name: Update Nix pnpmDeps Hash

on:
  workflow_dispatch:
  push:
    branches:
      - main
    paths:
      - 'pnpm-lock.yaml'

permissions:
  contents: write
  pull-requests: write

jobs:
  update:
    if: github.event_name == 'workflow_dispatch' || !github.event.repository.fork
    runs-on: ubuntu-latest
    steps:
      # Why?
      #
      # failed to
      # $ nix build .#airi-pnpm-deps
      # > airi-pnpm-deps> Running phase: fixupPhase
      # > error: writing to file: No space left on device
      - name: Free Disk Space
        uses: jlumbroso/free-disk-space@54081f138730dfa15788a46383842cd2f914a1be # v1.3.1

      - uses: actions/checkout@v6
        with:
          ref: main # Use main regardless of workflow_dispatch branch
          # Authenticate git with PAT so that pushing to head retriggers CI
          token: ${{ secrets.HASH_UPDATE_TOKEN }}

      - uses: cachix/install-nix-action@v31
        with:
          extra_nix_config: experimental-features = nix-command flakes

      - name: Update Hash
        run: nix/update-pnpm-deps-hash.sh

      - name: Check for changes
        id: changes
        run: |
          if git diff --quiet; then
            echo "has_changes=false" >> "$GITHUB_OUTPUT"
          else
            echo "has_changes=true" >> "$GITHUB_OUTPUT"
          fi

      - name: Create PR
        if: steps.changes.outputs.has_changes == 'true'
        env:
          # Create PR with PAT to trigger CI
          GH_TOKEN: ${{ secrets.HASH_UPDATE_TOKEN }}
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add nix/pnpm-deps-hash.txt
          git commit -m 'chore(nix): update pnpmDeps hash'
          git push -f origin HEAD:chore/update-nix-pnpm-deps-hash

          # Create PR if it doesn't already exist
          existing_pr=$(gh pr list --head chore/update-nix-pnpm-deps-hash --json number -q '.[0].number' 2>/dev/null || true)
          if [ -z "$existing_pr" ]; then
            gh pr create \
              --base main \
              --head chore/update-nix-pnpm-deps-hash \
              --title 'chore(nix): update pnpmDeps hash' \
              --body 'Auto-generated by CI to keep Nix pnpmDeps hash up-to-date.'
          fi

          # Enable auto-merge so PR merges once checks pass
          gh pr merge --squash --auto --delete-branch chore/update-nix-pnpm-deps-hash