# Builds the release source package in CI for a draft release (typically
# created via support/release.py), uploads the zip to that release, and
# attaches a SLSA v1.0 provenance attestation generated by the OpenSSF
# slsa-github-generator. The maintainer reviews the draft (which by then has
# both the zip and *.intoto.jsonl attached) and clicks Publish to finalize.
#
# This makes the provenance attest to the actual build that produced the
# artifact, rather than just attesting to a hash observed after the fact.
#
# GitHub does not fire `release: created` for draft releases, so release.py
# triggers this workflow explicitly via workflow_dispatch, passing the tag to
# attach to and the ref to build from. The `release: created` trigger is kept
# for non-draft releases created directly through the GitHub UI.

name: release

on:
  release:
    types: [created]
  workflow_dispatch:
    inputs:
      tag_name:
        description: "Release tag to attach the artifacts to (e.g. 12.2.0)"
        required: true
        type: string
      ref:
        description: "Git ref to build the source package from"
        required: false
        default: release
        type: string

permissions: read-all

jobs:
  build:
    name: Build source package
    runs-on: ubuntu-latest
    permissions:
      contents: write
    outputs:
      hashes: ${{ steps.hash.outputs.hashes }}
      package: ${{ steps.build.outputs.package }}
      tag: ${{ steps.vars.outputs.tag }}
    steps:
      - name: Resolve tag and ref for both event types
        id: vars
        run: |
          echo "tag=${{ github.event.release.tag_name || inputs.tag_name }}" >> "$GITHUB_OUTPUT"
          echo "ref=${{ github.event.release.target_commitish || inputs.ref }}" >> "$GITHUB_OUTPUT"

      - name: Checkout the release ref
        uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
        with:
          ref: ${{ steps.vars.outputs.ref }}
          persist-credentials: false

      - name: Build source zip via CPack
        id: build
        run: |
          cmake -B build .
          cmake --build build --target package_source
          pkg=$(ls build/fmt-*.zip)
          test -f "$pkg"
          echo "package=$pkg" >> "$GITHUB_OUTPUT"

      - name: Compute base64-encoded SHA-256 subjects
        id: hash
        run: |
          file="${{ steps.build.outputs.package }}"
          subjects=$(cd "$(dirname "$file")" && sha256sum "$(basename "$file")")
          echo "hashes=$(printf '%s' "$subjects" | base64 -w0)" >> "$GITHUB_OUTPUT"

      - name: Upload zip to the release
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          gh release upload "${{ steps.vars.outputs.tag }}" \
            "${{ steps.build.outputs.package }}" \
            --repo "${{ github.repository }}" --clobber

  # Generate the provenance only; do not let the generator upload it. With
  # upload-assets, the generator creates and publishes its own release (and
  # tag) to host the attestation, which duplicates our draft. Instead we
  # download the attestation artifact and attach it to the draft below.
  provenance:
    needs: [build]
    permissions:
      actions: read
      id-token: write
      contents: read
    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_generic_slsa3.yml@v2.1.0
    with:
      base64-subjects: ${{ needs.build.outputs.hashes }}
      provenance-name: "fmt-${{ needs.build.outputs.tag }}.intoto.jsonl"
      upload-assets: false

  attach-provenance:
    name: Attach provenance to the release
    needs: [build, provenance]
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - name: Download the provenance attestation
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
        with:
          name: ${{ needs.provenance.outputs.provenance-name }}

      - name: Attach provenance to the draft release
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          gh release upload "${{ needs.build.outputs.tag }}" \
            "${{ needs.provenance.outputs.provenance-name }}" \
            --repo "${{ github.repository }}" --clobber