/*
 * Copyright (C) 2006 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.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import com.android.internal.R;
import java.util.ArrayList;

/**
 * FrameLayout is designed to block out an area on the screen to display
 * a single item. Generally, FrameLayout should be used to hold a single child view, because it can
 * be difficult to organize child views in a way that's scalable to different screen sizes without
 * the children overlapping each other. You can, however, add multiple children to a FrameLayout
 * and control their position within the FrameLayout by assigning gravity to each child, using the
 * <a href="FrameLayout.LayoutParams.html#attr_android:layout_gravity">{@code
 * android:layout_gravity}</a> attribute.
 * <p>Child views are drawn in a stack, with the most recently added child on top.
 * The size of the FrameLayout is the size of its largest child (plus padding), visible
 * or not (if the FrameLayout's parent permits). Views that are {@link android.view.View#GONE} are
 * used for sizing
 * only if {@link #setMeasureAllChildren(boolean) setConsiderGoneChildrenWhenMeasuring()}
 * is set to true.
 *
 * @attr ref android.R.styleable#FrameLayout_measureAllChildren
 */
public class FrameLayout extends ViewGroup {
	private static final int DEFAULT_CHILD_GRAVITY = Gravity.TOP | Gravity.START;
	boolean mMeasureAllChildren = false;
	// private int mForegroundPaddingLeft = 0;
	// private int mForegroundPaddingTop = 0;
	// private int mForegroundPaddingRight = 0;
	// private int mForegroundPaddingBottom = 0;
	private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1);

	public FrameLayout(Context context) {
		super(context);
	}

	public FrameLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public FrameLayout(Context context, AttributeSet attrs,
			int defStyleAttr) {
		this(context, attrs, defStyleAttr, 0);
	}

	public FrameLayout(Context context, AttributeSet attrs,
			int defStyleAttr, int defStyleRes) {
		super(context, attrs, defStyleAttr, defStyleRes);
		final TypedArray a = context.obtainStyledAttributes(
				attrs, R.styleable.FrameLayout, defStyleAttr, defStyleRes);
		// saveAttributeDataForStyleable(context, R.styleable.FrameLayout,
		//         attrs, a, defStyleAttr, defStyleRes);
		if (a.getBoolean(R.styleable.FrameLayout_measureAllChildren, false)) {
			setMeasureAllChildren(true);
		}
		a.recycle();
	}

	/**
	 * Returns a set of layout parameters with a width of
	 * {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT},
	 * and a height of {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT}.
	 */
	@Override
	protected LayoutParams generateDefaultLayoutParams() {
		return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
	}

	int getPaddingLeftWithForeground() {
		// return isForegroundInsidePadding() ? Math.max(mPaddingLeft, mForegroundPaddingLeft) :
		// 	mPaddingLeft + mForegroundPaddingLeft;
		return paddingLeft;
	}

	int getPaddingRightWithForeground() {
		// return isForegroundInsidePadding() ? Math.max(mPaddingRight, mForegroundPaddingRight) :
		// 	mPaddingRight + mForegroundPaddingRight;
		return paddingRight;
	}

	private int getPaddingTopWithForeground() {
		// return isForegroundInsidePadding() ? Math.max(mPaddingTop, mForegroundPaddingTop) :
		// 	mPaddingTop + mForegroundPaddingTop;
		return paddingTop;
	}

	private int getPaddingBottomWithForeground() {
		// return isForegroundInsidePadding() ? Math.max(mPaddingBottom, mForegroundPaddingBottom) :
		// 	mPaddingBottom + mForegroundPaddingBottom;
		return paddingBottom;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		int count = getChildCount();
		final boolean measureMatchParentChildren =
				MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.EXACTLY ||
				MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY;
		mMatchParentChildren.clear();
		int maxHeight = 0;
		int maxWidth = 0;
		int childState = 0;
		for (int i = 0; i < count; i++) {
			final View child = getChildAt(i);
			if (mMeasureAllChildren || child.getVisibility() != GONE) {
				measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
				final LayoutParams lp = (LayoutParams) child.getLayoutParams();
				maxWidth = Math.max(maxWidth,
						child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
				maxHeight = Math.max(maxHeight,
						child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);
				childState = combineMeasuredStates(childState, child.getMeasuredState());
				if (measureMatchParentChildren) {
					if (lp.width == LayoutParams.MATCH_PARENT ||
							lp.height == LayoutParams.MATCH_PARENT) {
						mMatchParentChildren.add(child);
					}
				}
			}
		}
		// Account for padding too
		maxWidth += getPaddingLeftWithForeground() + getPaddingRightWithForeground();
		maxHeight += getPaddingTopWithForeground() + getPaddingBottomWithForeground();
		// Check against our minimum height and width
		maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
		maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());
		// Check against our foreground's minimum height and width
		// final Drawable drawable = getForeground();
		// if (drawable != null) {
		// 	maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
		// 	maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
		// }
		setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
				resolveSizeAndState(maxHeight, heightMeasureSpec,
						childState << MEASURED_HEIGHT_STATE_SHIFT));
		count = mMatchParentChildren.size();
		if (count > 1) {
			for (int i = 0; i < count; i++) {
				final View child = mMatchParentChildren.get(i);
				final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
				final int childWidthMeasureSpec;
				if (lp.width == LayoutParams.MATCH_PARENT) {
					final int width = Math.max(0, getMeasuredWidth()
							- getPaddingLeftWithForeground() - getPaddingRightWithForeground()
							- lp.leftMargin - lp.rightMargin);
					childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
							width, MeasureSpec.EXACTLY);
				} else {
					childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
							getPaddingLeftWithForeground() + getPaddingRightWithForeground() +
							lp.leftMargin + lp.rightMargin,
							lp.width);
				}
				final int childHeightMeasureSpec;
				if (lp.height == LayoutParams.MATCH_PARENT) {
					final int height = Math.max(0, getMeasuredHeight()
							- getPaddingTopWithForeground() - getPaddingBottomWithForeground()
							- lp.topMargin - lp.bottomMargin);
					childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
							height, MeasureSpec.EXACTLY);
				} else {
					childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec,
							getPaddingTopWithForeground() + getPaddingBottomWithForeground() +
							lp.topMargin + lp.bottomMargin,
							lp.height);
				}
				child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
			}
		}
	}

	@Override
	protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
		layoutChildren(left, top, right, bottom, false /* no force left gravity */);
	}

	void layoutChildren(int left, int top, int right, int bottom, boolean forceLeftGravity) {
		final int count = getChildCount();
		final int parentLeft = getPaddingLeftWithForeground();
		final int parentRight = right - left - getPaddingRightWithForeground();
		final int parentTop = getPaddingTopWithForeground();
		final int parentBottom = bottom - top - getPaddingBottomWithForeground();
		for (int i = 0; i < count; i++) {
			final View child = getChildAt(i);
			if (child.getVisibility() != GONE) {
				final LayoutParams lp = (LayoutParams) child.getLayoutParams();
				final int width = child.getMeasuredWidth();
				final int height = child.getMeasuredHeight();
				int childLeft;
				int childTop;
				int gravity = lp.gravity;
				if (gravity == -1) {
					gravity = DEFAULT_CHILD_GRAVITY;
				}
				final int layoutDirection = getLayoutDirection();
				final int absoluteGravity = Gravity.getAbsoluteGravity(gravity, layoutDirection);
				final int verticalGravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;
				switch (absoluteGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
					case Gravity.CENTER_HORIZONTAL:
						childLeft = parentLeft + (parentRight - parentLeft - width) / 2 +
						lp.leftMargin - lp.rightMargin;
						break;
					case Gravity.RIGHT:
						if (!forceLeftGravity) {
							childLeft = parentRight - width - lp.rightMargin;
							break;
						}
					case Gravity.LEFT:
					default:
						childLeft = parentLeft + lp.leftMargin;
				}
				switch (verticalGravity) {
					case Gravity.TOP:
						childTop = parentTop + lp.topMargin;
						break;
					case Gravity.CENTER_VERTICAL:
						childTop = parentTop + (parentBottom - parentTop - height) / 2 +
						lp.topMargin - lp.bottomMargin;
						break;
					case Gravity.BOTTOM:
						childTop = parentBottom - height - lp.bottomMargin;
						break;
					default:
						childTop = parentTop + lp.topMargin;
				}
				child.layout(childLeft, childTop, childLeft + width, childTop + height);
			}
		}
	}

	/**
	 * Sets whether to consider all children, or just those in
	 * the VISIBLE or INVISIBLE state, when measuring. Defaults to false.
	 *
	 * @param measureAll true to consider children marked GONE, false otherwise.
	 * Default value is false.
	 *
	 * @attr ref android.R.styleable#FrameLayout_measureAllChildren
	 */
	public void setMeasureAllChildren(boolean measureAll) {
		mMeasureAllChildren = measureAll;
	}

	/**
	 * Determines whether all children, or just those in the VISIBLE or
	 * INVISIBLE state, are considered when measuring.
	 *
	 * @return Whether all children are considered when measuring.
	 *
	 * @deprecated This method is deprecated in favor of
	 * {@link #getMeasureAllChildren() getMeasureAllChildren()}, which was
	 * renamed for consistency with
	 * {@link #setMeasureAllChildren(boolean) setMeasureAllChildren()}.
	 */
	@Deprecated
	public boolean getConsiderGoneChildrenWhenMeasuring() {
		return getMeasureAllChildren();
	}

	/**
	 * Determines whether all children, or just those in the VISIBLE or
	 * INVISIBLE state, are considered when measuring.
	 *
	 * @return Whether all children are considered when measuring.
	 */
	public boolean getMeasureAllChildren() {
		return mMeasureAllChildren;
	}

	@Override
	public LayoutParams generateLayoutParams(AttributeSet attrs) {
		return new FrameLayout.LayoutParams(getContext(), attrs);
	}

	@Override
	protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
		return p instanceof LayoutParams;
	}

	@Override
	protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
		// if (sPreserveMarginParamsInLayoutParamConversion) {
		// 	if (lp instanceof LayoutParams) {
		// 		return new LayoutParams((LayoutParams) lp);
		// 	} else if (lp instanceof MarginLayoutParams) {
		// 		return new LayoutParams((MarginLayoutParams) lp);
		// 	}
		// }
		return new LayoutParams(lp);
	}

	/**
	 * Per-child layout information for layouts that support margins.
	 * See {@link android.R.styleable#FrameLayout_Layout FrameLayout Layout Attributes}
	 * for a list of all child view attributes that this class supports.
	 *
	 * @attr ref android.R.styleable#FrameLayout_Layout_layout_gravity
	 */
	public static class LayoutParams extends MarginLayoutParams {
		/**
		 * Value for {@link #gravity} indicating that a gravity has not been
		 * explicitly specified.
		 */
		public static final int UNSPECIFIED_GRAVITY = -1;

		/**
		 * The gravity to apply with the View to which these layout parameters
		 * are associated.
		 * <p>
		 * The default value is {@link #UNSPECIFIED_GRAVITY}, which is treated
		 * by FrameLayout as {@code Gravity.TOP | Gravity.START}.
		 *
		 * @see android.view.Gravity
		 * @attr ref android.R.styleable#FrameLayout_Layout_layout_gravity
		 */
		public int gravity = UNSPECIFIED_GRAVITY;

		public LayoutParams(Context c, AttributeSet attrs) {
			super(c, attrs);
			final TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.FrameLayout_Layout);
			gravity = a.getInt(R.styleable.FrameLayout_Layout_layout_gravity, UNSPECIFIED_GRAVITY);
			a.recycle();
		}

		public LayoutParams(int width, int height) {
			super(width, height);
		}

		/**
		 * Creates a new set of layout parameters with the specified width, height
		 * and gravity.
		 *
		 * @param width the width, either {@link #MATCH_PARENT},
		 *              {@link #WRAP_CONTENT} or a fixed size in pixels
		 * @param height the height, either {@link #MATCH_PARENT},
		 *               {@link #WRAP_CONTENT} or a fixed size in pixels
		 * @param gravity the gravity
		 *
		 * @see android.view.Gravity
		 */
		public LayoutParams(int width, int height, int gravity) {
			super(width, height);
			this.gravity = gravity;
		}

		public LayoutParams(ViewGroup.LayoutParams source) {
			super(source);
		}

		public LayoutParams(ViewGroup.MarginLayoutParams source) {
			super(source);
		}

		/**
		 * Copy constructor. Clones the width, height, margin values, and
		 * gravity of the source.
		 *
		 * @param source The layout params to copy from.
		 */
		public LayoutParams(LayoutParams source) {
			super(source);
			this.gravity = source.gravity;
		}
	}
}