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' };

class Keyfilter {
    constructor(config) {
        if (config === undefined || config.length === 0) {
            return;
        }
        this.actions = new Map();
        for (let index = 0; index < config.length; index++) {
            this.setAction(config[index]);
        }
        this.currentCombo = undefined;
    }
    getCommand(command) {
        if (command === undefined || global.config?.commands === undefined) {
            return;
        }
        const result = global.config.commands[command];
        if (result === undefined) {
            return;
        }
        result.name = command;
        return result;
    }
    getActionType(type) {
        let result = ACTION_KEYDOWN;
        if (isNaN(type)) {
            switch (type.toLowerCase()) {
                case ACTION_KEYUP.action:
                    result = ACTION_KEYUP;
                    break;
                case ACTION_KEYHOLD.action:
                    result = ACTION_KEYHOLD;
                    break;
            }
        } else {
            switch (type) {
                case ACTION_KEYUP.id:
                    result = ACTION_KEYUP;
                    break;
                case ACTION_KEYHOLD.id:
                    result = ACTION_KEYHOLD;
                    break;
            }
        }
        return result;
    }
    setAction(config) {
        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: this.getActionType(config.type),
                event: config.event,
                command: this.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(parsedEvent)) {
                    return this.setComboResult(this.getFilterResult(parsedEvent.key, parsedEvent.type.action));
                }
                if (this.isPartOfCombo(parsedEvent)) {
                    if (parsedEvent.ignore) {
                        continue;
                    }
                    return this.setComboResult(this.getFilterResult(parsedEvent.key, parsedEvent.type.action));
                }
                if (!this.isParsedEventValid(key, event, parsedEvent)) {
                    continue;
                }
                if (this.shouldBeDelayed(event)) {
                    const result = this.getFilterResult(parsedEvent.key, event.type.action, event.command);
                    result.delayed = true;
                    return result;
                }
                event.captured = new Date().getTime();
                return this.getFilterResult(parsedEvent.key, event.type.action, event.command);
            }
        }
    }
    isParsedEventValid(key, value, parsed) {
        if (value.event !== parsed.event || value.type.id !== parsed.type.id) {
            return false;
        }
        if (value.combo === undefined || value.combo.length === 0) {
            return key === parsed.key;
        }
        if (this.currentCombo === undefined) {
            return key.startsWith(parsed.key);
        }
        for (let index = 0; index < this.currentCombo.possibilities.length; index++) {
            if (this.currentCombo.possibilities[index].combo[0].toUpperCase() === parsed.key) {
                this.resetCurrentCombo();
                return true;
            }
        }
        return false;
    }
    setComboResult(result) {
        if (result === undefined || this.currentCombo === undefined) {
            return;
        }
        if (!this.currentCombo.finished) {
            result.combo = { possibilities: this.currentCombo.possibilities.length };
        } else {
            result.combo = {
                finished: true,
                done: this.currentCombo.done
            };
            result.command = this.currentCombo.command;
        }
        return result
    }
    getFilterResult(key, type, command) {
        if (key === undefined || type === undefined) {
            return;
        }
        return {
            key: key,
            type: type,
            command: command
        };
    }
    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 = this.getActionType(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(parsedEvent) {
        if (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(JSON.parse(JSON.stringify(actionEvent)));
        }
        if (possibilities.length === 0) {
            return false;
        }
        this.currentCombo = {
            key: parsedEvent.key.toUpperCase(),
            timestamp: new Date().getTime(),
            type: parsedEvent.type,
            event: parsedEvent.event,
            done: [parsedEvent.key],
            possibilities: possibilities
        };
        return true;
    }
    isPartOfCombo(parsedEvent) {
        if (this.hasComboTimedOut()) {
            this.resetCurrentCombo();
        }
        if (this.currentCombo === undefined || this.currentCombo.type.id !== parsedEvent.type.id || this.currentCombo.event !== parsedEvent.event) {
            return false;
        }
        let possibilities = [];
        for (let index = 0; index < this.currentCombo.possibilities.length; index++) {
            const possibility = this.currentCombo.possibilities[index];
            if (possibility.combo.length === 0) {
                break;
            }
            if (possibility.combo[0].toUpperCase() !== parsedEvent.key) {
                continue;
            }
            possibility.combo.shift();
            possibilities.push(possibility);
        }
        if (possibilities.length === 0) {
            return false;
        }
        this.currentCombo.timestamp = new Date().getTime();
        this.currentCombo.done.push(parsedEvent.key);
        this.currentCombo.possibilities = possibilities;
        this.currentCombo.finished = false;
        if (this.currentCombo.possibilities.length === 1 && this.currentCombo.possibilities[0].combo.length === 0) {
            const tmp = this.currentCombo.possibilities[0];
            delete tmp.combo;
            tmp.finished = true;
            tmp.timestamp = this.currentCombo.timestamp;
            tmp.done = this.currentCombo.done;
            this.currentCombo = tmp;
        }
        return true;
    }
    hasComboTimedOut() {
        return global.config?.combos?.delay !== undefined &&
            this.currentCombo?.timestamp !== undefined &&
            new Date().getTime() - this.currentCombo.timestamp > global.config?.combos?.delay;
    }
    resetCurrentCombo() {
        this.currentCombo = undefined;
    }
    isValid() {
        return this.actions != undefined && this.actions.size > 0;
    }

}




module.exports = Keyfilter;