From c262cd5d6e07c53c8cb92ec0e7ccb10719125cff Mon Sep 17 00:00:00 2001
From: Daniel Gultsch <daniel@gultsch.de>
Date: Sun, 5 Nov 2017 21:34:40 +0100
Subject: [PATCH] support for basic IM styling

---
 .../ui/ConversationFragment.java              |   5 +
 .../ui/adapter/MessageAdapter.java            |   8 +-
 .../conversations/utils/ImStyleParser.java    | 108 ++++++++++++++
 .../conversations/utils/StylingHelper.java    | 134 ++++++++++++++++++
 4 files changed, 253 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/eu/siacs/conversations/utils/ImStyleParser.java
 create mode 100644 src/main/java/eu/siacs/conversations/utils/StylingHelper.java

diff --git a/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java b/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
index 3658275da..63816d193 100644
--- a/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
+++ b/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
@@ -15,6 +15,8 @@ import android.support.v13.view.inputmethod.InputConnectionCompat;
 import android.support.v13.view.inputmethod.InputContentInfoCompat;
 import android.text.Editable;
 import android.text.InputType;
+import android.text.TextWatcher;
+import android.text.style.StyleSpan;
 import android.util.Log;
 import android.util.Pair;
 import android.view.ContextMenu;
@@ -73,6 +75,7 @@ import eu.siacs.conversations.ui.adapter.MessageAdapter.OnContactPictureLongClic
 import eu.siacs.conversations.ui.widget.EditMessage;
 import eu.siacs.conversations.ui.widget.ListSelectionManager;
 import eu.siacs.conversations.utils.NickValidityChecker;
+import eu.siacs.conversations.utils.StylingHelper;
 import eu.siacs.conversations.utils.UIHelper;
 import eu.siacs.conversations.xmpp.XmppConnection;
 import eu.siacs.conversations.xmpp.chatstate.ChatState;
@@ -462,6 +465,8 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 			}
 		});
 
+		mEditMessage.addTextChangedListener(new StylingHelper.MessageEditorStyler(mEditMessage));
+
 		mEditMessage.setOnEditorActionListener(mEditorActionListener);
 		mEditMessage.setRichContentListener(new String[]{"image/*"}, mEditorContentListener);
 
diff --git a/src/main/java/eu/siacs/conversations/ui/adapter/MessageAdapter.java b/src/main/java/eu/siacs/conversations/ui/adapter/MessageAdapter.java
index 2f35d49e0..b4b74faa3 100644
--- a/src/main/java/eu/siacs/conversations/ui/adapter/MessageAdapter.java
+++ b/src/main/java/eu/siacs/conversations/ui/adapter/MessageAdapter.java
@@ -68,6 +68,7 @@ import eu.siacs.conversations.utils.CryptoHelper;
 import eu.siacs.conversations.utils.Emoticons;
 import eu.siacs.conversations.utils.GeoHelper;
 import eu.siacs.conversations.utils.Patterns;
+import eu.siacs.conversations.utils.StylingHelper;
 import eu.siacs.conversations.utils.UIHelper;
 import eu.siacs.conversations.xmpp.mam.MamReference;
 
@@ -473,8 +474,11 @@ public class MessageAdapter extends ArrayAdapter<Message> implements CopyTextVie
 			}
 			Matcher matcher = Emoticons.generatePattern(body).matcher(body);
 			while(matcher.find()) {
-					body.setSpan(new RelativeSizeSpan(1.2f), matcher.start(), matcher.end(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-				}
+				body.setSpan(new RelativeSizeSpan(1.2f), matcher.start(), matcher.end(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
+			}
+
+			StylingHelper.format(body, true);
+
 			Linkify.addLinks(body, XMPP_PATTERN, "xmpp");
 			Linkify.addLinks(body, Patterns.AUTOLINK_WEB_URL, "http", WEBURL_MATCH_FILTER, WEBURL_TRANSFORM_FILTER);
 			Linkify.addLinks(body, GeoHelper.GEO_URI, "geo");
diff --git a/src/main/java/eu/siacs/conversations/utils/ImStyleParser.java b/src/main/java/eu/siacs/conversations/utils/ImStyleParser.java
new file mode 100644
index 000000000..1d164bf48
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/utils/ImStyleParser.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2017, Daniel Gultsch All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation and/or
+ * other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package eu.siacs.conversations.utils;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class ImStyleParser {
+
+	final static List<Character> KEYWORDS = Arrays.asList('*', '_', '~', '`');
+	final static List<Character> NO_SUB_PARSING_KEYWORDS = Arrays.asList('`');
+	final static boolean ALLOW_EMPTY = false;
+
+	public static List<Style> parse(CharSequence text) {
+		return parse(text, 0, text.length() - 1);
+	}
+
+	public static List<Style> parse(CharSequence text, int start, int end) {
+		List<Style> styles = new ArrayList<>();
+		for (int i = start; i <= end; ++i) {
+			char c = text.charAt(i);
+			if (KEYWORDS.contains(c) && precededByWhiteSpace(text, i, start) && !followedByWhitespace(text, i, end)) {
+				int to = seekEnd(text, c, i + 1, end);
+				if (to != -1 && (to != i + 1 || ALLOW_EMPTY)) {
+					styles.add(new Style(c, i, to));
+					if (!NO_SUB_PARSING_KEYWORDS.contains(c)) {
+						styles.addAll(parse(text, i + 1, to - 1));
+					}
+					i = to;
+				}
+			}
+		}
+		return styles;
+	}
+
+	private static boolean precededByWhiteSpace(CharSequence text, int index, int start) {
+		return index == start || Character.isWhitespace(text.charAt(index - 1));
+	}
+
+	private static boolean followedByWhitespace(CharSequence text, int index, int end) {
+		return index >= end || Character.isWhitespace(text.charAt(index + 1));
+	}
+
+	private static int seekEnd(CharSequence text, char needle, int start, int end) {
+		for (int i = start; i <= end; ++i) {
+			char c = text.charAt(i);
+			if (c == needle) {
+				return i;
+			} else if (c == '\n') {
+				return -1;
+			}
+		}
+		return -1;
+	}
+
+	public static class Style {
+
+		private final char c;
+		private final int start;
+		private final int end;
+
+		public Style(char c, int start, int end) {
+			this.c = c;
+			this.start = start;
+			this.end = end;
+		}
+
+		public char getCharacter() {
+			return c;
+		}
+
+		public int getStart() {
+			return start;
+		}
+
+		public int getEnd() {
+			return end;
+		}
+	}
+}
diff --git a/src/main/java/eu/siacs/conversations/utils/StylingHelper.java b/src/main/java/eu/siacs/conversations/utils/StylingHelper.java
new file mode 100644
index 000000000..268612a3d
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/utils/StylingHelper.java
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2017, Daniel Gultsch All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation and/or
+ * other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package eu.siacs.conversations.utils;
+
+import android.graphics.Color;
+import android.graphics.Typeface;
+import android.support.annotation.ColorInt;
+import android.text.Editable;
+import android.text.ParcelableSpan;
+import android.text.Spanned;
+import android.text.TextWatcher;
+import android.text.style.ForegroundColorSpan;
+import android.text.style.StrikethroughSpan;
+import android.text.style.StyleSpan;
+import android.text.style.TypefaceSpan;
+import android.widget.EditText;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class StylingHelper {
+
+	private static List<? extends Class<? extends ParcelableSpan>> SPAN_CLASSES = Arrays.asList(
+			StyleSpan.class,
+			StrikethroughSpan.class,
+			TypefaceSpan.class,
+			ForegroundColorSpan.class
+	);
+
+	public static void clear(final Editable editable) {
+		final int end = editable.length() - 1;
+		for(Class<?extends ParcelableSpan> clazz : SPAN_CLASSES) {
+			for (ParcelableSpan span : editable.getSpans(0, end, clazz)) {
+				editable.removeSpan(span);
+			}
+		}
+	}
+
+	public static void format(final Editable editable) {
+		format(editable, false);
+	}
+
+	public static void format(final Editable editable, final boolean replaceStyleAnnotation) {
+		for (ImStyleParser.Style style : ImStyleParser.parse(editable)) {
+			editable.setSpan(createSpanForStyle(style), style.getStart(), style.getEnd(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+			if (replaceStyleAnnotation) {
+				editable.replace(style.getStart(), style.getStart() + 1, "\u200B");
+				editable.replace(style.getEnd(), style.getEnd() + 1, "\u200B");
+			}
+		}
+	}
+
+	public static void format(final Editable editable, @ColorInt int color) {
+		for(ImStyleParser.Style style : ImStyleParser.parse(editable)) {
+			editable.setSpan(createSpanForStyle(style), style.getStart() + 1, style.getEnd() - 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+			editable.setSpan(new ForegroundColorSpan(color),style.getStart(),style.getStart()+1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+			editable.setSpan(new ForegroundColorSpan(color),style.getEnd(),style.getEnd()+1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+		}
+	}
+
+	private static ParcelableSpan createSpanForStyle(ImStyleParser.Style style) {
+		switch (style.getCharacter()) {
+			case '*':
+				return new StyleSpan(Typeface.BOLD);
+			case '_':
+				return new StyleSpan(Typeface.ITALIC);
+			case '~':
+				return new StrikethroughSpan();
+			case '`':
+				return new TypefaceSpan("monospace");
+			default:
+				throw new AssertionError("Unknown Style");
+		}
+	}
+
+	public static class MessageEditorStyler implements TextWatcher {
+
+		private final EditText mEditText;
+
+		public MessageEditorStyler(EditText editText) {
+			this.mEditText = editText;
+		}
+
+		@Override
+		public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
+
+		}
+
+		@Override
+		public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
+
+		}
+
+		@Override
+		public void afterTextChanged(Editable editable) {
+			clear(editable);
+			final int color = mEditText.getCurrentTextColor();
+			final int syntaxColor = Color.argb(
+					Math.round(Color.alpha(color) * 0.5f),
+					Color.red(color),
+					Color.green(color),
+					Color.blue(color)
+			);
+			format(editable,syntaxColor);
+		}
+	}
+}