/*
 * 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 com.android.internal.R;

import android.annotation.AttrRes;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.StyleRes;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.ViewHierarchyEncoder;
import android.widget.RemoteViews.RemoteView;

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
 */
@RemoteView
public class FrameLayout extends ViewGroup {
 private static final int DEFAULT_CHILD_GRAVITY = Gravity.TOP | Gravity.START;

 @ViewDebug.ExportedProperty(category = "measurement")
 boolean mMeasureAllChildren = false;

 @ViewDebug.ExportedProperty(category = "padding")
 private int mForegroundPaddingLeft = 0;

 @ViewDebug.ExportedProperty(category = "padding")
 private int mForegroundPaddingTop = 0;

 @ViewDebug.ExportedProperty(category = "padding")
 private int mForegroundPaddingRight = 0;

 @ViewDebug.ExportedProperty(category = "padding")
 private int mForegroundPaddingBottom = 0;

 private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1);

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

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

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

 public FrameLayout(@NonNull Context context, @Nullable AttributeSet attrs,
 @AttrRes int defStyleAttr, @StyleRes int defStyleRes) {
 super(context, attrs, defStyleAttr, defStyleRes);

 final TypedArray a = context.obtainStyledAttributes(
 attrs, R.styleable.FrameLayout, defStyleAttr, defStyleRes);

 if (a.getBoolean(R.styleable.FrameLayout_measureAllChildren, false)) {
 setMeasureAllChildren(true);
 }

 a.recycle();
 }

 /**
 * Describes how the foreground is positioned. Defaults to START and TOP.
 *
 * @param foregroundGravity See {@link android.view.Gravity}
 *
 * @see #getForegroundGravity()
 *
 * @attr ref android.R.styleable#View_foregroundGravity
 */
 @android.view.RemotableViewMethod
 public void setForegroundGravity(int foregroundGravity) {
 if (getForegroundGravity() != foregroundGravity) {
 super.setForegroundGravity(foregroundGravity);

 // calling get* again here because the set above may apply default constraints
 final Drawable foreground = getForeground();
 if (getForegroundGravity() == Gravity.FILL && foreground != null) {
 Rect padding = new Rect();
 if (foreground.getPadding(padding)) {
 mForegroundPaddingLeft = padding.left;
 mForegroundPaddingTop = padding.top;
 mForegroundPaddingRight = padding.right;
 mForegroundPaddingBottom = padding.bottom;
 }
 } else {
 mForegroundPaddingLeft = 0;
 mForegroundPaddingTop = 0;
 mForegroundPaddingRight = 0;
 mForegroundPaddingBottom = 0;
 }

 requestLayout();
 }
 }

 /**
 * 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;
 }

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

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

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

 @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
 */
 @android.view.RemotableViewMethod
 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
 public boolean shouldDelayChildPressedState() {
 return false;
 }

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

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

 @Override
 public CharSequence getAccessibilityClassName() {
 return FrameLayout.class.getName();
 }

 /** @hide */
 @Override
 protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) {
 super.encodeProperties(encoder);

 encoder.addProperty("measurement:measureAllChildren", mMeasureAllChildren);
 encoder.addProperty("padding:foregroundPaddingLeft", mForegroundPaddingLeft);
 encoder.addProperty("padding:foregroundPaddingTop", mForegroundPaddingTop);
 encoder.addProperty("padding:foregroundPaddingRight", mForegroundPaddingRight);
 encoder.addProperty("padding:foregroundPaddingBottom", mForegroundPaddingBottom);
 }

 /**
 * 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(@NonNull Context c, @Nullable 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 weight.
 *
 * @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(@NonNull ViewGroup.LayoutParams source) {
 super(source);
 }

 public LayoutParams(@NonNull 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(@NonNull LayoutParams source) {
 super(source);

 this.gravity = source.gravity;
 }
 }
}