From 633aaf877d9f468a4fa9ae121f3abb66c3077409 Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Sun, 25 Sep 2011 13:30:25 +0400
Subject: [PATCH] syntax highlighting

---
 .../calculator/CalculatorEditText.java        | 94 ++++++++++++++-----
 .../android/calculator/CalculatorView.java    |  4 +
 2 files changed, 73 insertions(+), 25 deletions(-)

diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorEditText.java b/src/main/java/org/solovyev/android/calculator/CalculatorEditText.java
index 3cac4bdc..c060a77a 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorEditText.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorEditText.java
@@ -7,9 +7,13 @@ package org.solovyev.android.calculator;
 
 import android.content.Context;
 import android.content.res.ColorStateList;
+import android.graphics.Color;
+import android.text.Html;
 import android.util.AttributeSet;
+import android.util.Log;
 import android.widget.EditText;
-import org.solovyev.common.exceptions.SersoException;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.math.MathEntityType;
 
 /**
  * User: serso
@@ -36,36 +40,76 @@ public class CalculatorEditText extends EditText {
 		super.setTextColor(colors);	//To change body of overridden methods use File | Settings | File Templates.
 	}
 
-	@Override
-	public void setText(CharSequence text, BufferType type) {
-		/*try {
-			final List<Pair<Integer, Integer>> groupSymbols = new ArrayList<Pair<Integer, Integer>>();
+	public void redraw() {
+		String text = getText().toString();
+		int selectionStart = getSelectionStart();
+		int selectionEnd = getSelectionEnd();
 
-			final Stack<Pair<Integer, Integer>> groupSymbolsStack = new Stack<Pair<Integer, Integer>>();
-			for (int i = 0; i < text.length(); i++) {
-				char ch = text.charAt(i);
-				if (MathEntityType.openGroupSymbols.contains(ch)) {
-					groupSymbolsStack.push(new Pair<Integer, Integer>(i, null));
-				} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
-					final Pair<Integer, Integer> pair = groupSymbolsStack.pop();
-					if (pair != null) {
-						pair.setSecond(i);
-						groupSymbols.add(0, pair);
-					} else {
-						throw new NoPairGroupSymbolException();
-					}
-				}
+		int maxNumberOfOpenGroupSymbols = 0;
+		int numberOfOpenGroupSymbols = 0;
+		for (int i = 0; i < text.length(); i++) {
+			char ch = text.charAt(i);
+			if (MathEntityType.openGroupSymbols.contains(ch)) {
+				numberOfOpenGroupSymbols++;
+				maxNumberOfOpenGroupSymbols = Math.max(maxNumberOfOpenGroupSymbols, numberOfOpenGroupSymbols);
+			} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
+				numberOfOpenGroupSymbols--;
 			}
+		}
 
-			text = insertHtml(text, groupSymbols);
-		} catch (NoPairGroupSymbolException e) {
-			// do nothing
-		}*/
+		if (maxNumberOfOpenGroupSymbols > 0) {
 
-		super.setText(text, type);
+			final StringBuilder sb = new StringBuilder();
+
+			processGroup(sb, text, 0, 0, maxNumberOfOpenGroupSymbols);
+
+			Log.d(CalculatorEditText.class.getName(), sb.toString());
+
+			super.setText(Html.fromHtml(sb.toString()), BufferType.EDITABLE);
+		} else {
+			super.setText(text, BufferType.EDITABLE);
+		}
+
+		setSelection(selectionStart, selectionEnd);
 	}
 
-	private class NoPairGroupSymbolException extends SersoException {
+	private int processGroup(@NotNull StringBuilder result, @NotNull String s, int i, int numberOfOpenings, int maxNumberOfGroups) {
 
+		result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
+
+		for (; i < s.length(); i++) {
+			char ch = s.charAt(i);
+
+			if (MathEntityType.openGroupSymbols.contains(ch)) {
+				result.append(ch);
+				result.append("</font>");
+				i = processGroup(result, s, i + 1, numberOfOpenings + 1, maxNumberOfGroups);
+				result.append("<font color=\"").append(getColor(maxNumberOfGroups, numberOfOpenings)).append("\">");
+				if (i < s.length() && MathEntityType.closeGroupSymbols.contains(s.charAt(i))) {
+					result.append(s.charAt(i));
+				}
+			} else if (MathEntityType.closeGroupSymbols.contains(ch)) {
+				break;
+			} else {
+				result.append(ch);
+			}
+		}
+
+		result.append("</font>");
+
+
+		return i;
+	}
+
+	private String getColor(int numberOfOpenGroupSymbols, int numberOfOpenings) {
+		final int baseColor = Color.WHITE;
+
+		double c = 1;
+
+		int i = ((int)(255 * c)) * numberOfOpenings / (numberOfOpenGroupSymbols + 1);
+
+		int result = Color.rgb( Color.red(baseColor) - i, Color.green(baseColor) - i, Color.blue(baseColor) - i);
+
+		return "#" + Integer.toHexString(result).substring(2);
 	}
 }
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorView.java b/src/main/java/org/solovyev/android/calculator/CalculatorView.java
index 0def0da2..54d288e1 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorView.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorView.java
@@ -118,6 +118,8 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 		final String editorStateAfter = this.editor.getText().toString();
 		if (!editorStateBefore.equals(editorStateAfter)) {
 
+			editor.redraw();
+
 			currentRunner.setObject(new Runnable() {
 				@Override
 				public void run() {
@@ -240,6 +242,8 @@ public class CalculatorView implements CursorControl, HistoryControl<CalculatorH
 		synchronized (history) {
 			setValuesFromHistory(this.editor, editorHistoryState.getEditorState());
 			setValuesFromHistory(this.display, editorHistoryState.getDisplayState());
+
+			editor.redraw();
 		}
 	}