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, combos) {
        if ((keys === undefined || keys.length === 0) && (combos === undefined || combos.length === 0)) {
            return;
        }
        this.actions = new Map();
        for (var index = 0; index < keys.length; index++) {
            this.setAction(keys[index]);
        }
        this.currentCombo = undefined;
    }
    setAction(config) {
        var type = ACTION_KEYDOWN;
        switch (config.type.toLowerCase()) {
            case ACTION_KEYUP.action:
                type = ACTION_KEYUP;
                break;
            case ACTION_KEYHOLD.action:
                type = ACTION_KEYHOLD;
                break;
        }
        this.actions.set(config.key.toUpperCase(),
            {
                type: type,
                event: config.event,
                command: config.command,
                args: config.args,
                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();
        var lines = input.split("\n");
        for (var index = 0; index < lines.length; index++) {
            var line = lines[index];
            if (line.length === 0) {
                continue;
            }
            if (!line.startsWith(LINE_START)) {
                continue;
            }
            const parsedEvent = this.parseLine(line);
            if (parsedEvent === undefined) {
                continue;
            }
            for (var [key, event] of this.actions) {
                if (this.currentCombo === undefined && !this.isParsedEventValid(key, event, parsedEvent)) {
                    continue;
                }
                if (this.isStartOfCombo(key, event)) {
                    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.hasComboFinished()) {
                        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) {
        return key === parsed.key && (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 = this.replaceVariables(
            {
                key: key,
                type: event.type.action,
                command: event.command,
                args: event.args,
                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;
        }
    }
    replaceVariables(filtered) {
        for (var index = 0; index < filtered.args.length; index++) {
            filtered.args[index] = filtered.args[index].replace(VARIABLE_KEY, filtered.key);
            filtered.args[index] = filtered.args[index].replace(VARIABLE_TYPE, filtered.type);
        }
        return filtered;
    }
    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) {
        if (this.currentCombo !== undefined || event.combo === undefined) {
            return false;
        }
        this.currentCombo = {
            key: key,
            type: event.type,
            start: new Date().getTime(),
            done: [key],
            remaining: JSON.parse(JSON.stringify(event.combo)),
            finished: this.hasComboFinished()
        };
        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;
        }
        if (this.currentCombo.remaining[0].toUpperCase() !== parsedEvent.key) {
            return false;
        }
        this.currentCombo.key = parsedEvent.key;
        this.currentCombo.done.push(parsedEvent.key);
        this.currentCombo.remaining.shift();
        this.currentCombo.finished = this.hasComboFinished();
        return true;
    }
    hasComboFinished() {
        return this.currentCombo !== undefined &&
            this.currentCombo.remaining !== undefined &&
            this.currentCombo.remaining.length === 0;
    }
    hasComboTimedOut() {
        return this.currentCombo !== undefined &&
            this.currentCombo.delay !== undefined &&
            this.currentCombo.start !== undefined &&
            new Date().getTime() - this.currentCombo.start > this.currentCombo.delay;
    }
    resetCurrentCombo() {
        this.currentCombo = undefined;
    }
    isValid() {
        return this.actions != undefined && this.actions.size > 0;
    }
}



module.exports = Keyfilter;