name: Version Bump Check

on:
  pull_request:
    branches: [main]

jobs:
  version-bump-check:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout PR branch
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Check version bump
        run: |
          echo "Checking that all version numbers have been incremented..."

          # Get the base branch (main)
          git fetch origin main:refs/remotes/origin/main

          # Function to validate version bump (X.Y.Z format)
          # Valid bumps:
          #   - X.Y.Z -> X.Y.(Z+1)   patch bump
          #   - X.Y.Z -> X.(Y+1).0   minor bump
          #   - X.Y.Z -> (X+1).0.0   major bump
          # Returns: 0 if valid bump, 1 if invalid
          # Sets global BUMP_ERROR with error message on failure
          validate_version_bump() {
            local main_ver="$1"
            local pr_ver="$2"
            BUMP_ERROR=""

            # Split versions into components
            local main_x main_y main_z pr_x pr_y pr_z
            IFS='.' read -r main_x main_y main_z <<< "$main_ver"
            IFS='.' read -r pr_x pr_y pr_z <<< "$pr_ver"

            # Case 1: Major bump (X+1).0.0
            if [ "$pr_x" -eq $((main_x + 1)) ] && [ "$pr_y" -eq 0 ] && [ "$pr_z" -eq 0 ]; then
              return 0
            fi

            # Case 2: Minor bump X.(Y+1).0
            if [ "$pr_x" -eq "$main_x" ] && [ "$pr_y" -eq $((main_y + 1)) ] && [ "$pr_z" -eq 0 ]; then
              return 0
            fi

            # Case 3: Patch bump X.Y.(Z+1)
            if [ "$pr_x" -eq "$main_x" ] && [ "$pr_y" -eq "$main_y" ] && [ "$pr_z" -eq $((main_z + 1)) ]; then
              return 0
            fi

            # Invalid bump - determine error message
            if [ "$pr_x" -lt "$main_x" ] || \
               ([ "$pr_x" -eq "$main_x" ] && [ "$pr_y" -lt "$main_y" ]) || \
               ([ "$pr_x" -eq "$main_x" ] && [ "$pr_y" -eq "$main_y" ] && [ "$pr_z" -le "$main_z" ]); then
              BUMP_ERROR="Version must be incremented, not decreased or unchanged"
            elif [ "$pr_x" -gt $((main_x + 1)) ]; then
              BUMP_ERROR="Major version can only increase by 1 (expected $((main_x + 1)).0.0)"
            elif [ "$pr_x" -eq $((main_x + 1)) ]; then
              BUMP_ERROR="Major bump requires Y=0 and Z=0 (expected $((main_x + 1)).0.0)"
            elif [ "$pr_y" -gt $((main_y + 1)) ]; then
              BUMP_ERROR="Minor version can only increase by 1 (expected $main_x.$((main_y + 1)).0)"
            elif [ "$pr_y" -eq $((main_y + 1)) ]; then
              BUMP_ERROR="Minor bump requires Z=0 (expected $main_x.$((main_y + 1)).0)"
            elif [ "$pr_z" -gt $((main_z + 1)) ]; then
              BUMP_ERROR="Patch version can only increase by 1 (expected $main_x.$main_y.$((main_z + 1)))"
            else
              BUMP_ERROR="Invalid version bump pattern"
            fi
            return 1
          }

          # Files to check
          FILES=(
            ".claude-plugin/plugin.json"
            ".claude-plugin/marketplace.json"
            "README.md"
          )

          exit_code=0

          for file in "${FILES[@]}"; do
            echo ""
            echo "=== Checking $file ==="

            # Get version from main branch
            if [ "$file" = "README.md" ]; then
              # Extract version from README.md format: **Current Version: X.Y.Z**
              main_version=$(git show origin/main:"$file" 2>/dev/null | grep -oP '\*\*Current Version: \K[0-9]+\.[0-9]+\.[0-9]+' | head -1)
              pr_version=$(grep -oP '\*\*Current Version: \K[0-9]+\.[0-9]+\.[0-9]+' "$file" | head -1)
            else
              # Extract version from JSON files
              main_version=$(git show origin/main:"$file" 2>/dev/null | grep -oP '"version":\s*"\K[0-9]+\.[0-9]+\.[0-9]+' | head -1)
              pr_version=$(grep -oP '"version":\s*"\K[0-9]+\.[0-9]+\.[0-9]+' "$file" | head -1)
            fi

            echo "  Main branch version: $main_version"
            echo "  PR branch version:   $pr_version"

            if [ -z "$main_version" ]; then
              echo "  WARNING: Could not find version in main branch (new file?)"
              continue
            fi

            if [ -z "$pr_version" ]; then
              echo "  ERROR: Could not find version in PR branch"
              exit_code=1
              continue
            fi

            if validate_version_bump "$main_version" "$pr_version"; then
              echo "  OK: Valid version bump"
            else
              echo "  ERROR: $BUMP_ERROR"
              exit_code=1
            fi
          done

          echo ""
          if [ $exit_code -ne 0 ]; then
            echo "========================================"
            echo "FAILED: Version bump validation failed."
            echo ""
            echo "Valid version bump patterns (exactly +1):"
            echo "  - Patch: X.Y.Z -> X.Y.(Z+1)"
            echo "  - Minor: X.Y.Z -> X.(Y+1).0"
            echo "  - Major: X.Y.Z -> (X+1).0.0"
            echo ""
            echo "Please update version in ALL of these files:"
            echo "  - .claude-plugin/plugin.json"
            echo "  - .claude-plugin/marketplace.json"
            echo "  - README.md (Current Version line)"
            echo "========================================"
          else
            echo "========================================"
            echo "PASSED: All version bumps are valid (+1 increment)."
            echo "========================================"
          fi

          exit $exit_code