gitlify/src/diff-parser.js

A powerful CLI tool to analyze uncommitted git changes with detailed reports, function detection, and beautiful terminal output

class DiffParser {
  parseDiff(diffData) {
    const files = [];
    const combinedDiff = diffData.combined;
    
    if (!combinedDiff.trim()) {
      return files;
    }

    const diffBlocks = this.splitDiffIntoBlocks(combinedDiff);
    
    for (const block of diffBlocks) {
      const fileInfo = this.parseDiffBlock(block);
      if (fileInfo) {
        files.push(fileInfo);
      }
    }

    return files;
  }

  splitDiffIntoBlocks(diff) {
    const blocks = [];
    const lines = diff.split('\n');
    let currentBlock = [];
    
    for (const line of lines) {
      if (line.startsWith('diff --git')) {
        if (currentBlock.length > 0) {
          blocks.push(currentBlock.join('\n'));
        }
        currentBlock = [line];
      } else {
        currentBlock.push(line);
      }
    }
    
    if (currentBlock.length > 0) {
      blocks.push(currentBlock.join('\n'));
    }
    
    return blocks;
  }

  parseDiffBlock(block) {
    const lines = block.split('\n');
    if (lines.length === 0) return null;

    // Extract file path from diff header
    const diffHeader = lines[0];
    const fileMatch = diffHeader.match(/diff --git a\/(.+) b\/(.+)/);
    if (!fileMatch) return null;

    const filePath = fileMatch[1];
    
    // Parse hunks (chunks of changes)
    const hunks = this.parseHunks(lines.slice(1));
    
    // Calculate totals
    let totalAdditions = 0;
    let totalDeletions = 0;
    const changedLines = [];
    
    for (const hunk of hunks) {
      totalAdditions += hunk.additions;
      totalDeletions += hunk.deletions;
      changedLines.push(...hunk.changedLines);
    }

    return {
      filePath,
      totalAdditions,
      totalDeletions,
      hunks,
      changedLines: changedLines.sort((a, b) => a.lineNumber - b.lineNumber)
    };
  }

  parseHunks(lines) {
    const hunks = [];
    let currentHunk = null;
    
    for (const line of lines) {
      // Hunk header: @@ -oldStart,oldCount +newStart,newCount @@
      const hunkMatch = line.match(/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@/);
      if (hunkMatch) {
        if (currentHunk) {
          hunks.push(currentHunk);
        }
        
        const [, oldStart, oldCount, newStart, newCount] = hunkMatch;
        currentHunk = {
          oldStart: parseInt(oldStart),
          oldCount: parseInt(oldCount) || 1,
          newStart: parseInt(newStart),
          newCount: parseInt(newCount) || 1,
          additions: 0,
          deletions: 0,
          changedLines: []
        };
        continue;
      }
      
      if (!currentHunk) continue;
      
      // Count additions and deletions
      if (line.startsWith('+') && !line.startsWith('+++')) {
        currentHunk.additions++;
        currentHunk.changedLines.push({
          type: 'addition',
          lineNumber: currentHunk.newStart + currentHunk.additions - 1,
          content: line.substring(1)
        });
      } else if (line.startsWith('-') && !line.startsWith('---')) {
        currentHunk.deletions++;
        currentHunk.changedLines.push({
          type: 'deletion',
          lineNumber: currentHunk.oldStart + currentHunk.deletions - 1,
          content: line.substring(1)
        });
      }
    }
    
    if (currentHunk) {
      hunks.push(currentHunk);
    }
    
    return hunks;
  }
}

module.exports = DiffParser;