# Copyright 2015 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Runs the Microsoft Message Compiler (mc.exe).
#
# Usage: message_compiler.py <environment_file> [<args to mc.exe>*]


import difflib
import filecmp
import os
import re
import shutil
import subprocess
import sys
import tempfile


def main():
    env_file, rest = sys.argv[1], sys.argv[2:]

    # Parse some argument flags.
    header_dir = None
    resource_dir = None
    input_file = None
    for i, arg in enumerate(rest):
        if arg == '-h' and len(rest) > i + 1:
            assert header_dir == None
            header_dir = rest[i + 1]
        elif arg == '-r' and len(rest) > i + 1:
            assert resource_dir == None
            resource_dir = rest[i + 1]
        elif arg.endswith('.mc') or arg.endswith('.man'):
            assert input_file == None
            input_file = arg

    # Copy checked-in outputs to final location.
    THIS_DIR = os.path.abspath(os.path.dirname(__file__))
    assert header_dir == resource_dir
    source = os.path.join(
        THIS_DIR,
        "..",
        "..",
        "third_party",
        "win_build_output",
        re.sub(r'^(?:[^/]+/)?gen/', 'mc/', header_dir),
    )
    # Set copy_function to shutil.copy to update the timestamp on the destination.
    shutil.copytree(
        source, header_dir, copy_function=shutil.copy, dirs_exist_ok=True
    )

    # On non-Windows, that's all we can do.
    if sys.platform != 'win32':
        return

    # On Windows, run mc.exe on the input and check that its outputs are
    # identical to the checked-in outputs.

    # Read the environment block from the file. This is stored in the format used
    # by CreateProcess. Drop last 2 NULs, one for list terminator, one for
    # trailing vs. separator.
    env_pairs = open(env_file).read()[:-2].split('\0')
    env_dict = dict([item.split('=', 1) for item in env_pairs])

    extension = os.path.splitext(input_file)[1]
    if extension in ['.man', '.mc']:
        # For .man files, mc's output changed significantly from Version 10.0.15063
        # to Version 10.0.16299.  We should always have the output of the current
        # default SDK checked in and compare to that. Early out if a different SDK
        # is active. This also happens with .mc files.
        # TODO(thakis): Check in new baselines and compare to 16299 instead once
        # we use the 2017 Fall Creator's Update by default.
        mc_help = subprocess.check_output(
            ['mc.exe', '/?'], env=env_dict, stderr=subprocess.STDOUT, shell=True
        )
        version = re.search(
            rb'Message Compiler\s+Version (\S+)', mc_help
        ).group(1)
        if version != b'10.0.22621':
            return

    # mc writes to stderr, so this explicitly redirects to stdout and eats it.
    try:
        tmp_dir = tempfile.mkdtemp()
        delete_tmp_dir = True
        if header_dir:
            rest[rest.index('-h') + 1] = tmp_dir
            header_dir = tmp_dir
        if resource_dir:
            rest[rest.index('-r') + 1] = tmp_dir
            resource_dir = tmp_dir

        # This needs shell=True to search the path in env_dict for the mc
        # executable.
        subprocess.check_output(
            ['mc.exe'] + rest,
            env=env_dict,
            stderr=subprocess.STDOUT,
            shell=True,
        )
        # We require all source code (in particular, the header generated here) to
        # be UTF-8. jinja can output the intermediate .mc file in UTF-8 or UTF-16LE.
        # However, mc.exe only supports Unicode via the -u flag, and it assumes when
        # that is specified that the input is UTF-16LE (and errors out on UTF-8
        # files, assuming they're ANSI). Even with -u specified and UTF16-LE input,
        # it generates an ANSI header, and includes broken versions of the message
        # text in the comment before the value. To work around this, for any invalid
        # // comment lines, we simply drop the line in the header after building it.
        # Also, mc.exe apparently doesn't always write #define lines in
        # deterministic order, so manually sort each block of #defines.
        if header_dir:
            header_file = os.path.join(
                header_dir,
                os.path.splitext(os.path.basename(input_file))[0] + '.h',
            )
            header_contents = []
            with open(header_file, 'rb') as f:
                define_block = []  # The current contiguous block of #defines.
                for line in f.readlines():
                    if line.startswith(b'//') and b'?' in line:
                        continue
                    if line.startswith(b'#define '):
                        define_block.append(line)
                        continue
                    # On the first non-#define line, emit the sorted preceding #define
                    # block.
                    header_contents += sorted(
                        define_block, key=lambda s: s.split()[-1]
                    )
                    define_block = []
                    header_contents.append(line)
                # If the .h file ends with a #define block, flush the final block.
                header_contents += sorted(
                    define_block, key=lambda s: s.split()[-1]
                )
            with open(header_file, 'wb') as f:
                f.write(b''.join(header_contents))

        # mc.exe invocation and post-processing are complete, now compare the output
        # in tmp_dir to the checked-in outputs.
        diff = filecmp.dircmp(tmp_dir, source)
        if diff.diff_files or set(diff.left_list) != set(diff.right_list):
            print(
                'mc.exe output different from files in %s, see %s'
                % (source, tmp_dir)
            )
            diff.report()
            for f in diff.diff_files:
                if f.endswith('.bin'):
                    continue
                fromfile = os.path.join(source, f)
                tofile = os.path.join(tmp_dir, f)
                print(
                    ''.join(
                        difflib.unified_diff(
                            open(fromfile).readlines(),
                            open(tofile).readlines(),
                            fromfile,
                            tofile,
                        )
                    )
                )
            delete_tmp_dir = False
            sys.exit(1)
    except subprocess.CalledProcessError as e:
        print(e.output)
        sys.exit(e.returncode)
    finally:
        if os.path.exists(tmp_dir) and delete_tmp_dir:
            shutil.rmtree(tmp_dir)


if __name__ == '__main__':
    main()