#!/usr/bin/python3
import enum, socket, traceback, subprocess, curses
from curses.textpad import Textbox, rectangle

class MenuType(str, enum.Enum):
    DOC = '0'
    MENU = '1'
    QUERY = '7'
    BIN = '9'
    HTML = 'h'
    INFO = 'i'
    SOUND = 's'
    IMAGE = 'I'
    GIF = 'g'

ESC_WHITE = '\033[1;37m'
ESC_CYAN  = '\033[1;36m'
ESC_RESET = '\033[0m'
ESC_RED   = '\033[1;31m'
ESC_GREEN = '\033[1;32m'
ESC_YELLO = '\033[1;33m'
ESC_BLUE  = '\033[1;34m'

class Fetcher(object):
    def __init__(self):
        self.mode = MenuType.MENU
        self.host = 'ake.crabdance.com'
        self.port = 70
        self.path = ''

        self.history = []

    def go(self, mode=None, host=None, port=None, path=None, query=None):
        self.history.append((
            self.mode, self.host, self.port, self.path
        ))
        if mode is not None:
            self.mode = mode
        if host is not None:
            self.host = host
        if port is not None:
            self.port = int(port)
        if path is not None:
            self.path = path
        if mode == MenuType.QUERY:
            self.path += '\t{}'.format(query)

    def back(self):
        try:
            mode, host, port, path = self.history.pop()
            self.mode = mode
            self.host = host
            self.port = port
            self.path = path
        except:
            print('No entries in history')

    def fetch(self):
        try:
            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            s.connect((self.host, self.port))
            s.sendall('{}\r\n'.format(self.path).encode('utf-8'))
            resp = b''
            while True:
                chunk = s.recv(1024)
                if not chunk:
                    break
                resp += chunk
            return resp
        except:
            traceback_exc()
            print('Failed to fetch data')
            return None

class Navigator(Fetcher):
    def __init__(self):
        super().__init__()
        self.links = []
        self.buffer = []
    def goto(self, num):
        if num <= 0 or num > len(self.links):
            print('\tWrong link number')
        else:
            self.go(*self.links[num - 1])
    def render(self):
        self.buffer = []
        if self.mode == MenuType.BIN:
            print('Enter filename or leave empty to ignore')
            filename = input('Save as: ')
            if filename == '':
                return
        elif self.mode == MenuType.HTML:
            if self.path.lower().startswith('url:'):
                subprocess.call(['/usr/bin/xdg-open', self.path[4:]])
            else:
                subprocess.call(['/usr/bin/lynx', 'gopher://{}:{}/0{}'.format(self.host, self.port, self.path)])
            self.back()
            return
        
        data = self.fetch()
        if self.mode == MenuType.DOC:
            self.buffer = data.decode('utf-8').split('\n')
        elif self.mode == MenuType.BIN:
            with open(filename, 'wb') as f:
                f.write(data)
        elif self.mode == MenuType.MENU:
            self.links = []
            items = [item.split('\t') for item in data.decode('utf-8').split('\n')]
            for item in items:
                if len(item) < 4:
                    continue
                itype = item[0][0]
                itext = item[0][1:]
                if itype == MenuType.INFO:
                    self.buffer.append((None, itext))
                elif itype == MenuType.DOC:
                    self.links.append((itype, item[2], item[3], item[1]))
                    self.buffer.append((
                        len(self.links),
                        itext
                    ))
                elif itype == MenuType.MENU:
                    self.links.append((itype, item[2], item[3], item[1]))
                    self.buffer.append((
                        len(self.links),
                        itext
                    ))
                elif itype == MenuType.BIN or itype == MenuType.SOUND or itype == MenuType.IMAGE or itype == MenuType.GIF:
                    self.links.append((itype, item[2], item[3], item[1]))
                    self.buffer.append((
                        len(self.links),
                        itext
                    ))
                elif itype == MenuType.QUERY:
                    self.links.append((itype, item[2], item[3], item[1]))
                    self.buffer.append((
                        len(self.links),
                        itext
                    ))
                elif itype == MenuType.HTML:
                    self.links.append((itype, item[2], item[3], item[1]))
                    self.buffer.append((
                        len(self.links),
                        itext
                    ))
                else:
                    self.buffer.append('\tUnknown type: {}'.format(itype))
        else:
            self.buffer.append('\tNot yet implemented')

def display_help():
    print('''Omsk subway -- commandline gopher navigator
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Commands:

exit       -- exit program
help       -- view this help
back       -- return to previous menu
index      -- return to server index
@<host>    -- request server's index
<selector> -- request menu by selector on current
              server
''')

def main(stdscr):
    navi.render()
    start = 0
    link = 0
    key = None
    while True:
        stdscr.clear()
        stdscr.addstr(0, 0, 'start: {}, key: {}, url: gopher://{}:{}/{}{}'.format(start, key, navi.host, navi.port, navi.mode, navi.path))
        stdscr.refresh()
        for i in range(min(start + curses.LINES - 1, len(navi.buffer) - start)):
            if navi.mode == MenuType.MENU:
                if navi.buffer[i + start][0] == None:
                    text = '\t' + navi.buffer[i + start][1]
                elif navi.buffer[i + start][0] == link + 1:
                    text = '[*]\t' + navi.buffer[i + start][1]
                else:
                    text = '[ ]\t' + navi.buffer[i + start][1]
            else:
                text = navi.buffer[i + start]
            try:
                stdscr.addstr(i + 1, 0, text)
            except:
                pass
        stdscr.move(curses.LINES - 1, 0)
        stdscr.refresh()
        key = stdscr.getkey()
        if key == 'KEY_PPAGE':
            start = max(0, start - curses.LINES - 1)
        elif key == 'KEY_NPAGE':
            start = start + curses.LINES - 1
        elif key == '\n':
            if navi.links[link][0] == MenuType.QUERY:
                stdscr.move(curses.LINES - 1, 0)
                curses.echo()
                s = stdscr.getstr(0, 0, curses.COLS).decode('utf-8')
                navi.go(*navi.links[link], query=s)
            else:
                navi.goto(link + 1)
            link = 0
            start = 0
            navi.render()
        elif key == 'b':
            navi.back()
            link = 0
            start = 0
            navi.render()
        elif key == 'KEY_UP':
            link = (link - 1) % len(navi.links)        
        elif key == 'KEY_DOWN':
            link = (link + 1) % len(navi.links)
        elif key == 'q':
            break

if __name__ == '__main__':
    navi = Navigator()
    curses.wrapper(main)