name: Auto-merge MDX Entry PRs

on:
  workflow_run:
    workflows: ['PR Review']
    types: [completed]
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'Pull request number to merge.'
        required: true
        type: string

concurrency:
  group: auto-merge-mdx-main
  cancel-in-progress: false

jobs:
  automerge:
    name: Auto-merge
    if: |
      github.repository_owner == 'thedaviddias' &&
      (
        github.event_name == 'workflow_dispatch' ||
        github.event.workflow_run.conclusion == 'success'
      )
    permissions:
      contents: write
      pull-requests: write
    runs-on: ubuntu-latest
    steps:
      - name: Collect PR context
        id: context
        uses: actions/github-script@v8
        env:
          DISPATCH_PR_NUMBER: ${{ inputs.pr_number }}
        with:
          github-token: ${{ secrets.PAT_TOKEN }}
          script: |
            const fs = require('node:fs')
            let pullRequestRef = null

            if (context.eventName === 'workflow_dispatch') {
              const prNumber = Number(process.env.DISPATCH_PR_NUMBER)

              if (!Number.isInteger(prNumber) || prNumber <= 0) {
                core.setFailed('workflow_dispatch requires a valid pr_number input.')
                return
              }

              pullRequestRef = { number: prNumber }
            } else {
              pullRequestRef = context.payload.workflow_run.pull_requests[0]
            }

            if (!pullRequestRef) {
              // workflow_run.pull_requests is empty for fork PRs — find the PR by head SHA
              const headSha = context.payload.workflow_run.head_sha
              const { data: openPrs } = await github.rest.pulls.list({
                owner: context.repo.owner,
                repo: context.repo.repo,
                state: 'open',
                sort: 'updated',
                direction: 'desc',
                per_page: 10
              })

              const matchingPr = openPrs.find(pr => pr.head.sha === headSha)

              if (!matchingPr) {
                core.setOutput('is_community_pr', 'false')
                core.setOutput('pr_number', '')
                return
              }

              pullRequestRef = { number: matchingPr.number }
            }

            const { data: pullRequest } = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: pullRequestRef.number
            })

            const [files, commits] = await Promise.all([
              github.paginate(github.rest.pulls.listFiles, {
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: pullRequest.number,
                per_page: 100
              }),
              github.paginate(github.rest.pulls.listCommits, {
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: pullRequest.number,
                per_page: 100
              })
            ])

            const payload = {
              authorLogin: pullRequest.user.login,
              commits: commits.map(commit => ({
                authorLogin: commit.author?.login ?? null,
                committerLogin: commit.committer?.login ?? null
              })),
              files: files.map(file => ({
                additions: file.additions,
                changes: file.changes,
                deletions: file.deletions,
                filename: file.filename,
                previousFilename: file.previous_filename ?? null,
                status: file.status
              })),
              headRefName: pullRequest.head.ref,
              title: pullRequest.title
            }

            const tempDir = process.env.RUNNER_TEMP || '/tmp'
            fs.writeFileSync(`${tempDir}/pr-context.json`, JSON.stringify(payload, null, 2))
            core.setOutput(
              'is_community_pr',
              String(pullRequest.title.startsWith('feat(community):'))
            )
            core.setOutput('pr_number', String(pullRequest.number))
            core.setOutput('pr_head_sha', pullRequest.head.sha)

      - name: Checkout
        if: steps.context.outputs.pr_number != '' && steps.context.outputs.is_community_pr == 'true'
        uses: actions/checkout@v6

      - name: Install
        if: steps.context.outputs.pr_number != '' && steps.context.outputs.is_community_pr == 'true'
        uses: ./.github/actions/install

      - name: Classify PR
        if: steps.context.outputs.pr_number != '' && steps.context.outputs.is_community_pr == 'true'
        id: classify
        run: pnpm exec tsx scripts/pr-triage.ts "$RUNNER_TEMP/pr-context.json" > classification.json

      - name: Merge PR
        if: steps.context.outputs.pr_number != '' && steps.context.outputs.is_community_pr == 'true' && steps.classify.outputs.automerge_eligible == 'true' && steps.classify.outputs.manual_websites_json_change != 'true'
        env:
          GH_TOKEN: ${{ secrets.PAT_TOKEN }}
          PR_HEAD_SHA: ${{ steps.context.outputs.pr_head_sha }}
          PR_NUMBER: ${{ steps.context.outputs.pr_number }}
        run: |
          for attempt in 1 2 3; do
            gh pr merge "$PR_NUMBER" \
              --repo "$GITHUB_REPOSITORY" \
              --squash \
              --admin \
              --match-head-commit "$PR_HEAD_SHA" && exit 0

            sleep 5
          done

          echo "Failed to merge PR #${PR_NUMBER} with admin privileges after retries." >&2
          exit 1

      - name: Report failed merge
        if: failure() && steps.context.outputs.pr_number != '' && steps.context.outputs.is_community_pr == 'true' && steps.classify.outputs.automerge_eligible == 'true' && steps.classify.outputs.manual_websites_json_change != 'true'
        uses: actions/github-script@v8
        env:
          PR_NUMBER: ${{ steps.context.outputs.pr_number }}
        with:
          github-token: ${{ secrets.PAT_TOKEN }}
          script: |
            const prNumber = Number(process.env.PR_NUMBER)

            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
              body:
                'Auto-merge tried to merge this PR with administrator privileges but GitHub still rejected it. This usually means the PR has merge conflicts or the token does not have the expected bypass capability.'
            })