/*
 * 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 com.android.server.am;

import static com.android.server.am.ActivityManagerService.TAG;
import static com.android.server.am.ActivityStackSupervisor.DEBUG_ADD_REMOVE;

import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityOptions;
import android.app.IThumbnailRetriever;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.graphics.Bitmap;
import android.os.UserHandle;
import android.util.Slog;

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

final class TaskRecord extends ThumbnailHolder {
    final int taskId;       // Unique identifier for this task.
    final String affinity;  // The affinity name for this task, or null.
    Intent intent;          // The original intent that started the task.
    Intent affinityIntent;  // Intent of affinity-moved activity that started this task.
    ComponentName origActivity; // The non-alias activity component of the intent.
    ComponentName realActivity; // The actual activity component that started the task.
    int numActivities;      // Current number of activities in this task.
    long lastActiveTime;    // Last time this task was active, including sleep.
    boolean rootWasReset;   // True if the intent at the root of the task had
                            // the FLAG_ACTIVITY_RESET_TASK_IF_NEEDED flag.
    boolean askedCompatMode;// Have asked the user about compat mode for this task.

    String stringName;      // caching of toString() result.
    int userId;             // user for which this task was created

    int numFullscreen;      // Number of fullscreen activities.

    /** List of all activities in the task arranged in history order */
    final ArrayList<ActivityRecord> mActivities = new ArrayList<ActivityRecord>();

    /** Current stack */
    ActivityStack stack;

    private boolean mApplicationTask = true;

    TaskRecord(int _taskId, ActivityInfo info, Intent _intent, ActivityStack _stack) {
        taskId = _taskId;
        affinity = info.taskAffinity;
        setIntent(_intent, info);
        stack = _stack;
    }

    void touchActiveTime() {
        lastActiveTime = android.os.SystemClock.elapsedRealtime();
    }

    long getInactiveDuration() {
        return android.os.SystemClock.elapsedRealtime() - lastActiveTime;
    }

    void setIntent(Intent _intent, ActivityInfo info) {
        stringName = null;

        if (info.targetActivity == null) {
            if (_intent != null) {
                // If this Intent has a selector, we want to clear it for the
                // recent task since it is not relevant if the user later wants
                // to re-launch the app.
                if (_intent.getSelector() != null || _intent.getSourceBounds() != null) {
                    _intent = new Intent(_intent);
                    _intent.setSelector(null);
                    _intent.setSourceBounds(null);
                }
            }
            if (ActivityManagerService.DEBUG_TASKS) Slog.v(ActivityManagerService.TAG,
                    "Setting Intent of " + this + " to " + _intent);
            intent = _intent;
            realActivity = _intent != null ? _intent.getComponent() : null;
            origActivity = null;
        } else {
            ComponentName targetComponent = new ComponentName(
                    info.packageName, info.targetActivity);
            if (_intent != null) {
                Intent targetIntent = new Intent(_intent);
                targetIntent.setComponent(targetComponent);
                targetIntent.setSelector(null);
                targetIntent.setSourceBounds(null);
                if (ActivityManagerService.DEBUG_TASKS) Slog.v(ActivityManagerService.TAG,
                        "Setting Intent of " + this + " to target " + targetIntent);
                intent = targetIntent;
                realActivity = targetComponent;
                origActivity = _intent.getComponent();
            } else {
                intent = null;
                realActivity = targetComponent;
                origActivity = new ComponentName(info.packageName, info.name);
            }
        }

        if (intent != null &&
                (intent.getFlags()&Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) != 0) {
            // Once we are set to an Intent with this flag, we count this
            // task as having a true root activity.
            rootWasReset = true;
        }

        if (info.applicationInfo != null) {
            userId = UserHandle.getUserId(info.applicationInfo.uid);
        }
    }

    ActivityRecord getTopActivity() {
        for (int i = mActivities.size() - 1; i >= 0; --i) {
            final ActivityRecord r = mActivities.get(i);
            if (r.finishing) {
                continue;
            }
            return r;
        }
        return null;
    }

    /**
     * Reorder the history stack so that the activity at the given index is
     * brought to the front.
     */
    final void moveActivityToFrontLocked(ActivityRecord newTop) {
        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Removing and adding activity " + newTop
            + " to stack at top", new RuntimeException("here").fillInStackTrace());

        getTopActivity().frontOfTask = false;
        mActivities.remove(newTop);
        mActivities.add(newTop);
        newTop.frontOfTask = true;
    }

    void addActivityAtBottom(ActivityRecord r) {
        addActivityAtIndex(0, r);
    }

    void addActivityToTop(ActivityRecord r) {
        addActivityAtIndex(mActivities.size(), r);
    }

    void addActivityAtIndex(int index, ActivityRecord r) {
        // Remove r first, and if it wasn't already in the list and it's fullscreen, count it.
        if (!mActivities.remove(r) && r.fullscreen) {
            // Was not previously in list.
            numFullscreen++;
        }
        // Only set this to be an application task if it has not already been set as home task.
        if (mApplicationTask) {
            mApplicationTask = r.isApplicationActivity();
        }
        mActivities.add(index, r);
    }

    /** @return true if this was the last activity in the task */
    boolean removeActivity(ActivityRecord r) {
        if (mActivities.remove(r) && r.fullscreen) {
            // Was previously in list.
            numFullscreen--;
        }
        return mActivities.size() == 0;
    }

    /**
     * Completely remove all activities associated with an existing
     * task starting at a specified index.
     */
    final void performClearTaskAtIndexLocked(int activityNdx) {
        int numActivities = mActivities.size();
        for ( ; activityNdx < numActivities; ++activityNdx) {
            final ActivityRecord r = mActivities.get(activityNdx);
            if (r.finishing) {
                continue;
            }
            if (stack.finishActivityLocked(r, Activity.RESULT_CANCELED, null, "clear", false)) {
                --activityNdx;
                --numActivities;
            }
        }
    }

    /**
     * Completely remove all activities associated with an existing task.
     */
    final void performClearTaskLocked() {
        performClearTaskAtIndexLocked(0);
    }

    /**
     * Perform clear operation as requested by
     * {@link Intent#FLAG_ACTIVITY_CLEAR_TOP}: search from the top of the
     * stack to the given task, then look for
     * an instance of that activity in the stack and, if found, finish all
     * activities on top of it and return the instance.
     *
     * @param newR Description of the new activity being started.
     * @return Returns the old activity that should be continued to be used,
     * or null if none was found.
     */
    final ActivityRecord performClearTaskLocked(ActivityRecord newR, int launchFlags) {
        int numActivities = mActivities.size();
        for (int activityNdx = numActivities - 1; activityNdx >= 0; --activityNdx) {
            ActivityRecord r = mActivities.get(activityNdx);
            if (r.finishing) {
                continue;
            }
            if (r.realActivity.equals(newR.realActivity)) {
                // Here it is!  Now finish everything in front...
                final ActivityRecord ret = r;

                for (++activityNdx; activityNdx < numActivities; ++activityNdx) {
                    r = mActivities.get(activityNdx);
                    if (r.finishing) {
                        continue;
                    }
                    ActivityOptions opts = r.takeOptionsLocked();
                    if (opts != null) {
                        ret.updateOptionsLocked(opts);
                    }
                    if (stack.finishActivityLocked(r, Activity.RESULT_CANCELED, null, "clear",
                            false)) {
                        --activityNdx;
                        --numActivities;
                    }
                }

                // Finally, if this is a normal launch mode (that is, not
                // expecting onNewIntent()), then we will finish the current
                // instance of the activity so a new fresh one can be started.
                if (ret.launchMode == ActivityInfo.LAUNCH_MULTIPLE
                        && (launchFlags & Intent.FLAG_ACTIVITY_SINGLE_TOP) == 0) {
                    if (!ret.finishing) {
                        stack.finishActivityLocked(ret, Activity.RESULT_CANCELED, null,
                                "clear", false);
                        return null;
                    }
                }

                return ret;
            }
        }

        return null;
    }

    public ActivityManager.TaskThumbnails getTaskThumbnailsLocked() {
        TaskAccessInfo info = getTaskAccessInfoLocked(true);
        final ActivityRecord resumedActivity = stack.mResumedActivity;
        if (resumedActivity != null && resumedActivity.thumbHolder == this) {
            info.mainThumbnail = stack.screenshotActivities(resumedActivity);
        }
        if (info.mainThumbnail == null) {
            info.mainThumbnail = lastThumbnail;
        }
        return info;
    }

    public Bitmap getTaskTopThumbnailLocked() {
        final ActivityRecord resumedActivity = stack.mResumedActivity;
        if (resumedActivity != null && resumedActivity.task == this) {
            // This task is the current resumed task, we just need to take
            // a screenshot of it and return that.
            return stack.screenshotActivities(resumedActivity);
        }
        // Return the information about the task, to figure out the top
        // thumbnail to return.
        TaskAccessInfo info = getTaskAccessInfoLocked(true);
        if (info.numSubThumbbails <= 0) {
            return info.mainThumbnail != null ? info.mainThumbnail : lastThumbnail;
        }
        return info.subtasks.get(info.numSubThumbbails-1).holder.lastThumbnail;
    }

    public ActivityRecord removeTaskActivitiesLocked(int subTaskIndex,
            boolean taskRequired) {
        TaskAccessInfo info = getTaskAccessInfoLocked(false);
        if (info.root == null) {
            if (taskRequired) {
                Slog.w(TAG, "removeTaskLocked: unknown taskId " + taskId);
            }
            return null;
        }

        if (subTaskIndex < 0) {
            // Just remove the entire task.
            performClearTaskAtIndexLocked(info.rootIndex);
            return info.root;
        }

        if (subTaskIndex >= info.subtasks.size()) {
            if (taskRequired) {
                Slog.w(TAG, "removeTaskLocked: unknown subTaskIndex " + subTaskIndex);
            }
            return null;
        }

        // Remove all of this task's activities starting at the sub task.
        TaskAccessInfo.SubTask subtask = info.subtasks.get(subTaskIndex);
        performClearTaskAtIndexLocked(subtask.index);
        return subtask.activity;
    }

    boolean isApplicationTask() {
        return mApplicationTask;
    }

    public TaskAccessInfo getTaskAccessInfoLocked(boolean inclThumbs) {
        final TaskAccessInfo thumbs = new TaskAccessInfo();
        // How many different sub-thumbnails?
        final int NA = mActivities.size();
        int j = 0;
        ThumbnailHolder holder = null;
        while (j < NA) {
            ActivityRecord ar = mActivities.get(j);
            if (!ar.finishing) {
                thumbs.root = ar;
                thumbs.rootIndex = j;
                holder = ar.thumbHolder;
                if (holder != null) {
                    thumbs.mainThumbnail = holder.lastThumbnail;
                }
                j++;
                break;
            }
            j++;
        }

        if (j >= NA) {
            return thumbs;
        }

        ArrayList<TaskAccessInfo.SubTask> subtasks = new ArrayList<TaskAccessInfo.SubTask>();
        thumbs.subtasks = subtasks;
        while (j < NA) {
            ActivityRecord ar = mActivities.get(j);
            j++;
            if (ar.finishing) {
                continue;
            }
            if (ar.thumbHolder != holder && holder != null) {
                thumbs.numSubThumbbails++;
                holder = ar.thumbHolder;
                TaskAccessInfo.SubTask sub = new TaskAccessInfo.SubTask();
                sub.holder = holder;
                sub.activity = ar;
                sub.index = j-1;
                subtasks.add(sub);
            }
        }
        if (thumbs.numSubThumbbails > 0) {
            thumbs.retriever = new IThumbnailRetriever.Stub() {
                @Override
                public Bitmap getThumbnail(int index) {
                    if (index < 0 || index >= thumbs.subtasks.size()) {
                        return null;
                    }
                    TaskAccessInfo.SubTask sub = thumbs.subtasks.get(index);
                    ActivityRecord resumedActivity = stack.mResumedActivity;
                    if (resumedActivity != null && resumedActivity.thumbHolder == sub.holder) {
                        return stack.screenshotActivities(resumedActivity);
                    }
                    return sub.holder.lastThumbnail;
                }
            };
        }
        return thumbs;
    }

    /**
     * Find the activity in the history stack within the given task.  Returns
     * the index within the history at which it's found, or < 0 if not found.
     */
    final ActivityRecord findActivityInHistoryLocked(ActivityRecord r) {
        final ComponentName realActivity = r.realActivity;
        for (int activityNdx = mActivities.size() - 1; activityNdx >= 0; --activityNdx) {
            ActivityRecord candidate = mActivities.get(activityNdx);
            if (candidate.finishing) {
                continue;
            }
            if (candidate.realActivity.equals(realActivity)) {
                return candidate;
            }
        }
        return null;
    }

    void dump(PrintWriter pw, String prefix) {
        if (numActivities != 0 || rootWasReset || userId != 0) {
            pw.print(prefix); pw.print("numActivities="); pw.print(numActivities);
                    pw.print(" rootWasReset="); pw.print(rootWasReset);
                    pw.print(" userId="); pw.print(userId);
                    pw.print(" numFullscreen="); pw.println(numFullscreen);
        }
        if (affinity != null) {
            pw.print(prefix); pw.print("affinity="); pw.println(affinity);
        }
        if (intent != null) {
            StringBuilder sb = new StringBuilder(128);
            sb.append(prefix); sb.append("intent={");
            intent.toShortString(sb, false, true, false, true);
            sb.append('}');
            pw.println(sb.toString());
        }
        if (affinityIntent != null) {
            StringBuilder sb = new StringBuilder(128);
            sb.append(prefix); sb.append("affinityIntent={");
            affinityIntent.toShortString(sb, false, true, false, true);
            sb.append('}');
            pw.println(sb.toString());
        }
        if (origActivity != null) {
            pw.print(prefix); pw.print("origActivity=");
            pw.println(origActivity.flattenToShortString());
        }
        if (realActivity != null) {
            pw.print(prefix); pw.print("realActivity=");
            pw.println(realActivity.flattenToShortString());
        }
        pw.print(prefix); pw.print("Activities="); pw.println(mActivities);
        if (!askedCompatMode) {
            pw.print(prefix); pw.print("askedCompatMode="); pw.println(askedCompatMode);
        }
        pw.print(prefix); pw.print("lastThumbnail="); pw.print(lastThumbnail);
                pw.print(" lastDescription="); pw.println(lastDescription);
        pw.print(prefix); pw.print("lastActiveTime="); pw.print(lastActiveTime);
                pw.print(" (inactive for ");
                pw.print((getInactiveDuration()/1000)); pw.println("s)");
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder(128);
        if (stringName != null) {
            sb.append(stringName);
            sb.append(" U=");
            sb.append(userId);
            sb.append(" sz=");
            sb.append(mActivities.size());
            sb.append('}');
            return sb.toString();
        }
        sb.append("TaskRecord{");
        sb.append(Integer.toHexString(System.identityHashCode(this)));
        sb.append(" #");
        sb.append(taskId);
        if (affinity != null) {
            sb.append(" A=");
            sb.append(affinity);
        } else if (intent != null) {
            sb.append(" I=");
            sb.append(intent.getComponent().flattenToShortString());
        } else if (affinityIntent != null) {
            sb.append(" aI=");
            sb.append(affinityIntent.getComponent().flattenToShortString());
        } else {
            sb.append(" ??");
        }
        stringName = sb.toString();
        return toString();
    }
}