multitouch 0.1.0

name: Release

on:
  push:
    branches:
      - main
    paths:
      - Cargo.toml

  # Also publish if you manually create a GitHub release.
  release:
    types: [published]

jobs:
  create-release:
    name: Create GitHub release
    if: github.event_name == 'push'
    runs-on: macos-latest

    permissions:
      contents: write

    outputs:
      changed: ${{ steps.version.outputs.changed }}
      tag: ${{ steps.version.outputs.tag }}

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install Rust
        uses: dtolnay/rust-toolchain@stable

      - name: Check whether version changed
        id: version
        shell: bash
        run: |
          set -euo pipefail

          NEW_VERSION="$(
            cargo metadata --no-deps --format-version 1 |
            python3 -c '
          import json, sys
          data = json.load(sys.stdin)
          for package in data["packages"]:
              if package["name"] == "multitouch":
                  print(package["version"])
                  break
          '
          )"

          BEFORE="${{ github.event.before }}"

          # Get the previous Cargo.toml from before this push.
          if [[ "$BEFORE" == "0000000000000000000000000000000000000000" ]]; then
            echo "No previous commit to compare against."
            echo "changed=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          OLD_VERSION="$(
            git show "${BEFORE}:Cargo.toml" |
            python3 -c '
          import sys, tomllib
          data = tomllib.loads(sys.stdin.read())
          print(data["package"]["version"])
          '
          )"

          echo "Previous version: $OLD_VERSION"
          echo "Current version:  $NEW_VERSION"

          if [[ "$OLD_VERSION" == "$NEW_VERSION" ]]; then
            echo "Cargo.toml changed, but the package version did not."
            echo "changed=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          TAG="v${NEW_VERSION}"

          echo "changed=true" >> "$GITHUB_OUTPUT"
          echo "tag=$TAG" >> "$GITHUB_OUTPUT"

      - name: Verify package
        if: steps.version.outputs.changed == 'true'
        run: cargo publish --package multitouch --dry-run

      - name: Create tag and GitHub release
        if: steps.version.outputs.changed == 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.version.outputs.tag }}
        run: |
          set -euo pipefail

          # Makes this idempotent if the workflow is re-run.
          if gh release view "$TAG" >/dev/null 2>&1; then
            echo "Release $TAG already exists."
            exit 0
          fi

          gh release create "$TAG" \
            --target "$GITHUB_SHA" \
            --title "$TAG" \
            --generate-notes

  publish:
    name: Publish to crates.io
    needs: create-release

    # Run either:
    # 1. after this workflow created a release from a version bump, or
    # 2. when somebody manually publishes a GitHub release.
    if: >-
      always() &&
      (
        (
          github.event_name == 'push' &&
          needs.create-release.result == 'success' &&
          needs.create-release.outputs.changed == 'true'
        ) ||
        github.event_name == 'release'
      )

    runs-on: macos-latest

    permissions:
      contents: read
      id-token: write

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Install Rust
        uses: dtolnay/rust-toolchain@stable

      - name: Verify release version
        env:
          CREATED_TAG: ${{ needs.create-release.outputs.tag }}
          RELEASE_TAG: ${{ github.event.release.tag_name }}
        shell: bash
        run: |
          set -euo pipefail

          VERSION="$(
            cargo metadata --no-deps --format-version 1 |
            python3 -c '
          import json, sys
          data = json.load(sys.stdin)
          for package in data["packages"]:
              if package["name"] == "multitouch":
                  print(package["version"])
                  break
          '
          )"

          if [[ "${{ github.event_name }}" == "release" ]]; then
            TAG="$RELEASE_TAG"
          else
            TAG="$CREATED_TAG"
          fi

          EXPECTED="v${VERSION}"

          if [[ "$TAG" != "$EXPECTED" ]]; then
            echo "Release tag '$TAG' does not match Cargo.toml version '$EXPECTED'."
            exit 1
          fi

          echo "Publishing multitouch $VERSION"

      - name: Authenticate with crates.io
        id: auth
        uses: rust-lang/crates-io-auth-action@v1

      - name: Publish
        env:
          CARGO_REGISTRY_TOKEN: ${{ steps.auth.outputs.token }}
        run: cargo publish --package multitouch