name: Add Branch Prefix to PR Title

on:
  pull_request:
    types: [opened, reopened]

permissions:
  pull-requests: write

jobs:
  add-branch-prefix:
    runs-on: ubuntu-latest
    steps:
      - name: Add branch prefix to PR title
        uses: actions/github-script@v7
        with:
          script: |
            const baseBranch = context.payload.pull_request.base.ref;
            const currentTitle = context.payload.pull_request.title;

            // Strictly match:
            // - amd-staging-rocgdb-<version>
            // - amd-temp-<name>
            const validBranchPattern = /^(amd-staging-rocgdb-\d+|amd-temp-[a-zA-Z0-9-]+)$/;
            if (!validBranchPattern.test(baseBranch)) {
              core.info(`Skipping: base branch '${baseBranch}' does not match allowed patterns`);
              core.info(`Allowed: 'amd-staging-rocgdb-<version>' or 'amd-temp-<name>'`);
              return;
            }

            // Check if title already has the specific branch prefix
            const escapedBranch = baseBranch.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
            const prefixPattern = new RegExp(`^\\[${escapedBranch}\\]\\s`);
            if (prefixPattern.test(currentTitle)) {
              core.info(`Skipping: title already has [${baseBranch}] prefix: ${currentTitle}`);
              return;
            }

            // Add the branch prefix
            const newTitle = `[${baseBranch}] ${currentTitle}`;

            core.info(`Updating PR title from: ${currentTitle}`);
            core.info(`                      to: ${newTitle}`);

            await github.rest.pulls.update({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number,
              title: newTitle
            });