from __future__ import absolute_import
from __future__ import print_function
from flask import Flask, request, jsonify
import os
import sys
import json
from typing import Any, Dict, Mapping, Union, List
from werkzeug.exceptions import BadRequest
from six.moves.configparser import SafeConfigParser
import optparse

our_dir = os.path.dirname(os.path.abspath(__file__))

# For dev setups, we can find the API in the repo itself.
if os.path.exists(os.path.join(our_dir, '../api/zulip')):
    sys.path.insert(0, '../api')

from zulip import Client
from bots_api.run import get_lib_module
from bots_api.bot_lib import ExternalBotHandler, StateHandler

bots_config = {}  # type: Dict[str, Mapping[str, str]]
available_bots = []  # type: List[str]
bots_lib_module = {}  # type: Dict[str, Any]

def read_config_file(config_file_path):
    # type: (str) -> None
    parser = SafeConfigParser()
    parser.read(config_file_path)

    for section in parser.sections():
        bots_config[section] = {
            "email": parser.get(section, 'email'),
            "key": parser.get(section, 'key'),
            "site": parser.get(section, 'site'),
        }

def load_lib_modules():
    # type: () -> None
    for bot in available_bots:
        path = "bots/" + str(bot) + "/" + str(bot) + ".py"
        try:
            bots_lib_module[bot] = get_lib_module(path)
        except Exception:
            print("\n ERROR: Bot \"{}\" doesn't exists. Please make sure you have set up the flaskbotrc "
                  "file correctly.\n".format(bot))
            sys.exit(1)

app = Flask(__name__)

@app.route('/bots/<bot>', methods=['POST'])
def handle_bot(bot):
    # type: (str) -> Union[str, BadRequest]
    if bot not in available_bots:
        return BadRequest("requested bot service {} not supported".format(bot))

    client = Client(email=bots_config[bot]["email"],
                    api_key=bots_config[bot]["key"],
                    site=bots_config[bot]["site"])
    try:
        restricted_client = ExternalBotHandler(client)
    except SystemExit:
        return BadRequest("Cannot fetch user profile for bot {}, make sure you have set up the flaskbotrc "
                          "file correctly.".format(bot))
    message_handler = bots_lib_module[bot].handler_class()

    # TODO: Handle stateful bots properly.
    state_handler = StateHandler()

    event = json.loads(request.data)
    message_handler.handle_message(message=event["message"],
                                   client=restricted_client,
                                   state_handler=state_handler)
    return "Success!"

if __name__ == "__main__":
    usage = '''
                zulip-bot-server --config-file <path to flaskbotrc> --hostname <address> --port <port>
                Example: zulip-bot-server --config-file ~/flaskbotrc
                (This program loads the bot configurations from the
                config file (flaskbotrc here) and loads the bot modules.
                It then starts the server and fetches the requests to the
                above loaded modules and returns the success/failure result)
                Please make sure you have a current flaskbotrc file with the
                configurations of the required bots.
                Hostname and Port are optional arguments. Default hostname is
                127.0.0.1 and default port is 5002.
                See lib/readme.md for more context.
                '''

    parser = optparse.OptionParser(usage=usage)
    parser.add_option('--config-file',
                      action='store',
                      help='(config file for the zulip bot server (flaskbotrc))')
    parser.add_option('--hostname',
                      action='store',
                      default="127.0.0.1",
                      help='(address on which you want to run the server)')
    parser.add_option('--port',
                      action='store',
                      default=5002,
                      help='(port on which you want to run the server)')
    (options, args) = parser.parse_args()
    if not options.config_file:  # if flaskbotrc is not given
        parser.error('Flaskbotrc not given')

    read_config_file(options.config_file)
    available_bots = list(bots_config.keys())
    load_lib_modules()

    app.run(host=options.hostname, port=options.port, debug=True)