1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.printspooler.ui;
18
19import android.os.Handler;
20import android.os.Looper;
21import android.os.Message;
22import android.os.ParcelFileDescriptor;
23import android.print.PageRange;
24import android.print.PrintAttributes.MediaSize;
25import android.print.PrintAttributes.Margins;
26import android.print.PrintDocumentInfo;
27import android.support.v7.widget.GridLayoutManager;
28import android.support.v7.widget.RecyclerView;
29import android.support.v7.widget.RecyclerView.ViewHolder;
30import android.support.v7.widget.RecyclerView.LayoutManager;
31import android.view.View;
32import com.android.internal.os.SomeArgs;
33import com.android.printspooler.R;
34import com.android.printspooler.model.MutexFileProvider;
35import com.android.printspooler.widget.PrintContentView;
36import com.android.printspooler.widget.EmbeddedContentContainer;
37import com.android.printspooler.widget.PrintOptionsLayout;
38
39import java.io.File;
40import java.io.FileNotFoundException;
41import java.util.ArrayList;
42import java.util.List;
43
44class PrintPreviewController implements MutexFileProvider.OnReleaseRequestCallback,
45        PageAdapter.PreviewArea, EmbeddedContentContainer.OnSizeChangeListener {
46
47    private final PrintActivity mActivity;
48
49    private final MutexFileProvider mFileProvider;
50    private final MyHandler mHandler;
51
52    private final PageAdapter mPageAdapter;
53    private final GridLayoutManager mLayoutManger;
54
55    private final PrintOptionsLayout mPrintOptionsLayout;
56    private final RecyclerView mRecyclerView;
57    private final PrintContentView mContentView;
58    private final EmbeddedContentContainer mEmbeddedContentContainer;
59
60    private final PreloadController mPreloadController;
61
62    private int mDocumentPageCount;
63
64    public PrintPreviewController(PrintActivity activity, MutexFileProvider fileProvider) {
65        mActivity = activity;
66        mHandler = new MyHandler(activity.getMainLooper());
67        mFileProvider = fileProvider;
68
69        mPrintOptionsLayout = (PrintOptionsLayout) activity.findViewById(R.id.options_container);
70        mPageAdapter = new PageAdapter(activity, activity, this);
71
72        final int columnCount = mActivity.getResources().getInteger(
73                R.integer.preview_page_per_row_count);
74
75        mLayoutManger = new GridLayoutManager(mActivity, columnCount);
76
77        mRecyclerView = (RecyclerView) activity.findViewById(R.id.preview_content);
78        mRecyclerView.setLayoutManager(mLayoutManger);
79        mRecyclerView.setAdapter(mPageAdapter);
80        mRecyclerView.setItemViewCacheSize(0);
81        mPreloadController = new PreloadController(mRecyclerView);
82        mRecyclerView.setOnScrollListener(mPreloadController);
83
84        mContentView = (PrintContentView) activity.findViewById(R.id.options_content);
85        mEmbeddedContentContainer = (EmbeddedContentContainer) activity.findViewById(
86                R.id.embedded_content_container);
87        mEmbeddedContentContainer.setOnSizeChangeListener(this);
88    }
89
90    @Override
91    public void onSizeChanged(int width, int height) {
92        mPageAdapter.onPreviewAreaSizeChanged();
93    }
94
95    public boolean isOptionsOpened() {
96        return mContentView.isOptionsOpened();
97    }
98
99    public void closeOptions() {
100        mContentView.closeOptions();
101    }
102
103    public void setUiShown(boolean shown) {
104        if (shown) {
105            mRecyclerView.setVisibility(View.VISIBLE);
106        } else {
107            mRecyclerView.setVisibility(View.GONE);
108        }
109    }
110
111    public void onOrientationChanged() {
112        // Adjust the print option column count.
113        final int optionColumnCount = mActivity.getResources().getInteger(
114                R.integer.print_option_column_count);
115        mPrintOptionsLayout.setColumnCount(optionColumnCount);
116        mPageAdapter.onOrientationChanged();
117    }
118
119    public int getFilePageCount() {
120        return mPageAdapter.getFilePageCount();
121    }
122
123    public PageRange[] getSelectedPages() {
124        return mPageAdapter.getSelectedPages();
125    }
126
127    public PageRange[] getRequestedPages() {
128        return mPageAdapter.getRequestedPages();
129    }
130
131    public void onContentUpdated(boolean documentChanged, int documentPageCount,
132            PageRange[] writtenPages, PageRange[] selectedPages, MediaSize mediaSize,
133            Margins minMargins) {
134        boolean contentChanged = false;
135
136        if (documentChanged) {
137            contentChanged = true;
138        }
139
140        if (documentPageCount != mDocumentPageCount) {
141            mDocumentPageCount = documentPageCount;
142            contentChanged = true;
143        }
144
145        if (contentChanged) {
146            // If not closed, close as we start over.
147            if (mPageAdapter.isOpened()) {
148                Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
149                mHandler.enqueueOperation(operation);
150            }
151        }
152
153        // The content changed. In this case we have to invalidate
154        // all rendered pages and reopen the file...
155        if ((contentChanged || !mPageAdapter.isOpened()) && writtenPages != null) {
156            Message operation = mHandler.obtainMessage(MyHandler.MSG_OPEN);
157            mHandler.enqueueOperation(operation);
158        }
159
160        // Update the attributes before after closed to avoid flicker.
161        SomeArgs args = SomeArgs.obtain();
162        args.arg1 = writtenPages;
163        args.arg2 = selectedPages;
164        args.arg3 = mediaSize;
165        args.arg4 = minMargins;
166        args.argi1 = documentPageCount;
167
168        Message operation = mHandler.obtainMessage(MyHandler.MSG_UPDATE, args);
169        mHandler.enqueueOperation(operation);
170
171        // If document changed and has pages we want to start preloading.
172        if (contentChanged && writtenPages != null) {
173            operation = mHandler.obtainMessage(MyHandler.MSG_START_PRELOAD);
174            mHandler.enqueueOperation(operation);
175        }
176    }
177
178    @Override
179    public void onReleaseRequested(final File file) {
180        // This is called from the async task's single threaded executor
181        // thread, i.e. not on the main thread - so post a message.
182        mHandler.post(new Runnable() {
183            @Override
184            public void run() {
185                // At this point the other end will write to the file, hence
186                // we have to close it and reopen after the write completes.
187                if (mPageAdapter.isOpened()) {
188                    Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
189                    mHandler.enqueueOperation(operation);
190                }
191            }
192        });
193    }
194
195    public void destroy(Runnable callback) {
196        mHandler.cancelQueuedOperations();
197        mRecyclerView.setAdapter(null);
198        mPageAdapter.destroy(callback);
199    }
200
201    @Override
202    public int getWidth() {
203        return mEmbeddedContentContainer.getWidth();
204    }
205
206    @Override
207    public int getHeight() {
208        return mEmbeddedContentContainer.getHeight();
209    }
210
211    @Override
212    public void setColumnCount(int columnCount) {
213        mLayoutManger.setSpanCount(columnCount);
214    }
215
216    @Override
217    public void setPadding(int left, int top , int right, int bottom) {
218        mRecyclerView.setPadding(left, top, right, bottom);
219    }
220
221    private final class MyHandler extends Handler {
222        public static final int MSG_OPEN = 1;
223        public static final int MSG_CLOSE = 2;
224        public static final int MSG_UPDATE = 4;
225        public static final int MSG_START_PRELOAD = 5;
226
227        private boolean mAsyncOperationInProgress;
228
229        private final Runnable mOnAsyncOperationDoneCallback = new Runnable() {
230            @Override
231            public void run() {
232                mAsyncOperationInProgress = false;
233                handleNextOperation();
234            }
235        };
236
237        private final List<Message> mPendingOperations = new ArrayList<>();
238
239        public MyHandler(Looper looper) {
240            super(looper, null, false);
241        }
242
243        public void cancelQueuedOperations() {
244            mPendingOperations.clear();
245        }
246
247        public void enqueueOperation(Message message) {
248            mPendingOperations.add(message);
249            handleNextOperation();
250        }
251
252        public void handleNextOperation() {
253            while (!mPendingOperations.isEmpty() && !mAsyncOperationInProgress) {
254                Message operation = mPendingOperations.remove(0);
255                handleMessage(operation);
256            }
257        }
258
259        @Override
260        public void handleMessage(Message message) {
261            switch (message.what) {
262                case MSG_OPEN: {
263                    try {
264                        File file = mFileProvider.acquireFile(PrintPreviewController.this);
265                        ParcelFileDescriptor pfd = ParcelFileDescriptor.open(file,
266                                ParcelFileDescriptor.MODE_READ_ONLY);
267
268                        mAsyncOperationInProgress = true;
269                        mPageAdapter.open(pfd, new Runnable() {
270                            @Override
271                            public void run() {
272                                if (mDocumentPageCount == PrintDocumentInfo.PAGE_COUNT_UNKNOWN) {
273                                    mDocumentPageCount = mPageAdapter.getFilePageCount();
274                                    mActivity.updateOptionsUi();
275                                }
276                                mOnAsyncOperationDoneCallback.run();
277                            }
278                        });
279                    } catch (FileNotFoundException fnfe) {
280                        /* ignore - file guaranteed to be there */
281                    }
282                } break;
283
284                case MSG_CLOSE: {
285                    mAsyncOperationInProgress = true;
286                    mPageAdapter.close(new Runnable() {
287                        @Override
288                        public void run() {
289                            mFileProvider.releaseFile();
290                            mOnAsyncOperationDoneCallback.run();
291                        }
292                    });
293                } break;
294
295                case MSG_UPDATE: {
296                    SomeArgs args = (SomeArgs) message.obj;
297                    PageRange[] writtenPages = (PageRange[]) args.arg1;
298                    PageRange[] selectedPages = (PageRange[]) args.arg2;
299                    MediaSize mediaSize = (MediaSize) args.arg3;
300                    Margins margins = (Margins) args.arg4;
301                    final int pageCount = args.argi1;
302                    args.recycle();
303
304                    mPageAdapter.update(writtenPages, selectedPages, pageCount,
305                            mediaSize, margins);
306
307                } break;
308
309                case MSG_START_PRELOAD: {
310                    mPreloadController.startPreloadContent();
311                } break;
312            }
313        }
314    }
315
316    private final class PreloadController extends RecyclerView.OnScrollListener {
317        private final RecyclerView mRecyclerView;
318
319        private int mOldScrollState;
320
321        public PreloadController(RecyclerView recyclerView) {
322            mRecyclerView = recyclerView;
323            mOldScrollState = mRecyclerView.getScrollState();
324        }
325
326        @Override
327        public void onScrollStateChanged(RecyclerView recyclerView, int state) {
328            switch (mOldScrollState) {
329                case RecyclerView.SCROLL_STATE_SETTLING: {
330                    if (state == RecyclerView.SCROLL_STATE_IDLE
331                            || state == RecyclerView.SCROLL_STATE_DRAGGING){
332                        startPreloadContent();
333                    }
334                } break;
335
336                case RecyclerView.SCROLL_STATE_IDLE:
337                case RecyclerView.SCROLL_STATE_DRAGGING: {
338                    if (state == RecyclerView.SCROLL_STATE_SETTLING) {
339                        stopPreloadContent();
340                    }
341                } break;
342            }
343            mOldScrollState = state;
344        }
345
346        public void startPreloadContent() {
347            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
348            if (pageAdapter != null && pageAdapter.isOpened()) {
349                PageRange shownPages = computeShownPages();
350                if (shownPages != null) {
351                    pageAdapter.startPreloadContent(shownPages);
352                }
353            }
354        }
355
356        public void stopPreloadContent() {
357            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
358            if (pageAdapter != null && pageAdapter.isOpened()) {
359                pageAdapter.stopPreloadContent();
360            }
361        }
362
363        private PageRange computeShownPages() {
364            final int childCount = mRecyclerView.getChildCount();
365            if (childCount > 0) {
366                LayoutManager layoutManager = mRecyclerView.getLayoutManager();
367
368                View firstChild = layoutManager.getChildAt(0);
369                ViewHolder firstHolder = mRecyclerView.getChildViewHolder(firstChild);
370
371                View lastChild = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
372                ViewHolder lastHolder = mRecyclerView.getChildViewHolder(lastChild);
373
374                return new PageRange(firstHolder.getPosition(), lastHolder.getPosition());
375            }
376            return null;
377        }
378    }
379}
380