from __future__ import annotations

import os
import shlex
from pathlib import Path

CONTAINER_REPO_ROOT = Path(os.environ["INFINITO_SRC_DIR"])


def _require_env(name: str) -> str:
    val = os.environ.get(name)
    if val is None or not str(val).strip():
        raise RuntimeError(f"Required environment variable is missing or empty: {name}")
    return str(val).strip()


def should_use_mirrors() -> bool:
    """True iff image references should be rewritten to the GHCR mirror."""
    from .profile import Profile

    return Profile().image_mirror_enabled()


def _exec_env() -> dict[str, str]:
    """
    All variables are mandatory. No fallbacks.
    """
    return {
        "INFINITO_RUNNING_ON_GITHUB": _require_env("INFINITO_RUNNING_ON_GITHUB"),
        "GITHUB_REPOSITORY_OWNER": _require_env("GITHUB_REPOSITORY_OWNER"),
        "GITHUB_REPOSITORY": _require_env("GITHUB_REPOSITORY"),
        "INFINITO_GHCR_MIRROR_PREFIX": _require_env("INFINITO_GHCR_MIRROR_PREFIX"),
    }


def generate_ci_mirrors_file(compose, *, inventory_dir: str) -> str:
    """
    Generate mirrors.yml inside the container using cli.contributing.mirror.resolver.

    Writes:
      <inventory_dir>/mirrors.yml
    """
    inv_root = str(inventory_dir).rstrip("/")
    if not inv_root:
        raise RuntimeError("inventory_dir must not be empty")

    env = _exec_env()
    ghcr_namespace = env["GITHUB_REPOSITORY_OWNER"].lower()
    ghcr_repository = env["GITHUB_REPOSITORY"].split("/", 1)[-1].lower()
    ghcr_prefix = env["INFINITO_GHCR_MIRROR_PREFIX"].strip().strip("/")
    if not ghcr_prefix:
        raise RuntimeError("INFINITO_GHCR_MIRROR_PREFIX must not be empty")

    mirrors_path = f"{inv_root}/mirrors.yml"
    repo_root = str(CONTAINER_REPO_ROOT)

    cmd = [
        "bash",
        "-lc",
        (
            "set -euo pipefail; "
            f"mkdir -p {shlex.quote(inv_root)}; "
            '"${PYTHON:-python3}" -m cli.contributing.mirror.resolver '
            f"--repo-root {shlex.quote(repo_root)} "
            f"--ghcr-namespace {shlex.quote(ghcr_namespace)} "
            f"--ghcr-repository {shlex.quote(ghcr_repository)} "
            f"--ghcr-prefix {shlex.quote(ghcr_prefix)} "
            f"> {shlex.quote(mirrors_path)}; "
            f"echo '[init] mirrors generated:' {shlex.quote(mirrors_path)}; "
            f"wc -l {shlex.quote(mirrors_path)}"
        ),
    ]

    compose.exec(
        cmd,
        check=True,
        workdir=repo_root,
        extra_env=env,
    )

    return mirrors_path