#!/usr/bin/env python3
"""
Linux 命令沙盒练习平台 Server
- 集成 sandbox.py 沙盒引擎
- 路由：/ → HTML 页面, /api/run → 命令执行, /api/check → 任务检查
"""

import http.server
import urllib.parse
import json
import os
import base64
import hashlib

# ==============================
# 认证配置
# ==============================
# 预置用户：{username: password_hash}
# 生成方式：hashlib.sha256(b"password").hexdigest()
USERS = {
    # 默认管理员账户
    "admin": hashlib.sha256(b"safe_linux_2026").hexdigest(),
    # 可添加更多用户
}

# Token 有效期（秒）
TOKEN_TTL = 86400  # 24 小时


def check_auth(request_body: bytes = None) -> tuple[bool, str]:
    """
    检查 Authorization 请求头
    支持: Bearer token 或 Basic auth
    """
    # 默认允许访问（未启用强制认证）
    # 启用:true 改为 True
    ENABLE_AUTH = False

    if not ENABLE_AUTH:
        return True, "admin"

    if not request_body:
        return False, "Missing Authorization header"

    # 解析请求头
    # 实际在 do_GET 中通过 headers 获取
    return True, "admin"  # 暂时 Allow-All，后续优化

# 导入沙盒模块
from sandbox import LinuxSandbox

SANDBOX = LinuxSandbox()

# ==============================
# 任务数据加载
# ==============================
TASKS_FILE = os.path.join(os.path.dirname(__file__), "COURSE_TASKS.json")


def load_tasks():
    """加载课程任务"""
    try:
        with open(TASKS_FILE, "r", encoding="utf-8") as f:
            return json.load(f)
    except Exception as e:
        print(f"Error loading tasks: {e}")
        return {"levels": []}


TASKS = load_tasks()

# ==============================
# Handler 类
# ==============================
class LinuxSandboxHandler(http.server.BaseHTTPRequestHandler):
    def send_json(self, data, status=200):
        """发送 JSON 响应"""
        self.send_response(status)
        self.send_header("Content-Type", "application/json; charset=utf-8")
        self.end_headers()
        self.wfile.write(json.dumps(data, ensure_ascii=False).encode("utf-8"))

    def send_text(self, text, status=200):
        """发送纯文本响应"""
        self.send_response(status)
        self.send_header("Content-Type", "text/plain; charset=utf-8")
        self.end_headers()
        self.wfile.write(text.encode("utf-8"))

    def do_GET(self):
        parsed = urllib.parse.urlparse(self.path)
        path = parsed.path

        # 🔐 认证检查（跳过 / 登录页 / API 登录）
        if path not in ["/", "/login.html", "/api/login", "/api/logout"]:
            # 检查 Cookie 或 Authorization
            auth_header = self.headers.get("Authorization", "")
            token = self.headers.get("X-Token", "")
            
            # 简化：如果带了有效 token 或直接 local 环境（127.0.0.1）则放行
            if not self.check_auth(auth_header, token):
                # 对公网域名强制认证
                if "xiaoxiaoluohao.indevs.in" in self.headers.get("Host", ""):
                    self.send_json({"error": "Authentication required"}, 401)
                    return

        # 1. 主页：返回 HTML 页面
        if path == "/":
            html_path = os.path.join(os.path.dirname(__file__), "index.html")
            try:
                with open(html_path, "rb") as f:
                    self.send_response(200)
                    self.send_header("Content-Type", "text/html; charset=utf-8")
                    self.end_headers()
                    self.wfile.write(f.read())
            except Exception as e:
                self.send_response(500)
                self.send_header("Content-Type", "text/plain")
                self.end_headers()
                self.wfile.write(f"Error: {e}".encode())

        # 2. 命令执行 API
        elif path == "/api/run":
            query = urllib.parse.parse_qs(parsed.query)
            cmd = query.get("cmd", [""])[0]
            if not cmd:
                self.send_json({"error": "No command provided"}, 400)
                return

            # 执行沙盒命令
            result = SANDBOX.execute(cmd)
            self.send_json(result)

        # 3. 任务检查 API
        elif path == "/api/check":
            query = urllib.parse.parse_qs(parsed.query)
            task_id = query.get("task_id", [""])[0]

            if not task_id:
                self.send_json({"error": "-task_id required"}, 400)
                return

            # 查找任务
            task = None
            for level in TASKS.get("levels", []):
                for t in level.get("challenges", []):
                    if t.get("id") == task_id:
                        task = t
                        break
                if task:
                    break

            if not task:
                self.send_json({"error": "Task not found"}, 404)
                return

            # 获取当前命令执行结果
            current_cmd = query.get("last_cmd", [""])[0]
            current_output = query.get("output", [""])[0]

            # 检查是否匹配
            success = False
            message = task.get("fail_message", "❌ 未通过测试")

            # 尝试匹配 solution
            for sol in task.get("solution", []):
                if current_cmd.strip() == sol.strip():
                    success = True
                    message = "✅ 回答正确！🎉"
                    break

            # 如果没匹配上，检查 success_test 逻辑
            if not success and "success_test" in task:
                if self.evaluate_test(task["success_test"], current_output):
                    success = True
                    message = "✅ 回答正确！🎉"

            self.send_json({
                "task_id": task_id,
                "success": success,
                "message": message,
                "hint": task.get("hint", "💡 没有提示"),
                "title": task.get("title", "未知任务"),
            })

        # 4. 获取课程总览
        elif path == "/api/tasks":
            self.send_json(TASKS)

        # 404
        else:
            self.send_response(404)
            self.send_header("Content-Type", "text/plain")
            self.end_headers()
            self.wfile.write(b"Not Found")

    def check_auth(self, auth_header: str, token: str) -> bool:
        """认证检查：支持 Bearer token / X-Token header"""
        # 本地环境直接放行
        if self.client_address[0] == "127.0.0.1":
            return True
        
        # 公网场景：验证 token
        if token:
            # 简化版：验证预置 token（生产环境应加密存储）
            valid_tokens = ["safe_linux_2026"]
            return token in valid_tokens
        
        # Bearer token 支持
        if auth_header.startswith("Bearer "):
            token = auth_header[7:]
            return token in ["safe_linux_2026"]
        
        return False

    def evaluate_test(self, test_expr: str, output: str) -> bool:
        """简单评估 success_test 表达式"""
        try:
            # 支持简单的 if/contains 语法
            # if output contains 'xxx' then pass
            if "contains" in test_expr:
                parts = test_expr.split("'")
                if len(parts) >= 3:
                    keyword = parts[1]
                    return keyword in output
            elif "==" in test_expr:
                parts = test_expr.split("==")
                if len(parts) == 2:
                    expected = parts[1].strip().strip("'")
                    return output.strip() == expected
            return False
        except Exception:
            return False

    def log_message(self, format, *args):
        pass  # Suppress logging

    # ==============================
    # Auth APIs
    # ==============================
    def do_POST(self):
        parsed = urllib.parse.urlparse(self.path)
        path = parsed.path

        # /api/login
        if path == "/api/login":
            content_length = int(self.headers.get("Content-Length", 0))
            body = self.rfile.read(content_length).decode()
            try:
                data = json.loads(body)
                username = data.get("username", "")
                password = data.get("password", "")
                
                # 简单验证
                if username in USERS:
                    pwd_hash = hashlib.sha256(password.encode()).hexdigest()
                    if pwd_hash == USERS[username]:
                        # 返回成功 token
                        self.send_json({
                            "success": True,
                            "token": "safe_linux_2026",
                            "message": "✅ 登录成功！"
                        })
                        return
                
                self.send_json({"success": False, "error": "❌ 用户名或密码错误"}, 401)
            except Exception as e:
                self.send_json({"success": False, "error": str(e)}, 400)

        # /api/logout
        elif path == "/api/logout":
            self.send_json({"success": True, "message": "👋 已退出登录"})

        else:
            self.send_response(404)
            self.end_headers()
            self.wfile.write(b"Not Found")


if __name__ == "__main__":
    PORT = 8084
    print(f"🌱 Linux Sandbox Practice Server with Auth 启动中... http://127.0.0.1:{PORT}")
    print("📚 地址: https://linux.xiaoxiaoluohao.indevs.in")
    print("🔑 Account: admin / safe_linux_2026")
    http.server.HTTPServer(("127.0.0.1", PORT), LinuxSandboxHandler).serve_forever()