sync-preview.yml

name: Sync Preview Branch

on:
  pull_request:
    types: [opened, synchronize, reopened, closed]
  push:
    branches: [main]

concurrency:
  group: preview-sync
  cancel-in-progress: false

jobs:
  sync-preview:
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Configure Git
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

      - name: Reset preview to main
        run: |
          git checkout -B preview origin/main

      - name: Get all open PRs
        id: get-prs
        uses: actions/github-script@v7
        with:
          script: |
            const { data: prs } = await github.rest.pulls.list({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'open',
              sort: 'created',
              direction: 'asc'
            });

            // Filter out draft PRs if desired
            const activePRs = prs.filter(pr => !pr.draft);

            // Return PR numbers and their branch names
            const prInfo = activePRs.map(pr => ({
              number: pr.number,
              branch: pr.head.ref,
              title: pr.title
            }));

            console.log(`Found ${prInfo.length} open PRs to merge`);
            return prInfo;

      - name: Merge PRs into preview
        id: merge-prs
        uses: actions/github-script@v7
        with:
          script: |
            const prs = ${{ steps.get-prs.outputs.result }};
            const { exec: executeCommand } = require('child_process');
            const util = require('util');
            const execPromise = util.promisify(executeCommand);

            // Helper function to escape shell arguments
            const escapeShellArg = (arg) => {
              return arg.replace(/'/g, "'\\''");
            };

            const conflicts = [];
            const merged = [];

            for (const pr of prs) {
              console.log(`Attempting to merge PR #${pr.number}: ${pr.title}`);

              try {
                // Fetch the PR branch - branch name is safe as it comes from GitHub
                await execPromise(`git fetch origin ${pr.branch}:refs/remotes/origin/${pr.branch}`);

                // Try to merge with properly escaped title
                const safeTitle = escapeShellArg(pr.title);
                const mergeResult = await execPromise(`git merge origin/${pr.branch} --no-edit -m 'Merge PR #${pr.number}: ${safeTitle}'`);
                console.log(`Successfully merged PR #${pr.number}`);
                merged.push(pr.number);
              } catch (error) {
                console.log(`Conflict detected with PR #${pr.number}`);
                conflicts.push(pr);

                // Abort the merge
                try {
                  await execPromise('git merge --abort');
                } catch (e) {
                  // Already aborted or not in merge state
                }

                // Post comment on the PR about the conflict
                if (context.eventName === 'pull_request' && context.payload.pull_request.number === pr.number) {
                  // This is the PR that triggered the workflow
                  await github.rest.issues.createComment({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    issue_number: pr.number,
                    body: `⚠️ **Merge Conflict Detected**\n\nThis PR has conflicts with the current preview branch (main + other open PRs).\n\nPlease resolve conflicts with the main branch or wait for conflicting PRs to be merged first.\n\nPRs merged before this one: ${merged.join(', ') || 'none'}`
                  });
                }
              }
            }

            const result = { conflicts, merged };
            core.setOutput('conflicts', JSON.stringify(conflicts));
            core.setOutput('merged', JSON.stringify(merged));
            core.setOutput('result', JSON.stringify(result));

            return result;

      - name: Push preview branch
        id: push-preview
        run: |
          # Check if remote preview branch exists
          if git ls-remote --exit-code --heads origin preview > /dev/null 2>&1; then
            # preview branch exists, check for changes
            if git diff --quiet origin/preview; then
              echo "No changes to push"
              echo "pushed=false" >> $GITHUB_OUTPUT
            else
              git push origin preview --force-with-lease
              echo "pushed=true" >> $GITHUB_OUTPUT
              echo "Preview branch updated successfully"
            fi
          else
            # preview branch does not exist, push it
            git push origin preview
            echo "pushed=true" >> $GITHUB_OUTPUT
            echo "Preview branch created and pushed"
          fi
        continue-on-error: true

      - name: Handle push failure
        if: steps.push-preview.outcome == 'failure'
        run: |
          # Force push if lease fails (someone else updated preview)
          git push origin preview --force
          echo "Preview branch force-pushed due to concurrent update"

      - name: Post deployment status comment
        if: github.event_name == 'pull_request' && steps.push-preview.outputs.pushed == 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const prNumber = context.payload.pull_request.number;
            const mergeResult = ${{ steps.merge-prs.outputs.result }};

            let comment = '🚀 **Preview Deployment Update**\n\n';

            if (mergeResult.merged.includes(prNumber)) {
              comment += '✅ This PR has been successfully merged into the preview branch.\n\n';
              comment += 'The preview environment will update shortly at: **https://docs.preview.trakrf.id**\n\n';

              if (mergeResult.conflicts.length > 0) {
                comment += `⚠️ Note: The following PRs have conflicts and were not included in preview:\n`;
                mergeResult.conflicts.forEach(pr => {
                  comment += `- PR #${pr.number}: ${pr.title}\n`;
                });
              }
            }

            // Only post if we have something meaningful to say
            if (mergeResult.merged.includes(prNumber) || mergeResult.conflicts.some(c => c.number === prNumber)) {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body: comment
              });
            }