action.yml

name: "OpenAPI Diff"
description: "Run oasdiff changelog between base and head OpenAPI specs"
author: "Framna Denmark"

inputs:
  base:
    description: "Path to the base OpenAPI spec file"
    required: true
  head:
    description: "Path to the head OpenAPI spec file"
    required: true
  format:
    description: "Output format: table (default), text, html, or json"
    required: false
    default: "table"

outputs:
  diff:
    description: "The formatted diff output"
    value: ${{ steps.render.outputs.result }}
  has-changes:
    description: "Whether there are changes (true/false)"
    value: ${{ steps.render.outputs.has_changes }}

runs:
  using: composite
  steps:
    - name: Install oasdiff
      shell: bash
      run: |
        if ! command -v oasdiff &> /dev/null; then
          curl -sSfL https://raw.githubusercontent.com/tufin/oasdiff/main/install.sh | sh -s -- -b /usr/local/bin
        fi

    - name: Run oasdiff and render
      id: render
      shell: bash
      env:
        BASE_SPEC: ${{ inputs.base }}
        HEAD_SPEC: ${{ inputs.head }}
        OUTPUT_FORMAT: ${{ inputs.format }}
      run: |
        set +e

        # For table format, use JSON and render with jq
        if [ "$OUTPUT_FORMAT" = "table" ] || [ -z "$OUTPUT_FORMAT" ]; then
          DIFF=$(oasdiff changelog "$BASE_SPEC" "$HEAD_SPEC" --format json 2>&1)
          EXIT_CODE=$?
        else
          DIFF=$(oasdiff changelog "$BASE_SPEC" "$HEAD_SPEC" --format "$OUTPUT_FORMAT" 2>&1)
          EXIT_CODE=$?
        fi
        set -e

        # Handle missing files
        if [ $EXIT_CODE -ne 0 ] && echo "$DIFF" | grep -q "no such file"; then
          {
            echo "result<<EOF"
            echo "_Spec file not found in one of the branches_"
            echo "EOF"
          } >> $GITHUB_OUTPUT
          echo "has_changes=false" >> $GITHUB_OUTPUT
          exit 0
        fi

        # Handle empty output
        if [ -z "$DIFF" ] || [ "$DIFF" = "null" ] || [ "$DIFF" = "[]" ]; then
          {
            echo "result<<EOF"
            echo "_No changes_"
            echo "EOF"
          } >> $GITHUB_OUTPUT
          echo "has_changes=false" >> $GITHUB_OUTPUT
          exit 0
        fi

        # For non-table formats, output directly with path cleanup
        if [ "$OUTPUT_FORMAT" != "table" ] && [ -n "$OUTPUT_FORMAT" ]; then
          DIFF=$(echo "$DIFF" | sed 's|pr/||g; s|base/||g; s|head/||g')
          {
            echo "result<<EOF"
            echo "$DIFF"
            echo "EOF"
          } >> $GITHUB_OUTPUT
          echo "has_changes=true" >> $GITHUB_OUTPUT
          exit 0
        fi

        # Render JSON as markdown table using jq
        RENDERED=$(echo "$DIFF" | jq -r '
          if length == 0 then
            "_No changes_"
          else
            # Count by level
            (map(select(.level == 3)) | length) as $breaking |
            (map(select(.level == 2)) | length) as $warnings |
            (map(select(.level == 1)) | length) as $info |
            (length) as $total |

            # Build summary parts
            ([
              (if $breaking > 0 then "\($breaking) breaking" else empty end),
              (if $warnings > 0 then "\($warnings) warning" else empty end),
              (if $info > 0 then "\($info) info" else empty end)
            ] | join(", ")) as $summary |

            # Output summary, table header, and rows
            (if $breaking > 0 then "**\($total) changes:** \($summary)" else "\($total) changes: \($summary)" end),
            "",
            "| | Endpoint | Change |",
            "|:---:|:---|:---|",
            (sort_by(-.level, .path, .operation) | .[] |
              (if .level == 3 then "🔴" elif .level == 2 then "🟡" else "🟢" end) as $emoji |
              (if .path then "`\(.operation)` \(.path | gsub("pr/|base/|head/"; ""))" else "_\(.section)_" end) as $endpoint |
              "| \($emoji) | \($endpoint) | \(.text) |"
            )
          end
        ')

        # Output results
        {
          echo "result<<EOF"
          echo "$RENDERED"
          echo "EOF"
        } >> $GITHUB_OUTPUT

        if [ "$RENDERED" = "_No changes_" ]; then
          echo "has_changes=false" >> $GITHUB_OUTPUT
        else
          echo "has_changes=true" >> $GITHUB_OUTPUT
        fi