name: Rust Setup + Cache
description: Install Rust toolchain and cache cargo/rustup dependencies for Gitea Actions
author: eric

inputs:
  toolchain:
    description: Rust toolchain to install (e.g., stable, 1.75.0, nightly)
    default: stable
    required: false

outputs:
  cache-hit:
    description: "Whether a cache entry was found"
    value: ${{ steps.cache.outputs.cache-hit }}

runs:
  using: composite
  steps:
    # Gitea Actions does not have Cargo.lock by default (cargo generates it on first build),
    # and hashFiles() globs don't work reliably here. Use shell hashing instead.
    - name: Compute cache key
      id: cache-key
      shell: bash
      run: |
        # Hash both files; if Cargo.lock doesn't exist yet, only Cargo.toml is hashed
        HASH=$( (cat Cargo.toml 2>/dev/null || true; cat Cargo.lock 2>/dev/null || true) | sha256sum | cut -d' ' -f1)
        echo "hash=$HASH" >> $GITHUB_OUTPUT
        echo "fingerprint=$HASH" >> $GITHUB_ENV

    - name: Lookup cache (debug)
      id: cache-lookup
      uses: https://gitea.com/actions/cache@v3
      with:
        path: ~/.cargo/registry
        key: rust-linux-${{ steps.cache-key.outputs.hash }}
        lookup-only: true

    - name: Show lookup result
      shell: bash
      run: |
        echo "cache-hit (lookup): ${{ steps.cache-lookup.outputs.cache-hit }}"
        echo "key used: rust-linux-${{ steps.cache-key.outputs.hash }}"

    - name: Cache cargo + rustup
      id: cache
      uses: https://gitea.com/actions/cache@v3
      with:
        path: |
          ~/.cargo/registry
          ~/.cargo/git
          ~/.rustup/toolchains
          ~/.rustup/settings.toml
          target
        key: rust-linux-${{ steps.cache-key.outputs.hash }}
        restore-keys: rust-linux-

    - name: Setup Rust
      shell: bash
      run: |
        # If toolchain was cached, rustup will skip download — install still runs for metadata
        curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs \
          | sh -s -- -y --default-toolchain ${{ inputs.toolchain }}
        # Add cargo bin to PATH for subsequent steps
        echo "$HOME/.cargo/bin" >> $GITHUB_PATH

    - name: Show cached sizes
      shell: bash
      run: |
        echo "=== ~/.cargo ===" && du -sh ~/.cargo 2>/dev/null || echo "(empty)"
        echo "=== ~/.rustup ===" && du -sh ~/.rustup 2>/dev/null || echo "(empty)"
        echo "=== target ==="   && du -sh target 2>/dev/null   || echo "(empty)"