var warn = require("./tools/tools").warn;
var commands = require("./commands");
var functions = require("./functions");

function Trigger (trigger, interpreter) {

    var self = this, fn;

    this.name = trigger.getAttribute("name") || null;
    this.event = trigger.getAttribute("event") || null;
    this.special = trigger.getAttribute("special") || null;
    this.fnName = trigger.getAttribute("function") || null;
    this.scene = trigger.getAttribute("scene") || null;
    this.interpreter = interpreter;
    this.isSubscribed = false;

    if (this.name === null) {
        warn(interpreter.bus, "No 'name' attribute specified on 'trigger' element.", trigger);
        return;
    }

    if (this.event === null) {

        warn(interpreter.bus, "No 'event' attribute specified on 'trigger' element '" +
            this.name + "'.", trigger);

        return;
    }

    if (this.special === null && this.fnName === null && this.scene === null) {

        warn(interpreter.bus, "No suitable action or function found for trigger element '" +
            this.name + "'.", trigger);

        return;
    }

    if (this.scene) {

        fn = function () {
            commands.sub(trigger, interpreter);
            interpreter.index = 0;
            interpreter.currentElement = 0;
            interpreter.next();
        };
    }

    this.isKeyEvent = false;
    this.key = null;

    if (this.special !== null && this.special !== "next") {

        warn(interpreter.bus, "Unknown special specified on trigger element '" +
            this.name + "'.", trigger);

        return;
    }

    if (this.special === "next") {

        fn = function () {

            if (self.interpreter.state === "pause" || self.interpreter.waitCounter > 0) {
                return;
            }

            self.interpreter.next();
        };
    }

    if (this.fnName !== null) {

        if (typeof functions[this.fnName] !== "function") {

            warn(interpreter.bus, "Unknown function specified on trigger element '" +
                this.name + "'.", trigger);

            return;
        }

        fn = function () {
            functions[self.fnName](self.interpreter, trigger);
        };
    }

    switch (this.event) {

        case "keyup":
        case "keydown":
        case "keypress":

            this.isKeyEvent = true;
            this.key = trigger.getAttribute("key") || null;

            if (this.key === null) {

                warn(interpreter.bus, "No 'key' attribute specified on trigger element '" +
                    this.name + "'.", trigger);

                return;
            }

            if (
                typeof interpreter.game.keys.keys[this.key] === "undefined" ||
                interpreter.game.keys.keys[this.key] === null
            ) {

                warn(interpreter.bus, "Unknown key '" + this.key + "' specified on trigger " +
                    "element '" + this.name + "'.", trigger);

                return;
            }

            this.fn = function (data) {

                if (data.keys[self.key].kc !== data.event.keyCode) {
                    return;
                }

                if (interpreter.keysDisabled > 0) {
                    return;
                }

                fn();
            };

            return;

        default:
            this.fn = fn;
    }
}

Trigger.prototype.activate = function () {

    if (this.isSubscribed === true) {
        return;
    }

    this.interpreter.bus.subscribe(this.fn, this.event);
    this.isSubscribed = true;
};

Trigger.prototype.deactivate = function () {

    if (this.isSubscribed === false) {
        return;
    }

    this.interpreter.bus.unsubscribe(this.fn, this.event);
    this.isSubscribed = false;
};

module.exports = Trigger;