// BlendShape Animation SDK - Engine Agnostic
class BlendShapeAnimator {
    constructor(config = {}) {
        this.morphTargetAdapter = null;
        this.animationFrames = [];
        this.isPlaying = false;
        this.currentFrameIndex = 0;
        this.animationStartTime = 0;
        this.idleAnimations = {};
        this.blendShapeScale = config.blendShapeScale || 1.0;
        this.dataFps = config.dataFps || 30;

        // 空闲动画参数
        this.blinkParams = config.blinkParams || {
            intervalMin: 2000,
            intervalMax: 5000,
            duration: 150,
            speed: 100
        };

        this.eyeLookParams = config.eyeLookParams || {
            intervalMin: 2000,
            intervalMax: 6000,
            durationMin: 1000,
            durationMax: 2500,
            speed: 250
        };

        this.expressionParams = config.expressionParams || {
            intervalMin: 3000,
            intervalMax: 8000,
            speed: 400
        };

        this.enabledExpressions = new Set();
        this.expressionDurations = {};

        // 状态标志
        this.isBlinkEnabled = false;
        this.isEyeLookEnabled = false;
        this.isExpressionEnabled = false;

        // 定时器
        this.blinkInterval = null;
        this.eyeLookInterval = null;

        // 回调
        this.onStatusChange = config.onStatusChange || (() => {});

        // 启动空闲动画循环
        this._updateIdleAnimations();
    }

    // 设置形态键适配器
    setMorphTargetAdapter(adapter) {
        this.morphTargetAdapter = adapter;
    }

    // 加载动画帧数据
    loadAnimationFrames(frames) {
        this.animationFrames = frames;
    }

    // 播放动画
    playAnimation() {
        if (this.animationFrames.length === 0) {
            this.onStatusChange('error', '请先加载动画数据');
            return;
        }

        if (!this.morphTargetAdapter) {
            this.onStatusChange('error', '未设置形态键适配器');
            return;
        }

        // 停止随机表情
        if (this.isExpressionEnabled && window.ExpressionLibrary) {
            window.ExpressionLibrary.randomPlayer.stop();
        }

        this.stopAnimation();
        this.isPlaying = true;
        this.currentFrameIndex = 0;
        this.animationStartTime = performance.now();

        this._animateFrame();
        this.onStatusChange('info', '播放中...');
    }

    // 停止动画
    stopAnimation() {
        this.isPlaying = false;

        // 恢复随机表情
        if (this.isExpressionEnabled && window.ExpressionLibrary) {
            window.ExpressionLibrary.randomPlayer.start();
        }

        this.onStatusChange('info', '已停止');
    }

    // 内部动画帧处理
    _animateFrame() {
        if (!this.isPlaying) return;

        const now = performance.now();
        const frameDuration = 1000 / this.dataFps;
        const elapsed = now - this.animationStartTime;
        const exactFrame = elapsed / frameDuration;
        const targetFrameIndex = Math.floor(exactFrame);

        if (targetFrameIndex >= this.animationFrames.length) {
            this.stopAnimation();
            return;
        }

        const currentFrame = this.animationFrames[targetFrameIndex];
        const nextFrame = this.animationFrames[Math.min(targetFrameIndex + 1, this.animationFrames.length - 1)];
        const frameProgress = exactFrame - targetFrameIndex;
        const smoothProgress = this._easeOutQuad(frameProgress);

        for (const key in currentFrame.blendShapes) {
            const currentValue = currentFrame.blendShapes[key] || 0;
            const nextValue = nextFrame.blendShapes[key] || 0;
            const interpolatedValue = this._lerp(currentValue, nextValue, smoothProgress);
            const scaledValue = interpolatedValue * this.blendShapeScale;

            this.morphTargetAdapter.setInfluence(key, scaledValue);
        }

        this.currentFrameIndex = targetFrameIndex;
        requestAnimationFrame(() => this._animateFrame());
    }

    // 设置空闲动画
    setIdleAnimation(name, target, duration = 200, easing = 'easeOutQuad') {
        this.idleAnimations[name] = {
            target: target,
            duration: duration,
            easing: easing,
            startTime: null,
            startValue: this.idleAnimations[name]?.target || 0
        };
    }

    // 更新空闲动画
    _updateIdleAnimations() {
        const now = performance.now();

        for (const name in this.idleAnimations) {
            const anim = this.idleAnimations[name];

            if (!this.morphTargetAdapter) continue;

            if (!anim.startTime) {
                anim.startTime = now;
                anim.startValue = this.morphTargetAdapter.getInfluence(name) || 0;
            }

            const elapsed = now - anim.startTime;
            const duration = anim.duration || 200;
            let progress = Math.min(elapsed / duration, 1.0);

            progress = this._applyEasing(progress, anim.easing);
            const currentValue = this._lerp(anim.startValue, anim.target, progress);

            this.morphTargetAdapter.setInfluence(name, currentValue);

            if (progress >= 1.0) {
                if (anim.target === 0) {
                    delete this.idleAnimations[name];
                } else {
                    anim.startTime = null;
                }
            }
        }

        requestAnimationFrame(() => this._updateIdleAnimations());
    }

    // 眨眼控制
    toggleBlink(enabled) {
        this.isBlinkEnabled = enabled;

        if (enabled) {
            this._startRandomBlink();
            this.onStatusChange('success', '随机眨眼已开启');
        } else {
            this._stopRandomBlink();
            this.onStatusChange('info', '随机眨眼已关闭');
        }
    }

    _startRandomBlink() {
        this._stopRandomBlink();

        const scheduleNext = () => {
            const delay = this.blinkParams.intervalMin + Math.random() * (this.blinkParams.intervalMax - this.blinkParams.intervalMin);
            this.blinkInterval = setTimeout(() => {
                if (this.isBlinkEnabled) {
                    this._doBlink();
                    scheduleNext();
                }
            }, delay);
        };

        scheduleNext();
    }

    _stopRandomBlink() {
        if (this.blinkInterval) {
            clearTimeout(this.blinkInterval);
            this.blinkInterval = null;
        }
    }

    _doBlink() {
        const blinkShapes = ['eyeblinkleft', 'eyeblinkright'];

        blinkShapes.forEach(name => {
            this.setIdleAnimation(name, 1.0, this.blinkParams.speed, 'easeOutQuad');
        });

        setTimeout(() => {
            blinkShapes.forEach(name => {
                this.setIdleAnimation(name, 0, this.blinkParams.speed + 20, 'easeInOutQuad');
            });
        }, this.blinkParams.duration);
    }

    // 眼球移动控制
    toggleEyeLook(enabled) {
        this.isEyeLookEnabled = enabled;

        if (enabled) {
            this._startRandomEyeLook();
            this.onStatusChange('success', '眼球移动已开启');
        } else {
            this._stopRandomEyeLook();
            this._resetEyeLook();
            this.onStatusChange('info', '眼球移动已关闭');
        }
    }

    _startRandomEyeLook() {
        this._stopRandomEyeLook();

        const scheduleNext = () => {
            const delay = this.eyeLookParams.intervalMin + Math.random() * (this.eyeLookParams.intervalMax - this.eyeLookParams.intervalMin);
            this.eyeLookInterval = setTimeout(() => {
                if (this.isEyeLookEnabled) {
                    this._doRandomEyeLook();
                    scheduleNext();
                }
            }, delay);
        };

        scheduleNext();
    }

    _stopRandomEyeLook() {
        if (this.eyeLookInterval) {
            clearTimeout(this.eyeLookInterval);
            this.eyeLookInterval = null;
        }
    }

    _doRandomEyeLook() {
        const directions = [
            { shapes: {} },
            { shapes: { 'eyelookupleft': 0.3, 'eyelookupright': 0.3 } },
            { shapes: { 'eyelookdownleft': 0.3, 'eyelookdownright': 0.3 } },
            { shapes: { 'eyelookinleft': 0.4, 'eyelookoutright': 0.4 } },
            { shapes: { 'eyelookoutleft': 0.4, 'eyelookinright': 0.4 } }
        ];

        const direction = directions[Math.floor(Math.random() * directions.length)];
        const eyeLookShapes = [
            'eyelookupleft', 'eyelookupright',
            'eyelookdownleft', 'eyelookdownright',
            'eyelookinleft', 'eyelookinright',
            'eyelookoutleft', 'eyelookoutright'
        ];

        eyeLookShapes.forEach(name => {
            this.setIdleAnimation(name, 0, this.eyeLookParams.speed * 0.8, 'easeInOutQuad');
        });

        for (const [name, value] of Object.entries(direction.shapes)) {
            this.setIdleAnimation(name, value, this.eyeLookParams.speed, 'easeInOutQuad');
        }

        const holdDuration = this.eyeLookParams.durationMin + Math.random() * (this.eyeLookParams.durationMax - this.eyeLookParams.durationMin);
        setTimeout(() => {
            if (this.isEyeLookEnabled) {
                eyeLookShapes.forEach(name => {
                    this.setIdleAnimation(name, 0, this.eyeLookParams.speed * 1.2, 'easeInOutQuad');
                });
            }
        }, holdDuration);
    }

    _resetEyeLook() {
        const eyeLookShapes = [
            'eyelookupleft', 'eyelookupright',
            'eyelookdownleft', 'eyelookdownright',
            'eyelookinleft', 'eyelookinright',
            'eyelookoutleft', 'eyelookoutright'
        ];

        eyeLookShapes.forEach(name => {
            this.setIdleAnimation(name, 0, this.eyeLookParams.speed, 'easeInOutQuad');
        });
    }

    // 随机表情控制
    toggleRandomExpression(enabled) {
        if (!window.ExpressionLibrary) {
            this.onStatusChange('error', '表情库未加载');
            return;
        }

        this.isExpressionEnabled = enabled;

        if (enabled) {
            window.ExpressionLibrary.randomPlayer.intervalMin = this.expressionParams.intervalMin;
            window.ExpressionLibrary.randomPlayer.intervalMax = this.expressionParams.intervalMax;

            if (!this.isPlaying) {
                window.ExpressionLibrary.randomPlayer.start();
            }
            this.onStatusChange('success', '随机表情已开启');
        } else {
            window.ExpressionLibrary.randomPlayer.stop();
            this.onStatusChange('info', '随机表情已关闭');
        }
    }

    // 缓动函数
    _easeOutQuad(t) {
        return t * (2 - t);
    }

    _lerp(start, end, t) {
        return start + (end - start) * t;
    }

    _applyEasing(t, type) {
        switch(type) {
            case 'easeOutQuad':
                return t * (2 - t);
            case 'easeInOutQuad':
                return t < 0.5 ? 2 * t * t : -1 + (4 - 2 * t) * t;
            case 'easeInOutCubic':
                return t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
            case 'easeOutCubic':
                return 1 - Math.pow(1 - t, 3);
            case 'linear':
            default:
                return t;
        }
    }

    // 更新配置
    updateConfig(key, value) {
        if (key === 'blendShapeScale') {
            this.blendShapeScale = value;
        } else if (this[key]) {
            this[key] = value;
        }
    }
}

// 导出到全局
if (typeof window !== 'undefined') {
    window.BlendShapeAnimator = BlendShapeAnimator;
}