name: vociferate/coverage-gate
description: >
  Enforce per-package code coverage thresholds against Go coverage profiles.
  Supports JSON policy files with per-package overrides and global minimums.

inputs:
  profile:
    description: Path to Go coverage profile file (output from `go test -coverprofile=...`).
    required: false
    default: coverage.out
  policy:
    description: Path to JSON file defining coverage thresholds and per-package overrides.
    required: false
    default: docs/coverage-thresholds.json
  src-root:
    description: Source root directory for package discovery (passed to `go list ./...`).
    required: false
    default: .
  summary-file:
    description: Optional file path to append markdown summary of coverage results.
    required: false
    default: ''

outputs:
  passed:
    description: 'Boolean: true if all packages meet threshold, false if any failed.'
    value: ${{ steps.gate.outputs.passed }}
  total-coverage:
    description: Repository-wide statement coverage percentage.
    value: ${{ steps.gate.outputs.total_coverage }}
  packages-checked:
    description: Number of packages evaluated against policy.
    value: ${{ steps.gate.outputs.packages_checked }}
  packages-failed:
    description: Number of packages below threshold.
    value: ${{ steps.gate.outputs.packages_failed }}

runs:
  using: composite
  steps:
    - id: gate
      shell: bash
      working-directory: ${{ github.action_path }}
      env:
        PROFILE: ${{ inputs.profile }}
        POLICY: ${{ inputs.policy }}
        SRC_ROOT: ${{ inputs.src-root }}
        SUMMARY_FILE: ${{ inputs.summary-file }}
      run: |
        set -euo pipefail

        # Run coverage gate and capture output
        EXIT_CODE=0
        OUTPUT=$(go run . \
          --profile "$PROFILE" \
          --policy "$POLICY" \
          --src-root "$SRC_ROOT" \
        ) || EXIT_CODE=$?

        echo "$OUTPUT"

        # Parse summary from output (tool prints JSON stats on last line)
        SUMMARY_LINE=$(echo "$OUTPUT" | tail -1)

        # Determine pass/fail
        if [[ $EXIT_CODE -eq 0 ]]; then
          echo "passed=true" >> "$GITHUB_OUTPUT"
        else
          echo "passed=false" >> "$GITHUB_OUTPUT"
        fi

        # Extract metrics (tool outputs: packages_checked, packages_failed, total_coverage on summary line)
        if echo "$SUMMARY_LINE" | jq . &>/dev/null; then
          echo "total_coverage=$(echo "$SUMMARY_LINE" | jq -r '.total_coverage')" >> "$GITHUB_OUTPUT"
          echo "packages_checked=$(echo "$SUMMARY_LINE" | jq -r '.packages_checked')" >> "$GITHUB_OUTPUT"
          echo "packages_failed=$(echo "$SUMMARY_LINE" | jq -r '.packages_failed')" >> "$GITHUB_OUTPUT"

          # Append to summary file if provided
          if [[ -n "$SUMMARY_FILE" ]]; then
            {
              echo "## Coverage Gate Results"
              echo
              echo "- **Passed:** $([ "$EXIT_CODE" -eq 0 ] && echo '✓ Yes' || echo '✗ No')"
              echo "- **Total Coverage:** $(echo "$SUMMARY_LINE" | jq -r '.total_coverage')%"
              echo "- **Packages Checked:** $(echo "$SUMMARY_LINE" | jq -r '.packages_checked')"
              echo "- **Packages Failed:** $(echo "$SUMMARY_LINE" | jq -r '.packages_failed')"
            } >> "$SUMMARY_FILE"
          fi
        fi

        exit $EXIT_CODE