import os
import re
import shutil
import subprocess
import uuid
from contextlib import suppress
from pathlib import Path

from flask import Flask, request, jsonify

from args import ARGS_BUILDER

BASE_DIR = Path(__file__).parent
CODE_DIR = Path(BASE_DIR, 'code')
DEMO_DIR = Path(BASE_DIR, 'demo')

LANG_SUFFIX = {
    'c': '.c',
    'cpp': '.cpp',
    'java': '.java',
    'csharp': '.cs',
    'vbscript': '.vb',
    'php': '.php',
    'python': '.py',
    'ruby': '.rb',
    'golang': '.go',
    'rust': '.rs',
    'javascript': '.js',
    'typescript': '.ts',
    'lua': '.lua',
    'kotlin': '.kt'
}

app = Flask(__name__)


@app.get('/')
def index():
    """ 首页 """
    return app.send_static_file('index.html')


@app.post('/get_code_demo')
def get_demo():
    """ 获取演示代码 """
    # 获取请求参数
    lang = request.form.get('lang')
    prev_lang = request.form.get('prev_lang')
    prev_code = request.form.get('prev_code')
    # 读取示例代码
    try:
        # 读取上次选择的编程语言对应的示例代码
        with open(Path(DEMO_DIR, 'demo' + LANG_SUFFIX.get(prev_lang)), 'r', encoding='UTF-8') as f:
            code = f.read()
        # 检查示例代码是否被编辑
        # 示例代码未被编辑或被清空，则返回当前选择的编程语言对应的示例代码
        # 示例代码已被编辑且不为空，则不再返回新的示例代码，以防止覆盖用户编写的代码
        prev_code = replace_whitespace(prev_code)
        code = replace_whitespace(code)
        if not prev_code or code == prev_code:
            with open(Path(DEMO_DIR, 'demo' + LANG_SUFFIX.get(lang)), 'r', encoding='UTF-8') as f:
                code = f.read()
        else:
            code = None
    except FileNotFoundError:
        return jsonify(success=False, message='Failed', code=None)
    # 返回示例代码
    return jsonify(success=True, message='Succeeded', code=code)


@app.post('/compile')
def compile_code():
    """ 编译、执行代码，并返回执行结果 """
    # 获取请求参数
    code = request.form.get('code')
    lang = request.form.get('lang')
    stdin = (request.form.get('stdin') or '').replace('\\n', '\n')
    # 根据语言类型，构建代码编译和运行的终端命令
    args_builder = ARGS_BUILDER.get(lang)
    if args_builder is None:
        return jsonify({'success': False, 'message': '不支持该语言'})
    else:
        code_path = Path(CODE_DIR, uuid.uuid4().hex)
        try:
            compile_args, run_args, compile_filename, source_filename = args_builder(code_path, code)
        except Exception as e:
            return jsonify({'success': False, 'message': str(e)})
    # 保存源代码
    save_code(source_filename, code)
    # 编译、运行代码，并返回运行结果
    try:
        if compile_args:
            # 编译代码
            process = subprocess.Popen(compile_args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
            try:
                output, _ = process.communicate(timeout=30)
            except subprocess.TimeoutExpired:
                # 编译超时
                process.kill()
                return jsonify(success=False, message='编译超时')
            else:
                # 检查是否编译成功
                if compile_filename is not None:
                    if not (compile_filename.is_file() or Path(compile_filename.__str__() + '.exe').is_file()):
                        return jsonify(success=False, message=f'{decode(output)}')
        # 运行代码
        # TODO 代码安全性尚未考虑
        process = subprocess.Popen(run_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
        for item in stdin.split('\n'):
            # 写入标准输入
            process.stdin.write(item.encode('UTF-8') + b'\n')
        try:
            # 防止程序中的等待输入阻塞程序（也可以接收用户输入）
            output, _ = process.communicate(timeout=30)
        except subprocess.TimeoutExpired:
            # 运行超时
            process.kill()
            return jsonify(success=False, message='运行超时')
        # 返回运行结果
        return jsonify(success=True, message=f'{decode(output)}')
    except Exception as e:
        return jsonify(success=False, message=f'未知错误：{e}')
    finally:
        with suppress(FileNotFoundError):
            shutil.rmtree(code_path)


def save_code(filename, code):
    filename = Path(filename)
    os.makedirs(filename.parent)
    with open(filename, 'w', encoding='UTF-8') as f:
        f.write(code)


def decode(data: bytes):
    try:
        s = data.decode('UTF-8')
    except UnicodeDecodeError:
        s = data.decode('GBK')
    return s


def replace_whitespace(text):
    pattern = r'\s'  # 正则表达式：匹配任何空白符
    replacement = ''  # 替换为空字符串
    new_text = re.sub(pattern, replacement, text)
    return new_text


if __name__ == '__main__':
    app.run(host='0.0.0.0')