#!/usr/bin/env python3
import os
import subprocess
import sys
from pathlib import Path

ROOT = Path(".").resolve()
TEST_DIR = ROOT / "tests"
CPP_EXTENSIONS = {".c", ".cc", ".cpp", ".cxx", ".h", ".hh", ".hpp", ".hxx"}

TEST_PATTERNS = [
    "test_{name}.cpp",
    "test_{name}.h",
    "{name}_test.cpp",
    "{name}_test.h",
    "{name}test.cpp",
    "{name}test.h",
    "{name}gtest.cpp",
    "{name}gtest.h",
]

def run(cmd: str) -> str:
    return subprocess.check_output(cmd, shell=True, text=True).strip()

def changed_files():
    target = os.environ.get("CHANGE_TARGET", "origin/main")
    out = run(f"git diff --name-only {target}...HEAD")
    return [line.strip() for line in out.splitlines() if line.strip()]

def is_cpp_file(path: Path) -> bool:
    return path.suffix.lower() in CPP_EXTENSIONS

def require_clang_format():
    if not (ROOT / ".clang-format").exists():
        print("ERROR: .clang-format fehlt im Repository-Root.")
        sys.exit(1)

def check_format(path: Path):
    subprocess.check_call(f"clang-format --dry-run --Werror '{path}'", shell=True)

def candidate_names(path: Path):
    stem = path.stem.lower()
    names = {stem}
    for suffix in ["_p", "_impl", "_private", "_priv", "_ui"]:
        if stem.endswith(suffix):
            names.add(stem[:-len(suffix)])
    return sorted(n for n in names if n)

def has_related_test(path: Path) -> bool:
    if not TEST_DIR.exists():
        return False

    test_files = [p for p in TEST_DIR.rglob("*") if p.is_file()]
    test_names = [p.name.lower() for p in test_files]

    for name in candidate_names(path):
        for pattern in TEST_PATTERNS:
            if pattern.format(name=name).lower() in test_names:
                return True
        for test_name in test_names:
            if name in test_name and ("test" in test_name or "gtest" in test_name):
                return True
    return False

def main():
    require_clang_format()

    files = changed_files()
    if not files:
        print("Keine geänderten Dateien erkannt.")
        return

    for rel in files:
        path = ROOT / rel
        if not path.exists():
            continue
        if is_cpp_file(path):
            print(f"Prüfe: {rel}")
            try:
                check_format(path)
            except subprocess.CalledProcessError:
                print(f"ERROR: Formatfehler in {rel}")
                sys.exit(1)

            if not has_related_test(path):
                print(f"ERROR: Kein passender Test unter tests/ für {rel} gefunden.")
                sys.exit(1)

    print("Policy-Checks erfolgreich.")

if __name__ == "__main__":
    main()