Initial commit

src/github/operations/branch.ts

@@ -0,0 +1,121 @@
+#!/usr/bin/env bun
+
+/**
+ * Setup the appropriate branch based on the event type:
+ * - For PRs: Checkout the PR branch
+ * - For Issues: Create a new branch
+ */
+
+import { $ } from "bun";
+import * as core from "@actions/core";
+import type { ParsedGitHubContext } from "../context";
+import type { GitHubPullRequest } from "../types";
+import type { Octokits } from "../api/client";
+import type { FetchDataResult } from "../data/fetcher";
+
+export type BranchInfo = {
+  defaultBranch: string;
+  claudeBranch?: string;
+  currentBranch: string;
+};
+
+export async function setupBranch(
+  octokits: Octokits,
+  githubData: FetchDataResult,
+  context: ParsedGitHubContext,
+): Promise<BranchInfo> {
+  const { owner, repo } = context.repository;
+  const entityNumber = context.entityNumber;
+  const isPR = context.isPR;
+
+  // Get the default branch first
+  const repoResponse = await octokits.rest.repos.get({
+    owner,
+    repo,
+  });
+  const defaultBranch = repoResponse.data.default_branch;
+
+  if (isPR) {
+    const prData = githubData.contextData as GitHubPullRequest;
+    const prState = prData.state;
+
+    // Check if PR is closed or merged
+    if (prState === "CLOSED" || prState === "MERGED") {
+      console.log(
+        `PR #${entityNumber} is ${prState}, creating new branch from default...`,
+      );
+      // Fall through to create a new branch like we do for issues
+    } else {
+      // Handle open PR: Checkout the PR branch
+      console.log("This is an open PR, checking out PR branch...");
+
+      const branchName = prData.headRefName;
+
+      // Execute git commands to checkout PR branch
+      await $`git fetch origin ${branchName}`;
+      await $`git checkout ${branchName}`;
+
+      console.log(`Successfully checked out PR branch for PR #${entityNumber}`);
+
+      // For open PRs, return branch info
+      return {
+        defaultBranch,
+        currentBranch: branchName,
+      };
+    }
+  }
+
+  // Creating a new branch for either an issue or closed/merged PR
+  const entityType = isPR ? "pr" : "issue";
+  console.log(`Creating new branch for ${entityType} #${entityNumber}...`);
+
+  const timestamp = new Date()
+    .toISOString()
+    .replace(/[:-]/g, "")
+    .replace(/\.\d{3}Z/, "")
+    .split("T")
+    .join("_");
+
+  const newBranch = `claude/${entityType}-${entityNumber}-${timestamp}`;
+
+  try {
+    // Get the SHA of the default branch
+    const defaultBranchRef = await octokits.rest.git.getRef({
+      owner,
+      repo,
+      ref: `heads/${defaultBranch}`,
+    });
+
+    const currentSHA = defaultBranchRef.data.object.sha;
+
+    console.log(`Current SHA: ${currentSHA}`);
+
+    // Create branch using GitHub API
+    await octokits.rest.git.createRef({
+      owner,
+      repo,
+      ref: `refs/heads/${newBranch}`,
+      sha: currentSHA,
+    });
+
+    // Checkout the new branch
+    await $`git fetch origin ${newBranch}`;
+    await $`git checkout ${newBranch}`;
+
+    console.log(
+      `Successfully created and checked out new branch: ${newBranch}`,
+    );
+
+    // Set outputs for GitHub Actions
+    core.setOutput("CLAUDE_BRANCH", newBranch);
+    core.setOutput("DEFAULT_BRANCH", defaultBranch);
+    return {
+      defaultBranch,
+      claudeBranch: newBranch,
+      currentBranch: newBranch,
+    };
+  } catch (error) {
+    console.error("Error creating branch:", error);
+    process.exit(1);
+  }
+}