name: Update Rust Version

on:
  schedule:
    # Run weekly on Monday at 9 AM UTC
    - cron: '0 9 * * 1'
  workflow_dispatch: # Allow manual triggering

permissions: {}

jobs:
  check-rust-version:
    name: Check and update Rust version
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          ref: main
          persist-credentials: false
          token: ${{ secrets.BACKPORT_TOKEN }}

      - name: Get latest stable Rust version
        id: latest-rust
        run: |
          # Fetch the latest stable Rust version from GitHub releases API
          LATEST_VERSION=$(curl -s https://api.github.com/repos/rust-lang/rust/releases | jq -r '[.[] | select(.prerelease == false and .draft == false)][0].tag_name')
          echo "version=$LATEST_VERSION" >> $GITHUB_OUTPUT
          echo "Latest stable Rust version: $LATEST_VERSION"

      - name: Get current Rust version
        id: current-rust
        run: |
          # Extract current version from rust-toolchain.toml
          CURRENT_VERSION=$(grep '^channel=' rust-toolchain.toml | sed 's/channel="\(.*\)"/\1/')
          echo "version=$CURRENT_VERSION" >> $GITHUB_OUTPUT
          echo "Current Rust version: $CURRENT_VERSION"

      - name: Compare versions
        id: compare
        run: |
          if [ "${{ steps.latest-rust.outputs.version }}" != "${{ steps.current-rust.outputs.version }}" ]; then
            echo "needs_update=true" >> $GITHUB_OUTPUT
            echo "Rust version needs update: ${{ steps.current-rust.outputs.version }} -> ${{ steps.latest-rust.outputs.version }}"
          else
            echo "needs_update=false" >> $GITHUB_OUTPUT
            echo "Rust version is up to date"
          fi

      - name: Update rust-toolchain.toml
        if: steps.compare.outputs.needs_update == 'true'
        run: |
          sed -i 's/channel="[0-9]*\.[0-9]*\.[0-9]*"/channel="${{ steps.latest-rust.outputs.version }}"/' rust-toolchain.toml
          echo "Updated rust-toolchain.toml"

      - name: Update flake.nix
        if: steps.compare.outputs.needs_update == 'true'
        run: |
          # Update stable_toolchain version in flake.nix
          sed -i 's/stable_toolchain = pkgs\.rust-bin\.stable\."[0-9]*\.[0-9]*\.[0-9]*"\.default/stable_toolchain = pkgs.rust-bin.stable."${{ steps.latest-rust.outputs.version }}".default/' flake.nix
          echo "Updated flake.nix"

      - name: Create Pull Request
        if: steps.compare.outputs.needs_update == 'true'
        uses: peter-evans/create-pull-request@271a8d0340265f705b14b6d32b9829c1cb33d45e # v7.0.8
        with:
          token: ${{ secrets.BACKPORT_TOKEN }}
          author: Rust Update Bot <bot@cashudevkit.org>
          title: "chore: update Rust to ${{ steps.latest-rust.outputs.version }}"
          body: |
            Automated Rust version update from **${{ steps.current-rust.outputs.version }}** to **${{ steps.latest-rust.outputs.version }}**.

            ## Changes
            - Updated `rust-toolchain.toml` to use Rust ${{ steps.latest-rust.outputs.version }}
            - Updated `flake.nix` stable_toolchain to use Rust ${{ steps.latest-rust.outputs.version }}

            ## Testing
            The CI will run all tests with the new Rust version. Please review the test results before merging.

            ## Release Notes
            Check the [Rust release notes](https://github.com/rust-lang/rust/blob/master/RELEASES.md) for details on what's new in this version.

            ---
            🤖 Automated changes by [create-pull-request](https://github.com/peter-evans/create-pull-request) GitHub action
          commit-message: "chore: update Rust to ${{ steps.latest-rust.outputs.version }}"
          labels: rust-version
          branch: rust-update-${{ steps.latest-rust.outputs.version }}

      - name: No update needed
        if: steps.compare.outputs.needs_update == 'false'
        run: |
          echo "✓ Rust version is already up to date (${{ steps.current-rust.outputs.version }})"