# server/test_ota_endpoint.py
import base64
import hashlib
import json
from pathlib import Path

import pytest

from server.ota_endpoint import ota_check_impl, ota_firmware_impl


def write_firmware(firmware_dir: Path, version: str, data: bytes = b"fake_fw") -> None:
    sig = bytes(64)  # zero sig (not validated server-side)
    manifest = {
        "version": version,
        "size": len(data),
        "sha256": hashlib.sha256(data).hexdigest(),
    }
    (firmware_dir / "current.bin").write_bytes(data)
    (firmware_dir / "current.sig").write_bytes(sig)
    (firmware_dir / "manifest.json").write_text(json.dumps(manifest))


@pytest.fixture(autouse=True)
def patch_firmware_dir(tmp_path, monkeypatch):
    import server.ota_endpoint as mod
    monkeypatch.setattr(mod, "FIRMWARE_DIR", tmp_path)
    yield tmp_path


def test_check_no_update_same_version(tmp_path):
    write_firmware(tmp_path, "1.0.0")
    result = ota_check_impl(current_version="1.0.0", firmware_dir=tmp_path)
    assert result["update"] is False


def test_check_no_update_newer_local(tmp_path):
    write_firmware(tmp_path, "1.0.0")
    result = ota_check_impl(current_version="1.1.0", firmware_dir=tmp_path)
    assert result["update"] is False


def test_check_update_available(tmp_path):
    write_firmware(tmp_path, "1.1.0", data=b"new firmware")
    result = ota_check_impl(current_version="1.0.0", firmware_dir=tmp_path)
    assert result["update"] is True
    assert result["version"] == "1.1.0"
    assert result["size"] == len(b"new firmware")
    assert "sha256" in result
    assert "sig_b64" in result
    sig_bytes = base64.b64decode(result["sig_b64"])
    assert len(sig_bytes) == 64


def test_check_no_manifest(tmp_path):
    result = ota_check_impl(current_version="1.0.0", firmware_dir=tmp_path)
    assert result["update"] is False


def test_firmware_endpoint_returns_binary(tmp_path):
    fw_data = b"firmware binary content"
    write_firmware(tmp_path, "1.1.0", data=fw_data)
    content = ota_firmware_impl(firmware_dir=tmp_path)
    assert content == fw_data


def test_firmware_endpoint_missing_raises(tmp_path):
    import server.ota_endpoint as mod
    with pytest.raises(mod.FirmwareNotFoundError):
        ota_firmware_impl(firmware_dir=tmp_path)


def test_check_malformed_manifest(tmp_path):
    (tmp_path / "manifest.json").write_text("not valid json{{{")
    result = ota_check_impl(current_version="1.0.0", firmware_dir=tmp_path)
    assert result["update"] is False


def test_check_wrong_arity_version_no_update(tmp_path):
    write_firmware(tmp_path, "1.2")  # wrong arity server version
    result = ota_check_impl(current_version="1.0.0", firmware_dir=tmp_path)
    # server "1.2" → (0,0,0) ≤ client (1,0,0) → no update
    assert result["update"] is False