"""Exercise the release gate without TI tools or hardware."""
from pathlib import Path
import shutil
import struct
import subprocess
import tempfile
import unittest

ROOT = Path(__file__).resolve().parents[2]
LIMIT = (0x3FFF - (128 + 1)) * 2


def image(size):
    header = struct.pack('<H', 0x08AA) + bytes(16) + struct.pack('<HH', 0, 0x8000)
    words = (size - 30) // 2
    return header + struct.pack('<HHH', words, 0, 0x8000) + bytes(words * 2) + bytes(2)


class FirmwareGateTest(unittest.TestCase):
    def check_image(self, data, success):
        with tempfile.TemporaryDirectory() as directory:
            source = Path(directory) / 'candidate.pending'
            output = Path(directory) / 'firmware.bin'
            source.write_bytes(data)
            result = subprocess.run([
                shutil.which('powershell') or 'pwsh', '-NoProfile', '-ExecutionPolicy', 'Bypass',
                '-File', str(ROOT / 'check_firmware.ps1'), '-Path', str(source),
                '-PublishPath', str(output),
            ], capture_output=True)
            self.assertEqual(result.returncode == 0, success, result.stderr.decode(errors='replace'))
            self.assertEqual(output.exists(), success)
            if success:
                self.assertEqual(output.read_bytes(), data)
                self.assertFalse(source.exists())
            return result.stdout + result.stderr

    def test_exact_boundary_is_accepted(self):
        self.check_image(image(LIMIT), True)

    def test_34a95bc5_size_is_rejected(self):
        diagnostic = self.check_image(image(32518), False)
        self.assertIn(b'overlaps saved parameters by 10 bytes', diagnostic)

    def test_missing_boot_terminator_is_rejected(self):
        self.check_image(image(100)[:-2], False)

    def test_partial_block_is_rejected(self):
        self.check_image(image(100)[:-10], False)

    def test_wrong_format_is_rejected(self):
        self.check_image(bytes(100), False)


if __name__ == '__main__':
    unittest.main()