const logger = require('./logger.js');
const util = require('./util.js');
const Keyfilter = require('./keyfilter.js');
const cli = require('./cli.js');
const spawn = require('child_process').spawn;
const sudo = require('sudo');

const inputDevices = '/dev/input/';
const inputDevicesById = '/dev/input/by-id/';

class Watcher {
    constructor(config, callback) {
        if (config === undefined || config.device === undefined) {
            return;
        }
        for (let key in config) {
            this[key] = config[key];
        }
        this.keyfilter = new Keyfilter(config.keys);
        this.restart = config.restart;
        this.callback = callback;
    }
    async start() {
        if (this.process !== undefined) {
            return;
        }
        if (this.sudo) {
            logger.debug('starting sudo watcher \'' + this.device + '\'...');
            this.process = sudo(['evtest', this.device], { cachePassword: true, prompt: 'sudo password:' });
        } else {
            logger.debug('starting watcher \'' + this.device + '\'...');
            this.process = spawn('evtest', [this.device]);
        }
        try {
            await this.attachListeners();
        } catch (err) {
            logger.error(err);
        }

    }
    stop() {
        if (this.process === undefined) {
            return;
        }
        logger.debug('stopping watcher \'' + this.device + '\'...');
        this.process.kill();
        logger.info('watcher \'' + this.device + '\' stopped');
    }
    async attachListeners() {
        if (this.process === undefined) {
            return;
        }
        this.addStdOutListener();
        this.addStdErrListener();
        this.addErrorListener();
        this.addCloseListener();
        await this.addSpawnListener();
    }
    addStdOutListener() {
        if (this.process === undefined) {
            return;
        }
        logger.debug('adding stdout listener to watcher \'' + this.device + '\'...');
        this.process.stdout.on('data', (data) => {
            if (this.keyfilter == undefined) {
                return;
            }
            let filtered = this.keyfilter.filter(data);
            if (filtered === undefined) {
                return;
            }
            logger.debug('handling captured \'' + filtered.type + '\' event for key \'' + filtered.key + '\' from watcher \'' + this.device + '\'...');
            if (filtered.delayed) {
                logger.debug('delaying captured event...');
                return;
            }
            if (filtered.combo) {
                if (!filtered.combo.finished) {
                    logger.debug('captured event is part of ' + filtered.combo.possibilities + ' possible combo(s) and not yet finished')
                    return;
                }
                logger.debug('captured event finished combo \'' + filtered.combo.done.toString().toUpperCase()+ '\'');
            }
            this.keyfilter.resetCurrentCombo();
            logger.info('executing command \'' + filtered.command.name + '\' registered for captured event...');
            cli.execute(filtered.command.cmd, filtered.command.args, filtered.command.sudo)
                .then(logger.info)
                .catch(logger.error);
        });
    }
    addStdErrListener() {
        if (this.process === undefined) {
            return;
        }
        logger.debug('adding stderr listener to watcher \'' + this.device + '\'...');
        this.process.stderr.on('data', (data) => {
            this.error = data.toString().trim();
        });
    }
    addSpawnListener() {
        return new Promise((resolve, reject) => {
            logger.debug('adding spawn listener to watcher \'' + this.device + '\'...');
            this.process.on('spawn', () => {
                logger.info('watcher \'' + this.device + '\' initialized and capturing configured events');
                resolve();
            });
        });
    }
    addCloseListener() {
        if (this.process === undefined) {
            return;
        }
        logger.debug('adding close listener to watcher \'' + this.device + '\'...');
        this.process.on('close', (code) => {
            if (code === undefined) {
                code = 0;
                if (this.error !== undefined) {
                    code = 1;
                }
            }
            if (this.error !== undefined) {
                logger.error('watcher \'' + this.device + '\' encountered an error > ' + this.error);
                this.restart = false;
            }
            this.process = undefined;
            this.code = code;
            logger.info('watcher \'' + this.device + '\' finished with exit code ' + code);
            if (this.callback !== undefined) {
                this.callback(this);
            }
        });
    }
    addErrorListener(reject) {
        if (this.process === undefined) {
            return;
        }
        logger.debug('adding error listener to \'' + this.device + '\'...');
        this.process.on('error', (err) => {
            reject(logger.error('watcher \'' + this.device + '\' encountered an error >>> ' + err));
        });
    }
    check() {
        return new Promise((resolve, reject) => {
            if (!this.keyfilter.isValid()) {
                reject('no key(s) defined for watcher \'' + this.device + '\'');
            }
            Promise.any([this.device, inputDevices + this.device, inputDevicesById + this.device].map(util.getFileInfo))
                .then((result) => {
                    if (result.path !== this.device) {
                        logger.info('resolved watcher for device \'' + this.device + '\' to \'' + result.path + '\'')
                    }
                    this.device = result.path;
                    resolve(this);
                })
                .catch(reject);
        });
    }
}
module.exports = Watcher;