/**
* Git-style unified diff generator
*
* Generates readable diffs for displaying file changes.
* Used by AiderTool and RawAiderTool for dry-run previews.
*/
export class DiffGenerator {
/**
* Generate git-style unified diff
*
* NOTE: This is a simplified implementation that assumes line-by-line changes.
* For production use, consider using a proper diff library like 'diff' npm package
* which implements the Myers algorithm for better diff quality.
*
* @param original - Original content
* @param modified - Modified content
* @param path - File path for diff header
* @returns Unified diff string
*/
generateDiff(original: string, modified: string, path: string): string {
const originalLines = original.split('\n');
const modifiedLines = modified.split('\n');
const diff: string[] = [];
diff.push(`--- a/${path}`);
diff.push(`+++ b/${path}`);
// Simple line-by-line comparison
// TODO: Replace with Myers diff algorithm for better results
let i = 0;
let j = 0;
while (i < originalLines.length || j < modifiedLines.length) {
if (i < originalLines.length && j < modifiedLines.length) {
if (originalLines[i] === modifiedLines[j]) {
// Lines match - show context
diff.push(` ${originalLines[i]}`);
i++;
j++;
} else {
// Lines differ - show both
diff.push(`-${originalLines[i]}`);
diff.push(`+${modifiedLines[j]}`);
i++;
j++;
}
} else if (i < originalLines.length) {
// Only original lines remain - deletions
diff.push(`-${originalLines[i]}`);
i++;
} else {
// Only modified lines remain - additions
diff.push(`+${modifiedLines[j]}`);
j++;
}
}
return diff.join('\n');
}
/**
* Generate compact summary of changes
*
* @param original - Original content
* @param modified - Modified content
* @returns Summary string with line counts
*/
generateSummary(original: string, modified: string): string {
const originalLines = original.split('\n');
const modifiedLines = modified.split('\n');
let additions = 0;
let deletions = 0;
let changes = 0;
const minLength = Math.min(originalLines.length, modifiedLines.length);
// Count changes in overlapping lines
for (let i = 0; i < minLength; i++) {
if (originalLines[i] !== modifiedLines[i]) {
changes++;
}
}
// Count additions (modified has more lines)
if (modifiedLines.length > originalLines.length) {
additions = modifiedLines.length - originalLines.length;
}
// Count deletions (original has more lines)
if (originalLines.length > modifiedLines.length) {
deletions = originalLines.length - modifiedLines.length;
}
const parts: string[] = [];
if (changes > 0) parts.push(`${changes} changed`);
if (additions > 0) parts.push(`${additions} added`);
if (deletions > 0) parts.push(`${deletions} deleted`);
return parts.length > 0 ? parts.join(', ') : 'no changes';
}
}
