src/extensions/jg_animation/index.js

const BlockType = require('../../extension-support/block-type');
const ArgumentType = require('../../extension-support/argument-type');
const Cast = require('../../util/cast');
const Clone = require('../../util/clone');

const getStateOfSprite = (target) => {
    return {
        x: target.x,
        y: target.y,
        size: target.size,
        stretch: Clone.simple(target.stretch), // array
        transform: Clone.simple(target.transform), // array
        direction: target.direction,
        rotationStyle: target.rotationStyle,
        visible: target.visible,
        effects: Clone.simple(target.effects || {}), // object
        currentCostume: target.currentCostume,
        tintColor: target.tintColor
    };
};
const setStateOfSprite = (target, state) => {
    target.setXY(state.x, state.y);
    target.setSize(state.size);
    target.setStretch(...state.stretch);
    target.setTransform(state.transform);
    target.setDirection(state.direction);
    target.setRotationStyle(state.rotationStyle);
    target.setVisible(state.visible);
    if (state.effects) {
        for (const effect in state.effects) {
            target.setEffect(effect, state.effects[effect]);
        }
    }
    target.setCostume(state.currentCostume);
};

// i've decided to tell ChatGPT to generate these due to some conditions:
// - the color util does NOT have these implemented
// - we know hsvToDecimal will ONLY get an HSV generated by decimalToHSV, and we know hsvToDecimal will have decimals in it's params
// - these functions need to be as performant as possible (i dont know how to do that, so the AI may know better)
//   we already only run these if we really need to anyways, as it will be slow
//
// i could be completely wrong and these functions suck, but i dont really have any way of judging that
// this seems to be good for now, we only use them for tintColor anyways to make sure its not a mess
function decimalToHSV(decimalColor, hsv = { h: 0, s: 0, v: 0 }) {
    const r = (decimalColor >> 16) & 255;
    const g = (decimalColor >> 8) & 255;
    const b = decimalColor & 255;

    const max = Math.max(r, g, b);
    const min = Math.min(r, g, b);
    const delta = max - min;

    let h;

    // Calculate hue
    if (delta === 0) {
        h = 0;
    } else if (max === r) {
        h = (0.5 + ((g - b) / delta) % 6) | 0;
    } else if (max === g) {
        h = (0.5 + ((b - r) / delta + 2)) | 0;
    } else {
        h = (0.5 + ((r - g) / delta + 4)) | 0;
    }

    hsv.h = (0.5 + (h * 60 + 360) % 360) | 0;
    hsv.s = max === 0 ? 0 : (delta / max);
    hsv.v = max / 255;

    return hsv;
}
function hsvToDecimal(h, s, v) {
    const c = v * s;
    const x = c * (1 - Math.abs(((h / 60) % 2) - 1));
    const m = v - c;

    let r, g, b;

    if (h < 60) {
        [r, g, b] = [c, x, 0];
    } else if (h < 120) {
        [r, g, b] = [x, c, 0];
    } else if (h < 180) {
        [r, g, b] = [0, c, x];
    } else if (h < 240) {
        [r, g, b] = [0, x, c];
    } else if (h < 300) {
        [r, g, b] = [x, 0, c];
    } else {
        [r, g, b] = [c, 0, x];
    }

    const decimalR = (0.5 + (r + m) * 255) | 0;
    const decimalG = (0.5 + (g + m) * 255) | 0;
    const decimalB = (0.5 + (b + m) * 255) | 0;

    return (decimalR << 16) | (decimalG << 8) | decimalB;
}

/**
   * @param {number} time should be 0-1
   * @param {number} a value at 0
   * @param {number} b value at 1
   * @returns {number}
   */
const interpolate = (time, a, b) => {
    // don't restrict range of time as some easing functions are expected to go outside the range
    const multiplier = b - a;
    const result = time * multiplier + a;
    return result;
};

const snap = (x) => 1;
const snapcenter = (x) => Math.round(x);
const snapend = (x) => Math.ceil(x);

const linear = (x) => x;

const sine = (x, dir) => {
    switch (dir) {
        case "in": {
            return 1 - Math.cos((x * Math.PI) / 2);
        }
        case "out": {
            return Math.sin((x * Math.PI) / 2);
        }
        case "in out": {
            return -(Math.cos(Math.PI * x) - 1) / 2;
        }
        default:
            return 0;
    }
};

const quad = (x, dir) => {
    switch (dir) {
        case "in": {
            return x * x;
        }
        case "out": {
            return 1 - (1 - x) * (1 - x);
        }
        case "in out": {
            return x < 0.5 ? 2 * x * x : 1 - Math.pow(-2 * x + 2, 2) / 2;
        }
        default:
            return 0;
    }
};

const cubic = (x, dir) => {
    switch (dir) {
        case "in": {
            return x * x * x;
        }
        case "out": {
            return 1 - Math.pow(1 - x, 3);
        }
        case "in out": {
            return x < 0.5 ? 4 * x * x * x : 1 - Math.pow(-2 * x + 2, 3) / 2;
        }
        default:
            return 0;
    }
};

const quart = (x, dir) => {
    switch (dir) {
        case "in": {
            return x * x * x * x;
        }
        case "out": {
            return 1 - Math.pow(1 - x, 4);
        }
        case "in out": {
            return x < 0.5 ? 8 * x * x * x * x : 1 - Math.pow(-2 * x + 2, 4) / 2;
        }
        default:
            return 0;
    }
};

const quint = (x, dir) => {
    switch (dir) {
        case "in": {
            return x * x * x * x * x;
        }
        case "out": {
            return 1 - Math.pow(1 - x, 5);
        }
        case "in out": {
            return x < 0.5
                ? 16 * x * x * x * x * x
                : 1 - Math.pow(-2 * x + 2, 5) / 2;
        }
        default:
            return 0;
    }
};

const expo = (x, dir) => {
    switch (dir) {
        case "in": {
            return x === 0 ? 0 : Math.pow(2, 10 * x - 10);
        }
        case "out": {
            return x === 1 ? 1 : 1 - Math.pow(2, -10 * x);
        }
        case "in out": {
            return x === 0
                ? 0
                : x === 1
                    ? 1
                    : x < 0.5
                        ? Math.pow(2, 20 * x - 10) / 2
                        : (2 - Math.pow(2, -20 * x + 10)) / 2;
        }
        default:
            return 0;
    }
};

const circ = (x, dir) => {
    switch (dir) {
        case "in": {
            return 1 - Math.sqrt(1 - Math.pow(x, 2));
        }
        case "out": {
            return Math.sqrt(1 - Math.pow(x - 1, 2));
        }
        case "in out": {
            return x < 0.5
                ? (1 - Math.sqrt(1 - Math.pow(2 * x, 2))) / 2
                : (Math.sqrt(1 - Math.pow(-2 * x + 2, 2)) + 1) / 2;
        }
        default:
            return 0;
    }
};

const back = (x, dir) => {
    switch (dir) {
        case "in": {
            const c1 = 1.70158;
            const c3 = c1 + 1;
            return c3 * x * x * x - c1 * x * x;
        }
        case "out": {
            const c1 = 1.70158;
            const c3 = c1 + 1;
            return 1 + c3 * Math.pow(x - 1, 3) + c1 * Math.pow(x - 1, 2);
        }
        case "in out": {
            const c1 = 1.70158;
            const c2 = c1 * 1.525;
            return x < 0.5
                ? (Math.pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2
                : (Math.pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
        }
        default:
            return 0;
    }
};

const elastic = (x, dir) => {
    switch (dir) {
        case "in": {
            const c4 = (2 * Math.PI) / 3;
            return x === 0
                ? 0
                : x === 1
                    ? 1
                    : -Math.pow(2, 10 * x - 10) * Math.sin((x * 10 - 10.75) * c4);
        }
        case "out": {
            const c4 = (2 * Math.PI) / 3;
            return x === 0
                ? 0
                : x === 1
                    ? 1
                    : Math.pow(2, -10 * x) * Math.sin((x * 10 - 0.75) * c4) + 1;
        }
        case "in out": {
            const c5 = (2 * Math.PI) / 4.5;
            return x === 0
                ? 0
                : x === 1
                    ? 1
                    : x < 0.5
                        ? -(Math.pow(2, 20 * x - 10) * Math.sin((20 * x - 11.125) * c5)) / 2
                        : (Math.pow(2, -20 * x + 10) * Math.sin((20 * x - 11.125) * c5)) / 2 +
                        1;
        }
        default:
            return 0;
    }
};

const bounce = (x, dir) => {
    switch (dir) {
        case "in": {
            return 1 - bounce(1 - x, "out");
        }
        case "out": {
            const n1 = 7.5625;
            const d1 = 2.75;
            if (x < 1 / d1) {
                return n1 * x * x;
            } else if (x < 2 / d1) {
                return n1 * (x -= 1.5 / d1) * x + 0.75;
            } else if (x < 2.5 / d1) {
                return n1 * (x -= 2.25 / d1) * x + 0.9375;
            } else {
                return n1 * (x -= 2.625 / d1) * x + 0.984375;
            }
        }
        case "in out": {
            return x < 0.5
                ? (1 - bounce(1 - 2 * x, "out")) / 2
                : (1 + bounce(2 * x - 1, "out")) / 2;
        }
        default:
            return 0;
    }
};

const EasingMethods = {
    linear,
    sine,
    quad,
    cubic,
    quart,
    quint,
    expo,
    circ,
    back,
    elastic,
    bounce,
    snap,
    snapcenter,
    snapend,
};

class AnimationExtension {
    constructor(runtime) {
        /**
         * The runtime instantiating this block package.
         * @type {Runtime}
         */
        this.runtime = runtime;
        this.animations = Object.create(null);
        this.progressingTargets = [];
        this.progressingTargetData = Object.create(null);

        this.runtime.on('RUNTIME_PRE_PAUSED', () => {
            for (const targetId in this.progressingTargetData) {
                const targetData = this.progressingTargetData[targetId];
                for (const animationName in targetData) {
                    const animationData = targetData[animationName];
                    animationData.projectPaused = true;
                }
            }
            this.runtime.updateCurrentMSecs();
            this.runtime.emit('ANIMATIONS_FORCE_STEP');
        });
        this.runtime.on('RUNTIME_UNPAUSED', () => {
            this.runtime.updateCurrentMSecs(); // currentMSecs is the same as when we originally paused, fix that
            for (const targetId in this.progressingTargetData) {
                const targetData = this.progressingTargetData[targetId];
                for (const animationName in targetData) {
                    const animationData = targetData[animationName];
                    animationData.projectPaused = false;
                }
            }
        });
    }

    now() {
        return this.runtime.currentMSecs;
    }

    deserialize(data) {
        this.animations = data;
    }
    serialize() {
        return this.animations;
    }
    orderCategoryBlocks(blocks) {
        const buttons = {
            create: blocks[0],
            delete: blocks[1]
        };
        const varBlock = blocks[2];
        blocks.splice(0, 3);
        // create the variable block xml's
        const varBlocks = Object.keys(this.animations)
            .map(animationName => varBlock.replace('{animationId}', animationName));
        if (varBlocks.length <= 0) {
            return [buttons.create];
        }
        // push the button to the top of the var list
        varBlocks.reverse();
        varBlocks.push(buttons.delete);
        varBlocks.push(buttons.create);
        // merge the category blocks and variable blocks into one block list
        blocks = varBlocks
            .reverse()
            .concat(blocks);
        return blocks;
    }

    getInfo() {
        return {
            id: "jgAnimation",
            name: "Animation",
            isDynamic: true,
            orderBlocks: this.orderCategoryBlocks.bind(this),
            blocks: [
                { opcode: 'createAnimation', text: 'New Animation', blockType: BlockType.BUTTON, },
                { opcode: 'deleteAnimation', text: 'Delete an Animation', blockType: BlockType.BUTTON, },
                {
                    opcode: 'getAnimation', text: '[ANIMATION]', blockType: BlockType.REPORTER,
                    arguments: {
                        ANIMATION: { menu: 'animations', defaultValue: '{animationId}', type: ArgumentType.STRING, }
                    },
                },
                { text: "Animations", blockType: BlockType.LABEL, },
                {
                    opcode: "playAnimation",
                    blockType: BlockType.COMMAND,
                    text: "play [ANIM] [OFFSET] and [FORWARDS] after last keyframe",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                        OFFSET: {
                            type: ArgumentType.STRING,
                            menu: 'offsetMenu',
                        },
                        FORWARDS: {
                            type: ArgumentType.STRING,
                            menu: 'forwardsMenu',
                        },
                    },
                },
                {
                    opcode: "pauseAnimation",
                    blockType: BlockType.COMMAND,
                    text: "pause [ANIM]",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "unpauseAnimation",
                    blockType: BlockType.COMMAND,
                    text: "unpause [ANIM]",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "stopAnimation",
                    blockType: BlockType.COMMAND,
                    text: "stop [ANIM]",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                { text: "Keyframes", blockType: BlockType.LABEL, },
                {
                    opcode: "addStateKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "add current state with [EASING] [DIRECTION] as keyframe with duration [LENGTH] in animation [ANIM]",
                    arguments: {
                        EASING: {
                            type: ArgumentType.STRING,
                            menu: 'easingMode',
                        },
                        DIRECTION: {
                            type: ArgumentType.STRING,
                            menu: 'easingDir',
                        },
                        LENGTH: {
                            type: ArgumentType.NUMBER,
                            defaultValue: 1,
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "addJSONKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "add keyframe JSON [JSON] as keyframe in animation [ANIM]",
                    arguments: {
                        JSON: {
                            type: ArgumentType.STRING,
                            defaultValue: '{}',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "setStateKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "set keyframe [IDX] in animation [ANIM] to current state with [EASING] [DIRECTION] and duration [LENGTH] ",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        EASING: {
                            type: ArgumentType.STRING,
                            menu: 'easingMode',
                        },
                        DIRECTION: {
                            type: ArgumentType.STRING,
                            menu: 'easingDir',
                        },
                        LENGTH: {
                            type: ArgumentType.NUMBER,
                            defaultValue: 1,
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "setJSONKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "set keyframe [IDX] in animation [ANIM] to JSON [JSON]",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        JSON: {
                            type: ArgumentType.STRING,
                            defaultValue: '{}',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "deleteKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "delete keyframe [IDX] from [ANIM]",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "deleteAllKeyframes",
                    blockType: BlockType.COMMAND,
                    text: "delete all keyframes [ANIM]",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "getKeyframe",
                    blockType: BlockType.REPORTER,
                    text: "get keyframe [IDX] from [ANIM]",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "getKeyframeCount",
                    blockType: BlockType.REPORTER,
                    disableMonitor: true,
                    text: "amount of keyframes in [ANIM]",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "isPausedAnimation",
                    blockType: BlockType.BOOLEAN,
                    disableMonitor: true,
                    hideFromPalette: true,
                    text: "is [ANIM] paused?",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "isPropertyAnimation",
                    blockType: BlockType.BOOLEAN,
                    disableMonitor: true,
                    text: "is [ANIM] [ANIMPROP]?",
                    arguments: {
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                        ANIMPROP: {
                            type: ArgumentType.STRING,
                            menu: 'animationDataProperty',
                        },
                    },
                },
                { text: "Operations", blockType: BlockType.LABEL, },
                {
                    opcode: "goToKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "go to keyframe [IDX] in [ANIM]",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
                {
                    opcode: "snapToKeyframe",
                    blockType: BlockType.COMMAND,
                    text: "snap to keyframe [IDX] in [ANIM]",
                    arguments: {
                        IDX: {
                            type: ArgumentType.NUMBER,
                            defaultValue: '1',
                        },
                        ANIM: {
                            type: ArgumentType.STRING,
                            menu: 'animations',
                        },
                    },
                },
            ],
            menus: {
                animations: '_animationsMenu',
                easingMode: {
                    acceptReporters: true,
                    items: Object.keys(EasingMethods),
                },
                easingDir: {
                    acceptReporters: true,
                    items: ["in", "out", "in out"],
                },
                animationDataProperty: {
                    acceptReporters: false,
                    items: ["playing", "paused"],
                },
                offsetMenu: {
                    acceptReporters: false,
                    items: [
                        { text: "relative to current state", value: "relative" },
                        { text: "snapped to first keyframe", value: "snapped" }
                    ],
                },
                forwardsMenu: {
                    acceptReporters: false,
                    items: [
                        { text: "stay", value: "stay" },
                        { text: "reset to original state", value: "reset" },
                    ],
                },
            }
        };
    }

    _animationsMenu() {
        const animations = Object.keys(this.animations);
        if (animations.length <= 0) {
            return [
                {
                    text: '',
                    value: ''
                }
            ];
        }
        return animations.map(animation => ({
            text: animation,
            value: animation
        }));
    }
    _parseKeyframeOrKeyframes(string) {
        let json;
        try {
            json = JSON.parse(string);
        } catch {
            json = {};
        }
        if (typeof json !== 'object') {
            return {};
        }
        if (Array.isArray(json)) {
            for (const item of json) {
                if (typeof item !== 'object') {
                    return {};
                }
            }
        }
        return json;
    }
    _tweenValue(start, end, easeMethod, easeDirection, progress) {
        if (!Object.prototype.hasOwnProperty.call(EasingMethods, easeMethod)) {
            // Unknown method
            return start;
        }
        const easingFunction = EasingMethods[easeMethod];

        const tweened = easingFunction(progress, easeDirection);
        return interpolate(tweened, start, end);
    }
    _progressAnimation(target, startState, endState, mode, direction, progress) {
        const tweenNum = (start, end) => {
            return this._tweenValue(start, end, mode, direction, progress);
        };
        const staticValue = tweenNum(0, 1);
        target.setXY(
            tweenNum(startState.x, endState.x),
            tweenNum(startState.y, endState.y)
        );
        target.setSize(tweenNum(startState.size, endState.size));
        target.setStretch(
            tweenNum(startState.stretch[0], endState.stretch[0]),
            tweenNum(startState.stretch[1], endState.stretch[1])
        );
        target.setTransform([
            tweenNum(startState.transform[0], endState.transform[0]),
            tweenNum(startState.transform[1], endState.transform[1])
        ]);
        target.setDirection(tweenNum(startState.direction, endState.direction));
        target.setRotationStyle(Math.round(staticValue) === 0 ? startState.rotationStyle : endState.rotationStyle);
        target.setVisible(Math.round(staticValue) === 0 ? startState.visible : endState.visible);
        for (const effect in startState.effects) {
            if (effect === 'tintColor' && startState.effects.tintColor !== endState.effects.tintColor) {
                const startHsv = decimalToHSV(startState.effects.tintColor - 1);
                const endHsv = decimalToHSV(endState.effects.tintColor - 1);
                const currentHsv = {
                    h: tweenNum(startHsv.h, endHsv.h),
                    s: tweenNum(startHsv.s, endHsv.s),
                    v: tweenNum(startHsv.v, endHsv.v),
                };
                target.setEffect('tintColor', hsvToDecimal(currentHsv.h, currentHsv.s, currentHsv.v));
                continue;
            }
            target.setEffect(effect, tweenNum(startState.effects[effect], endState.effects[effect]));
        }
        target.setCostume(Math.round(staticValue) === 0 ? startState.currentCostume : endState.currentCostume);
    }

    createAnimation() {
        const newAnimation = prompt('Create animation named:', 'animation ' + (Object.keys(this.animations).length + 1));
        if (!newAnimation) return;
        if (newAnimation in this.animations) return alert(`"${newAnimation}" is taken!`);
        this.animations[newAnimation] = {
            keyframes: []
        };
        vm.emitWorkspaceUpdate();
        this.serialize();
    }
    deleteAnimation() {
        const animationName = prompt('Which animation would you like to delete?');
        if (animationName in this.animations) {
            for (const target of this.runtime.targets) {
                this.stopAnimation({
                    ANIM: animationName
                }, {
                    target
                });
            }
            delete this.animations[animationName];
        }
        vm.emitWorkspaceUpdate();
        this.serialize();
    }

    getAnimation(args) {
        const animationName = Cast.toString(args.ANIMATION);
        if (!(animationName in this.animations)) return '{}';
        return JSON.stringify(this.animations[animationName]);
    }

    addKeyframe(animation, state) {
        if (!(animation in this.animations)) {
            return;
        }
        this.animations[animation].keyframes.push(state);
    }
    setKeyframe(animation, state, idx) {
        if (!(animation in this.animations)) {
            return;
        }
        const keyframes = this.animations[animation].keyframes;
        if (idx > keyframes.length - 1) {
            return;
        }
        if (idx < 0) {
            return;
        }
        keyframes[idx] = state;
    }
    addStateKeyframe(args, util) {
        const animationName = Cast.toString(args.ANIM);
        const state = getStateOfSprite(util.target);
        this.addKeyframe(animationName, {
            ...state,
            easingMode: Cast.toString(args.EASING),
            easingDir: Cast.toString(args.DIRECTION),
            keyframeLength: Cast.toNumber(args.LENGTH)
        });
    }
    addJSONKeyframe(args) {
        const animationName = Cast.toString(args.ANIM);
        const parsedKeyframe = this._parseKeyframeOrKeyframes(args.JSON);
        if (Array.isArray(parsedKeyframe)) {
            for (const keyframe of parsedKeyframe) {
                this.addKeyframe(animationName, keyframe);
            }
        } else {
            this.addKeyframe(animationName, parsedKeyframe);
        }
    }
    setStateKeyframe(args, util) {
        const animationName = Cast.toString(args.ANIM);
        const index = Cast.toNumber(args.IDX) - 1;
        const state = getStateOfSprite(util.target);
        this.setKeyframe(animationName, {
            ...state,
            easingMode: Cast.toString(args.EASING),
            easingDir: Cast.toString(args.DIRECTION),
            keyframeLength: Cast.toNumber(args.LENGTH)
        }, index);
    }
    setJSONKeyframe(args) {
        const animationName = Cast.toString(args.ANIM);
        const index = Cast.toNumber(args.IDX) - 1;
        const parsedKeyframe = this._parseKeyframeOrKeyframes(args.JSON);
        if (Array.isArray(parsedKeyframe)) {
            return;
        } else {
            this.setKeyframe(animationName, parsedKeyframe, index);
        }
    }
    deleteKeyframe(args) {
        const animationName = Cast.toString(args.ANIM);
        const idx = Cast.toNumber(args.IDX);
        if (!(animationName in this.animations)) {
            return;
        }
        this.animations[animationName].keyframes.splice(idx - 1, 1);
    }
    deleteAllKeyframes(args) {
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return;
        }
        this.animations[animationName].keyframes = [];
    }
    getKeyframe(args) {
        const animationName = Cast.toString(args.ANIM);
        const idx = Cast.toNumber(args.IDX) - 1;
        if (!(animationName in this.animations)) {
            return '{}';
        }
        const animation = this.animations[animationName];
        const keyframe = animation.keyframes[idx];
        if (!keyframe) return '{}';
        return JSON.stringify(keyframe);
    }
    getKeyframeCount(args) {
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return '{}';
        }
        const animation = this.animations[animationName];
        return animation.keyframes.length;
    }

    goToKeyframe(args, util) {
        const animationName = Cast.toString(args.ANIM);
        const idx = Cast.toNumber(args.IDX) - 1;
        if (!(animationName in this.animations)) {
            return;
        }
        const animation = this.animations[animationName];
        const keyframe = animation.keyframes[idx];
        if (!keyframe) return;
        // start animating
        const spriteTarget = util.target;
        const currentState = getStateOfSprite(spriteTarget);
        const startTime = this.now();
        const endTime = this.now() + (keyframe.keyframeLength * 1000); // 2.65s should be 2650ms
        if (endTime <= startTime) {
            // this frame is instant
            setStateOfSprite(spriteTarget, keyframe);
            return;
        }
        // this will run each step
        let finishedAnim = false;
        const frameHandler = () => {
            const currentTime = this.now();
            if (currentTime >= endTime) {
                this.runtime.off('RUNTIME_STEP_START', frameHandler);
                setStateOfSprite(spriteTarget, keyframe);
                finishedAnim = true;
                return;
            }
            const progress = (currentTime - startTime) / (endTime - startTime);
            this._progressAnimation(spriteTarget, currentState, keyframe, keyframe.easingMode, keyframe.easingDir, progress);
        };
        frameHandler();
        this.runtime.once('PROJECT_STOP_ALL', () => {
            if (!finishedAnim) {
                // finishedAnim is only true if we already removed it
                this.runtime.off('RUNTIME_STEP_START', frameHandler);
            }
        });
        this.runtime.on('RUNTIME_STEP_START', frameHandler);
    }
    snapToKeyframe(args, util) {
        const animationName = Cast.toString(args.ANIM);
        const idx = Cast.toNumber(args.IDX) - 1;
        if (!(animationName in this.animations)) {
            return;
        }
        const animation = this.animations[animationName];
        const keyframe = animation.keyframes[idx];
        if (!keyframe) return;
        setStateOfSprite(util.target, keyframe);
    }

    // MULTIPLE ANIMATIONS CAN PLAY AT ONCE ON THE SAME SPRITE! remember this
    playAnimation(args, util) {
        const spriteTarget = util.target;
        const id = spriteTarget.id;
        const animationName = Cast.toString(args.ANIM);
        const isRelative = args.OFFSET !== 'snapped';
        const isForwards = args.FORWARDS !== 'reset';
        if (!(animationName in this.animations)) {
            return;
        }
        const animation = this.animations[animationName];
        const firstKeyframe = animation.keyframes[0];
        // check if we are unpausing
        let existingAnimationState = this.progressingTargetData[id];
        if (this.progressingTargets.includes(id) && existingAnimationState && existingAnimationState[animationName]) {
            // we are playing this animation already?
            const animationState = existingAnimationState[animationName];
            if (animationState.paused) {
                animationState.paused = false;
                return;
            }
            if (!animationState.forceStop) {
                return; // this animation isnt stopped, still actively playing
            } else {
                // force an animation update to fully cancel the animation
                // console.log('before', performance.now());
                this.runtime.emit('ANIMATIONS_FORCE_SPECIFIC_STEP', id, animationName);
                // console.log('after', performance.now());
            }
        }
        // we can start initializing our animation, but first check if we can skip a lot of work here
        if (!firstKeyframe) {
            return;
        }
        // there are a couple cases where we can do nothing or do little to nothing
        // relative mode basically ignores the first keyframe, we only care about things after
        // if we are relative, if we are ignoring the first keyframe and the second keyframe doesnt exist, we can just do nothing
        // forwards mode entails we want to stay in the state that the last keyframe put us in, the name comes from what CSS calls it
        // if we are relative and we arent going forwards, then nothing should happen (second keyframe doesnt exist and we ignored the first)
        // if we arent relative and we arent going forwards, then nothing should happen (we shouldnt be in the state of the first keyframe)
        const secondKeyframe = animation.keyframes[1];
        if (!secondKeyframe) {
            if (isForwards && !isRelative) {
                // we really should only do this if we arent relative & we should stay in this state when the animation ends
                setStateOfSprite(spriteTarget, firstKeyframe);
            }
            // we are relative OR we shouldnt stay in the state of the last keyframe
            return;
        }
        // initialize for animation
        if (!this.progressingTargets.includes(id)) {
            // we are playing any animation, so we need to say we are animating atm
            this.progressingTargets.push(id);
        }
        if (!existingAnimationState) {
            // we are playing any animation, initialize data
            const data = Object.create(null);
            this.progressingTargetData[id] = data;
            existingAnimationState = this.progressingTargetData[id];
        }
        // set our data
        existingAnimationState[animationName] = {};
        const animationState = existingAnimationState[animationName];
        animationState.forceStop = false;
        animationState.paused = false;
        animationState.projectPaused = false;
        // we can start animating now
        // some of our math needs to allow our offset if we are in relative mode
        // there are some exceptions to relative mode:
        // - tintColor should only be the current state's color until a keyframe changes it from the first
        // - some effects should act like multipliers and others should add to each keyframes effects
        // - rotation mode shoould only be the current state's rotation mode on the first keyframe
        // - costume should stay the same until the animation changes the costume from the first keyframe
        const finalAnimation = Clone.simple(animation);
        // patchy fix, but it makes the animation actually be timed properly
        finalAnimation.keyframes[0].keyframeLength = 0.001; // 1ms
        const initialState = getStateOfSprite(spriteTarget);
        const fakeEffects = { tintColor: 0xffffff + 1 };
        if (isRelative) {
            // update the keyframes of the animation
            let initialCostume = firstKeyframe.currentCostume ?? initialState.currentCostume;
            let initialRotation = firstKeyframe.rotationStyle ?? initialState.rotationStyle;
            let initialTintColor = (firstKeyframe.effects || fakeEffects).tintColor ?? fakeEffects.tintColor;
            let shouldUpdateCostume = false;
            let shouldUpdateRotationStyle = false;
            let shouldUpdateTintColor = false;
            for (const keyframe of finalAnimation.keyframes) {
                // offset based on initial position
                keyframe.x -= firstKeyframe.x;
                keyframe.y -= firstKeyframe.y;
                keyframe.size /= firstKeyframe.size / 100;
                keyframe.stretch = [keyframe.stretch[0] / (firstKeyframe.stretch[0] / 100), keyframe.stretch[1] / (firstKeyframe.stretch[1] / 100)];
                keyframe.transform = [keyframe.transform[0] - firstKeyframe.transform[0], keyframe.transform[1] - firstKeyframe.transform[1]];
                keyframe.direction -= firstKeyframe.direction - 90;
                // change regulars
                keyframe.x += initialState.x;
                keyframe.y += initialState.y;
                keyframe.size *= initialState.size / 100;
                keyframe.stretch = [keyframe.stretch[0] * (initialState.stretch[0] / 100), keyframe.stretch[1] * (initialState.stretch[1] / 100)];
                keyframe.transform = [keyframe.transform[0] + initialState.transform[0], keyframe.transform[1] + initialState.transform[1]];
                keyframe.direction += initialState.direction - 90;
                // exceptions
                if (!shouldUpdateCostume) {
                    shouldUpdateCostume = initialCostume !== keyframe.currentCostume;
                }
                if (!shouldUpdateRotationStyle) {
                    shouldUpdateRotationStyle = initialRotation !== keyframe.rotationStyle;
                }
                if (!shouldUpdateTintColor) {
                    shouldUpdateTintColor = initialTintColor !== (keyframe.effects || fakeEffects).tintColor;
                }
                // handle exceptions
                if (!shouldUpdateCostume) {
                    keyframe.currentCostume = initialState.currentCostume;
                }
                if (!shouldUpdateRotationStyle) {
                    keyframe.rotationStyle = initialState.rotationStyle;
                }
                if (!shouldUpdateTintColor) {
                    if (!keyframe.effects) keyframe.effects = {};
                    keyframe.effects.tintColor = initialState.effects.tintColor;
                }
                for (const effect in keyframe.effects) {
                    if (effect === 'tintColor') continue;
                    const value = keyframe.effects[effect];
                    const initValue = initialState.effects[effect];
                    switch (effect) {
                        case 'ghost':
                            // 0 for invis, 1 for visible
                            const newGhost = (1 - (value / 100)) * (1 - (initValue / 100));
                            keyframe.effects[effect] = (1 - newGhost) * 100;
                            break;
                        default:
                            keyframe.effects[effect] += initialState.effects[effect];
                            break;
                    }
                }
            }
        }
        if (!isRelative) {
            setStateOfSprite(spriteTarget, firstKeyframe);
        }
        // play animation
        const stopAllHandler = () => {
            animationState.forceStop = true;
            this.runtime.emit('ANIMATIONS_FORCE_SPECIFIC_STEP', id, animationName);
        }
        const forceSpecificStepHandler = (targetId, targetAnimationName) => {
            if (targetId !== id) return;
            if (targetAnimationName !== animationName) return;
            // yep he's talking to us
            // console.log('forced step', targetId, targetAnimationName, animationState.forceStop);
            // console.log('during', performance.now());
            frameHandler();
        };
        const animationEnded = (forceStop) => {
            if (!isForwards) {
                setStateOfSprite(spriteTarget, initialState);
            } else if (!forceStop) {
                const lastKeyframe = finalAnimation.keyframes[finalAnimation.keyframes.length - 1];
                setStateOfSprite(spriteTarget, lastKeyframe);
            }
            this.runtime.off('RUNTIME_STEP_START', frameHandler);
            this.runtime.off('ANIMATIONS_FORCE_STEP', frameHandler);
            this.runtime.off('ANIMATIONS_FORCE_SPECIFIC_STEP', forceSpecificStepHandler);
            this.runtime.off('PROJECT_STOP_ALL', stopAllHandler);
            // remove our registered data
            const totalSpriteData = this.progressingTargetData[id];
            if (totalSpriteData) {
                if (totalSpriteData[animationName]) {
                    delete totalSpriteData[animationName];
                }
                const totalAnimationsPlaying = Object.keys(totalSpriteData);
                if (totalAnimationsPlaying.length <= 0) {
                    delete this.progressingTargetData[id];
                    if (this.progressingTargets.includes(id)) {
                        const idx = this.progressingTargets.indexOf(id);
                        this.progressingTargets.splice(idx, 1);
                    }
                }
            }
        };
        let startTime = this.now();
        // calculate length
        let animationLength = 0;
        let keyframeStartTimes = [];
        let keyframeEndTimes = [];
        let _lastKeyframeTime = 0;
        for (const keyframe of finalAnimation.keyframes) {
            animationLength += keyframe.keyframeLength * 1000;
            keyframeStartTimes.push(startTime + _lastKeyframeTime);
            keyframeEndTimes.push(startTime + (keyframe.keyframeLength * 1000) + _lastKeyframeTime);
            _lastKeyframeTime += keyframe.keyframeLength * 1000;
        }
        // get timings & info
        let currentKeyframe = 0; // updates at the end of a frame
        let currentState = getStateOfSprite(spriteTarget); // updates at the end of a frame
        const lastKeyframe = finalAnimation.keyframes.length - 1;
        let endTime = this.now() + animationLength;
        let isPaused = false;
        let pauseStartTime = 0;
        const frameHandler = () => {
            const currentTime = this.now();
            if (animationState.forceStop) {
                // prematurely end the animation
                animationEnded(true);
                return;
            }
            if (animationState.paused || animationState.projectPaused) {
                isPaused = true;
                if (pauseStartTime === 0) {
                    pauseStartTime = this.now();
                }
            }
            if (isPaused) {
                // check if still paused & handle if not
                if (!animationState.paused && !animationState.projectPaused) {
                    isPaused = false;
                    const pauseTime = this.now() - pauseStartTime; // amount of time we were paused for
                    startTime += pauseTime;
                    endTime += pauseTime;
                    keyframeStartTimes = keyframeStartTimes.map(time => time + pauseTime);
                    keyframeEndTimes = keyframeEndTimes.map(time => time + pauseTime);
                    pauseStartTime = 0;
                }
                if (isPaused) {
                    return;
                }
            }
            if (currentTime >= endTime) {
                animationEnded();
                return;
            }
            const keyframe = finalAnimation.keyframes[currentKeyframe];
            const keyframeStart = keyframeStartTimes[currentKeyframe];
            const keyframeEnd = keyframeEndTimes[currentKeyframe];
            // const animationProgress = (currentTime - startTime) / (endTime - startTime);
            const keyframeProgress = (currentTime - keyframeStart) / (keyframeEnd - keyframeStart);
            if (keyframeProgress > 1) {
                if (currentKeyframe + 1 > lastKeyframe) {
                    return animationEnded();
                }
                setStateOfSprite(spriteTarget, keyframe);
                currentState = getStateOfSprite(spriteTarget);
                currentKeyframe += 1;
                // wait another step to continue the next frame
                return;
            }
            this._progressAnimation(spriteTarget, currentState, keyframe, keyframe.easingMode, keyframe.easingDir, keyframeProgress);
        };
        frameHandler();
        this.runtime.once('PROJECT_STOP_ALL', stopAllHandler);
        this.runtime.on('RUNTIME_STEP_START', frameHandler);
        this.runtime.on('ANIMATIONS_FORCE_STEP', frameHandler);
        this.runtime.on('ANIMATIONS_FORCE_SPECIFIC_STEP', forceSpecificStepHandler);
    }
    pauseAnimation(args, util) {
        const id = util.target.id;
        if (!this.progressingTargets.includes(id)) return; // we arent doing ANY animation
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return;
        }
        const info = this.progressingTargetData[id];
        if (!info) return;
        if (!(animationName in info)) {
            return;
        }
        info[animationName].paused = true;
    }
    unpauseAnimation(args, util) {
        const id = util.target.id;
        if (!this.progressingTargets.includes(id)) return; // we arent doing ANY animation
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return;
        }
        const info = this.progressingTargetData[id];
        if (!info) return;
        if (!(animationName in info)) {
            return;
        }
        info[animationName].paused = false;
    }
    stopAnimation(args, util) {
        const id = util.target.id;
        if (!this.progressingTargets.includes(id)) return; // we arent doing ANY animation
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return;
        }
        const info = this.progressingTargetData[id];
        if (!info) return;
        if (!(animationName in info)) {
            return;
        }
        info[animationName].forceStop = true;
        this.runtime.emit('ANIMATIONS_FORCE_SPECIFIC_STEP', id, animationName);
    }

    isPausedAnimation(args, util) { // HIDDEN FROM PALETTE
        const id = util.target.id;
        if (!this.progressingTargets.includes(id)) return false; // we arent doing ANY animation
        const animationName = Cast.toString(args.ANIM);
        if (!(animationName in this.animations)) {
            return false;
        }
        const info = this.progressingTargetData[id];
        if (!info) return;
        if (!(animationName in info)) {
            return false;
        }
        return info[animationName].paused;
    }
    isPropertyAnimation(args, util) {
        const id = util.target.id;
        if (!this.progressingTargets.includes(id)) return false; // we arent doing ANY animation (we arent paused OR playing)
        const animationName = Cast.toString(args.ANIM);
        const animationDataProp = Cast.toString(args.ANIMPROP);
        if (!(animationName in this.animations)) {
            return false; // (we arent paused OR playing)
        }
        const info = this.progressingTargetData[id];
        if (!info) return false; // (we arent paused OR playing)
        if (!(animationName in info)) {
            return false; // (we arent paused OR playing)
        }
        if (animationDataProp === 'paused') {
            return info[animationName].paused;
        }
        return true; // data exists, therefore we are playing the animation currently
    }
}

module.exports = AnimationExtension;