import { promises as fs } from 'fs';
import * as path from 'path';
interface DiffResult {
additions: number;
deletions: number;
formatted: string;
patches: DiffPatch[];
}
interface DiffPatch {
start: number;
end: number;
type: 'addition' | 'deletion' | 'modification';
content: string;
}
interface DiffOptions {
format?: 'unified' | 'side-by-side' | 'inline';
contextLines?: number;
ignoreWhitespace?: boolean;
}
export class DiffManager {
async diffFiles(file1: string, file2: string, options: DiffOptions = {}): Promise<DiffResult> {
const content1 = await fs.readFile(file1, 'utf-8');
const content2 = await fs.readFile(file2, 'utf-8');
return this.diff(content1, content2, options);
}
diff(text1: string, text2: string, options: DiffOptions = {}): DiffResult {
const lines1 = text1.split('\n');
const lines2 = text2.split('\n');
const patches: DiffPatch[] = [];
let additions = 0;
let deletions = 0;
// Simple line-by-line diff algorithm
const maxLines = Math.max(lines1.length, lines2.length);
let formatted = '';
for (let i = 0; i < maxLines; i++) {
const line1 = lines1[i];
const line2 = lines2[i];
if (line1 === undefined && line2 !== undefined) {
// Addition
additions++;
formatted += `+ ${line2}\n`;
patches.push({
start: i,
end: i,
type: 'addition',
content: line2
});
} else if (line1 !== undefined && line2 === undefined) {
// Deletion
deletions++;
formatted += `- ${line1}\n`;
patches.push({
start: i,
end: i,
type: 'deletion',
content: line1
});
} else if (line1 !== line2) {
// Modification
deletions++;
additions++;
formatted += `- ${line1}\n`;
formatted += `+ ${line2}\n`;
patches.push({
start: i,
end: i,
type: 'modification',
content: `${line1} -> ${line2}`
});
} else {
// No change
if (options.format === 'unified') {
formatted += ` ${line1}\n`;
}
}
}
return {
additions,
deletions,
formatted,
patches
};
}
async patchFile(filePath: string, patches: DiffPatch[]): Promise<void> {
const content = await fs.readFile(filePath, 'utf-8');
const lines = content.split('\n');
// Apply patches in reverse order to maintain line numbers
patches.sort((a, b) => b.start - a.start);
for (const patch of patches) {
switch (patch.type) {
case 'addition':
lines.splice(patch.start, 0, patch.content);
break;
case 'deletion':
lines.splice(patch.start, 1);
break;
case 'modification':
lines[patch.start] = patch.content.split(' -> ')[1];
break;
}
}
await fs.writeFile(filePath, lines.join('\n'), 'utf-8');
}
}
