
    python_version: str
    python_version_short: str
    image_name: str
    service_name: str
    librechat_version: str
    rag_version: str
    uv_version: str


def extract_python_version(version_string: str) -> tuple[str, str]:
    """
    Extract Python version from uv dependency string.
    Examples:
        "==3.14.2" -> ("3.14.2", "3.14")
        "^3.14.2"  -> ("3.14.2", "3.14")
    """
    clean = re.sub(r"^[=^~><]+", "", version_string.strip())
    parts = clean.split(".")
    if len(parts) >= 2:
        return clean, f"{parts[0]}.{parts[1]}"
    raise ValueError(f"Invalid Python version format: {version_string}")


def load_build_config(base_dir: Path | None = None) -> BuildConfig:
    """Load build configuration from pyproject.toml."""
    if base_dir is None:
        base_dir = Path(__file__).resolve().parent.parent

    toml_path = base_dir / "pyproject.toml"
    if not toml_path.exists():
        raise FileNotFoundError(f"pyproject.toml not found: {toml_path}")

    with open(toml_path, "rb") as f:
        data = tomllib.load(f)

    project = data["project"]
    alfred = data["tool"]["alfred"]

    python_full, python_short = extract_python_version(project["requires-python"])

    return BuildConfig(
        alfred_version=project["version"],
        python_version=python_full,
        python_version_short=python_short,
        image_name=alfred["image_name"],
        service_name=alfred["service_name"],
        librechat_version=alfred["librechat_version"],
        rag_version=alfred["rag_version"],
        uv_version=alfred["uv_version"],
    )


def write_env_make(config: BuildConfig, base_dir: Path | None = None) -> None:
    """Write .env.make file for Makefile."""
    if base_dir is None:
        base_dir = Path(__file__).resolve().parent.parent

    lines = [
        "# Auto-generated from pyproject.toml — do not edit manually",
        f"export ALFRED_VERSION={config.alfred_version}",
        f"export PYTHON_VERSION={config.python_version}",
        f"export PYTHON_VERSION_SHORT={config.python_version_short}",
        f"export IMAGE_NAME={config.image_name}",
        f"export SERVICE_NAME={config.service_name}",
        f"export LIBRECHAT_VERSION={config.librechat_version}",
        f"export RAG_VERSION={config.rag_version}",
        f"export UV_VERSION={config.uv_version}",
    ]

    env_make_path = base_dir / ".env.make"
    env_make_path.write_text("\n".join(lines) + "\n")