1/*
  2 * Copyright (c) 2017, Daniel Gultsch All rights reserved.
  3 *
  4 * Redistribution and use in source and binary forms, with or without modification,
  5 * are permitted provided that the following conditions are met:
  6 *
  7 * 1. Redistributions of source code must retain the above copyright notice, this
  8 * list of conditions and the following disclaimer.
  9 *
 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
 11 * this list of conditions and the following disclaimer in the documentation and/or
 12 * other materials provided with the distribution.
 13 *
 14 * 3. Neither the name of the copyright holder nor the names of its contributors
 15 * may be used to endorse or promote products derived from this software without
 16 * specific prior written permission.
 17 *
 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 21 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 25 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 28 */
 29
 30package eu.siacs.conversations.utils;
 31
 32import android.content.Context;
 33import android.graphics.Color;
 34import android.graphics.Typeface;
 35import android.text.Editable;
 36import android.text.ParcelableSpan;
 37import android.text.Spannable;
 38import android.text.SpannableString;
 39import android.text.Spanned;
 40import android.text.TextWatcher;
 41import android.text.style.BackgroundColorSpan;
 42import android.text.style.ForegroundColorSpan;
 43import android.text.style.StrikethroughSpan;
 44import android.text.style.StyleSpan;
 45import android.text.style.TypefaceSpan;
 46import android.widget.EditText;
 47import android.widget.TextView;
 48
 49import androidx.annotation.ColorInt;
 50import androidx.core.content.ContextCompat;
 51
 52import java.util.ArrayList;
 53import java.util.Arrays;
 54import java.util.List;
 55
 56import eu.siacs.conversations.R;
 57import eu.siacs.conversations.entities.Message;
 58import eu.siacs.conversations.ui.text.QuoteSpan;
 59
 60public class StylingHelper {
 61
 62	private static final List<? extends Class<? extends ParcelableSpan>> SPAN_CLASSES = Arrays.asList(
 63			StyleSpan.class,
 64			StrikethroughSpan.class,
 65			TypefaceSpan.class,
 66			ForegroundColorSpan.class
 67	);
 68
 69	public static void clear(final Editable editable) {
 70		final int end = editable.length() - 1;
 71		for (Class<? extends ParcelableSpan> clazz : SPAN_CLASSES) {
 72			for (ParcelableSpan span : editable.getSpans(0, end, clazz)) {
 73				editable.removeSpan(span);
 74			}
 75		}
 76	}
 77
 78	public static void format(final Editable editable, int start, int end, @ColorInt int textColor) {
 79		for (ImStyleParser.Style style : ImStyleParser.parse(editable, start, end)) {
 80			final int keywordLength = style.getKeyword().length();
 81			editable.setSpan(createSpanForStyle(style), style.getStart() + keywordLength, style.getEnd() - keywordLength + 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
 82			makeKeywordOpaque(editable, style.getStart(), style.getStart() + keywordLength, textColor);
 83			makeKeywordOpaque(editable, style.getEnd() - keywordLength + 1, style.getEnd() + 1, textColor);
 84		}
 85	}
 86
 87	public static void format(final Editable editable, @ColorInt int textColor) {
 88		int end = 0;
 89		Message.MergeSeparator[] spans = editable.getSpans(0, editable.length() - 1, Message.MergeSeparator.class);
 90		for (Message.MergeSeparator span : spans) {
 91			format(editable, end, editable.getSpanStart(span), textColor);
 92			end = editable.getSpanEnd(span);
 93		}
 94		format(editable, end, editable.length() - 1, textColor);
 95	}
 96
 97	public static void highlight(final Context context, final Editable editable, List<String> needles, boolean dark) {
 98		for (String needle : needles) {
 99			if (!FtsUtils.isKeyword(needle)) {
100				highlight(context, editable, needle, dark);
101			}
102		}
103	}
104
105	public static List<String> filterHighlightedWords(List<String> terms) {
106		List<String> words = new ArrayList<>();
107		for (String term : terms) {
108			if (!FtsUtils.isKeyword(term)) {
109				StringBuilder builder = new StringBuilder();
110				for (int codepoint, i = 0; i < term.length(); i += Character.charCount(codepoint)) {
111					codepoint = term.codePointAt(i);
112					if (Character.isLetterOrDigit(codepoint)) {
113						builder.append(Character.toChars(codepoint));
114					} else if (builder.length() > 0) {
115						words.add(builder.toString());
116						builder.delete(0, builder.length());
117					}
118				}
119				if (builder.length() > 0) {
120					words.add(builder.toString());
121				}
122			}
123		}
124		return words;
125	}
126
127	private static void highlight(final Context context, final Editable editable, String needle, boolean dark) {
128		final int length = needle.length();
129		String string = editable.toString();
130		int start = indexOfIgnoreCase(string, needle, 0);
131		while (start != -1) {
132			int end = start + length;
133			editable.setSpan(new BackgroundColorSpan(ContextCompat.getColor(context, dark ? R.color.blue_a100 : R.color.blue_a400)), start, end, SpannableString.SPAN_EXCLUSIVE_EXCLUSIVE);
134			editable.setSpan(new ForegroundColorSpan(ContextCompat.getColor(context, dark ? R.color.black87 : R.color.white)), start, end, SpannableString.SPAN_EXCLUSIVE_EXCLUSIVE);
135			start = indexOfIgnoreCase(string, needle, start + length);
136		}
137
138	}
139
140	static CharSequence subSequence(CharSequence charSequence, int start, int end) {
141		if (start == 0 && charSequence.length() + 1 == end) {
142			return charSequence;
143		}
144		if (charSequence instanceof Spannable) {
145			Spannable spannable = (Spannable) charSequence;
146			Spannable sub = (Spannable) spannable.subSequence(start, end);
147			for (Class<? extends ParcelableSpan> clazz : SPAN_CLASSES) {
148				ParcelableSpan[] spannables = spannable.getSpans(start, end, clazz);
149				for (ParcelableSpan parcelableSpan : spannables) {
150					int beginSpan = spannable.getSpanStart(parcelableSpan);
151					int endSpan = spannable.getSpanEnd(parcelableSpan);
152					if (beginSpan >= start && endSpan <= end) {
153						continue;
154					}
155					sub.setSpan(clone(parcelableSpan), Math.max(beginSpan - start, 0), Math.min(Math.max(sub.length() - 1, 0), endSpan), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
156				}
157			}
158			return sub;
159		} else {
160			return charSequence.subSequence(start, end);
161		}
162	}
163
164	private static ParcelableSpan clone(ParcelableSpan span) {
165		if (span instanceof ForegroundColorSpan) {
166			return new ForegroundColorSpan(((ForegroundColorSpan) span).getForegroundColor());
167		} else if (span instanceof TypefaceSpan) {
168			return new TypefaceSpan(((TypefaceSpan) span).getFamily());
169		} else if (span instanceof StyleSpan) {
170			return new StyleSpan(((StyleSpan) span).getStyle());
171		} else if (span instanceof StrikethroughSpan) {
172			return new StrikethroughSpan();
173		} else {
174			throw new AssertionError("Unknown Span");
175		}
176	}
177
178	public static boolean isDarkText(TextView textView) {
179		int argb = textView.getCurrentTextColor();
180		return Color.red(argb) + Color.green(argb) + Color.blue(argb) == 0;
181	}
182
183	private static ParcelableSpan createSpanForStyle(ImStyleParser.Style style) {
184		switch (style.getKeyword()) {
185			case "*":
186				return new StyleSpan(Typeface.BOLD);
187			case "_":
188				return new StyleSpan(Typeface.ITALIC);
189			case "~":
190				return new StrikethroughSpan();
191			case "`":
192			case "```":
193				return new TypefaceSpan("monospace");
194			default:
195				throw new AssertionError("Unknown Style");
196		}
197	}
198
199	private static void makeKeywordOpaque(final Editable editable, int start, int end, @ColorInt int fallbackTextColor) {
200		QuoteSpan[] quoteSpans = editable.getSpans(start, end, QuoteSpan.class);
201		@ColorInt int textColor = quoteSpans.length > 0 ? quoteSpans[0].getColor() : fallbackTextColor;
202		@ColorInt int keywordColor = transformColor(textColor);
203		editable.setSpan(new ForegroundColorSpan(keywordColor), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
204	}
205
206	private static
207	@ColorInt
208	int transformColor(@ColorInt int c) {
209		return Color.argb(Math.round(Color.alpha(c) * 0.45f), Color.red(c), Color.green(c), Color.blue(c));
210	}
211
212	private static int indexOfIgnoreCase(final String haystack, final String needle, final int start) {
213		if (haystack == null || needle == null) {
214			return -1;
215		}
216		final int endLimit = haystack.length() - needle.length() + 1;
217		if (start > endLimit) {
218			return -1;
219		}
220		if (needle.length() == 0) {
221			return start;
222		}
223		for (int i = start; i < endLimit; i++) {
224			if (haystack.regionMatches(true, i, needle, 0, needle.length())) {
225				return i;
226			}
227		}
228		return -1;
229	}
230
231	public static class MessageEditorStyler implements TextWatcher {
232
233		private final EditText mEditText;
234
235		public MessageEditorStyler(EditText editText) {
236			this.mEditText = editText;
237		}
238
239		@Override
240		public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
241
242		}
243
244		@Override
245		public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
246
247		}
248
249		@Override
250		public void afterTextChanged(Editable editable) {
251			clear(editable);
252			format(editable, mEditText.getCurrentTextColor());
253		}
254	}
255}