#!/usr/bin/env python3

# Copyright (C) 2023 Igalia S.L.
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import argparse
import json
import os
import re

parser = argparse.ArgumentParser(
    description='This tool takes the compile_commands.json output by CMake and expands any UnifiedSources in it to regular sources.'
)
parser.add_argument('input_file')
parser.add_argument('output_file')
parser.add_argument('source_dir')
parser.add_argument('build_dir')

args = parser.parse_args()
source_dir = args.source_dir
build_dir = args.build_dir

generated_compile_commands = []

with open(args.input_file) as f:
    compile_commands = json.load(f)

for entry in compile_commands:
    entry_file = entry['file']
    if not 'UnifiedSource' in entry_file:
        generated_compile_commands.append(entry)
        continue

    # The paths we expect are in the style of:
    # - WebKit/WebKitBuild/Release/DerivedSources/WebKit/unified-sources/UnifiedSource-54928a2b-29.cpp
    # - WebKit/WebKitBuild/Release/WebCore/DerivedSources/unified-sources/UnifiedSource-42f7b70e-5.cpp
    # And Windows too:
    # - WebKit\WebKitBuild\Release\WebCore\DerivedSources\unified-sources\UnifiedSource-42f7b70e-5.cpp
    # So we extract the parent folders to map them to the source folders.
    parent_dir_1, parent_dir_2 = entry_file.rsplit(os.path.sep, maxsplit=4)[1:3]
    search_directories = [
        os.path.join(build_dir, parent_dir_1, parent_dir_2),
    ]

    if parent_dir_1 == 'DerivedSources':
        search_directories.append(os.path.join(source_dir, 'Source', parent_dir_2))
    else:
        search_directories.append(os.path.join(source_dir, 'Source', parent_dir_1))

    with open(entry_file) as f:
        for line in f.readlines():
            include_path = line[10:-2]  # Extract header from `#include "HEADER"\n`
            for d in search_directories:
                include_file = os.path.join(d, include_path)

                if os.path.exists(include_file):
                    generated_compile_commands.append({
                        "directory": entry["directory"],
                        "command": entry["command"].replace(entry_file, include_file),
                        "file": include_file,
                    })
                    break

output_directory = os.path.dirname(args.output_file)
if not os.path.isdir(output_directory):
    os.makedirs(output_directory)

with open(args.output_file, 'w') as f:
    json.dump(generated_compile_commands, f, indent=2)