#!/usr/bin/env python3

import os
import socket
import subprocess

class Connection():
    def __init__(self, sock):
        self.sock = sock
        self.buffer = ""

    def read_until(self, sep):
        while sep not in self.buffer:
            self.buffer += self.sock.recv(4096)
        res, self.buffer = self.buffer.split(sep, 1)
        return res

    def read_line(self):
        return self.read_until("\r\n")

    def read_request(self):
        request_line = self.read_line()
        method, path, version = request_line.split(" ", 3)

        headers = {}

        line = self.read_line()
        while len(line):
            k, v = line.split(":", 1)
            headers[k] = v.strip()
            line = self.read_line()

        # we do not read the body

        return Request(method, path, headers)


class Request():
    def __init__(self, method, path, headers):
        self.method = method
        self.path = path
        self.headers = headers

    def __str__(self):
        return "Request(method='{}' path='{}' headers='{}')".format(self.method,
                                                                    self.path,
                                                                    self.headers)


MSGS = {
    200: "OK",
    400: "Bad Request",
    401: "Unauthorized",
    403: "Forbidden",
    404: "Not Found",
    500: "Internal Server Error",
}


def respond(conn, status_code, content):
    conn.send("HTTP/1.1 {} {}\r\n".format(status_code, MSGS[status_code]), 0)
    conn.send("Content-Length: {}\r\n".format(len(content)))
    conn.send("\r\n", 0)
    conn.send(content, 0)


def respond_to(conn, req):
    content = ""
    try:
        path = os.getcwd() + req.path
        if os.path.exists(path):
            if os.access(path, os.X_OK):
                content = subprocess.check_output([path])
            else:
                with open(path, 'r') as f:
                    content = f.read()
            status_code = 200
        else:
            status_code = 404
    except Exception as e:
        content = str(e)
        status_code = 500
    respond(conn, status_code, content)


def accept(s):
    conn, addr_info = s.accept()
    connection = Connection(conn)
    req = connection.read_request()
    respond_to(conn, req)


def accept_loop(s):
    while True:
        accept(s)


def listen():
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
    s.bind(('', 8080))
    s.listen(5)

    accept_loop(s)

if __name__ == '__main__':
    listen()