# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
# for details. All rights reserved. Use of this source code is governed by a
# BSD-style license that can be found in the LICENSE file.
"""Top-level presubmit script for Dart.

See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
for more details about the presubmit API built into gcl.
"""

import imp
import os
import os.path
import scm
import subprocess
import tempfile
import platform

def is_cpp_file(path):
    return path.endswith('.cc') or path.endswith('.h')


def _CheckNnbdSdkSync(input_api, output_api):
    files = [git_file.LocalPath() for git_file in input_api.AffectedTextFiles()]
    unsynchronized_files = []
    for file in files:
        if file.startswith('sdk/'):
            nnbd_file = 'sdk_nnbd/' + file[4:]
            if not nnbd_file in files:
                unsynchronized_files.append(nnbd_file)
    if unsynchronized_files:
        return [
            output_api.PresubmitPromptWarning(
                'Changes were made to sdk/ that were not made to sdk_nnbd/\n'
                'Please update these files as well:\n'
                '\n'
                '%s' % ('\n'.join(unsynchronized_files)))
        ]
    return []


def _CheckNnbdTestSync(input_api, output_api):
    """Make sure that any forked SDK tests are kept in sync. If a CL touches
    a test, the test's counterpart (if it exists at all) should be in the CL
    too.
    """
    DIRS = ["co19", "corelib", "language", "lib", "standalone"]

    files = [git_file.LocalPath() for git_file in input_api.AffectedTextFiles()]
    unsynchronized = []
    for file in files:
        for dir in DIRS:
            legacy_dir = "tests/{}_2/".format(dir)
            nnbd_dir = "tests/{}/".format(dir)

            counterpart = None
            if file.startswith(legacy_dir):
                counterpart = file.replace(legacy_dir, nnbd_dir)
            elif file.startswith(nnbd_dir):
                counterpart = file.replace(nnbd_dir, legacy_dir)

            if counterpart:
                # Changed one file with a potential counterpart. If it exists
                # on disc, make sure it is also in the CL.
                if counterpart not in files and os.path.exists(counterpart):
                    unsynchronized.append("- {} -> {}".format(
                        file, counterpart))
                break

    # TODO(rnystrom): Currently, we only warn if a test does exist in both
    # places on disc but only one is touched by a CL. We don't warn for files
    # that only exist on one side because the migration isn't complete and the
    # CL may be migrating. Once the migration is complete, consider making
    # these checks more rigorous.

    if unsynchronized:
        return [
            output_api.PresubmitPromptWarning(
                'Make sure to keep the forked legacy and NNBD tests in sync.\n'
                'You may need to synchronize these files:\n' +
                '\n'.join(unsynchronized))
        ]

    return []


def _CheckFormat(input_api,
                 identification,
                 extension,
                 windows,
                 hasFormatErrors,
                 should_skip=lambda path: False):
    local_root = input_api.change.RepositoryRoot()
    upstream = input_api.change._upstream
    unformatted_files = []
    for git_file in input_api.AffectedTextFiles():
        if git_file.LocalPath().startswith("pkg/front_end/testcases/"):
            continue
        if should_skip(git_file.LocalPath()):
            continue
        filename = git_file.AbsoluteLocalPath()
        if filename.endswith(extension) and hasFormatErrors(filename=filename):
            old_version_has_errors = False
            try:
                path = git_file.LocalPath()
                if windows:
                    # Git expects a linux style path.
                    path = path.replace(os.sep, '/')
                old_contents = scm.GIT.Capture(['show', upstream + ':' + path],
                                               cwd=local_root,
                                               strip_out=False)
                if hasFormatErrors(contents=old_contents):
                    old_version_has_errors = True
            except subprocess.CalledProcessError as e:
                old_version_has_errors = False

            if old_version_has_errors:
                print("WARNING: %s has existing and possibly new %s issues" %
                      (git_file.LocalPath(), identification))
            else:
                unformatted_files.append(filename)

    return unformatted_files


def _CheckDartFormat(input_api, output_api):
    local_root = input_api.change.RepositoryRoot()
    upstream = input_api.change._upstream
    utils = imp.load_source('utils',
                            os.path.join(local_root, 'tools', 'utils.py'))

    prebuilt_dartfmt = os.path.join(utils.CheckedInSdkPath(), 'bin', 'dartfmt')

    windows = utils.GuessOS() == 'win32'
    if windows:
        prebuilt_dartfmt += '.bat'

    if not os.path.isfile(prebuilt_dartfmt):
        print('WARNING: dartfmt not found: %s' % (prebuilt_dartfmt))
        return []

    def HasFormatErrors(filename=None, contents=None):
        # Don't look for formatting errors in multitests. Since those are very
        # sensitive to whitespace, many cannot be formatted with dartfmt without
        # breaking them.
        if filename and filename.endswith('_test.dart'):
            with open(filename) as f:
                contents = f.read()
                if '//#' in contents:
                    return False

        args = [prebuilt_dartfmt, '--set-exit-if-changed']
        if not contents:
            args += [filename, '-n']

        process = subprocess.Popen(
            args, stdout=subprocess.PIPE, stdin=subprocess.PIPE)
        process.communicate(input=contents)

        # Check for exit code 1 explicitly to distinguish it from a syntax error
        # in the file (exit code 65). The repo contains many Dart files that are
        # known to have syntax errors for testing purposes and which can't be
        # parsed and formatted. Don't treat those as errors.
        return process.returncode == 1

    unformatted_files = _CheckFormat(input_api, "dartfmt", ".dart", windows,
                                     HasFormatErrors)

    if unformatted_files:
        lineSep = " \\\n"
        if windows:
            lineSep = " ^\n"
        return [
            output_api.PresubmitError(
                'File output does not match dartfmt.\n'
                'Fix these issues with:\n'
                '%s -w%s%s' % (prebuilt_dartfmt, lineSep,
                               lineSep.join(unformatted_files)))
        ]

    return []


def _CheckStatusFiles(input_api, output_api):
    local_root = input_api.change.RepositoryRoot()
    upstream = input_api.change._upstream
    utils = imp.load_source('utils',
                            os.path.join(local_root, 'tools', 'utils.py'))

    dart = os.path.join(utils.CheckedInSdkPath(), 'bin', 'dart')
    lint = os.path.join(local_root, 'pkg', 'status_file', 'bin', 'lint.dart')

    windows = utils.GuessOS() == 'win32'
    if windows:
        dart += '.exe'

    if not os.path.isfile(dart):
        print('WARNING: dart not found: %s' % dart)
        return []

    if not os.path.isfile(lint):
        print('WARNING: Status file linter not found: %s' % lint)
        return []

    def HasFormatErrors(filename=None, contents=None):
        args = [dart, lint] + (['-t'] if contents else [filename])
        process = subprocess.Popen(
            args, stdout=subprocess.PIPE, stdin=subprocess.PIPE)
        process.communicate(input=contents)
        return process.returncode != 0

    def should_skip(path):
        return (path.startswith("pkg/status_file/test/data/") or
                path.startswith("pkg/front_end/"))

    unformatted_files = _CheckFormat(input_api, "status file", ".status",
                                     windows, HasFormatErrors, should_skip)

    if unformatted_files:
        normalize = os.path.join(local_root, 'pkg', 'status_file', 'bin',
                                 'normalize.dart')
        lineSep = " \\\n"
        if windows:
            lineSep = " ^\n"
        return [
            output_api.PresubmitError(
                'Status files are not normalized.\n'
                'Fix these issues with:\n'
                '%s %s -w%s%s' % (dart, normalize, lineSep,
                                  lineSep.join(unformatted_files)))
        ]

    return []


def _CheckValidHostsInDEPS(input_api, output_api):
    """Checks that DEPS file deps are from allowed_hosts."""
    # Run only if DEPS file has been modified to annoy fewer bystanders.
    if all(f.LocalPath() != 'DEPS' for f in input_api.AffectedFiles()):
        return []
    # Outsource work to gclient verify
    try:
        input_api.subprocess.check_output(['gclient', 'verify'])
        return []
    except input_api.subprocess.CalledProcessError, error:
        return [
            output_api.PresubmitError(
                'DEPS file must have only dependencies from allowed hosts.',
                long_text=error.output)
        ]


def _CheckLayering(input_api, output_api):
    """Run VM layering check.

  This check validates that sources from one layer do not reference sources
  from another layer accidentally.
  """

    # Run only if .cc or .h file was modified.
    if all(not is_cpp_file(f.LocalPath()) for f in input_api.AffectedFiles()):
        return []

    local_root = input_api.change.RepositoryRoot()
    compiler_layering_check = imp.load_source(
        'compiler_layering_check',
        os.path.join(local_root, 'runtime', 'tools',
                     'compiler_layering_check.py'))
    errors = compiler_layering_check.DoCheck(local_root)
    embedder_layering_check = imp.load_source(
        'embedder_layering_check',
        os.path.join(local_root, 'runtime', 'tools',
                     'embedder_layering_check.py'))
    errors += embedder_layering_check.DoCheck(local_root)
    if errors:
        return [
            output_api.PresubmitError(
                'Layering check violation for C++ sources.',
                long_text='\n'.join(errors))
        ]

    return []


def _CheckClangTidy(input_api, output_api):
    """Run clang-tidy on VM changes."""

    # Only run clang-tidy on linux x64.
    if platform.system() != 'Linux' or platform.machine() != 'x86_64':
        return []

    # Run only for modified .cc or .h files.
    files = []
    for f in input_api.AffectedFiles():
        path = f.LocalPath()
        if is_cpp_file(path) and os.path.isfile(path): files.append(path)

    if not files:
        return []

    args = [
        'tools/sdks/dart-sdk/bin/dart',
        'runtime/tools/run_clang_tidy.dart',
    ]
    args.extend(files)
    stdout = input_api.subprocess.check_output(args).strip()
    if not stdout:
        return []

    return [
        output_api.PresubmitError(
            'The `clang-tidy` linter revealed issues:',
            long_text=stdout)
    ]


def _CommonChecks(input_api, output_api):
    results = []
    results.extend(_CheckNnbdSdkSync(input_api, output_api))
    results.extend(_CheckNnbdTestSync(input_api, output_api))
    results.extend(_CheckValidHostsInDEPS(input_api, output_api))
    results.extend(_CheckDartFormat(input_api, output_api))
    results.extend(_CheckStatusFiles(input_api, output_api))
    results.extend(_CheckLayering(input_api, output_api))
    results.extend(_CheckClangTidy(input_api, output_api))
    results.extend(
        input_api.canned_checks.CheckPatchFormatted(input_api, output_api))
    return results


def CheckChangeOnCommit(input_api, output_api):
    return _CommonChecks(input_api, output_api)


def CheckChangeOnUpload(input_api, output_api):
    return _CommonChecks(input_api, output_api)