Update diff colors (#4747)

Co-authored-by: Jacob Richman <jacob314@gmail.com>

packages/cli/src/ui/components/ThemeDialog.tsx

@@ -279,18 +279,23 @@ export function ThemeDialog({
               >
                 {colorizeCode(
                   `# function
--def fibonacci(n):
--    a, b = 0, 1
--    for _ in range(n):
--        a, b = b, a + b
--    return a`,
+def fibonacci(n):
+    a, b = 0, 1
+    for _ in range(n):
+        a, b = b, a + b
+    return a`,
                   'python',
                   codeBlockHeight,
                   colorizeCodeWidth,
                 )}
                 <Box marginTop={1} />
                 <DiffRenderer
-                  diffContent={`--- a/old_file.txt\n+++ b/new_file.txt\n@@ -1,6 +1,7 @@\n # function\n-def fibonacci(n):\n-    a, b = 0, 1\n-    for _ in range(n):\n-        a, b = b, a + b\n-    return a\n+def fibonacci(n):\n+    a, b = 0, 1\n+    for _ in range(n):\n+        a, b = b, a + b\n+    return a\n+\n+print(fibonacci(10))\n`}
+                  diffContent={`--- a/util.py
++++ b/util.py
+@@ -1,2 +1,2 @@
+- print("Hello, " + name)
++ print(f"Hello, {name}!")
+`}
                   availableTerminalHeight={diffHeight}
                   terminalWidth={colorizeCodeWidth}
                   theme={previewTheme}

packages/cli/src/ui/components/messages/DiffRenderer.test.tsx

@@ -130,8 +130,8 @@ index 0000001..0000002 100644
     );
     const output = lastFrame();
     const lines = output!.split('\n');
-    expect(lines[0]).toBe('1    - old line');
-    expect(lines[1]).toBe('1    + new line');
+    expect(lines[0]).toBe('1 - old line');
+    expect(lines[1]).toBe('1 + new line');
   });
 
   it('should handle diff with only header and no changes', () => {
@@ -253,35 +253,35 @@ index 123..789 100644
       {
         terminalWidth: 80,
         height: undefined,
-        expected: `1      console.log('first hunk');
-2    - const oldVar = 1;
-2    + const newVar = 1;
-3      console.log('end of first hunk');
+        expected: ` 1   console.log('first hunk');
+ 2 - const oldVar = 1;
+ 2 + const newVar = 1;
+ 3   console.log('end of first hunk');
 ════════════════════════════════════════════════════════════════════════════════
-20     console.log('second hunk');
-21   - const anotherOld = 'test';
-21   + const anotherNew = 'test';
-22     console.log('end of second hunk');`,
+20   console.log('second hunk');
+21 - const anotherOld = 'test';
+21 + const anotherNew = 'test';
+22   console.log('end of second hunk');`,
       },
       {
         terminalWidth: 80,
         height: 6,
         expected: `... first 4 lines hidden ...
 ════════════════════════════════════════════════════════════════════════════════
-20     console.log('second hunk');
-21   - const anotherOld = 'test';
-21   + const anotherNew = 'test';
-22     console.log('end of second hunk');`,
+20   console.log('second hunk');
+21 - const anotherOld = 'test';
+21 + const anotherNew = 'test';
+22   console.log('end of second hunk');`,
       },
       {
         terminalWidth: 30,
         height: 6,
         expected: `... first 10 lines hidden ...
-       'test';
-21   + const anotherNew =
-       'test';
-22     console.log('end of
-       second hunk');`,
+   ;
+21 + const anotherNew = 'test'
+   ;
+22   console.log('end of
+     second hunk');`,
       },
     ])(
       'with terminalWidth $terminalWidth and height $height',
@@ -329,11 +329,11 @@ fileDiff Index: file.txt
     );
     const output = lastFrame();
 
-    expect(output).toEqual(`1    - const oldVar = 1;
-1    + const newVar = 1;
+    expect(output).toEqual(` 1 - const oldVar = 1;
+ 1 + const newVar = 1;
 ════════════════════════════════════════════════════════════════════════════════
-20   - const anotherOld = 'test';
-20   + const anotherNew = 'test';`);
+20 - const anotherOld = 'test';
+20 + const anotherNew = 'test';`);
   });
 
   it('should correctly render a new file with no file extension correctly', () => {

packages/cli/src/ui/components/messages/DiffRenderer.tsx

@@ -8,7 +8,7 @@ import React from 'react';
 import { Box, Text } from 'ink';
 import { Colors } from '../../colors.js';
 import crypto from 'crypto';
-import { colorizeCode } from '../../utils/CodeColorizer.js';
+import { colorizeCode, colorizeLine } from '../../utils/CodeColorizer.js';
 import { MaxSizedBox } from '../shared/MaxSizedBox.js';
 
 interface DiffLine {
@@ -157,7 +157,6 @@ export const DiffRenderer: React.FC<DiffRendererProps> = ({
       tabWidth,
       availableTerminalHeight,
       terminalWidth,
-      theme,
     );
   }
 
@@ -170,7 +169,6 @@ const renderDiffContent = (
   tabWidth = DEFAULT_TAB_WIDTH,
   availableTerminalHeight: number | undefined,
   terminalWidth: number,
-  theme?: import('../../themes/theme.js').Theme,
 ) => {
   // 1. Normalize whitespace (replace tabs with spaces) *before* further processing
   const normalizedLines = parsedLines.map((line) => ({
@@ -191,6 +189,18 @@ const renderDiffContent = (
     );
   }
 
+  const maxLineNumber = Math.max(
+    0,
+    ...displayableLines.map((l) => l.oldLine ?? 0),
+    ...displayableLines.map((l) => l.newLine ?? 0),
+  );
+  const gutterWidth = Math.max(1, maxLineNumber.toString().length);
+
+  const fileExtension = filename?.split('.').pop() || null;
+  const language = fileExtension
+    ? getLanguageFromExtension(fileExtension)
+    : null;
+
   // Calculate the minimum indentation across all displayable lines
   let baseIndentation = Infinity; // Start high to find the minimum
   for (const line of displayableLines) {
@@ -237,27 +247,25 @@ const renderDiffContent = (
         ) {
           acc.push(
             <Box key={`gap-${index}`}>
-              <Text wrap="truncate">{'═'.repeat(terminalWidth)}</Text>
+              <Text wrap="truncate" color={Colors.Gray}>
+                {'═'.repeat(terminalWidth)}
+              </Text>
             </Box>,
           );
         }
 
         const lineKey = `diff-line-${index}`;
         let gutterNumStr = '';
-        let color: string | undefined = undefined;
         let prefixSymbol = ' ';
-        let dim = false;
 
         switch (line.type) {
           case 'add':
             gutterNumStr = (line.newLine ?? '').toString();
-            color = theme?.colors?.AccentGreen || 'green';
             prefixSymbol = '+';
             lastLineNumber = line.newLine ?? null;
             break;
           case 'del':
             gutterNumStr = (line.oldLine ?? '').toString();
-            color = theme?.colors?.AccentRed || 'red';
             prefixSymbol = '-';
             // For deletions, update lastLineNumber based on oldLine if it's advancing.
             // This helps manage gaps correctly if there are multiple consecutive deletions
@@ -268,7 +276,6 @@ const renderDiffContent = (
             break;
           case 'context':
             gutterNumStr = (line.newLine ?? '').toString();
-            dim = true;
             prefixSymbol = ' ';
             lastLineNumber = line.newLine ?? null;
             break;
@@ -280,13 +287,26 @@ const renderDiffContent = (
 
         acc.push(
           <Box key={lineKey} flexDirection="row">
-            <Text color={Colors.Gray}>{gutterNumStr.padEnd(4)} </Text>
-            <Text color={color} dimColor={dim}>
-              {prefixSymbol}{' '}
-            </Text>
-            <Text color={color} dimColor={dim} wrap="wrap">
-              {displayContent}
+            <Text color={Colors.Gray}>
+              {gutterNumStr.padStart(gutterWidth)}{' '}
             </Text>
+            {line.type === 'context' ? (
+              <>
+                <Text>{prefixSymbol} </Text>
+                <Text wrap="wrap">
+                  {colorizeLine(displayContent, language)}
+                </Text>
+              </>
+            ) : (
+              <Text
+                backgroundColor={
+                  line.type === 'add' ? Colors.DiffAdded : Colors.DiffRemoved
+                }
+                wrap="wrap"
+              >
+                {prefixSymbol} {colorizeLine(displayContent, language)}
+              </Text>
+            )}
           </Box>,
         );
         return acc;