#!/usr/bin/env python3
"""Simple server written using an event loop."""

import email.message
import os
import sys

assert sys.version >= '3.3', 'Please use Python 3.3 or higher.'

import tulip
import tulip.http


class HttpServer(tulip.http.ServerHttpProtocol):

    def handle_request(self, request_info, message):
        print('method = {!r}; path = {!r}; version = {!r}'.format(
            request_info.method, request_info.uri, request_info.version))

        path = request_info.uri

        if (not (path.isprintable() and path.startswith('/')) or '/.' in path):
            print('bad path', repr(path))
            path = None
        else:
            path = '.' + path
            if not os.path.exists(path):
                print('no file', repr(path))
                path = None
            else:
                isdir = os.path.isdir(path)

        if not path:
            raise tulip.http.HttpStatusException(404)

        headers = email.message.Message()
        for hdr, val in message.headers:
            print(hdr, val)
            headers.add_header(hdr, val)

        if isdir and not path.endswith('/'):
            path = path + '/'
            raise tulip.http.HttpStatusException(
                302, headers=(('URI', path), ('Location', path)))

        response = tulip.http.Response(self.transport, 200)
        response.add_header('Transfer-Encoding', 'chunked')

        # content encoding
        accept_encoding = headers.get('accept-encoding', '').lower()
        if 'deflate' in accept_encoding:
            response.add_header('Content-Encoding', 'deflate')
            response.add_compression_filter('deflate')
        elif 'gzip' in accept_encoding:
            response.add_header('Content-Encoding', 'gzip')
            response.add_compression_filter('gzip')

        response.add_chunking_filter(1025)

        if isdir:
            response.add_header('Content-type', 'text/html')
            response.send_headers()

            response.write(b'<ul>\r\n')
            for name in sorted(os.listdir(path)):
                if name.isprintable() and not name.startswith('.'):
                    try:
                        bname = name.encode('ascii')
                    except UnicodeError:
                        pass
                    else:
                        if os.path.isdir(os.path.join(path, name)):
                            response.write(b'<li><a href="' + bname +
                                           b'/">' + bname + b'/</a></li>\r\n')
                        else:
                            response.write(b'<li><a href="' + bname +
                                           b'">' + bname + b'</a></li>\r\n')
            response.write(b'</ul>')
        else:
            response.add_header('Content-type', 'text/plain')
            response.send_headers()

            try:
                with open(path, 'rb') as fp:
                    chunk = fp.read(8196)
                    while chunk:
                        if not response.write(chunk):
                            break
                        chunk = fp.read(8196)
            except OSError:
                response.write(b'Cannot open')

        response.write_eof()
        self.close()


def main():
    host = '127.0.0.1'
    port = 8080
    if sys.argv[1:]:
        host = sys.argv[1]
        if sys.argv[2:]:
            port = int(sys.argv[2])
        elif ':' in host:
            host, port = host.split(':', 1)
            port = int(port)
    loop = tulip.get_event_loop()
    f = loop.start_serving(lambda: HttpServer(debug=True), host, port)
    x = loop.run_until_complete(f)
    print('serving on', x.getsockname())
    loop.run_forever()


if __name__ == '__main__':
    main()