name: 🏷️ Auto Assign PR

on:
  workflow_call:
  pull_request:
    types: [opened, reopened, synchronize, ready_for_review]


concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true
jobs:
  assign_pr_creator_or_pusher:
    name: Assign PR Creator or Pusher
    runs-on: ubuntu-latest
    timeout-minutes: 1
    env:
      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    permissions:
      pull-requests: write

    steps:
      - name: Determine user to assign
        id: get_assignee_user
        run: |
          ASSIGN_USER=""
          EVENT_ACTOR=""
          if [[ "${{ github.event.action }}" == "synchronize" ]]; then
            EVENT_ACTOR="${{ github.event.sender.login }}"
          else
            EVENT_ACTOR="${{ github.event.pull_request.user.login }}"
          fi

          KNOWN_BOTS=("dependabot[bot]" "github-actions[bot]" "github-copilot[bot]" "copilot-bot[bot]")

          IS_KNOWN_BOT=false
          for BOT in "${KNOWN_BOTS[@]}"; do
            if [[ "$EVENT_ACTOR" == "$BOT" ]]; then
              IS_KNOWN_BOT=true
              break
            fi
          done

          if $IS_KNOWN_BOT || [[ "$EVENT_ACTOR" =~ \[bot\]$ ]]; then
            echo "Skipping bot user: $EVENT_ACTOR"
            ASSIGN_USER=""
          else
            ASSIGN_USER="$EVENT_ACTOR"
            echo "Determined user: $ASSIGN_USER"
          fi
        
          echo "assigned_user=$ASSIGN_USER" >> "$GITHUB_OUTPUT"

      - name: Assign PR to determined user
        if: steps.get_assignee_user.outputs.assigned_user != ''
        run: |
          PR_NUMBER="${{ github.event.pull_request.number }}"
          ASSIGN_USER_LOGIN="${{ steps.get_assignee_user.outputs.assigned_user }}"

          echo "Attempting to assign PR #$PR_NUMBER to $ASSIGN_USER_LOGIN"
          # Notes:
          # - If the user is already assigned, `gh pr edit` succeeds without error.
          # - External-collaborator PRs may fail outright (token lacks write on that user) — we
          #   log and continue rather than failing the workflow.
          # - GitHub can also silently ignore assignees without push access while still exiting 0,
          #   so we re-read the PR's assignees after the edit and confirm the user actually landed
          #   before logging success.
          if gh pr edit "$PR_NUMBER" --add-assignee "$ASSIGN_USER_LOGIN" --repo "${{ github.repository }}"; then
            CURRENT_ASSIGNEES="$(gh pr view "$PR_NUMBER" --repo "${{ github.repository }}" --json assignees --jq '.assignees[].login' 2>/dev/null || true)"
            if grep -Fxq "$ASSIGN_USER_LOGIN" <<<"$CURRENT_ASSIGNEES"; then
              echo "Successfully assigned PR #$PR_NUMBER to $ASSIGN_USER_LOGIN"
            else
              echo "⚠ gh pr edit returned success but $ASSIGN_USER_LOGIN is not in the assignees list (likely silently ignored by GitHub — no push access)"
            fi
          else
            echo "❌ Failed to assign PR #$PR_NUMBER to $ASSIGN_USER_LOGIN, likely an external collaborator"
          fi