/**
* CommitChunker - Create embeddable chunks from git commits
*/
import { createHash } from "node:crypto";
import { COMMIT_TYPE_PATTERNS } from "./config.js";
import type { CommitChunk, CommitType, GitConfig, RawCommit } from "./types.js";
export class CommitChunker {
constructor(private config: GitConfig) {}
/**
* Classify commit type based on commit message
*/
classifyCommitType(commit: RawCommit): CommitType {
const message = `${commit.subject} ${commit.body}`.toLowerCase();
// Check each type's patterns
for (const { type, patterns } of COMMIT_TYPE_PATTERNS) {
for (const pattern of patterns) {
if (pattern.test(commit.subject) || pattern.test(message)) {
return type;
}
}
}
return "other";
}
/**
* Create embeddable chunks from a commit
* Currently produces one chunk per commit, but could be extended
* to handle very large commits differently
*/
createChunks(
commit: RawCommit,
repoPath: string,
diff?: string,
): CommitChunk[] {
const commitType = this.classifyCommitType(commit);
const content = this.formatChunkContent(commit, commitType, diff);
// Check if content exceeds max chunk size
if (content.length > this.config.maxChunkSize) {
// Truncate content but keep essential metadata visible
const truncatedContent = this.truncateContent(
content,
commit,
commitType,
);
return [
{
content: truncatedContent,
metadata: this.createMetadata(commit, commitType, repoPath),
},
];
}
return [
{
content,
metadata: this.createMetadata(commit, commitType, repoPath),
},
];
}
/**
* Generate deterministic chunk ID from commit content
*/
generateChunkId(chunk: CommitChunk): string {
// Use commit hash + repo path for deterministic ID
const data = `${chunk.metadata.commitHash}:${chunk.metadata.repoPath}`;
const hash = createHash("sha256").update(data).digest("hex");
return `gitcommit_${hash.substring(0, 16)}`;
}
/**
* Format the chunk content for embedding
*/
private formatChunkContent(
commit: RawCommit,
commitType: CommitType,
diff?: string,
): string {
const lines: string[] = [];
// Header section
lines.push(`Commit: ${commit.shortHash}`);
lines.push(`Type: ${commitType}`);
lines.push(`Author: ${commit.author}`);
lines.push(`Date: ${commit.date.toISOString().split("T")[0]}`);
lines.push("");
// Subject line
lines.push(`Subject: ${commit.subject}`);
lines.push("");
// Body (description) if present
if (commit.body.trim()) {
lines.push("Description:");
lines.push(commit.body.trim());
lines.push("");
}
// Files changed
if (this.config.includeFileList && commit.files.length > 0) {
lines.push(`Files changed (${commit.files.length}):`);
for (const file of commit.files.slice(0, 20)) {
// Limit to 20 files
lines.push(` - ${file}`);
}
if (commit.files.length > 20) {
lines.push(` ... and ${commit.files.length - 20} more files`);
}
lines.push("");
}
// Change stats
lines.push(`Changes: +${commit.insertions} -${commit.deletions}`);
// Diff preview if included
if (this.config.includeDiff && diff) {
lines.push("");
lines.push("Diff preview:");
lines.push(this.extractDiffPreview(diff));
}
return lines.join("\n");
}
/**
* Extract a readable preview from the diff
*/
private extractDiffPreview(diff: string): string {
// Remove the commit metadata from the top of git show output
const diffStart = diff.indexOf("diff --git");
if (diffStart === -1) return "";
const diffContent = diff.substring(diffStart);
// Extract just the actual changes (lines starting with + or -)
// but not the diff headers
const lines = diffContent.split("\n");
const changeLines: string[] = [];
let currentFile = "";
for (const line of lines) {
if (line.startsWith("diff --git")) {
// Extract filename from diff header
const match = line.match(/diff --git a\/.+ b\/(.+)/);
if (match) {
currentFile = match[1];
}
} else if (line.startsWith("@@")) {
// Include hunk header with file context
if (currentFile && changeLines.length > 0) {
changeLines.push(`--- ${currentFile} ---`);
}
changeLines.push(line);
} else if (
(line.startsWith("+") || line.startsWith("-")) &&
!line.startsWith("+++") &&
!line.startsWith("---")
) {
changeLines.push(line);
}
}
// Limit the preview size
const maxPreviewLines = 50;
if (changeLines.length > maxPreviewLines) {
return (
changeLines.slice(0, maxPreviewLines).join("\n") +
`\n... (${changeLines.length - maxPreviewLines} more lines)`
);
}
return changeLines.join("\n");
}
/**
* Truncate content while preserving essential information
*/
private truncateContent(
content: string,
commit: RawCommit,
commitType: CommitType,
): string {
// Keep the header and subject, truncate the rest
const essentialLines: string[] = [
`Commit: ${commit.shortHash}`,
`Type: ${commitType}`,
`Author: ${commit.author}`,
`Date: ${commit.date.toISOString().split("T")[0]}`,
"",
`Subject: ${commit.subject}`,
"",
];
// Add truncated body if present
if (commit.body.trim()) {
const maxBodyLength = 500;
const body = commit.body.trim();
if (body.length > maxBodyLength) {
essentialLines.push("Description:");
essentialLines.push(body.substring(0, maxBodyLength) + "...");
essentialLines.push("");
} else {
essentialLines.push("Description:");
essentialLines.push(body);
essentialLines.push("");
}
}
// Add file summary
if (commit.files.length > 0) {
essentialLines.push(`Files changed (${commit.files.length}):`);
for (const file of commit.files.slice(0, 10)) {
essentialLines.push(` - ${file}`);
}
if (commit.files.length > 10) {
essentialLines.push(` ... and ${commit.files.length - 10} more files`);
}
essentialLines.push("");
}
essentialLines.push(`Changes: +${commit.insertions} -${commit.deletions}`);
essentialLines.push("");
essentialLines.push("[content truncated due to size]");
return essentialLines.join("\n");
}
/**
* Create metadata object for a chunk
*/
private createMetadata(
commit: RawCommit,
commitType: CommitType,
repoPath: string,
): CommitChunk["metadata"] {
return {
commitHash: commit.hash,
shortHash: commit.shortHash,
author: commit.author,
authorEmail: commit.authorEmail,
date: commit.date.toISOString(),
subject: commit.subject,
commitType,
files: commit.files,
insertions: commit.insertions,
deletions: commit.deletions,
repoPath,
};
}
}
