"""Exercise the standalone PowerShell installer without modifying installed DSView."""
import os
from pathlib import Path
import shutil
import subprocess
import sys
import tempfile
import unittest

ROOT = Path(__file__).resolve().parents[1]
SHELL = shutil.which('powershell.exe') or shutil.which('pwsh')


@unittest.skipUnless(os.name == 'nt' and SHELL, 'Windows PowerShell required')
class InstallerTests(unittest.TestCase):
    def setUp(self):
        self.temp = tempfile.TemporaryDirectory(prefix='dsview installer ')
        self.addCleanup(self.temp.cleanup)
        self.app = Path(self.temp.name)/'DSView test'
        self.app.mkdir()
        (self.app/'DSView.exe').write_bytes(b'fixture, not executable')
        (self.app/'decoders/common').mkdir(parents=True)
        (self.app/'decoders/common/__init__.py').write_text('# existing common package\n')
        (self.app/'decoders/common/keep.txt').write_text('unrelated')

    def run_installer(self, *extra, script=None):
        return subprocess.run([SHELL, '-NoProfile', '-ExecutionPolicy', 'Bypass', '-File',
                               str(script or ROOT/'install_decoders.ps1'),
                               '-DsViewPath', str(self.app), *extra], capture_output=True, text=True)

    def test_install_import_and_update_backup(self):
        result = self.run_installer()
        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
        code = '''
import importlib, pathlib, sys, types
root = pathlib.Path(sys.argv[1])
sys.path.insert(0, str(root))
stub = types.ModuleType('sigrokdecode')
stub.Decoder = type('Decoder', (), {})
sys.modules['sigrokdecode'] = stub
for name in ('gate_driver_timing', 'transistor_pair', 'set_uart', 'set_can', 'pm35_uart'):
    module = importlib.import_module(name + '.pd')
    assert module.Decoder.api_version == 3
core = importlib.import_module('common.setgui_decoders.gate_timing')
pathlib.Path(core.__file__).resolve().relative_to(root)
assert '1SP0635' in core.PROFILES
'''
        check = subprocess.run([sys.executable, '-I', '-c', code, str(self.app/'decoders')],
                               cwd=self.app, capture_output=True, text=True)
        self.assertEqual(check.returncode, 0, check.stderr)
        target = self.app/'decoders/set_uart/pd.py'
        target.write_text('# old decoder\n')
        result = self.run_installer()
        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
        backups = list((self.app/'set-decoder-backups').glob('*/set_uart/pd.py'))
        self.assertEqual(len(backups), 1)
        self.assertEqual(backups[0].read_text(), '# old decoder\n')
        self.assertEqual(target.read_bytes(), (ROOT/'decoders/set_uart/pd.py').read_bytes())
        self.assertEqual((self.app/'decoders/common/keep.txt').read_text(), 'unrelated')
        self.assertEqual((self.app/'decoders/common/__init__.py').read_text(), '# existing common package\n')
        for name in ('gate_timing', 'transistor_pair', 'set_uart', 'set_can', 'pm35_uart'):
            self.assertEqual((self.app/('decoders/common/setgui_decoders/'+name+'.py')).read_bytes(),
                             (ROOT.parents[1]/('python/logic_analyzer/decoders/'+name+'.py')).read_bytes())

    def test_check_only_does_not_install(self):
        result = self.run_installer('-CheckOnly')
        self.assertEqual(result.returncode, 0, result.stderr)
        self.assertFalse((self.app/'decoders/set_uart').exists())
        self.assertFalse((self.app/'set-decoder-backups').exists())

    def test_copy_failure_restores_previous_decoders(self):
        old = self.app/'decoders/gate_driver_timing/pd.py'
        old.parent.mkdir()
        old.write_text('# original\n')
        runner = Path(self.temp.name)/'inject-failure.ps1'
        runner.write_text('''
param([string]$Installer, [string]$Target)
$ErrorActionPreference = 'Stop'
$global:installerTestFailed = $false
function Copy-Item {
    param([string]$LiteralPath, [string]$Destination, [switch]$Force)
    if (-not $global:installerTestFailed -and $Destination.Replace('\\', '/').EndsWith('/decoders/set_uart/pd.py')) {
        $global:installerTestFailed = $true
        throw 'Injected copy failure'
    }
    Microsoft.PowerShell.Management\\Copy-Item -LiteralPath $LiteralPath -Destination $Destination -Force:$Force
}
& $Installer -DsViewPath $Target
''', encoding='utf-8')
        result = subprocess.run([SHELL, '-NoProfile', '-ExecutionPolicy', 'Bypass', '-File',
                                 str(runner), '-Installer', str(ROOT/'install_decoders.ps1'),
                                 '-Target', str(self.app)], capture_output=True)
        self.assertNotEqual(result.returncode, 0)
        self.assertEqual(old.read_text(), '# original\n')
        self.assertFalse((old.parent/'__init__.py').exists())
        self.assertFalse((self.app/'decoders/set_uart/__init__.py').exists())
        self.assertEqual(len(list((self.app/'set-decoder-backups').glob('*/gate_driver_timing/pd.py'))), 1, result.stderr)

    def test_incomplete_target_is_untouched(self):
        (self.app/'DSView.exe').unlink()
        result = self.run_installer()
        self.assertNotEqual(result.returncode, 0)
        self.assertFalse((self.app/'decoders/set_uart').exists())

    def test_missing_source_is_detected_before_changes(self):
        source = Path(self.temp.name)/'empty-template/tools/dsview'
        source.mkdir(parents=True)
        shutil.copy2(ROOT/'install_decoders.ps1', source/'install_decoders.ps1')
        result = self.run_installer(script=source/'install_decoders.ps1')
        self.assertNotEqual(result.returncode, 0)
        self.assertFalse((self.app/'decoders/gate_driver_timing').exists())
        self.assertFalse((self.app/'set-decoder-backups').exists())


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