# encoding=utf-8
# Copyright © 2018 Intel Corporation

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# all copies or substantial portions of the Software.

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"""Run glcpp tests with various line endings."""

import argparse
import difflib
import errno
import io
import os
import subprocess
import sys

# The meson version handles windows paths better, but if it's not available
# fall back to shlex
try:
    from meson.mesonlib import split_args
except ImportError:
    from shlex import split as split_args


def arg_parser():
    parser = argparse.ArgumentParser()
    parser.add_argument('glcpp', help='Path to the he glcpp binary.')
    parser.add_argument('testdir', help='Path to tests and expected output.')
    parser.add_argument('--unix', action='store_true', help='Run tests for Unix style newlines')
    parser.add_argument('--windows', action='store_true', help='Run tests for Windows/Dos style newlines')
    parser.add_argument('--oldmac', action='store_true', help='Run tests for Old Mac (pre-OSX) style newlines')
    parser.add_argument('--bizarro', action='store_true', help='Run tests for Bizarro world style newlines')
    return parser.parse_args()


def parse_test_file(contents, nl_format):
    """Check for any special arguments and return them as a list."""
    # Disable "universal newlines" mode; we can't directly use `nl_format` as
    # the `newline` argument, because the "bizarro" test uses something Python
    # considers invalid.
    for l in contents.decode('utf-8').split(nl_format):
            if 'glcpp-args:' in l:
                return l.split('glcpp-args:')[1].strip().split()
    return []


def test_output(glcpp, contents, expfile, nl_format='\n'):
    """Test that the output of glcpp is what we expect."""
    extra_args = parse_test_file(contents, nl_format)

    proc = subprocess.Popen(
        glcpp + extra_args,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        stdin=subprocess.PIPE)
    actual, _ = proc.communicate(contents)
    actual = actual.decode('utf-8')

    if proc.returncode == 255:
        print("Test returned general error, possibly missing linker")
        sys.exit(77)

    with open(expfile, 'rb') as f:
        expected = f.read().decode('utf-8')

    # Bison 3.6 changed '$end' to 'end of file' in its error messages
    # See: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3181
    actual = actual.replace('$end', 'end of file')

    if actual == expected:
        return (True, [])
    return (False, difflib.unified_diff(actual.splitlines(), expected.splitlines()))


def test_unix(args):
    """Test files with unix style (\n) new lines."""
    total = 0
    passed = 0

    print('============= Testing for Correctness (Unix) =============')
    for filename in os.listdir(args.testdir):
        if not filename.endswith('.c'):
            continue

        print(   '{}:'.format(os.path.splitext(filename)[0]), end=' ')
        total += 1

        testfile = os.path.join(args.testdir, filename)
        with open(testfile, 'rb') as f:
            contents = f.read()
        valid, diff = test_output(args.glcpp, contents, testfile + '.expected')
        if valid:
            passed += 1
            print('PASS')
        else:
            print('FAIL')
            for l in diff:
                print(l, file=sys.stderr)

    if not total:
        raise Exception('Could not find any tests.')

    print('{}/{}'.format(passed, total), 'tests returned correct results')
    return total == passed


def _replace_test(args, replace):
    """Test files with non-unix style line endings. Print your own header."""
    total = 0
    passed = 0

    for filename in os.listdir(args.testdir):
        if not filename.endswith('.c'):
            continue

        print(   '{}:'.format(os.path.splitext(filename)[0]), end=' ')
        total += 1
        testfile = os.path.join(args.testdir, filename)

        with open(testfile, 'rt') as f:
            contents = f.read()
        contents = contents.replace('\n', replace).encode('utf-8')
        valid, diff = test_output(
            args.glcpp, contents, testfile + '.expected', nl_format=replace)

        if valid:
            passed += 1
            print('PASS')
        else:
            print('FAIL')
            for l in diff:
                print(l, file=sys.stderr)

    if not total:
        raise Exception('Could not find any tests.')

    print('{}/{}'.format(passed, total), 'tests returned correct results')
    return total == passed


def test_windows(args):
    """Test files with windows/dos style (\r\n) new lines."""
    print('============= Testing for Correctness (Windows) =============')
    return _replace_test(args, '\r\n')


def test_oldmac(args):
    """Test files with Old Mac style (\r) new lines."""
    print('============= Testing for Correctness (Old Mac) =============')
    return _replace_test(args, '\r')


def test_bizarro(args):
    """Test files with Bizarro world style (\n\r) new lines."""
    # This is allowed by the spec, but why?
    print('============= Testing for Correctness (Bizarro) =============')
    return _replace_test(args, '\n\r')


def main():
    args = arg_parser()

    wrapper = os.environ.get('MESON_EXE_WRAPPER')
    if wrapper is not None:
        args.glcpp = split_args(wrapper) + [args.glcpp]
    else:
        args.glcpp = [args.glcpp]

    success = True
    try:
        if args.unix:
            success = success and test_unix(args)
        if args.windows:
            success = success and test_windows(args)
        if args.oldmac:
            success = success and test_oldmac(args)
        if args.bizarro:
            success = success and test_bizarro(args)
    except OSError as e:
        if e.errno == errno.ENOEXEC:
            print('Skipping due to inability to run host binaries.',
                  file=sys.stderr)
            sys.exit(77)
        raise

    exit(0 if success else 1)


if __name__ == '__main__':
    main()