const express = require('express');
const axios = require('axios');
const app = express();
const port = 7000;

app.use(express.json({
    limit: '500mb'
}));

const API_KEY = process.env.API_KEY || "silly!"

const RETRY_ERROR_CODES = [408, 500, 502, 503, 504, 522, 524, 599];

async function main() {

    const responses = [];

    app.get('/', (req, res) => {
        res.send('Hello World!');
    });
    
    app.listen(port, () => {
        console.log(`Example app listening at http://localhost:${port}`);
    });

    async function RegisterResponse(instanceId, response) {
        if (!responses[instanceId]) {
            responses[instanceId] = []
        }
        responses[instanceId].push({
            id: response.id,
            data: response.data
        })
        console.log(`Response registered for instance ${instanceId}`);
        setTimeout(() => {
            if (!responses[instanceId]) {
                return;
            }
            responses[instanceId] = responses[instanceId].filter(resp => resp.id !== response.id);
            //console.log(`Response ${response.id} removed from instance ${instanceId}`);
        }, 60_000);
    }

    async function DoRequest(instanceId, requestObj) {
        const requestParams = requestObj.request || {};
        const method = requestParams.Method?.toLowerCase() || 'get';
        const url = requestParams.Url || '';
        const body = requestParams.Body || '';

        let headers = requestParams.Headers || null;
        // if headers is a an array or is an empty object, convert it to null
        if (headers && (Array.isArray(headers) || Object.keys(headers).length === 0)) {
            headers = null;
        }

        const shouldHaveBody = ['post', 'put', 'patch'].includes(method);

        console.log("DoRequest",instanceId,requestObj)

        try {
            const response = await axios({
                method: method,
                url: url,
                headers: headers,
                data: shouldHaveBody ? body : null
            });

            RegisterResponse(instanceId, {
                id: requestObj.id,
                data: response.data
            });
        } catch (error) {
            if (RETRY_ERROR_CODES.includes(error.response?.status)) {
                console.log(`Retrying request ${requestObj.id} for instance ${instanceId}`);
                SetTimeout(() => {
                    DoRequest(instanceId, requestObj);
                }, 5000);
            } else {
                RegisterResponse(instanceId, {
                    id: requestObj.id,
                    data: error.response?.data,
                    error: "yep there was an error"
                });
            }
        }
    }

    function getToSend(instanceId, waiting) {
        const toSend = [];
        const instanceResponses = responses[instanceId] || [];
        instanceResponses.forEach(respObj => {
            if (waiting.includes(respObj.id)) {
                toSend.push(respObj);
            }
        });
        return toSend;
    }

    app.post('/:instanceId', async (req, res) => {

        const apikey = req.headers['X-BatchHttp-Api-Key'];
        if (apikey !== API_KEY) {
            res.status(401).send({
                error: "Invalid API Key"
            });
            return;
        }

        const instanceId = req.params.instanceId;
        //console.log(`Instance ID: ${instanceId}`);
        const body = req.body;
        const requests = body.requests || [];
        const waiting = body.waiting || []
        //console.log(body);
        
        requests.forEach(requestObj => {
            DoRequest(instanceId,requestObj);
        });

        const startTime = Date.now();

        let toSend = []
        while (toSend.length === 0 && Date.now() - startTime < 1_000) {
            toSend = getToSend(instanceId, waiting);
            await new Promise(resolve => setTimeout(resolve, 10));
        }

        console.log(`${toSend.length} responses ready for instance ${instanceId}`);

        res.send({
            responses: toSend
        });
    })
}

main();