/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.support.design.widget;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.graphics.drawable.LayerDrawable;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.RequiresApi;
import android.support.design.R;
import android.support.v4.content.ContextCompat;
import android.support.v4.graphics.drawable.DrawableCompat;
import android.support.v4.view.ViewCompat;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.animation.Interpolator;

@RequiresApi(14)
class FloatingActionButtonImpl {
    static final Interpolator ANIM_INTERPOLATOR = AnimationUtils.FAST_OUT_LINEAR_IN_INTERPOLATOR;
    static final long PRESSED_ANIM_DURATION = 100;
    static final long PRESSED_ANIM_DELAY = 100;

    static final int ANIM_STATE_NONE = 0;
    static final int ANIM_STATE_HIDING = 1;
    static final int ANIM_STATE_SHOWING = 2;

    int mAnimState = ANIM_STATE_NONE;

    private final StateListAnimator mStateListAnimator;

    ShadowDrawableWrapper mShadowDrawable;

    private float mRotation;

    Drawable mShapeDrawable;
    Drawable mRippleDrawable;
    CircularBorderDrawable mBorderDrawable;
    Drawable mContentBackground;

    float mElevation;
    float mPressedTranslationZ;

    interface InternalVisibilityChangedListener {
        void onShown();
        void onHidden();
    }

    static final int SHOW_HIDE_ANIM_DURATION = 200;

    static final int[] PRESSED_ENABLED_STATE_SET = {android.R.attr.state_pressed,
            android.R.attr.state_enabled};
    static final int[] FOCUSED_ENABLED_STATE_SET = {android.R.attr.state_focused,
            android.R.attr.state_enabled};
    static final int[] ENABLED_STATE_SET = {android.R.attr.state_enabled};
    static final int[] EMPTY_STATE_SET = new int[0];

    final VisibilityAwareImageButton mView;
    final ShadowViewDelegate mShadowViewDelegate;

    private final Rect mTmpRect = new Rect();
    private ViewTreeObserver.OnPreDrawListener mPreDrawListener;

    FloatingActionButtonImpl(VisibilityAwareImageButton view,
            ShadowViewDelegate shadowViewDelegate) {
        mView = view;
        mShadowViewDelegate = shadowViewDelegate;

        mStateListAnimator = new StateListAnimator();

        // Elevate with translationZ when pressed or focused
        mStateListAnimator.addState(PRESSED_ENABLED_STATE_SET,
                createAnimator(new ElevateToTranslationZAnimation()));
        mStateListAnimator.addState(FOCUSED_ENABLED_STATE_SET,
                createAnimator(new ElevateToTranslationZAnimation()));
        // Reset back to elevation by default
        mStateListAnimator.addState(ENABLED_STATE_SET,
                createAnimator(new ResetElevationAnimation()));
        // Set to 0 when disabled
        mStateListAnimator.addState(EMPTY_STATE_SET,
                createAnimator(new DisabledElevationAnimation()));

        mRotation = mView.getRotation();
    }

    void setBackgroundDrawable(ColorStateList backgroundTint,
            PorterDuff.Mode backgroundTintMode, int rippleColor, int borderWidth) {
        // Now we need to tint the original background with the tint, using
        // an InsetDrawable if we have a border width
        mShapeDrawable = DrawableCompat.wrap(createShapeDrawable());
        DrawableCompat.setTintList(mShapeDrawable, backgroundTint);
        if (backgroundTintMode != null) {
            DrawableCompat.setTintMode(mShapeDrawable, backgroundTintMode);
        }

        // Now we created a mask Drawable which will be used for touch feedback.
        GradientDrawable touchFeedbackShape = createShapeDrawable();

        // We'll now wrap that touch feedback mask drawable with a ColorStateList. We do not need
        // to inset for any border here as LayerDrawable will nest the padding for us
        mRippleDrawable = DrawableCompat.wrap(touchFeedbackShape);
        DrawableCompat.setTintList(mRippleDrawable, createColorStateList(rippleColor));

        final Drawable[] layers;
        if (borderWidth > 0) {
            mBorderDrawable = createBorderDrawable(borderWidth, backgroundTint);
            layers = new Drawable[] {mBorderDrawable, mShapeDrawable, mRippleDrawable};
        } else {
            mBorderDrawable = null;
            layers = new Drawable[] {mShapeDrawable, mRippleDrawable};
        }

        mContentBackground = new LayerDrawable(layers);

        mShadowDrawable = new ShadowDrawableWrapper(
                mView.getContext(),
                mContentBackground,
                mShadowViewDelegate.getRadius(),
                mElevation,
                mElevation + mPressedTranslationZ);
        mShadowDrawable.setAddPaddingForCorners(false);
        mShadowViewDelegate.setBackgroundDrawable(mShadowDrawable);
    }

    void setBackgroundTintList(ColorStateList tint) {
        if (mShapeDrawable != null) {
            DrawableCompat.setTintList(mShapeDrawable, tint);
        }
        if (mBorderDrawable != null) {
            mBorderDrawable.setBorderTint(tint);
        }
    }

    void setBackgroundTintMode(PorterDuff.Mode tintMode) {
        if (mShapeDrawable != null) {
            DrawableCompat.setTintMode(mShapeDrawable, tintMode);
        }
    }


    void setRippleColor(int rippleColor) {
        if (mRippleDrawable != null) {
            DrawableCompat.setTintList(mRippleDrawable, createColorStateList(rippleColor));
        }
    }

    final void setElevation(float elevation) {
        if (mElevation != elevation) {
            mElevation = elevation;
            onElevationsChanged(elevation, mPressedTranslationZ);
        }
    }

    float getElevation() {
        return mElevation;
    }

    final void setPressedTranslationZ(float translationZ) {
        if (mPressedTranslationZ != translationZ) {
            mPressedTranslationZ = translationZ;
            onElevationsChanged(mElevation, translationZ);
        }
    }

    void onElevationsChanged(float elevation, float pressedTranslationZ) {
        if (mShadowDrawable != null) {
            mShadowDrawable.setShadowSize(elevation, elevation + mPressedTranslationZ);
            updatePadding();
        }
    }

    void onDrawableStateChanged(int[] state) {
        mStateListAnimator.setState(state);
    }

    void jumpDrawableToCurrentState() {
        mStateListAnimator.jumpToCurrentState();
    }

    void hide(@Nullable final InternalVisibilityChangedListener listener, final boolean fromUser) {
        if (isOrWillBeHidden()) {
            // We either are or will soon be hidden, skip the call
            return;
        }

        mView.animate().cancel();

        if (shouldAnimateVisibilityChange()) {
            mAnimState = ANIM_STATE_HIDING;

            mView.animate()
                    .scaleX(0f)
                    .scaleY(0f)
                    .alpha(0f)
                    .setDuration(SHOW_HIDE_ANIM_DURATION)
                    .setInterpolator(AnimationUtils.FAST_OUT_LINEAR_IN_INTERPOLATOR)
                    .setListener(new AnimatorListenerAdapter() {
                        private boolean mCancelled;

                        @Override
                        public void onAnimationStart(Animator animation) {
                            mView.internalSetVisibility(View.VISIBLE, fromUser);
                            mCancelled = false;
                        }

                        @Override
                        public void onAnimationCancel(Animator animation) {
                            mCancelled = true;
                        }

                        @Override
                        public void onAnimationEnd(Animator animation) {
                            mAnimState = ANIM_STATE_NONE;

                            if (!mCancelled) {
                                mView.internalSetVisibility(fromUser ? View.GONE : View.INVISIBLE,
                                        fromUser);
                                if (listener != null) {
                                    listener.onHidden();
                                }
                            }
                        }
                    });
        } else {
            // If the view isn't laid out, or we're in the editor, don't run the animation
            mView.internalSetVisibility(fromUser ? View.GONE : View.INVISIBLE, fromUser);
            if (listener != null) {
                listener.onHidden();
            }
        }
    }

    void show(@Nullable final InternalVisibilityChangedListener listener, final boolean fromUser) {
        if (isOrWillBeShown()) {
            // We either are or will soon be visible, skip the call
            return;
        }

        mView.animate().cancel();

        if (shouldAnimateVisibilityChange()) {
            mAnimState = ANIM_STATE_SHOWING;

            if (mView.getVisibility() != View.VISIBLE) {
                // If the view isn't visible currently, we'll animate it from a single pixel
                mView.setAlpha(0f);
                mView.setScaleY(0f);
                mView.setScaleX(0f);
            }

            mView.animate()
                    .scaleX(1f)
                    .scaleY(1f)
                    .alpha(1f)
                    .setDuration(SHOW_HIDE_ANIM_DURATION)
                    .setInterpolator(AnimationUtils.LINEAR_OUT_SLOW_IN_INTERPOLATOR)
                    .setListener(new AnimatorListenerAdapter() {
                        @Override
                        public void onAnimationStart(Animator animation) {
                            mView.internalSetVisibility(View.VISIBLE, fromUser);
                        }

                        @Override
                        public void onAnimationEnd(Animator animation) {
                            mAnimState = ANIM_STATE_NONE;
                            if (listener != null) {
                                listener.onShown();
                            }
                        }
                    });
        } else {
            mView.internalSetVisibility(View.VISIBLE, fromUser);
            mView.setAlpha(1f);
            mView.setScaleY(1f);
            mView.setScaleX(1f);
            if (listener != null) {
                listener.onShown();
            }
        }
    }

    final Drawable getContentBackground() {
        return mContentBackground;
    }

    void onCompatShadowChanged() {
        // Ignore pre-v21
    }

    final void updatePadding() {
        Rect rect = mTmpRect;
        getPadding(rect);
        onPaddingUpdated(rect);
        mShadowViewDelegate.setShadowPadding(rect.left, rect.top, rect.right, rect.bottom);
    }

    void getPadding(Rect rect) {
        mShadowDrawable.getPadding(rect);
    }

    void onPaddingUpdated(Rect padding) {}

    void onAttachedToWindow() {
        if (requirePreDrawListener()) {
            ensurePreDrawListener();
            mView.getViewTreeObserver().addOnPreDrawListener(mPreDrawListener);
        }
    }

    void onDetachedFromWindow() {
        if (mPreDrawListener != null) {
            mView.getViewTreeObserver().removeOnPreDrawListener(mPreDrawListener);
            mPreDrawListener = null;
        }
    }

    boolean requirePreDrawListener() {
        return true;
    }

    CircularBorderDrawable createBorderDrawable(int borderWidth, ColorStateList backgroundTint) {
        final Context context = mView.getContext();
        CircularBorderDrawable borderDrawable = newCircularDrawable();
        borderDrawable.setGradientColors(
                ContextCompat.getColor(context, R.color.design_fab_stroke_top_outer_color),
                ContextCompat.getColor(context, R.color.design_fab_stroke_top_inner_color),
                ContextCompat.getColor(context, R.color.design_fab_stroke_end_inner_color),
                ContextCompat.getColor(context, R.color.design_fab_stroke_end_outer_color));
        borderDrawable.setBorderWidth(borderWidth);
        borderDrawable.setBorderTint(backgroundTint);
        return borderDrawable;
    }

    CircularBorderDrawable newCircularDrawable() {
        return new CircularBorderDrawable();
    }

    void onPreDraw() {
        final float rotation = mView.getRotation();
        if (mRotation != rotation) {
            mRotation = rotation;
            updateFromViewRotation();
        }
    }

    private void ensurePreDrawListener() {
        if (mPreDrawListener == null) {
            mPreDrawListener = new ViewTreeObserver.OnPreDrawListener() {
                @Override
                public boolean onPreDraw() {
                    FloatingActionButtonImpl.this.onPreDraw();
                    return true;
                }
            };
        }
    }

    GradientDrawable createShapeDrawable() {
        GradientDrawable d = newGradientDrawableForShape();
        d.setShape(GradientDrawable.OVAL);
        d.setColor(Color.WHITE);
        return d;
    }

    GradientDrawable newGradientDrawableForShape() {
        return new GradientDrawable();
    }

    boolean isOrWillBeShown() {
        if (mView.getVisibility() != View.VISIBLE) {
            // If we not currently visible, return true if we're animating to be shown
            return mAnimState == ANIM_STATE_SHOWING;
        } else {
            // Otherwise if we're visible, return true if we're not animating to be hidden
            return mAnimState != ANIM_STATE_HIDING;
        }
    }

    boolean isOrWillBeHidden() {
        if (mView.getVisibility() == View.VISIBLE) {
            // If we currently visible, return true if we're animating to be hidden
            return mAnimState == ANIM_STATE_HIDING;
        } else {
            // Otherwise if we're not visible, return true if we're not animating to be shown
            return mAnimState != ANIM_STATE_SHOWING;
        }
    }

    private ValueAnimator createAnimator(@NonNull ShadowAnimatorImpl impl) {
        final ValueAnimator animator = new ValueAnimator();
        animator.setInterpolator(ANIM_INTERPOLATOR);
        animator.setDuration(PRESSED_ANIM_DURATION);
        animator.addListener(impl);
        animator.addUpdateListener(impl);
        animator.setFloatValues(0, 1);
        return animator;
    }

    private abstract class ShadowAnimatorImpl extends AnimatorListenerAdapter
            implements ValueAnimator.AnimatorUpdateListener {
        private boolean mValidValues;
        private float mShadowSizeStart;
        private float mShadowSizeEnd;

        @Override
        public void onAnimationUpdate(ValueAnimator animator) {
            if (!mValidValues) {
                mShadowSizeStart = mShadowDrawable.getShadowSize();
                mShadowSizeEnd = getTargetShadowSize();
                mValidValues = true;
            }

            mShadowDrawable.setShadowSize(mShadowSizeStart
                    + ((mShadowSizeEnd - mShadowSizeStart) * animator.getAnimatedFraction()));
        }

        @Override
        public void onAnimationEnd(Animator animator) {
            mShadowDrawable.setShadowSize(mShadowSizeEnd);
            mValidValues = false;
        }

        /**
         * @return the shadow size we want to animate to.
         */
        protected abstract float getTargetShadowSize();
    }

    private class ResetElevationAnimation extends ShadowAnimatorImpl {
        ResetElevationAnimation() {
        }

        @Override
        protected float getTargetShadowSize() {
            return mElevation;
        }
    }

    private class ElevateToTranslationZAnimation extends ShadowAnimatorImpl {
        ElevateToTranslationZAnimation() {
        }

        @Override
        protected float getTargetShadowSize() {
            return mElevation + mPressedTranslationZ;
        }
    }

    private class DisabledElevationAnimation extends ShadowAnimatorImpl {
        DisabledElevationAnimation() {
        }

        @Override
        protected float getTargetShadowSize() {
            return 0f;
        }
    }

    private static ColorStateList createColorStateList(int selectedColor) {
        final int[][] states = new int[3][];
        final int[] colors = new int[3];
        int i = 0;

        states[i] = FOCUSED_ENABLED_STATE_SET;
        colors[i] = selectedColor;
        i++;

        states[i] = PRESSED_ENABLED_STATE_SET;
        colors[i] = selectedColor;
        i++;

        // Default enabled state
        states[i] = new int[0];
        colors[i] = Color.TRANSPARENT;
        i++;

        return new ColorStateList(states, colors);
    }

    private boolean shouldAnimateVisibilityChange() {
        return ViewCompat.isLaidOut(mView) && !mView.isInEditMode();
    }

    private void updateFromViewRotation() {
        if (Build.VERSION.SDK_INT == 19) {
            // KitKat seems to have an issue with views which are rotated with angles which are
            // not divisible by 90. Worked around by moving to software rendering in these cases.
            if ((mRotation % 90) != 0) {
                if (mView.getLayerType() != View.LAYER_TYPE_SOFTWARE) {
                    mView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
                }
            } else {
                if (mView.getLayerType() != View.LAYER_TYPE_NONE) {
                    mView.setLayerType(View.LAYER_TYPE_NONE, null);
                }
            }
        }

        // Offset any View rotation
        if (mShadowDrawable != null) {
            mShadowDrawable.setRotation(-mRotation);
        }
        if (mBorderDrawable != null) {
            mBorderDrawable.setRotation(-mRotation);
        }
    }
}