name: 'Show Cache Stats'
description: 'Displays statistics for ccache and Bazel remote cache to help analyze cache performance and hit rates'
inputs:
  clear_stats:
    description: 'Whether to clear ccache stats after displaying (default: true)'
    required: true
    type: boolean
    default: true

runs:
  using: 'composite'
  steps:
    - name: Define cache summary helper
      shell: bash
      working-directory: ${{ github.workspace }}
      run: |
        set -euo pipefail
        cat > /tmp/cache_summary.sh <<'EOF'
        summarize_dir() {
          local path="$1"
          local top_n=${2:-10}
          local sub_n=${3:-5}
          if [ ! -e "$path" ]; then
            echo "Path $path not found"
            return
          fi
          echo "---------------"
          echo "Summary: $path"
          du -sh "$path" || true
          echo "Top ${top_n} entries at top level:"
          du -h --max-depth=1 "$path" 2>/dev/null | sort -hr | head -n "$top_n" || true
          echo "Showing up to ${sub_n} entries one level deeper for the largest top-level items:"
          while read -r line; do
            entry_path=$(echo "$line" | awk '{print $2}')
            [ -z "$entry_path" ] && continue
            if [ "$entry_path" = "$path" ]; then
              continue
            fi
            echo "-> $entry_path :"
            du -h --max-depth=1 "$entry_path" 2>/dev/null | sort -hr | head -n "$sub_n" || true
          done < <(du -h --max-depth=1 "$path" 2>/dev/null | sort -hr | head -n "$top_n")
          echo "---------------"
        }
        EOF

    - name: Show ccache Stats
      shell: bash
      working-directory: ${{ github.workspace }}
      run: |
        set -euo pipefail
        echo "===================="
        echo "=== ccache stats ==="
        echo "===================="
        
        if ! command -v ccache >/dev/null 2>&1; then
          echo "⚠️  ccache not installed, skipping ccache stats"
          echo "===================="
          exit 0
        fi
        
        ccache -s || true
        echo "====================="
        echo "=== ccache config ==="
        echo "====================="
        ccache -p || true
        echo "====================="

        STATS="$(ccache -s)"
        
        CACHEABLE=$(echo "$STATS" | awk '/Cacheable calls:/ {
          match($0, /[0-9]+/); 
          print substr($0, RSTART, RLENGTH)
        }' | head -n1)
        
        HITS=$(echo "$STATS" | awk '/^[[:space:]]*Hits:/ {
          match($0, /[0-9]+/); 
          print substr($0, RSTART, RLENGTH)
        }' | head -n1)
        
        DIRECT=$(echo "$STATS" | awk '/Direct:/ {
          match($0, /[0-9]+/); 
          print substr($0, RSTART, RLENGTH)
        }' | head -n1)
        
        if [ "${CACHEABLE:-0}" -gt 0 ]; then
          HIT_RATE=$(awk -v h="${HITS:-0}" -v c="$CACHEABLE" 'BEGIN{printf "%.1f", (h/c)*100}')
          DIRECT_RATE=$(awk -v d="${DIRECT:-0}" -v c="$CACHEABLE" 'BEGIN{printf "%.1f", (d/c)*100}')
        else
          HIT_RATE="0.0"
          DIRECT_RATE="0.0"
        fi
        
        echo "hit_rate=${HIT_RATE}%"
        echo "direct_rate=${DIRECT_RATE}%"

        if [ "${{ inputs.clear_stats }}" = "true" ]; then
          echo "=== ccache reset ==="
          echo "====================="
          ccache -z || true
          echo "====================="
          
          # Touch all files to prevent LRU eviction of freshly restored cache
          if [ -d /home/runner/.ccache ] && find /home/runner/.ccache -type f -print -quit 2>/dev/null | grep -q .; then
            echo "Updating ccache atime to prevent cache eviction..."
            find /home/runner/.ccache -type f -exec touch -t $(date -d "1 day ago" +%Y%m%d%H%M) {} +
            echo "✅ ccache atime updated"
          fi
          if [ -d /home/runner/.ld_cache ] && find /home/runner/.ld_cache -type f -print -quit 2>/dev/null | grep -q .; then
            echo "Updating LTO cache atime to prevent cache eviction..."
            find /home/runner/.ld_cache -type f -exec touch -t $(date -d "1 day ago" +%Y%m%d%H%M) {} +
            echo "✅ LTO cache atime updated"
          fi
        else
          echo "Keeping ccache stats for next run"
        fi

    - name: Show ccache folder Stats
      shell: bash
      working-directory: ${{ github.workspace }}
      run: |
        set -euo pipefail
        # shellcheck disable=SC1091
        source /tmp/cache_summary.sh

        echo "==============="
        echo "=== .ccache ==="
        echo "==============="
        summarize_dir /home/runner/.ccache 10 5 || true

    - name: Show Bazel Cache folder Stats
      shell: bash
      working-directory: ${{ github.workspace }}
      run: |
        set -euo pipefail
        # shellcheck disable=SC1091
        source /tmp/cache_summary.sh
        echo "===================="
        echo "=== .cache/bazel ==="
        echo "===================="
        summarize_dir /home/runner/.cache/bazel 10 5 || true
        
    - name: Show ld cache folder Stats
      shell: bash
      working-directory: ${{ github.workspace }}
      run: |
        set -euo pipefail
        # shellcheck disable=SC1091
        source /tmp/cache_summary.sh
        echo "================="
        echo "=== .ld_cache ==="
        echo "================="
        summarize_dir /home/runner/.ld_cache 10 5 || true