package org.nativescript.widgets;

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.util.AttributeSet;

/**
 * @author hhristov
 */
public class StackLayout extends LayoutBase {
	static final String TAG = "JS";
	private int _totalLength = 0;
	private Orientation _orientation = Orientation.vertical;

	public StackLayout(Context context) {
		this(context, null);
	}
	public StackLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}
	public StackLayout(Context context, AttributeSet attrs, int defStyleAttr) {
		super(context, attrs, defStyleAttr);
	}

	public Orientation getOrientation() {
		return this._orientation;
	}

	public void setOrientation(Orientation value) {
		this._orientation = value;
		this.requestLayout();
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		CommonLayoutParams.adjustChildrenLayoutParams(this, widthMeasureSpec, heightMeasureSpec);

		int childState = 0;
		int measureWidth = 0;
		int measureHeight = 0;

		int width = MeasureSpec.getSize(widthMeasureSpec);
		int widthMode = MeasureSpec.getMode(widthMeasureSpec);

		int height = MeasureSpec.getSize(heightMeasureSpec);
		int heightMode = MeasureSpec.getMode(heightMeasureSpec);

		boolean isVertical = this._orientation == Orientation.vertical;
		int verticalPadding = this.getPaddingTop() + this.getPaddingBottom();
		int horizontalPadding = this.getPaddingLeft() + this.getPaddingRight();

		int count = this.getChildCount();
		int measureSpecMode;
		int remainingLength;

		int mode = isVertical ? heightMode : widthMode;
		if (mode == MeasureSpec.UNSPECIFIED) {
			measureSpecMode = MeasureSpec.UNSPECIFIED;
			remainingLength = 0;
		} else {
			measureSpecMode = MeasureSpec.AT_MOST;
			remainingLength = isVertical ? height - verticalPadding : width - horizontalPadding;
		}

		int childMeasureSpec;
		if (isVertical) {
			int childWidth = (widthMode == MeasureSpec.UNSPECIFIED) ? 0 : width - horizontalPadding;
			childWidth = Math.max(0, childWidth);
			childMeasureSpec = MeasureSpec.makeMeasureSpec(childWidth, widthMode);
		} else {
			int childHeight = (heightMode == MeasureSpec.UNSPECIFIED) ? 0 : height - verticalPadding;
			childHeight = Math.max(0, childHeight);
			childMeasureSpec = MeasureSpec.makeMeasureSpec(childHeight, heightMode);
		}

		for (int i = 0; i < count; i++) {
			View child = this.getChildAt(i);
			if (child.getVisibility() == View.GONE) {
				continue;
			}

			if (isVertical) {
				// Measuring android.widget.ListView, with no height property set, with MeasureSpec.AT_MOST will
				// result in height required for all list view items or the maximum available space for the StackLayout.
				// Any following controls will be visible only if enough space left.
				CommonLayoutParams.measureChild(child, childMeasureSpec, MeasureSpec.makeMeasureSpec(remainingLength, measureSpecMode));

				if (measureSpecMode == MeasureSpec.AT_MOST && this.isUnsizedScrollableView(child)) {
					Log.e(TAG, "Avoid using ListView or ScrollView with no explicit height set inside StackLayout. Doing so might results in poor user interface performance and a poor user experience.");
				}

				final int childMeasuredWidth = CommonLayoutParams.getDesiredWidth(child);
				final int childMeasuredHeight = CommonLayoutParams.getDesiredHeight(child);

				measureWidth = Math.max(measureWidth, childMeasuredWidth);
				measureHeight += childMeasuredHeight;
				remainingLength = Math.max(0, remainingLength - childMeasuredHeight);
			} else {
				CommonLayoutParams.measureChild(child, MeasureSpec.makeMeasureSpec(remainingLength, measureSpecMode), childMeasureSpec);
				final int childMeasuredWidth = CommonLayoutParams.getDesiredWidth(child);
				final int childMeasuredHeight = CommonLayoutParams.getDesiredHeight(child);

				measureHeight = Math.max(measureHeight, childMeasuredHeight);
				measureWidth += childMeasuredWidth;
				remainingLength = Math.max(0, remainingLength - childMeasuredWidth);
			}

			childState = combineMeasuredStates(childState, child.getMeasuredState());
		}

		// Add in our padding
		measureWidth += horizontalPadding;
		measureHeight += verticalPadding;

		// Check against our minimum sizes
		measureWidth = Math.max(measureWidth, this.getSuggestedMinimumWidth());
		measureHeight = Math.max(measureHeight, this.getSuggestedMinimumHeight());

		this._totalLength = isVertical ? measureHeight : measureWidth;

		int widthSizeAndState = resolveSizeAndState(measureWidth, widthMeasureSpec, isVertical ? childState : 0);
		int heightSizeAndState = resolveSizeAndState(measureHeight, heightMeasureSpec, isVertical ? 0 : childState);

		this.setMeasuredDimension(widthSizeAndState, heightSizeAndState);
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		if (this._orientation == Orientation.vertical) {
			this.layoutVertical(l, t, r, b);
		} else {
			this.layoutHorizontal(l, t, r, b);
		}

		CommonLayoutParams.restoreOriginalParams(this);
	}

	private void layoutVertical(int left, int top, int right, int bottom) {

		int paddingLeft = this.getPaddingLeft();
		int paddingRight = this.getPaddingRight();
		int paddingTop = this.getPaddingTop();
		int paddingBottom = this.getPaddingBottom();

		int childTop = 0;
		int childLeft = paddingLeft;
		int childRight = right - left - paddingRight;

		int gravity = LayoutBase.getGravity(this);
		final int verticalGravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;

		switch (verticalGravity) {
			case Gravity.CENTER_VERTICAL:
				childTop = (bottom - top - this._totalLength) / 2 + paddingTop;
				break;

			case Gravity.BOTTOM:
				childTop = bottom - top - this._totalLength + paddingTop;
				break;

			case Gravity.TOP:
			case Gravity.FILL_VERTICAL:
			default:
				childTop = paddingTop;
				break;
		}

		for (int i = 0, count = this.getChildCount(); i < count; i++) {
			View child = this.getChildAt(i);
			if (child.getVisibility() == View.GONE) {
				continue;
			}

			int childHeight = CommonLayoutParams.getDesiredHeight(child);
			CommonLayoutParams.layoutChild(child, childLeft, childTop, childRight, childTop + childHeight);
			childTop += childHeight;
		}
	}

	@SuppressLint("RtlHardcoded")
	private void layoutHorizontal(int left, int top, int right, int bottom) {

		int paddingLeft = this.getPaddingLeft();
		int paddingRight = this.getPaddingRight();
		int paddingTop = this.getPaddingTop();
		int paddingBottom = this.getPaddingBottom();

		int childTop = paddingTop;
		int childLeft = 0;
		int childBottom = bottom - top - paddingBottom;

		int gravity = LayoutBase.getGravity(this);
		final int horizontalGravity = Gravity.getAbsoluteGravity(gravity, this.getLayoutDirection()) & Gravity.HORIZONTAL_GRAVITY_MASK;

		switch (horizontalGravity) {
			case Gravity.CENTER_HORIZONTAL:
				childLeft = (right - left - this._totalLength) / 2 + paddingLeft;
				break;

			case Gravity.RIGHT:
				childLeft = right - left - this._totalLength + paddingLeft;
				break;

			case Gravity.LEFT:
			case Gravity.FILL_HORIZONTAL:
			default:
				childLeft = paddingLeft;
				break;
		}

		for (int i = 0, count = this.getChildCount(); i < count; i++) {
			View child = this.getChildAt(i);
			if (child.getVisibility() == View.GONE) {
				continue;
			}

			int childWidth = CommonLayoutParams.getDesiredWidth(child);
			CommonLayoutParams.layoutChild(child, childLeft, childTop, childLeft + childWidth, childBottom);
			childLeft += childWidth;
		}
	}

	private boolean isUnsizedScrollableView(View child) {
		LayoutParams childLayoutParams = child.getLayoutParams();

		return childLayoutParams.height == -1 && (child instanceof android.widget.ListView || child instanceof VerticalScrollView);
	}
}