from __future__ import annotations

import os
import re
import shutil
import subprocess
import tempfile
from pathlib import Path
from typing import Optional, List
from urllib.parse import urlparse

from .config import SKIP_DIRS, MANIFEST_NAMES


def _safe_run(cmd: List[str], cwd: Optional[str | Path] = None, timeout: int = 120) -> subprocess.CompletedProcess:
    env = dict(os.environ)
    env["GIT_TERMINAL_PROMPT"] = "0"  # do not hang on private repos
    return subprocess.run(cmd, cwd=cwd, env=env, capture_output=True, text=True, timeout=timeout)


def normalize_git_url(url: str) -> str:
    if not url:
        return url
    url = url.strip()

    m = re.match(r"git@([^:]+):(.+)$", url)
    if m:
        host, path = m.group(1), m.group(2)
        if path.endswith(".git"):
            path = path[:-4]
        return f"https://{host}/{path}".rstrip("/")

    parsed = urlparse(url)
    if parsed.scheme in ("http", "https"):
        clean_path = parsed.path

        for marker in ("/tree/", "/blob/"):
            idx = clean_path.find(marker)
            if idx != -1:
                clean_path = clean_path[:idx]

        if clean_path.endswith(".git"):
            clean_path = clean_path[:-4]

        clean_path = clean_path.rstrip("/")
        return f"{parsed.scheme}://{parsed.netloc}{clean_path}"

    return url[:-4] if url.endswith(".git") else url


def checkout_repo(url: str, revision: Optional[str]) -> Path:
    url = normalize_git_url(url)
    tmpdir = Path(tempfile.mkdtemp(prefix="cvexplorer_repo_"))

    def must(p: subprocess.CompletedProcess, cmd: List[str]):
        if p.returncode != 0:
            raise RuntimeError(f"Command failed: {' '.join(cmd)}\n{p.stderr.strip()}")

    if revision:
        p = _safe_run(["git", "init"], cwd=tmpdir, timeout=30)
        must(p, ["git", "init"])

        p = _safe_run(["git", "remote", "add", "origin", url], cwd=tmpdir, timeout=30)
        must(p, ["git", "remote", "add", "origin", url])

        p = _safe_run(["git", "fetch", "--depth", "1", "origin", revision], cwd=tmpdir, timeout=120)
        must(p, ["git", "fetch", "--depth", "1", "origin", revision])

        p = _safe_run(["git", "checkout", "FETCH_HEAD"], cwd=tmpdir, timeout=30)
        must(p, ["git", "checkout", "FETCH_HEAD"])
    else:
        shutil.rmtree(tmpdir, ignore_errors=True)
        p = _safe_run(["git", "clone", "--depth", "1", url, str(tmpdir)], timeout=180)
        must(p, ["git", "clone", "--depth", "1", url, str(tmpdir)])

    return tmpdir


def find_manifests(repo_dir: Path, max_files: int = 25) -> List[Path]:
    found: List[Path] = []
    for root, dirs, files in os.walk(repo_dir):
        dirs[:] = [d for d in dirs if d not in SKIP_DIRS]
        for fname in files:
            if fname in MANIFEST_NAMES or fname.endswith(".csproj") or fname.endswith(".fsproj"):
                found.append(Path(root) / fname)
                if len(found) >= max_files:
                    break
        if len(found) >= max_files:
            break

    found.sort(key=lambda p: len(p.relative_to(repo_dir).parts))
    return found