#!/usr/bin/env python3

import json
import os

import asana
from asana.session import AsanaOAuth2Session
import urwid

import secrets
from ui.auth import AuthPrompt
from ui.constants import palette
from ui.ui import Ui, loading

from asana_service import AsanaService

class NotAuthedException(Exception):
    def __init__(self):
        super(NotAuthedException, self)

class CmdAsana(object):
    loop = None
    nav_stack = []

    """Try to get an Asana client using stored tokens

    Raises:
        NotAuthedException: the user has not authorized the app
    """
    def get_client(self):
        try:
            f = open('.oauth', 'r')
            auth_json = f.read()
            f.close()
            token = json.loads(auth_json)
            self.client = asana.Client.oauth(
                client_id=secrets.CLIENT_ID,
                client_secret=secrets.CLIENT_SECRET,
                token=token,
                token_updater=self.save_token,
                auto_refresh_url=AsanaOAuth2Session.token_url,
                auto_refresh_kwargs={
                    'client_id': secrets.CLIENT_ID,
                    'client_secret': secrets.CLIENT_SECRET
                }
            )
        except IOError:
            raise NotAuthedException()

    def authorize(self):
        self.client = asana.Client.oauth(
            client_id=secrets.CLIENT_ID,
            client_secret=secrets.CLIENT_SECRET,
            redirect_uri='urn:ietf:wg:oauth:2.0:oob',
            token_updater=self.save_token,
            auto_refresh_url=AsanaOAuth2Session.token_url,
            auto_refresh_kwargs={
                'client_id': secrets.CLIENT_ID,
                'client_secret': secrets.CLIENT_SECRET
            }
        )
        (url, _) = self.client.session.authorization_url()
        auth = AuthPrompt(url, self.auth_callback)

        try:
            import webbrowser
            webbrowser.open(url)
        except Exception:
            pass

        self.loop = urwid.MainLoop(
            auth.component(),
            unhandled_input=self.exit_handler,
            palette=palette
        )
        self.loop.run()

    def auth_callback(self, code):
        self.save_token(
            self.client.session.fetch_token(code=code))
        raise urwid.ExitMainLoop()


    def exit_handler(self, key):
        if key in ('q', 'Q', 'esc'):
            raise urwid.ExitMainLoop()
        if key == 'backspace':
            self.ui.go_back()

    def get_asana_service(self):
        self.asana_service = AsanaService(self.client)

    def get_ui(self):
        self.ui = Ui(self.asana_service, self.update)

    def run(self):
        self.placeholder = urwid.WidgetPlaceholder(loading())
        self.loop = urwid.MainLoop(
            self.placeholder,
            unhandled_input=self.exit_handler,
            palette=palette
        )
        self.ui.my_tasks()

    def update(self, widget):
        self.loop.widget.original_widget = widget
        try:
            self.loop.draw_screen()
        except Exception:
            self.loop.run()

    def save_token(self, token):
        f = open('.oauth', 'w')
        f.write(json.dumps(token))
        f.close()
        os.chmod('.oauth', 0o600)

def main():
    cmd_asana = CmdAsana()
    try:
        cmd_asana.get_client()
    except NotAuthedException:
        cmd_asana.authorize()

    cmd_asana.get_asana_service()
    cmd_asana.get_ui()

    cmd_asana.run()

if __name__ == "__main__":
    main()