"""
web server
"""
from socket import *
from select import *


class Handle():
    def __init__(self, ep, map, html):
        self.html = html  # 存储网页路径
        self._ep = ep
        self.map = map

    def close(self, fd):
        self._ep.unregister(fd)  # 不再关注
        self.map[fd].close()
        del self.map[fd]  # 维护字典

    # 处理数据收发
    def handle(self, fd):
        # 浏览器的http请求
        request = self.map[fd].recv(1024).decode()
        if not request:
            self.close(fd)
            return
        info = request.split(' ')[1]
        print("请求内容：", info)
        self._send_html(fd, info)
        self.close(fd)  # 每个内容访问后主动断开

    def _response(self, status, content: bytes):
        response = "HTTP/1.1 %s\r\n" % status
        response += "Content-Type:text/html\r\n"
        response += "\r\n"
        response = response.encode() + content
        return response

    # 组织响应并发送
    def _send_html(self, fd, info):
        if info == '/':
            # 主页比较特殊 --》 index.html
            filename = self.html + "/index.html"
        else:
            filename = self.html + info
        try:
            fr = open(filename, 'rb')
        except:
            with open(self.html + "/404.html", 'rb') as fr:
                data = fr.read()
            response = self._response("404 Not Found", data)
        else:
            response = self._response("200 OK", fr.read())
        finally:
            # 发送响应
            self.map[fd].send(response)


# 搭建网络结构
class WebServer:
    def __init__(self, host='', port=0, html=None):
        self.host = host
        self.port = port
        self.address = (host, port)
        self.html = html  # 网页位置
        self._ep = epoll()
        self.map = {}  # 存储文件描述符和对象的对应关系
        self.sock = self._create_socket()
        self._handle = Handle(self._ep, self.map, html)

    def _create_socket(self):
        sock = socket()
        sock.bind(self.address)
        sock.setblocking(False)  # 非阻塞
        return sock

    # 处理客户端连接
    def _connect(self, fd):
        # 监听套接字对象就绪 ：连接客户端
        conn, addr = self.map[fd].accept()
        conn.setblocking(False)
        # 关注conn读
        self._ep.register(conn, EPOLLIN)
        self.map[conn.fileno()] = conn  # 维护字典

    # 主体服务
    def serve_forever(self):
        self.sock.listen(5)
        self._ep.register(self.sock, EPOLLIN)
        self.map[self.sock.fileno()] = self.sock
        print("Listen the port %d" % self.port)
        # 循环监控IO对象的发生
        while True:
            events = self._ep.poll()  # [(fileno,event),()]
            for fd, event in events:
                if fd == self.sock.fileno():
                    self._connect(fd)
                else:
                    try:
                        self._handle.handle(fd)
                    except:
                        pass


if __name__ == '__main__':
    httpd = WebServer(host="0.0.0.0", port=8000, html="./static")
    httpd.serve_forever()  # 允许浏览器连接