name: Close stale PRs

on:
  workflow_dispatch:
    inputs:
      dryRun:
        description: "Log actions without closing PRs"
        type: boolean
        default: false
  schedule:
    - cron: "0 6 * * *"

permissions:
  contents: read
  issues: write
  pull-requests: write

jobs:
  close-stale-prs:
    runs-on: ubuntu-latest
    steps:
      - name: Close inactive PRs
        uses: actions/github-script@v8
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const DAYS_INACTIVE = 60
            const cutoff = new Date(Date.now() - DAYS_INACTIVE * 24 * 60 * 60 * 1000)
            const { owner, repo } = context.repo
            const dryRun = context.payload.inputs?.dryRun === "true"
            const stalePrs = []

            core.info(`Dry run mode: ${dryRun}`)

            const prs = await github.paginate(github.rest.pulls.list, {
              owner,
              repo,
              state: "open",
              per_page: 100,
              sort: "updated",
              direction: "asc",
            })

            for (const pr of prs) {
              const lastUpdated = new Date(pr.updated_at)
              if (lastUpdated > cutoff) {
                core.info(`PR ${pr.number} is fresh`)
                continue
              }

              stalePrs.push(pr)
            }

            if (!stalePrs.length) {
              core.info("No stale pull requests found.")
              return
            }

            for (const pr of stalePrs) {
              const issue_number = pr.number
              const closeComment = `Closing this pull request because it has had no updates for more than ${DAYS_INACTIVE} days. If you plan to continue working on it, feel free to reopen or open a new PR.`

              if (dryRun) {
                core.info(`[dry-run] Would close PR #${issue_number} from ${pr.user.login}`)
                continue
              }

              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number,
                body: closeComment,
              })

              await github.rest.pulls.update({
                owner,
                repo,
                pull_number: issue_number,
                state: "closed",
              })

              core.info(`Closed PR #${issue_number} from ${pr.user.login}`)
            }