import json
import sys

def load_b_file(filepath):
    """读取文件 B，并返回以 id 为 key 的字典"""
    b_data = {}
    with open(filepath, 'r', encoding='utf-8') as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            try:
                data = json.loads(line)
                # 只保留需要更新的字段
                if 'id' in data and 'answer_detail' in data:
                    b_data[data['id']] = data['answer_detail']
                else:
                    print(f"警告：文件 B 中缺少必要字段: {line}")
            except json.JSONDecodeError as e:
                print(f"解析失败（文件 B）：{e} -> {line[:50]}...")
    return b_data

def update_a_file(a_filepath, b_dict, output_filepath):
    """读取文件 A，根据 b_dict 替换 answer_detail，并写入输出文件"""
    with open(a_filepath, 'r', encoding='utf-8') as fin, \
         open(output_filepath, 'w', encoding='utf-8') as fout:

        for line_num, line in enumerate(fin, start=1):
            line = line.strip()
            if not line:
                continue
            try:
                data = json.loads(line)
                record_id = data.get('id')

                # 如果在 B 中有对应 id，则替换 answer_detail
                if record_id in b_dict:
                    data['answer_detail'] = b_dict[record_id]

                # 写回文件
                fout.write(json.dumps(data, ensure_ascii=False) + '\n')

            except json.JSONDecodeError as e:
                print(f"第 {line_num} 行解析失败：{e} -> {line[:50]}...")

def main():
    if len(sys.argv) != 4:
        print("用法: python replace_answer_detail.py <文件A路径> <文件B路径> <输出文件路径>")
        sys.exit(1)

    a_file = sys.argv[1]
    b_file = sys.argv[2]
    output_file = sys.argv[3]

    print("正在加载文件 B ...")
    b_dict = load_b_file(b_file)

    print(f"共加载 {len(b_dict)} 条记录。开始处理文件 A ...")
    update_a_file(a_file, b_dict, output_file)

    print("处理完成！结果已保存到:", output_file)

if __name__ == '__main__':
    main()