name: 'Cache'
description: 'Cache build files as tar.xz on the runner filesystem'
inputs:
  path:
    description: 'Directory to cache'
    required: false
    default: '~/.cache/'
  key-prefix:
    description: 'Prefix for the cache key'
    required: true
  key-file:
    description: 'File to hash for the cache key'
    required: true
outputs:
  cache-hit:
    description: 'true if exact key match found, false otherwise'
    value: ${{ steps.restore.outputs.cache-hit }}
runs:
  using: "composite"
  steps:
    - name: Restore cache
      id: restore
      shell: bash
      run: |
        CACHE_DIR="$HOME/.cache/.cache-store"
        mkdir -p "$CACHE_DIR"

        KEY_HASH=$(sha256sum "${{ inputs.key-file }}" | awk '{print $1}')
        CACHE_KEY="${{ inputs.key-prefix }}-${KEY_HASH}"
        ARCHIVE="${CACHE_DIR}/${CACHE_KEY}.tar.xz"

        EXPANDED_PATH=$(eval echo "${{ inputs.path }}")

        if [ -f "$ARCHIVE" ]; then
          echo "Cache hit: ${CACHE_KEY}"
          mkdir -p "$EXPANDED_PATH"
          tar -xf "$ARCHIVE" -C "/" 2>/dev/null || true
          echo "cache-hit=true" >> $GITHUB_OUTPUT
        else
          echo "Cache miss: ${CACHE_KEY}"
          echo "cache-hit=false" >> $GITHUB_OUTPUT
        fi

    - name: Save cache
      if: steps.restore.outputs.cache-hit != 'true'
      shell: bash
      run: |
        CACHE_DIR="$HOME/.cache/.cache-store"
        mkdir -p "$CACHE_DIR"

        KEY_HASH=$(sha256sum "${{ inputs.key-file }}" | awk '{print $1}')
        CACHE_KEY="${{ inputs.key-prefix }}-${KEY_HASH}"
        ARCHIVE="${CACHE_DIR}/${CACHE_KEY}.tar.xz"

        EXPANDED_PATH=$(eval echo "${{ inputs.path }}")

        if [ ! -d "$EXPANDED_PATH" ] || [ -z "$(ls -A "$EXPANDED_PATH" 2>/dev/null)" ]; then
          echo "Cache directory empty, skipping save"
          exit 0
        fi

        echo "Saving cache: ${CACHE_KEY}"
        REL_PATH="$(echo "$EXPANDED_PATH" | sed 's|^/||')"
        tar -cJf "$ARCHIVE" -C "/" "$REL_PATH" 2>/dev/null && echo "Cache saved" || echo "Cache save failed"