name: Update maintainers list
on:
  push:
    branches:
      - main
    paths:
      - lib/maintainers.nix
  schedule:
    # Update every Monday at 9 AM UTC
    - cron: "0 9 * * 1"
  workflow_dispatch:
    inputs:
      create_pr:
        description: "Create PR even if no changes"
        required: false
        default: false
        type: boolean
jobs:
  update-maintainers:
    runs-on: ubuntu-latest
    if: github.repository_owner == 'nix-community' || github.event_name == 'workflow_dispatch'
    permissions:
      contents: write
      pull-requests: write
      issues: write
    env:
      pr_branch: update/maintainers-${{ github.ref_name }}
    steps:
      - name: Create GitHub App token
        uses: actions/create-github-app-token@v3
        if: vars.CI_APP_ID
        id: app-token
        with:
          app-id: ${{ vars.CI_APP_ID }}
          private-key: ${{ secrets.CI_APP_PRIVATE_KEY }}
      - name: Get GitHub App user info
        id: user-info
        if: vars.CI_APP_ID
        env:
          GH_TOKEN: ${{ steps.app-token.outputs.token }}
          slug: ${{ steps.app-token.outputs.app-slug }}
        run: |
          name="$slug[bot]"
          id=$(gh api "/users/$name" --jq .id)
          {
            echo "id=$id"
            echo "name=$name"
            echo "email=$id+$name@users.noreply.github.com"
          } >> "$GITHUB_OUTPUT"
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          token: ${{ steps.app-token.outputs.token || github.token }}
      - name: Get Nixpkgs revision from flake.lock
        id: get-nixpkgs
        run: |
          echo "rev=$(jq -r '.nodes.nixpkgs.locked.rev' flake.lock)" >> "$GITHUB_OUTPUT"
      - name: Install Nix
        uses: cachix/install-nix-action@v31
        with:
          nix_path: nixpkgs=https://github.com/NixOS/nixpkgs/archive/${{ steps.get-nixpkgs.outputs.rev }}.tar.gz
      - name: Setup Git
        env:
          name: ${{ steps.user-info.outputs.name || 'github-actions[bot]' }}
          email: ${{ steps.user-info.outputs.email || '41898282+github-actions[bot]@users.noreply.github.com' }}
        run: |
          git config user.name "$name"
          git config user.email "$email"
      - name: Save old maintainers
        id: old-maintainers
        run: |
          echo "📄 Saving old maintainers file for comparison..."
          echo "old_maintainers=$(nix eval --file all-maintainers.nix --apply 'builtins.attrNames' --json 2>/dev/null || echo '[]')" >> "$GITHUB_OUTPUT"
      - name: Generate updated maintainers list
        run: |
          echo "::group::📋 Generating updated generated/all-maintainers.nix..."
          ./lib/python/generate-all-maintainers.py
          echo "::endgroup::"
          echo "::group::🎨 Formatting with nixfmt..."
          nix fmt all-maintainers.nix
          echo "::endgroup::"
      - name: Check for changes and compare maintainers
        id: check-changes
        env:
          old_maintainers: ${{ steps.old-maintainers.outputs.old_maintainers }}
        run: |
          if git diff --quiet all-maintainers.nix; then
            echo "No changes to all-maintainers.nix"
            echo "has_changes=false" >> "$GITHUB_OUTPUT"
            echo "maintainer_changes=No changes detected" >> "$GITHUB_OUTPUT"
          else
            echo "Changes detected in all-maintainers.nix"
            echo "has_changes=true" >> "$GITHUB_OUTPUT"
            # Get change statistics
            added=$(git diff --numstat all-maintainers.nix | cut -f1)
            removed=$(git diff --numstat all-maintainers.nix | cut -f2)
            echo "changes_summary=+$added -$removed lines" >> "$GITHUB_OUTPUT"

            # Compare old and new maintainers using nix eval
            echo "🔍 Comparing maintainers..."

            # Extract maintainer names from new file
            new_maintainers=$(nix eval --file all-maintainers.nix --apply 'builtins.attrNames' --json)

            # Compare using nix eval
            comparison=$(nix eval --expr "
              let
                old = builtins.fromJSON ''$old_maintainers'';
                new = builtins.fromJSON ''$new_maintainers'';
                oldSet = builtins.listToAttrs (map (name: { name = name; value = true; }) old);
                newSet = builtins.listToAttrs (map (name: { name = name; value = true; }) new);
                added = builtins.filter (name: !(oldSet ? \${name})) new;
                removed = builtins.filter (name: !(newSet ? \${name})) old;
              in {
                added = added;
                removed = removed;
                total_old = builtins.length old;
                total_new = builtins.length new;
              }
            " --json)

            # Format comparison output
            added_count=$(echo "$comparison" | jq '.added | length')
            removed_count=$(echo "$comparison" | jq '.removed | length')
            total_old=$(echo "$comparison" | jq '.total_old')
            total_new=$(echo "$comparison" | jq '.total_new')

            maintainer_summary="**Added:** $added_count maintainers"
            maintainer_summary="$maintainer_summary\n**Removed:** $removed_count maintainers"
            maintainer_summary="$maintainer_summary\n**Total:** $total_old → $total_new maintainers"

            if [ "$added_count" -gt 0 ]; then
              added_names=$(echo "$comparison" | jq -r '.added | join(", ")')
              maintainer_summary="$maintainer_summary\n\n**✅ Added:** $added_names"
            fi

            if [ "$removed_count" -gt 0 ]; then
              removed_names=$(echo "$comparison" | jq -r '.removed | join(", ")')
              maintainer_summary="$maintainer_summary\n\n**❌ Removed:** $removed_names"
            fi

            echo "maintainer_changes<<EOF" >> "$GITHUB_OUTPUT"
            echo -e "$maintainer_summary" >> "$GITHUB_OUTPUT"
            echo "EOF" >> "$GITHUB_OUTPUT"
          fi
      - name: Validate generated file
        if: steps.check-changes.outputs.has_changes == 'true'
        run: |
          echo "🔍 Validating generated all-maintainers.nix..."
          if nix-instantiate --eval ./all-maintainers.nix --strict > /dev/null; then
            echo "✅ Generated file has valid Nix syntax"
          else
            echo "❌ Generated file has invalid Nix syntax"
            exit 1
          fi
      - name: Create update branch
        run: |
          git branch -D "$pr_branch" || echo "Nothing to delete"
          git switch -c "$pr_branch"
      - name: Get info on the current PR
        id: open_pr_info
        env:
          GH_TOKEN: ${{ steps.app-token.outputs.token || github.token }}
        run: |
          # Query for info about the already open update PR
          info=$(
            gh api graphql -F owner='{owner}' -F repo='{repo}' -F branch="$pr_branch" -f query='
              query($owner:String!, $repo:String!, $branch:String!) {
                repository(owner: $owner, name: $repo) {
                  pullRequests(first: 1, states: OPEN, headRefName: $branch) {
                    nodes {
                      number
                      url
                    }
                  }
                }
              }
            ' | jq --raw-output '
              .data.repository.pullRequests.nodes[]
              | to_entries[]
              | "\(.key)=\(.value)"
            '
          )
          if [[ -n "$info" ]]; then
            echo "PR info:"
            echo "$info"
            echo "$info" >> "$GITHUB_OUTPUT"
          else
            echo "No PR is currently open"
          fi
      - name: Fetch current PR's branch
        if: steps.open_pr_info.outputs.number
        run: |
          git fetch origin "$pr_branch"
          git branch --set-upstream-to "origin/$pr_branch"
      - name: Create Pull Request
        id: create-pr
        if: steps.check-changes.outputs.has_changes == 'true' || github.event.inputs.create_pr == 'true'
        env:
          GH_TOKEN: ${{ steps.app-token.outputs.token || github.token }}
          title: "maintainers: update all-maintainers.nix"
          commit_body: |
            Automated update of the master maintainers list combining:
            - Home Manager specific maintainers from modules/lib/maintainers.nix
            - Nixpkgs maintainers referenced in Home Manager modules

            ${{ steps.check-changes.outputs.maintainer_changes }}

            Generated by: lib/python/generate-all-maintainers.py
          pr_url: ${{ steps.open_pr_info.outputs.url }}
          pr_num: ${{ steps.open_pr_info.outputs.number }}
          pr_body: |
            ## 📋 Summary

            This PR updates the master maintainers list (`all-maintainers.nix`) which combines:
            - **Home Manager specific maintainers** from `modules/lib/maintainers.nix`
            - **Nixpkgs maintainers** referenced in Home Manager modules

            ## 🔄 Changes

            **Statistics:** ${{ steps.check-changes.outputs.changes_summary || 'No content changes (format/comment updates only)' }}

            ${{ steps.check-changes.outputs.maintainer_changes }}

            The updated list includes all maintainers needed for review assignments across the Home Manager project.

            ## 🤖 Automation

            - **Generated by:** `lib/python/generate-all-maintainers.py`
            - **Trigger:** ${{ github.event_name == 'schedule' && 'Scheduled weekly update' || 'Manual workflow dispatch' }}
            - **Validation:** File syntax verified with `nix eval`

            ---
            🤖 *This PR was automatically created by the [update-maintainers workflow](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})*
        run: |
          # Commit the changes
          git add all-maintainers.nix
          git commit -m "$title" -m "$commit_body"

          echo "Pushing to remote branch $pr_branch"
          git push --force --set-upstream origin "$pr_branch"

          if [ -z "$pr_num" ]; then
            echo "Creating new pull request."
            PR_URL=$(
              gh pr create \
                --title "$title" \
                --body "$pr_body"
            )
          else
            PR_URL=$pr_url
            echo "Pull request already exists: $PR_URL"
            gh pr edit "$pr_num" --body "$pr_body"
          fi

          echo "pr_url=$PR_URL" >> "$GITHUB_OUTPUT"
      - name: Summary
        env:
          has_changes: ${{ steps.check-changes.outputs.has_changes }}
          changes: ${{ steps.check-changes.outputs.changes_summary }}
          pr_url: ${{ steps.create-pr.outputs.pr_url}}
          pr_num: ${{ steps.open_pr_info.outputs.number }}
        run: |
          if [[ "$has_changes" == "true" ]]; then
              if [[ -n "$pr_num" ]]; then
                echo "✅ Successfully updated PR with new changes."
                echo "$changes"
                echo "🔗 PR URL: $pr_url"
                echo "### ✅ PR Updated" >> "$GITHUB_STEP_SUMMARY"
                echo "[$pr_url]($pr_url)" >> "$GITHUB_STEP_SUMMARY"
              elif [[ -n "$pr_url" ]]; then
                echo "✅ Successfully created PR with maintainer updates."
                echo "$changes"
                echo "🔗 PR URL: $pr_url"
                echo "### ✅ PR Created" >> "$GITHUB_STEP_SUMMARY"
                echo "[$pr_url]($pr_url)" >> "$GITHUB_STEP_SUMMARY"
              else
                echo "❌ Failed to create or update pull request."
                echo "### ❌ PR Operation Failed" >> "$GITHUB_STEP_SUMMARY"
                echo "A pull request was intended but the URL was not captured. Please check the logs." >> "$GITHUB_STEP_SUMMARY"
              fi
          else
            echo "ℹ️ No changes detected - maintainers list is up to date."
            echo "### ℹ️ No Changes" >> "$GITHUB_STEP_SUMMARY"
            echo "The maintainers list is up-to-date. No PR was created." >> "$GITHUB_STEP_SUMMARY"
          fi
