/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * 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 org.nativescript.widgets;


import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.core.widget.ImageViewCompat;

class TabStrip extends LinearLayout {

	private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 0;
	private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26;
	private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 3;
	private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5;

	private final int mBottomBorderThickness;
	private final Paint mBottomBorderPaint;

	private final int mSelectedIndicatorThickness;
	private final Paint mSelectedIndicatorPaint;

	private final int mDefaultBottomBorderColor;

	private int mSelectedPosition;
	private float mSelectionOffset;

	private TabLayout.TabColorizer mCustomTabColorizer;
	private final SimpleTabColorizer mDefaultTabColorizer;

	private int mTabTextColor;
	private int mSelectedTabTextColor;
	private float mTabTextFontSize;
	private TabIconRenderingMode mIconRenderingMode;

	private boolean mShouldUpdateTabsTextColor;

	TabStrip(Context context) {
		this(context, null);
	}

	TabStrip(Context context, AttributeSet attrs) {
		super(context, attrs);

		setWillNotDraw(false);

		final float density = getResources().getDisplayMetrics().density;

		TypedValue outValue = new TypedValue();
		context.getTheme().resolveAttribute(android.R.attr.colorForeground, outValue, true);
		final int themeForegroundColor = outValue.data;

		mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor,
			DEFAULT_BOTTOM_BORDER_COLOR_ALPHA);

		mDefaultTabColorizer = new SimpleTabColorizer();
		mDefaultTabColorizer.setIndicatorColors(DEFAULT_SELECTED_INDICATOR_COLOR);

		mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density);
		mBottomBorderPaint = new Paint();
		mBottomBorderPaint.setColor(mDefaultBottomBorderColor);

		mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density);
		mSelectedIndicatorPaint = new Paint();

		TextView defaultTextView = new TextView(context);
		mTabTextColor = defaultTextView.getTextColors().getDefaultColor();
		mTabTextFontSize = defaultTextView.getTextSize();

		// Default selected color is the same as mTabTextColor
		mSelectedTabTextColor = mTabTextColor;
		mIconRenderingMode = TabIconRenderingMode.original;

		mShouldUpdateTabsTextColor = true;

		setMeasureWithLargestChildEnabled(true);
	}

	void setCustomTabColorizer(TabLayout.TabColorizer customTabColorizer) {
		mCustomTabColorizer = customTabColorizer;
		invalidate();
	}

	void setSelectedIndicatorColors(int... colors) {
		// Make sure that the custom colorizer is removed
		mCustomTabColorizer = null;
		mDefaultTabColorizer.setIndicatorColors(colors);
		invalidate();
	}

	void setIconRenderingMode(TabIconRenderingMode mode) {
		mIconRenderingMode = mode;
		updateTabsTextColor();
	}

	TabIconRenderingMode getIconRenderingMode() {
		return mIconRenderingMode;
	}

	void setTabTextColor(int color) {
		mTabTextColor = color;
		updateTabsTextColor();
	}

	int getTabTextColor() {
		return mTabTextColor;
	}

	void setSelectedTabTextColor(int color) {
		mSelectedTabTextColor = color;
		updateTabsTextColor();
	}

	int getSelectedTabTextColor() {
		return mSelectedTabTextColor;
	}

	void setShouldUpdateTabsTextColor(boolean value) {
		mShouldUpdateTabsTextColor = value;
	}

	private void updateTabsTextColor() {
		if (mShouldUpdateTabsTextColor) {
			final int childCount = getChildCount();
			int greyColor = Color.parseColor("#A2A2A2");
			for (int i = 0; i < childCount; i++) {
				LinearLayout linearLayout = (LinearLayout) getChildAt(i);
				ImageView imageView = (ImageView) linearLayout.getChildAt(0);
				TextView textView = (TextView) linearLayout.getChildAt(1);

				if (mIconRenderingMode == TabIconRenderingMode.template) {
					ColorStateList tint;
					if (i == mSelectedPosition) {
						tint = ColorStateList.valueOf(mSelectedTabTextColor);
					} else {
						tint = ColorStateList.valueOf(greyColor);
					}

					ImageViewCompat.setImageTintList(imageView, tint);
				} else {
					ImageViewCompat.setImageTintList(imageView, null);
				}

				if (i == mSelectedPosition) {
					textView.setTextColor(mSelectedTabTextColor);
				} else {
					textView.setTextColor(mTabTextColor);
				}
			}
		}
	}

	void setTabTextFontSize(float fontSize) {
		mTabTextFontSize = fontSize;
		updateTabsTextFontSize();
	}

	float getTabTextFontSize() {
		return mTabTextFontSize;
	}

	private void updateTabsTextFontSize() {
		final int childCount = getChildCount();
		for (int i = 0; i < childCount; i++) {
			LinearLayout linearLayout = (LinearLayout) getChildAt(i);
			TextView textView = (TextView) linearLayout.getChildAt(1);
			textView.setTextSize(mTabTextFontSize);
		}
	}

	// Used by TabLayout (the 'old' tab-view control)
	void onViewPagerPageChanged(int position, float positionOffset) {
		mSelectedPosition = position;
		mSelectionOffset = positionOffset;
		invalidate();
		updateTabsTextColor();
	}

	// Used by TabsBar
	void onTabsViewPagerPageChanged(int position, float positionOffset) {
		mSelectedPosition = position;
		mSelectionOffset = positionOffset;
		invalidate();
	}

	int getSelectedPosition() {
		return mSelectedPosition;
	}

	void setSelectedPosition(int position) {
		mSelectedPosition = position;
		invalidate();
		updateTabsTextColor();
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
		super.dispatchDraw(canvas);

		final int height = getHeight();
		final int childCount = getChildCount();
		final TabLayout.TabColorizer tabColorizer = mCustomTabColorizer != null
			? mCustomTabColorizer
			: mDefaultTabColorizer;

		// Thick colored underline below the current selection
		if (childCount > 0 && mSelectedPosition < childCount) {
			View selectedTitle = getChildAt(mSelectedPosition);
			int left = selectedTitle.getLeft();
			int right = selectedTitle.getRight();
			int color = tabColorizer.getIndicatorColor(mSelectedPosition);

			if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) {
				int nextColor = tabColorizer.getIndicatorColor(mSelectedPosition + 1);
				if (color != nextColor) {
					color = blendColors(nextColor, color, mSelectionOffset);
				}

				// Draw the selection partway between the tabs
				View nextTitle = getChildAt(mSelectedPosition + 1);
				left = (int) (mSelectionOffset * nextTitle.getLeft() +
					(1.0f - mSelectionOffset) * left);
				right = (int) (mSelectionOffset * nextTitle.getRight() +
					(1.0f - mSelectionOffset) * right);
			}

			mSelectedIndicatorPaint.setColor(color);

			canvas.drawRect(left, height - mSelectedIndicatorThickness, right,
				height, mSelectedIndicatorPaint);
		}

		// Thin underline along the entire bottom edge
		canvas.drawRect(0, height - mBottomBorderThickness, getWidth(), height, mBottomBorderPaint);
	}

	/**
	 * Set the alpha value of the {@code color} to be the given {@code alpha} value.
	 */
	private static int setColorAlpha(int color, byte alpha) {
		return Color.argb(alpha, Color.red(color), Color.green(color), Color.blue(color));
	}

	/**
	 * Blend {@code color1} and {@code color2} using the given ratio.
	 *
	 * @param ratio of which to blend. 1.0 will return {@code color1}, 0.5 will give an even blend,
	 *              0.0 will return {@code color2}.
	 */
	private static int blendColors(int color1, int color2, float ratio) {
		final float inverseRation = 1f - ratio;
		float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation);
		float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation);
		float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation);
		return Color.rgb((int) r, (int) g, (int) b);
	}

	private static class SimpleTabColorizer implements TabLayout.TabColorizer {
		private int[] mIndicatorColors;

		@Override
		public final int getIndicatorColor(int position) {
			return mIndicatorColors[position % mIndicatorColors.length];
		}

		void setIndicatorColors(int... colors) {
			mIndicatorColors = colors;
		}
	}
}