const logger = require('./logger.js');
const commands = require('./commands.js');
const http = require('http');

let server;
let api;

async function start() {
    const listen = global.config?.server?.listen || '0.0.0.0';
    const port = global.config?.server?.port;
    setupAPI();
    if (server === undefined) {
        server = http.createServer();
    }
    return new Promise((resolve, reject) => {
        server.listen(port, listen)
            .on('listening', function () {
                logger.info('server listening on ' + listen + ':' + port + '...');
                handleRequests();
                resolve();
            });
    });
}

function handleRequests() {
    server.on('request', (request, response) => {
        request.timestamp = new Date().getTime();
        respond(request, response);
    });
}

async function respond(request, response) {
    if (request === undefined || response === undefined) {
        return;
    }
    let endpoint = api[request.method]?.[request.url];
    let result = await commands.execute(endpoint);
    result.command = endpoint.command;
    result.args = endpoint.args;
    return finishRequest(request, response, result);
}

function finishRequest(request, response, result) {
    if (response === undefined) {
        return;
    }
    result.time = (new Date().getTime() - request.timestamp) + 'ms';
    let code = result.code || 200;
    if (result.error !== undefined && result.error.length > 0) {
        code = 501;
    }
    delete result.code;
    response.writeHead(code);
    const json = JSON.stringify(result);
    response.end(json);
    logger.http({ request: request, code: code, data: json });
}

function setupAPI() {
    const apiConfig = global.config?.api;
    if (apiConfig === undefined || apiConfig.length === 0) {
        throw new Error('no api endpoints configured - aborting');
    }
    const now = new Date().getTime();
    api = {};
    logger.debug('setting up api...');
    let index;
    for (index = 0; index < global.config.api.length; index++) {
        let endpoint = global.config.api[index];
        let key = endpoint.url;
        let method = endpoint.method.toUpperCase();
        delete endpoint.method;
        delete endpoint.url;
        let methodApi = api[method] || {};
        methodApi[key] = endpoint;
        api[method] = methodApi;
    }
    logger.debug('api setup with ' + index + ' endpoints after ' + (new Date().getTime() - now) + 'ms');
}

module.exports = {
    start
}