from __future__ import annotations

import argparse
import json
import os
from pathlib import Path

import pytest
from cryptography.exceptions import InvalidSignature
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey

from metin_release.commands import sign
from metin_release.errors import IntegrityError, KeyPermissionError, ValidationError
from metin_release.workspace import Context


def _ctx(script: Path) -> Context:
    return Context(sign_manifest_script=script)


def _write_toy_manifest(path: Path) -> None:
    path.write_bytes(json.dumps({"version": "test", "files": []}, indent=2).encode() + b"\n")


@pytest.mark.skipif(
    not Path("/home/jann/metin/repos/m2dev-client/scripts/sign-manifest.py").is_file(),
    reason="real sign-manifest.py not available",
)
def test_sign_produces_valid_signature(tmp_path: Path, test_keypair, sign_manifest_script: Path):
    key_path, pub_hex = test_keypair
    manifest_path = tmp_path / "manifest.json"
    _write_toy_manifest(manifest_path)

    ctx = _ctx(sign_manifest_script)
    args = argparse.Namespace(manifest=manifest_path, key=key_path, out=None)
    result = sign.run(ctx, args)

    sig_path = Path(result.data["artifacts"]["signature_path"])
    assert sig_path.is_file()
    sig = sig_path.read_bytes()
    assert len(sig) == 64

    # Verify it actually checks out against the public key.
    pub = Ed25519PublicKey.from_public_bytes(bytes.fromhex(pub_hex))
    pub.verify(sig, manifest_path.read_bytes())

    # Now corrupt the manifest; signature no longer verifies.
    manifest_path.write_bytes(b"tampered")
    with pytest.raises(InvalidSignature):
        pub.verify(sig, manifest_path.read_bytes())


def test_sign_rejects_loose_key_permissions(tmp_path: Path, sign_manifest_script: Path):
    key = tmp_path / "key"
    key.write_bytes(b"\x00" * 32)
    os.chmod(key, 0o644)
    manifest = tmp_path / "manifest.json"
    _write_toy_manifest(manifest)

    ctx = _ctx(sign_manifest_script)
    args = argparse.Namespace(manifest=manifest, key=key, out=None)
    with pytest.raises(KeyPermissionError):
        sign.run(ctx, args)


def test_sign_relative_key_path_rejected(tmp_path: Path, sign_manifest_script: Path):
    manifest = tmp_path / "manifest.json"
    _write_toy_manifest(manifest)
    ctx = _ctx(sign_manifest_script)
    args = argparse.Namespace(manifest=manifest, key=Path("relative/key"), out=None)
    with pytest.raises(ValidationError):
        sign.run(ctx, args)