auto_merge_approved_prs.yml

name: Auto Merge Approved PRs

on:
  schedule:
    - cron: '0 */1 * * *'  # Every 1 hour
  workflow_dispatch:  # Allow manual triggering

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

jobs:
  auto-merge-prs:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 1 # Only need latest commit for PR operations
          token: ${{ secrets.PAT_TOKEN }}

      - name: Configure git
        run: |
          git config --global user.email "action@github.com"
          git config --global user.name "GitHub Action"

      - name: Install GitHub CLI
        run: |
          curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg \
          && sudo chmod go+r /usr/share/keyrings/githubcli-archive-keyring.gpg \
          && echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | sudo tee /etc/apt/sources.list.d/github-cli.list > /dev/null \
          && sudo apt update \
          && sudo apt install gh -y

      - name: Check for running workflows
        id: check_workflows
        run: |
          gh_with_retry() {
            local max_attempts=5
            local base_sleep_seconds=2
            local attempt=1
            local stderr_file
            stderr_file=$(mktemp)

            while true; do
              if gh "$@" 2>"$stderr_file"; then
                rm -f "$stderr_file"
                return 0
              fi

              local exit_code=$?
              if [ "$attempt" -ge "$max_attempts" ]; then
                echo "gh command failed after $max_attempts attempts: gh $*" >&2
                cat "$stderr_file" >&2
                rm -f "$stderr_file"
                return "$exit_code"
              fi

              local sleep_for=$((base_sleep_seconds * attempt))
              echo "gh command failed (attempt $attempt/$max_attempts): gh $*" >&2
              cat "$stderr_file" >&2
              echo "Retrying in ${sleep_for}s..." >&2
              sleep "$sleep_for"
              attempt=$((attempt + 1))
            done
          }

          # Get all running workflows except this one
          running_workflows=$(gh_with_retry run list --status in_progress --json workflowName,name --repo "$GITHUB_REPOSITORY" --jq '.[].name' | grep -v "Auto Merge Approved PRs" | wc -l)
          echo "running_workflows=$running_workflows" >> $GITHUB_OUTPUT
          
          if [ "$running_workflows" -gt 0 ]; then
            echo "Found $running_workflows running workflows. Exiting to avoid conflicts."
            echo "should_continue=false" >> $GITHUB_OUTPUT
          else
            echo "No other workflows running. Proceeding with auto-merge."
            echo "should_continue=true" >> $GITHUB_OUTPUT
          fi
        env:
          GH_TOKEN: ${{ secrets.PAT_TOKEN }}
      
      - name: Find and merge approved PRs
        if: steps.check_workflows.outputs.should_continue == 'true'
        run: |
          gh_with_retry() {
            local max_attempts=5
            local base_sleep_seconds=2
            local attempt=1
            local stderr_file
            stderr_file=$(mktemp)

            while true; do
              if gh "$@" 2>"$stderr_file"; then
                rm -f "$stderr_file"
                return 0
              fi

              local exit_code=$?
              if [ "$attempt" -ge "$max_attempts" ]; then
                echo "gh command failed after $max_attempts attempts: gh $*" >&2
                cat "$stderr_file" >&2
                rm -f "$stderr_file"
                return "$exit_code"
              fi

              local sleep_for=$((base_sleep_seconds * attempt))
              echo "gh command failed (attempt $attempt/$max_attempts): gh $*" >&2
              cat "$stderr_file" >&2
              echo "Retrying in ${sleep_for}s..." >&2
              sleep "$sleep_for"
              attempt=$((attempt + 1))
            done
          }

          authorized_user="carlospolop"
          max_merges=2

          echo "Authorized user: $authorized_user"
          echo "Looking for PRs with exact comment 'merge' from $authorized_user..."

          # Get all open PRs, paginating through the full result set instead of
          # relying on `gh pr list`'s default page size.
          prs=$(gh_with_retry api --paginate "repos/$GITHUB_REPOSITORY/pulls?state=open&per_page=100" | jq -s 'add | map({number, title, url: .html_url, author: {login: .user.login}})')

          if [ "$prs" = "[]" ]; then
            echo "No open PRs found."
            exit 0
          fi

          # Create a temp file to track merge count
          echo "0" > /tmp/merged_count

          # Process each PR
          echo "$prs" | jq -r '.[] | @base64' | while IFS= read -r pr_data; do
            current_count=$(cat /tmp/merged_count)
            if [ "$current_count" -ge "$max_merges" ]; then
              echo "Reached maximum merge limit ($max_merges). Stopping."
              break
            fi

            pr_info=$(echo "$pr_data" | base64 --decode)
            pr_number=$(echo "$pr_info" | jq -r '.number')
            pr_title=$(echo "$pr_info" | jq -r '.title')
            pr_url=$(echo "$pr_info" | jq -r '.url')
            pr_author=$(echo "$pr_info" | jq -r '.author.login')

            echo "Checking PR #$pr_number: $pr_title (author: $pr_author)"

            # Special case: allow merge without "merge" comment for Research Update Enhanced PRs by the authorized user
            eligible_by_title=false
            if [[ "$pr_title" == "Research Update Enhanced"* && "$pr_author" == "$authorized_user" ]]; then
              echo "PR #$pr_number qualifies for direct merge based on title and author."
              eligible_by_title=true
            fi

            # Check if any comment from carlospolop contains exactly "merge"
            has_merge_comment=false
            if [ "$eligible_by_title" != true ]; then
              # Get all comments for this PR
              if ! comments=$(gh_with_retry pr view "$pr_number" --json comments --jq '.comments[]' --repo "$GITHUB_REPOSITORY"); then
                echo "Failed to fetch comments for PR #$pr_number after retries. Skipping PR."
                continue
              fi

              # Print all comment authors for debugging
              echo "Comments in PR #$pr_number:"
              echo "$comments" | jq -r '"  - Author: " + .author.login + " | Comment: " + (.body | split("\n")[0] | .[0:100])'

              echo "$comments" | jq -r '.author.login + "|" + .body' | while IFS='|' read -r comment_author comment_body; do
                if [ "$comment_author" = "$authorized_user" ]; then
                  if echo "$comment_body" | grep -iExq "merge"; then
                    echo "Found exact 'merge' comment from $authorized_user in PR #$pr_number"
                    echo "true" > /tmp/has_merge_comment_$pr_number
                    break
                  fi
                fi
              done
            fi

            if [ -f "/tmp/has_merge_comment_$pr_number" ]; then
              has_merge_comment=true
            fi

            if [ "$has_merge_comment" = true ] || [ "$eligible_by_title" = true ]; then
              echo "Attempting to merge PR #$pr_number..."

              # Get PR details including head branch
              if ! pr_details=$(gh_with_retry pr view "$pr_number" --json headRefName,baseRefName --repo "$GITHUB_REPOSITORY"); then
                echo "Failed to fetch details for PR #$pr_number after retries. Skipping PR."
                continue
              fi
              head_branch=$(echo "$pr_details" | jq -r '.headRefName')
              base_branch=$(echo "$pr_details" | jq -r '.baseRefName')

              # --- Polling for non-UNKNOWN mergeable status ---
              max_retries=10
              retry=0
              while true; do
                if ! pr_mergeable=$(gh_with_retry pr view "$pr_number" --json mergeable --jq '.mergeable' --repo "$GITHUB_REPOSITORY"); then
                  echo "Failed to fetch mergeable status for PR #$pr_number after retries."
                  pr_mergeable="UNKNOWN"
                fi
                if [ "$pr_mergeable" != "UNKNOWN" ]; then
                  break
                fi
                if [ $retry -ge $max_retries ]; then
                  echo "Timeout: mergeable status is still UNKNOWN after $max_retries retries"
                  break
                fi
                echo "mergeable status UNKNOWN, retrying in 2s..."
                sleep 2
                retry=$((retry + 1))
              done

              if [ "$pr_mergeable" = "MERGEABLE" ]; then
                if gh pr merge "$pr_number" --merge --delete-branch --repo "$GITHUB_REPOSITORY"; then
                  echo "Successfully merged PR #$pr_number: $pr_title"
                  current_count=$(cat /tmp/merged_count)
                  echo $((current_count + 1)) > /tmp/merged_count
                else
                  echo "Failed to merge PR #$pr_number: $pr_title"
                fi
              elif [ "$pr_mergeable" = "CONFLICTED" ] || [ "$pr_mergeable" = "CONFLICTING" ]; then
                echo "PR #$pr_number has conflicts. Skipping auto-merge so it can be resolved manually."
              else
                echo "PR #$pr_number is not mergeable (status: $pr_mergeable)"
              fi
            else
              echo "No exact 'merge' comment found from $authorized_user in PR #$pr_number"
            fi

            rm -f "/tmp/has_merge_comment_$pr_number"
          done

          final_count=$(cat /tmp/merged_count)
          echo "Auto-merge process completed. Merged $final_count PRs."
          rm -f /tmp/merged_count

        env:
          GH_TOKEN: ${{ secrets.PAT_TOKEN }}