import sys
import socket

PORT = 1900


class Session:
    def __init__(self):
        self.history = [Page('home')]
        self.current_page = 0

    def back(self):
        if self.current_page > 0:
            self.current_page -= 1
        self.render()

    def forward(self):
        if self.current_page < len(self.history) - 1:
            self.current_page += 1
        self.render()

    def load(self, url):
        self.current_page += 1
        if self.current_page >= len(self.history):
            self.history.append(Page(url))
        else:
            self.history[self.current_page] = Page(url)
        self.history[self.current_page].request()

    def render(self):
        print(self.history[self.current_page].content)


class Page:
    def __init__(self, url):
        self.url = url
        self.host, self.selector = parse_url(url)
        self.content = ''

    def request(self):
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
            sock.connect((self.host, PORT))
            selector = self.selector + '\r\n'
            sock.sendall(selector.encode('ascii'))
            buf = bytearray()
            while True:
                data = sock.recv(4096)
                if len(data) == 0:
                    break
                buf.extend(data)
            self.content = buf.decode('ascii')


def parse_url(url: str) -> (str, str):
    clean_url = url.replace('nex://', '')
    split_url = clean_url.split('/', 1)
    if len(split_url) == 1:
        return clean_url, ''
    return split_url[0], split_url[1]


if __name__ == '__main__':
    session = Session()
    while True:
        url = input('Enter a URL')
        session.load(url)
        session.render()
        command = input('Go [b]ack or [f]orward')
        if command == 'b':
            session.back()
        elif command == 'f':
            session.forward()