const config = require('../config.json');

const LINE_START = 'Event: time';

const ACTION_KEYUP = { id: 0, action: 'keyup' };
const ACTION_KEYDOWN = { id: 1, action: 'keydown' };
const ACTION_KEYHOLD = { id: 2, action: 'keyhold' };

const VARIABLE_KEY = '{{ key }}';
const VARIABLE_TYPE = '{{ type }}';

class Keyfilter {
    constructor(keys) {
        if ((keys === undefined || keys.length === 0)) {
            return;
        }
        this.actions = new Map();
        for (let index = 0; index < keys.length; index++) {
            this.setAction(keys[index]);
        }
        this.currentCombo = undefined;
    }
    setAction(config) {
        let type = ACTION_KEYDOWN;
        switch (config.type.toLowerCase()) {
            case ACTION_KEYUP.action:
                type = ACTION_KEYUP;
                break;
            case ACTION_KEYHOLD.action:
                type = ACTION_KEYHOLD;
                break;
        }
        let key = config.key.toUpperCase();
        if (config.combo !== undefined && config.combo.length > 0) {
            const tmp = JSON.parse(JSON.stringify(config.combo));
            tmp.unshift(config.key);
            key = tmp.toString().toUpperCase();
        }
        this.actions.set(key,
            {
                type: type,
                event: config.event,
                command: getCommand(config.command),
                combo: config.combo,
                delay: function () {
                    if (config.combo === undefined) {
                        return config.delay;
                    }
                    return config.delay || 1000;
                }(),
            }
        );
    }
    filter(input) {
        if (input === undefined || input.length === 0) {
            return;
        }
        input = input.toString();
        let lines = input.split("\n");
        for (let index = 0; index < lines.length; index++) {
            let line = lines[index];
            if (line.length === 0) {
                continue;
            }
            if (!line.startsWith(LINE_START)) {
                continue;
            }
            const parsedEvent = this.parseLine(line);
            if (parsedEvent === undefined) {
                continue;
            }
            for (let [key, event] of this.actions) {
                if (this.currentCombo === undefined && !this.isParsedEventValid(key, event, parsedEvent)) {
                    continue;
                }
                if (this.isStartOfCombo(key, event, parsedEvent)) {
                    return this.getFilterResult(key, event, 'combo', this.currentCombo);
                }
                if (this.isPartOfCombo(parsedEvent)) {
                    if (parsedEvent.ignore) {
                        continue;
                    }
                    const result = this.getFilterResult(key, event, 'combo', this.currentCombo);
                    if (this.currentCombo.finished) {
                        this.resetCurrentCombo();
                    }
                    return result;
                }
                if (!this.isParsedEventValid(key, event, parsedEvent)) {
                    continue;
                }
                if (this.shouldBeDelayed(event)) {
                    return this.getFilterResult(key, event, 'delayed', true);
                }
                event.captured = new Date().getTime();
                return this.getFilterResult(key, event);
            }
        }
    }
    isParsedEventValid(key, value, parsed) {
        let keyCheck = key === parsed.key;
        if (value.combo !== undefined && value.combo.length > 0) {
            keyCheck = key.includes(parsed.key);
        }
        return keyCheck && (value.event === undefined || value.event === parsed.event) && value.type.id === parsed.type;
    }
    getFilterResult(key, event, extraName, extra) {
        if (key === undefined || event === undefined) {
            return;
        }
        let result = {
            key: key,
            type: event.type.action,
            command: event.command,
            delay: event.delay
        };
        if (extraName !== undefined && extra !== undefined) {
            result[extraName] = extra;
        }
        return result;
    }
    parseLine(line) {
        try {
            const parts = line.split(',');
            const event = parts[1].substring(parts[1].indexOf('(') + 1, parts[1].lastIndexOf(')'));
            const key = parts[2].substring(parts[2].indexOf('(') + 1, parts[2].indexOf(')'));
            const type = parseInt(parts[3].split(' ').pop());
            return { event: event, key: key, type: type };
        } catch (err) {
            return;
        }
    }
    shouldBeDelayed(event) {
        if (event.delay === undefined || event.delay === 0 || event.captured === undefined) {
            return false;
        }
        return new Date().getTime() - event.captured < event.delay;
    }
    isStartOfCombo(key, event, parsedEvent) {
        if (event.combo === undefined || this.currentCombo !== undefined) {
            return false;
        }
        let possibilities = [];
        for (let [actionKey, actionEvent] of this.actions) {
            if (actionEvent.combo === undefined || actionEvent.combo.length === 0) {
                continue;
            }
            if (!actionKey.toUpperCase().startsWith(parsedEvent.key)) {
               continue;
            }
            possibilities.push(actionEvent.combo);
        }
        this.currentCombo = {
            key: key,
            type: event.type,
            delay: event.delay,
            timestamp: new Date().getTime(),
            done: [parsedEvent.key],
            possibilities: [event.combo]
        };
        return true;
    }
    isPartOfCombo(parsedEvent) {
        if (this.hasComboTimedOut()) {
            this.resetCurrentCombo();
        }
        if (this.currentCombo === undefined) {
            return false;
        }
        if (this.currentCombo.done.includes(parsedEvent.key)) {
            parsedEvent.ignore = true;
            return true;
        }
        if (this.currentCombo.type.id !== parsedEvent.type) {
            return false;
        }
        let combos = [];
        for (let index = 0; index < this.currentCombo.possibilities.length; index++) {
            const possibility = this.currentCombo.possibilities[index];
            if (possibility[0].toUpperCase() !== parsedEvent.key) {
                continue;
            }
            combos.push(possibility);
        }
        if (combos.length === 0) {
            return false;
        }
        this.currentCombo.key = parsedEvent.key;
        this.currentCombo.timestamp = new Date().getTime();
        this.currentCombo.done.push(parsedEvent.key);
        if (this.currentCombo.possibilities.length === 1) {
            this.currentCombo.finished = true;
        }
        return true;
    }
    hasComboTimedOut() {
        return false;
        const result = this.currentCombo !== undefined &&
            this.currentCombo.delay !== undefined &&
            this.currentCombo.timestamp !== undefined &&
            new Date().getTime() - this.currentCombo.timestamp > this.currentCombo.delay;
        return result;
    }
    resetCurrentCombo() {
        this.currentCombo = undefined;
    }
    isValid() {
        return this.actions != undefined && this.actions.size > 0;
    }

}

function getCommand(command) {
    if (command === undefined || config.commands === undefined) {
        return;
    }
    const result = config.commands[command];
    if (result === undefined) {
        return;
    }
    result.name = command;
    return result;
}


module.exports = Keyfilter;