import bodyParser from 'body-parser';
import express from 'express';
import fetch from 'isomorphic-fetch';
import moment from 'moment';
import * as uuidv4 from 'uuid';

import { IActivity, IBotData, IConversation, IConversationUpdateActivity, IMessageActivity } from './types';

const expiresIn = 1800;
const conversationsCleanupInterval = 10000;
const conversations: { [key: string]: IConversation } = {};
const botDataStore: { [key: string]: IBotData } = {};

export const getRouter = (serviceUrl: string, botUrl: string, conversationInitRequired = true, botId): express.Router => {
    const router = express.Router();

    router.use(bodyParser.json()); // for parsing application/json
    router.use(bodyParser.urlencoded({ extended: true })); // for parsing application/x-www-form-urlencoded
    router.use((req, res, next) => {
        res.header('Access-Control-Allow-Origin', '*');
        res.header('Access-Control-Allow-Methods', 'GET, PUT, POST, DELETE, PATCH, OPTIONS');
        res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization, x-ms-bot-agent');
        next();
    });

    // CLIENT ENDPOINT
    router.options(`/directline/${botId}/`, (req, res) => {
        res.status(200).end();
    });

    // Creates a conversation
    const reqs =  (req, res) => {
        
        const conversationId: string = uuidv4.v4().toString();
        conversations[conversationId] = {
            conversationId,
            history: [],
        };
        console.log('Created conversation with conversationId: ' + conversationId);

        const activity = createConversationUpdateActivity(serviceUrl, conversationId);
        fetch(botUrl, {
            method: 'POST',
            body: JSON.stringify(activity),
            headers: {
                'Content-Type': 'application/json',
            },
        }).then((response) => {
            res.status(response.status).send({
                conversationId,
                expiresIn,
            });
        });
    };

    router.post('/v3/directline/conversations',reqs );
    router.post(`/directline/${botId}/conversations`,reqs );

    // Reconnect API
    router.get('/v3/directline/conversations/:conversationId', (req, res) => { 
        const conversation = getConversation(req.params.conversationId, conversationInitRequired);
        if (conversation) {
            res.status(200).send(conversation);
        } else {
            // Conversation was never initialized
            res.status(400).send();
        }
        
        console.warn('/v3/directline/conversations/:conversationId not implemented'); 
    });

    // Gets activities from store (local history array for now)
    router.get(`/directline/${botId}/conversations/:conversationId/activities`, (req, res) => {
        const watermark = req.query.watermark && req.query.watermark !== 'null' ? Number(req.query.watermark) : 0;

        const conversation = getConversation(req.params.conversationId, conversationInitRequired);

        if (conversation) {
            // If the bot has pushed anything into the history array
            if (conversation.history.length > watermark) {
                const activities = conversation.history.slice(watermark);
                res.status(200).json({
                    activities,
                    watermark: watermark + activities.length,
                });
            } else {
                res.status(200).send({
                    activities: [],
                    watermark,
                });
            }
        } else {
            // Conversation was never initialized
            res.status(400).send();
        }
    });

    // Sends message to bot. Assumes message activities
    router.post(`/directline/${botId}/conversations/:conversationId/activities`, (req, res) => {
        const incomingActivity = req.body;
        // Make copy of activity. Add required fields
        const activity = createMessageActivity(incomingActivity, serviceUrl, req.params.conversationId);

        const conversation = getConversation(req.params.conversationId, conversationInitRequired);

        if (conversation) {
            conversation.history.push(activity);
            fetch(botUrl, {
                method: 'POST',
                body: JSON.stringify(activity),
                headers: {
                    'Content-Type': 'application/json',
                },
            }).then((response) => {
                res.status(response.status).json({ id: activity.id });
            });
        } else {
            // Conversation was never initialized
            res.status(400).send();
        }
    });

    router.post('/v3/directline/conversations/:conversationId/upload', (req, res) => { console.warn('/v3/directline/conversations/:conversationId/upload not implemented'); });
    router.get('/v3/directline/conversations/:conversationId/stream', (req, res) => { console.warn('/v3/directline/conversations/:conversationId/stream not implemented'); });

    // BOT CONVERSATION ENDPOINT

    router.post('/v3/conversations', (req, res) => { console.warn('/v3/conversations not implemented'); });

    router.post('/v3/conversations/:conversationId/activities', (req, res) => {
        let activity: IActivity;

        activity = req.body;
        activity.id = uuidv4.v4();
        activity.from = { id: 'id', name: 'Bot' };

        const conversation = getConversation(req.params.conversationId, conversationInitRequired);
        if (conversation) {
            conversation.history.push(activity);
            res.status(200).send();
        } else {
            // Conversation was never initialized
            res.status(400).send();
        }
    });

    router.post('/v3/conversations/:conversationId/activities/:activityId', (req, res) => {
        let activity: IActivity;

        activity = req.body;
        activity.id = uuidv4.v4();
        activity.from = { id: 'id', name: 'Bot' };

        const conversation = getConversation(req.params.conversationId, conversationInitRequired);
        if (conversation) {
            conversation.history.push(activity);
            res.status(200).send();
        } else {
            // Conversation was never initialized
            res.status(400).send();
        }
    });

    router.get('/v3/conversations/:conversationId/members', (req, res) => { console.warn('/v3/conversations/:conversationId/members not implemented'); });
    router.get('/v3/conversations/:conversationId/activities/:activityId/members', (req, res) => { console.warn('/v3/conversations/:conversationId/activities/:activityId/members'); });

    // BOTSTATE ENDPOINT

    router.get('/v3/botstate/:channelId/users/:userId', (req, res) => {
        console.log('Called GET user data');
        getBotData(req, res);
    });

    router.get('/v3/botstate/:channelId/conversations/:conversationId', (req, res) => {
        console.log(('Called GET conversation data'));
        getBotData(req, res);
    });

    router.get('/v3/botstate/:channelId/conversations/:conversationId/users/:userId', (req, res) => {
        console.log('Called GET private conversation data');
        getBotData(req, res);
    });

    router.post('/v3/botstate/:channelId/users/:userId', (req, res) => {
        console.log('Called POST setUserData');
        setUserData(req, res);
    });

    router.post('/v3/botstate/:channelId/conversations/:conversationId', (req, res) => {
        console.log('Called POST setConversationData');
        setConversationData(req, res);
    });

    router.post('/v3/botstate/:channelId/conversations/:conversationId/users/:userId', (req, res) => {
        setPrivateConversationData(req, res);
    });

    router.delete('/v3/botstate/:channelId/users/:userId', (req, res) => {
        console.log('Called DELETE deleteStateForUser');
        deleteStateForUser(req, res);
    });

    return router;
};

/**
 * @param app The express app where your offline-directline endpoint will live
 * @param port The port where your offline-directline will be hosted
 * @param botUrl The url of the bot (e.g. http://127.0.0.1:3978/api/messages)
 * @param conversationInitRequired Requires that a conversation is initialized before it is accessed, returning a 400
 * when not the case. If set to false, a new conversation reference is created on the fly. This is true by default.
 */
export const initializeRoutes = (app: express.Express, port: number, botUrl: string, conversationInitRequired = true, botId) => {
    conversationsCleanup();

    const directLineEndpoint = `http://127.0.0.1:${port}`;
    const router = getRouter(directLineEndpoint, botUrl, conversationInitRequired, botId);

    app.use(router);
    console.log(`Routing messages to bot on ${botUrl}`);

};

const getConversation = (conversationId: string, conversationInitRequired: boolean) => {

    // Create conversation on the fly when needed and init not required
    if (!conversations[conversationId] && !conversationInitRequired) {
        conversations[conversationId] = {
            conversationId,
            history: [],
        };
    }
    return conversations[conversationId];
};

const getBotDataKey = (channelId: string, conversationId: string, userId: string) => {
    return `$${channelId || '*'}!${conversationId || '*'}!${userId || '*'}`;
};

const setBotData = (channelId: string, conversationId: string, userId: string, incomingData: IBotData): IBotData => {
    const key = getBotDataKey(channelId, conversationId, userId);
    const newData: IBotData = {
        eTag: new Date().getTime().toString(),
        data: incomingData.data,
    };

    if (incomingData) {
        botDataStore[key] = newData;
    } else {
        delete botDataStore[key];
        newData.eTag = '*';
    }

    return newData;
};

const getBotData = (req: express.Request, res: express.Response) => {
    const key = getBotDataKey(req.params.channelId, req.params.conversationId, req.params.userId);
    console.log('Data key: ' + key);

    res.status(200).send(botDataStore[key] || { data: null, eTag: '*' });
};

const setUserData = (req: express.Request, res: express.Response) => {
    res.status(200).send(setBotData(req.params.channelId, req.params.conversationId, req.params.userId, req.body));
};

const setConversationData = (req: express.Request, res: express.Response) => {
    res.status(200).send(setBotData(req.params.channelId, req.params.conversationId, req.params.userId, req.body));
};

const setPrivateConversationData = (req: express.Request, res: express.Response) => {
    res.status(200).send(setBotData(req.params.channelId, req.params.conversationId, req.params.userId, req.body));
};

export const start = (server, botId)=>{

    initializeRoutes(server, Number(process.env.PORT), `http://127.0.0.1:${process.env.PORT}/api/messages/${botId}`, null, botId);
}

const deleteStateForUser = (req: express.Request, res: express.Response) => {
    Object.keys(botDataStore)
        .forEach((key) => {
            if (key.endsWith(`!{req.query.userId}`)) {
                delete botDataStore[key];
            }
        });
    res.status(200).send();
};

// CLIENT ENDPOINT HELPERS
const createMessageActivity = (incomingActivity: IMessageActivity, serviceUrl: string, conversationId: string): IMessageActivity => {
    return { ...incomingActivity, channelId: 'emulator', serviceUrl, conversation: { id: conversationId }, id: uuidv4.v4() };
};

const createConversationUpdateActivity = (serviceUrl: string, conversationId: string): IConversationUpdateActivity => {
    const activity:     IConversationUpdateActivity = {
        type: 'conversationUpdate',
        channelId: 'emulator',
        serviceUrl,
        conversation: { id: conversationId },
        id: uuidv4.v4(),
        membersAdded: [],
        membersRemoved: [],
        from: { id: 'offline-directline', name: 'Offline Directline Server' },
    };
    return activity;
};

const conversationsCleanup = () => {
    setInterval(() => {
        const expiresTime = moment().subtract(expiresIn, 'seconds');
        Object.keys(conversations).forEach((conversationId) => {
            if (conversations[conversationId].history.length > 0) {
                const lastTime = moment(conversations[conversationId].history[conversations[conversationId].history.length - 1].localTimestamp);
                if (lastTime < expiresTime) {
                    delete conversations[conversationId];
                    console.log('deleted cId: ' + conversationId);
                }
            }
        });
    }, conversationsCleanupInterval);
};