#!/usr/bin/env python3
import json
import subprocess
import os


def is_source_file(filepath):
    return filepath.endswith('.c') or filepath.endswith('.h') or filepath.endswith('.S')

dir_stack = []
rootdir = os.getcwd()

compile_db = []

make_output = subprocess.check_output(['make', '-nw']).decode('utf-8')

make_output_lines = make_output.split('\n')

for line in make_output_lines:
    line_parts = line.split(' ')
    new_line_parts = []

    if len(line_parts) >= 2 and 'Entering directory' in line:
        new_dir = line[line.find('`') + 1:-1]
        dir_stack.append(new_dir)
        continue

    if len(line_parts) >= 2 and 'Leaving directory' in line:
        dir_stack.pop()
        continue;

    if 'gcc' not in line_parts[0]:
        continue

    src_file = ''
    for part in line_parts:
        part = part.strip()
        if is_source_file(part):
            src_file = part
            part = os.path.join(dir_stack[-1], part)

        new_line_parts.append(part)

    if len(src_file) == 0:
        continue

    db_entry = {
            'directory': dir_stack[-1],
            'command': ' '.join(new_line_parts).strip(),
            'file': os.path.join(dir_stack[-1], src_file)
    }

    compile_db.append(db_entry)

os.system('make')

out_file = open('build/compile_commands.json', 'w')
json.dump(compile_db, out_file, indent=4)