/*
 * Copyright (C) 2012 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 com.android.server.wm;

import static com.android.server.am.ActivityStackSupervisor.HOME_STACK_ID;
import static com.android.server.wm.WindowManagerService.DEBUG_STACK;
import static com.android.server.wm.WindowManagerService.DEBUG_VISIBILITY;
import static com.android.server.wm.WindowManagerService.TAG;

import android.graphics.Rect;
import android.util.Slog;
import android.util.SparseArray;
import android.view.Display;
import android.view.DisplayInfo;
import android.view.InputChannel;

import java.io.PrintWriter;
import java.util.ArrayList;

class DisplayContentList extends ArrayList<DisplayContent> {
}

/**
 * Utility class for keeping track of the WindowStates and other pertinent contents of a
 * particular Display.
 *
 * IMPORTANT: No method from this class should ever be used without holding
 * WindowManagerService.mWindowMap.
 */
class DisplayContent {

    /** Unique identifier of this stack. */
    private final int mDisplayId;

    /** Z-ordered (bottom-most first) list of all Window objects. Assigned to an element
     * from mDisplayWindows; */
    private WindowList mWindows = new WindowList();

    // This protects the following display size properties, so that
    // getDisplaySize() doesn't need to acquire the global lock.  This is
    // needed because the window manager sometimes needs to use ActivityThread
    // while it has its global state locked (for example to load animation
    // resources), but the ActivityThread also needs get the current display
    // size sometimes when it has its package lock held.
    //
    // These will only be modified with both mWindowMap and mDisplaySizeLock
    // held (in that order) so the window manager doesn't need to acquire this
    // lock when needing these values in its normal operation.
    final Object mDisplaySizeLock = new Object();
    int mInitialDisplayWidth = 0;
    int mInitialDisplayHeight = 0;
    int mInitialDisplayDensity = 0;
    int mBaseDisplayWidth = 0;
    int mBaseDisplayHeight = 0;
    int mBaseDisplayDensity = 0;
    private final DisplayInfo mDisplayInfo = new DisplayInfo();
    private final Display mDisplay;

    // Accessed directly by all users.
    boolean layoutNeeded;
    int pendingLayoutChanges;
    final boolean isDefaultDisplay;

    /**
     * Window tokens that are in the process of exiting, but still
     * on screen for animations.
     */
    final ArrayList<WindowToken> mExitingTokens = new ArrayList<WindowToken>();

    /**
     * Application tokens that are in the process of exiting, but still
     * on screen for animations.
     */
    final AppTokenList mExitingAppTokens = new AppTokenList();

    /** Array containing the home StackBox and possibly one more which would contain apps. Array
     * is stored in display order with the current bottom stack at 0. */
    private ArrayList<StackBox> mStackBoxes = new ArrayList<StackBox>();

    /** True when the home StackBox is at the top of mStackBoxes, false otherwise. */
    private TaskStack mHomeStack = null;

    /** Save allocating when retrieving tasks */
    ArrayList<Task> mTmpTasks = new ArrayList<Task>();

    /** Sorted most recent at top, oldest at [0]. */
    ArrayList<TaskStack> mStackHistory = new ArrayList<TaskStack>();

    /** Forward motion events to mTapDetector. */
    InputChannel mTapInputChannel;

    /** Detect user tapping outside of current focused stack bounds .*/
    StackTapDetector mTapDetector;

    SparseArray<UserStacks> mUserStacks = new SparseArray<UserStacks>();

    /**
     * @param display May not be null.
     */
    DisplayContent(Display display) {
        mDisplay = display;
        mDisplayId = display.getDisplayId();
        display.getDisplayInfo(mDisplayInfo);
        isDefaultDisplay = mDisplayId == Display.DEFAULT_DISPLAY;
    }

    int getDisplayId() {
        return mDisplayId;
    }

    WindowList getWindowList() {
        return mWindows;
    }

    Display getDisplay() {
        return mDisplay;
    }

    DisplayInfo getDisplayInfo() {
        return mDisplayInfo;
    }

    boolean homeOnTop() {
        return mStackBoxes.get(0).mStack != mHomeStack;
    }

    void moveStack(TaskStack stack, boolean toTop) {
        mStackHistory.remove(stack);
        mStackHistory.add(toTop ? mStackHistory.size() : 0, stack);
    }

    /**
     * Retrieve the tasks on this display in stack order from the bottommost TaskStack up.
     * @return All the Tasks, in order, on this display.
     */
    ArrayList<Task> getTasks() {
        mTmpTasks.clear();
        // First do the tasks belonging to other users.
        final int numUserStacks = mUserStacks.size();
        for (int i = 0; i < numUserStacks; ++i) {
            UserStacks userStacks = mUserStacks.valueAt(i);
            ArrayList<TaskStack> stacks = userStacks.mSavedStackHistory;
            final int numStacks = stacks.size();
            for (int stackNdx = 0; stackNdx < numStacks; ++stackNdx) {
                TaskStack stack = stacks.get(stackNdx);
                if (stack != mHomeStack) {
                    if (WindowManagerService.DEBUG_LAYERS) Slog.i(TAG, "getTasks: mStackHistory=" +
                            mStackHistory);
                    mTmpTasks.addAll(stack.getTasks());
                }
            }
        }
        // Now do the current user's tasks.
        final int numStacks = mStackHistory.size();
        for (int stackNdx = 0; stackNdx < numStacks; ++stackNdx) {
            mTmpTasks.addAll(mStackHistory.get(stackNdx).getTasks());
        }
        if (WindowManagerService.DEBUG_LAYERS) Slog.i(TAG, "getTasks: mStackHistory=" +
                mStackHistory);
        return mTmpTasks;
    }

    TaskStack getHomeStack() {
        return mHomeStack;
    }

    public void updateDisplayInfo() {
        mDisplay.getDisplayInfo(mDisplayInfo);
    }

    /** @return The number of tokens in all of the Tasks on this display. */
    int numTokens() {
        getTasks();
        int count = 0;
        for (int taskNdx = mTmpTasks.size() - 1; taskNdx >= 0; --taskNdx) {
            count += mTmpTasks.get(taskNdx).mAppTokens.size();
        }
        return count;
    }

    /** Refer to {@link WindowManagerService#createStack(int, int, int, float)} */
    TaskStack createStack(int stackId, int relativeStackId, int position, float weight) {
        TaskStack newStack = null;
        if (DEBUG_STACK) Slog.d(TAG, "createStack: stackId=" + stackId + " relativeStackId="
                + relativeStackId + " position=" + position + " weight=" + weight);
        if (mStackBoxes.isEmpty()) {
            if (stackId != HOME_STACK_ID) {
                throw new IllegalArgumentException("createStack: First stackId not "
                        + HOME_STACK_ID);
            }
            StackBox newBox = new StackBox(this, null);
            mStackBoxes.add(newBox);
            newStack = new TaskStack(stackId, this);
            newStack.mStackBox = newBox;
            newBox.mStack = newStack;
            mHomeStack = newStack;
        } else {
            int stackBoxNdx;
            for (stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
                final StackBox box = mStackBoxes.get(stackBoxNdx);
                if (position == StackBox.TASK_STACK_GOES_OVER
                        || position == StackBox.TASK_STACK_GOES_UNDER) {
                    // Position indicates a new box is added at top level only.
                    if (box.contains(relativeStackId)) {
                        StackBox newBox = new StackBox(this, null);
                        newStack = new TaskStack(stackId, this);
                        newStack.mStackBox = newBox;
                        newBox.mStack = newStack;
                        final int offset = position == StackBox.TASK_STACK_GOES_OVER ? 1 : 0;
                        if (DEBUG_STACK) Slog.d(TAG, "createStack: inserting stack at " +
                                (stackBoxNdx + offset));
                        mStackBoxes.add(stackBoxNdx + offset, newBox);
                        break;
                    }
                } else {
                    // Remaining position values indicate a box must be split.
                    newStack = box.split(stackId, relativeStackId, position, weight);
                    if (newStack != null) {
                        break;
                    }
                }
            }
            if (stackBoxNdx < 0) {
                throw new IllegalArgumentException("createStack: stackId " + relativeStackId
                        + " not found.");
            }
        }
        if (newStack != null) {
            layoutNeeded = true;
        }
        return newStack;
    }

    /** Refer to {@link WindowManagerService#resizeStack(int, float)} */
    boolean resizeStack(int stackId, float weight) {
        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
            final StackBox box = mStackBoxes.get(stackBoxNdx);
            if (box.resize(stackId, weight)) {
                return true;
            }
        }
        return false;
    }

    void addStackBox(StackBox box, boolean toTop) {
        if (mStackBoxes.size() >= 2) {
            throw new RuntimeException("addStackBox: Too many toplevel StackBoxes!");
        }
        mStackBoxes.add(toTop ? mStackBoxes.size() : 0, box);
    }

    void removeStackBox(StackBox box) {
        if (DEBUG_STACK) Slog.d(TAG, "removeStackBox: box=" + box);
        final TaskStack stack = box.mStack;
        if (stack != null && stack.mStackId == HOME_STACK_ID) {
            // Never delete the home stack, even if it is empty.
            if (DEBUG_STACK) Slog.d(TAG, "removeStackBox: Not deleting home stack.");
            return;
        }
        mStackBoxes.remove(box);
    }

    /**
     * Move the home StackBox to the top or bottom of mStackBoxes. That is the only place
     * it is allowed to be. This is a nop if the home StackBox is already in the correct position.
     * @param toTop Move home to the top of mStackBoxes if true, to the bottom if false.
     * @return true if a change was made, false otherwise.
     */
    boolean moveHomeStackBox(boolean toTop) {
        if (DEBUG_STACK) Slog.d(TAG, "moveHomeStackBox: toTop=" + toTop);
        switch (mStackBoxes.size()) {
            case 0: throw new RuntimeException("moveHomeStackBox: No home StackBox!");
            case 1: return false; // Only the home StackBox exists.
            case 2:
                if (homeOnTop() ^ toTop) {
                    mStackBoxes.add(mStackBoxes.remove(0));
                    return true;
                }
                return false;
            default: throw new RuntimeException("moveHomeStackBox: Too many toplevel StackBoxes!");
        }
    }

    /**
     * Propagate the new bounds to all child stack boxes, applying weights as we move down.
     * @param contentRect The bounds to apply at the top level.
     */
    void setStackBoxSize(Rect contentRect) {
        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
            mStackBoxes.get(stackBoxNdx).setStackBoxSizes(contentRect);
        }
    }

    Rect getStackBounds(int stackId) {
        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
            Rect bounds = mStackBoxes.get(stackBoxNdx).getStackBounds(stackId);
            if (bounds != null) {
                return bounds;
            }
        }
        // Not in the visible stacks, try the saved ones.
        for (int userNdx = mUserStacks.size() - 1; userNdx >= 0; --userNdx) {
            UserStacks userStacks = mUserStacks.valueAt(userNdx);
            Rect bounds = userStacks.mSavedStackBox.getStackBounds(stackId);
            if (bounds != null) {
                return bounds;
            }
        }
        return null;
    }

    int stackIdFromPoint(int x, int y) {
        StackBox topBox = mStackBoxes.get(mStackBoxes.size() - 1);
        return topBox.stackIdFromPoint(x, y);
    }

    void switchUserStacks(int oldUserId, int newUserId) {
        final WindowList windows = getWindowList();
        for (int i = 0; i < windows.size(); i++) {
            final WindowState win = windows.get(i);
            if (win.isHiddenFromUserLocked()) {
                if (DEBUG_VISIBILITY) Slog.w(TAG, "user changing " + newUserId + " hiding "
                        + win + ", attrs=" + win.mAttrs.type + ", belonging to "
                        + win.mOwnerUid);
                win.hideLw(false);
            }
        }
        // Clear the old user's non-home StackBox
        mUserStacks.put(oldUserId, new UserStacks());
        UserStacks userStacks = mUserStacks.get(newUserId);
        if (userStacks != null) {
            userStacks.restore();
            mUserStacks.delete(newUserId);
        }
    }

    public void dump(String prefix, PrintWriter pw) {
        pw.print(prefix); pw.print("Display: mDisplayId="); pw.println(mDisplayId);
        final String subPrefix = "  " + prefix;
        pw.print(subPrefix); pw.print("init="); pw.print(mInitialDisplayWidth); pw.print("x");
            pw.print(mInitialDisplayHeight); pw.print(" "); pw.print(mInitialDisplayDensity);
            pw.print("dpi");
            if (mInitialDisplayWidth != mBaseDisplayWidth
                    || mInitialDisplayHeight != mBaseDisplayHeight
                    || mInitialDisplayDensity != mBaseDisplayDensity) {
                pw.print(" base=");
                pw.print(mBaseDisplayWidth); pw.print("x"); pw.print(mBaseDisplayHeight);
                pw.print(" "); pw.print(mBaseDisplayDensity); pw.print("dpi");
            }
            pw.print(" cur=");
            pw.print(mDisplayInfo.logicalWidth);
            pw.print("x"); pw.print(mDisplayInfo.logicalHeight);
            pw.print(" app=");
            pw.print(mDisplayInfo.appWidth);
            pw.print("x"); pw.print(mDisplayInfo.appHeight);
            pw.print(" rng="); pw.print(mDisplayInfo.smallestNominalAppWidth);
            pw.print("x"); pw.print(mDisplayInfo.smallestNominalAppHeight);
            pw.print("-"); pw.print(mDisplayInfo.largestNominalAppWidth);
            pw.print("x"); pw.println(mDisplayInfo.largestNominalAppHeight);
            pw.print(subPrefix); pw.print("layoutNeeded="); pw.println(layoutNeeded);
        for (int boxNdx = 0; boxNdx < mStackBoxes.size(); ++boxNdx) {
            pw.print(prefix); pw.print("StackBox #"); pw.println(boxNdx);
            mStackBoxes.get(boxNdx).dump(prefix + "  ", pw);
        }
        int ndx = numTokens();
        if (ndx > 0) {
            pw.println();
            pw.println("  Application tokens in Z order:");
            getTasks();
            for (int taskNdx = mTmpTasks.size() - 1; taskNdx >= 0; --taskNdx) {
                AppTokenList tokens = mTmpTasks.get(taskNdx).mAppTokens;
                for (int tokenNdx = tokens.size() - 1; tokenNdx >= 0; --tokenNdx) {
                    final AppWindowToken wtoken = tokens.get(tokenNdx);
                    pw.print("  App #"); pw.print(ndx--);
                            pw.print(' '); pw.print(wtoken); pw.println(":");
                    wtoken.dump(pw, "    ");
                }
            }
        }
        if (mExitingTokens.size() > 0) {
            pw.println();
            pw.println("  Exiting tokens:");
            for (int i=mExitingTokens.size()-1; i>=0; i--) {
                WindowToken token = mExitingTokens.get(i);
                pw.print("  Exiting #"); pw.print(i);
                pw.print(' '); pw.print(token);
                pw.println(':');
                token.dump(pw, "    ");
            }
        }
        if (mExitingAppTokens.size() > 0) {
            pw.println();
            pw.println("  Exiting application tokens:");
            for (int i=mExitingAppTokens.size()-1; i>=0; i--) {
                WindowToken token = mExitingAppTokens.get(i);
                pw.print("  Exiting App #"); pw.print(i);
                  pw.print(' '); pw.print(token);
                  pw.println(':');
                  token.dump(pw, "    ");
            }
        }
        if (mUserStacks.size() > 0) {
            pw.println();
            pw.println("  Saved user stacks:");
            for (int i = 0; i < mUserStacks.size(); ++i) {
                UserStacks userStacks = mUserStacks.valueAt(i);
                pw.print("  UserId="); pw.println(Integer.toHexString(mUserStacks.keyAt(i)));
                pw.print("  StackHistory="); pw.println(userStacks.mSavedStackHistory);
                pw.print("  StackBox="); userStacks.mSavedStackBox.dump("    ", pw);
            }
        }
        pw.println();
    }

    private final class UserStacks {
        final ArrayList<TaskStack> mSavedStackHistory;
        StackBox mSavedStackBox;
        int mBoxNdx;

        public UserStacks() {
            mSavedStackHistory = new ArrayList<TaskStack>(mStackHistory);
            for (int stackNdx = mStackHistory.size() - 1; stackNdx >=0; --stackNdx) {
                if (mStackHistory.get(stackNdx) != mHomeStack) {
                    mStackHistory.remove(stackNdx);
                }
            }
            mSavedStackBox = null;
            mBoxNdx = -1;
            for (int boxNdx = mStackBoxes.size() - 1; boxNdx >= 0; --boxNdx) {
                StackBox box = mStackBoxes.get(boxNdx);
                if (box.mStack != mHomeStack) {
                    mSavedStackBox = box;
                    mBoxNdx = boxNdx;
                    mStackBoxes.remove(boxNdx);
                    break;
                }
            }
        }

        void restore() {
            mStackHistory = mSavedStackHistory;
            if (mBoxNdx >= 0) {
                mStackBoxes.add(mBoxNdx, mSavedStackBox);
            }
        }
    }
}