#!/bin/bash

# Batch convert all PNG/JPG/JPEG to WebP
# Usage: ./convert_to_webp.sh
# Output: appends .webp to each filename (e.g., "file.png" -> "file.png.webp")
# This avoids filename collisions - you can clean up names later

set -e

echo "=== WebP Batch Conversion ==="
echo "Starting at: $(date)"
echo ""

TOTAL_ORIGINAL=0
TOTAL_WEBP=0
CONVERTED=0
SKIPPED=0

# Function to format bytes
format_bytes() {
    local bytes=$1
    if (( bytes >= 1073741824 )); then
        echo "$(echo "scale=2; $bytes / 1073741824" | bc) GB"
    elif (( bytes >= 1048576 )); then
        echo "$(echo "scale=2; $bytes / 1048576" | bc) MB"
    elif (( bytes >= 1024 )); then
        echo "$(echo "scale=2; $bytes / 1024" | bc) KB"
    else
        echo "$bytes B"
    fi
}

echo "Processing PNG files (lossless)..."
for f in *.png; do
    [ -f "$f" ] || continue
    
    original_size=$(stat -c%s "$f")
    TOTAL_ORIGINAL=$((TOTAL_ORIGINAL + original_size))
    
    output="${f}.webp"
    
    # Skip if already converted
    if [ -f "$output" ]; then
        echo "  SKIP (already exists): $f"
        SKIPPED=$((SKIPPED + 1))
        continue
    fi
    
    echo -n "  Converting: $f ... "
    cwebp -lossless "$f" -o "$output" > /dev/null 2>&1
    
    if [ -f "$output" ] && [ -s "$output" ]; then
        webp_size=$(stat -c%s "$output")
        TOTAL_WEBP=$((TOTAL_WEBP + webp_size))
        savings=$((original_size - webp_size))
        pct=$(echo "scale=1; $savings * 100 / $original_size" | bc)
        echo "DONE [$(format_bytes $original_size) -> $(format_bytes $webp_size) | ${pct}% saved]"
        CONVERTED=$((CONVERTED + 1))
    else
        echo "FAILED"
    fi
done

echo ""
echo "Processing JPG/JPEG files (quality 100)..."
for f in *.jpg *.jpeg; do
    [ -f "$f" ] || continue
    
    original_size=$(stat -c%s "$f")
    TOTAL_ORIGINAL=$((TOTAL_ORIGINAL + original_size))
    
    output="${f}.webp"
    
    # Skip if already converted
    if [ -f "$output" ]; then
        echo "  SKIP (already exists): $f"
        SKIPPED=$((SKIPPED + 1))
        continue
    fi
    
    echo -n "  Converting: $f ... "
    cwebp -q 100 "$f" -o "$output" > /dev/null 2>&1
    
    if [ -f "$output" ] && [ -s "$output" ]; then
        webp_size=$(stat -c%s "$output")
        TOTAL_WEBP=$((TOTAL_WEBP + webp_size))
        savings=$((original_size - webp_size))
        pct=$(echo "scale=1; $savings * 100 / $original_size" | bc)
        echo "DONE [$(format_bytes $original_size) -> $(format_bytes $webp_size) | ${pct}% saved]"
        CONVERTED=$((CONVERTED + 1))
    else
        echo "FAILED"
    fi
done

echo ""
echo "=== Summary ==="
echo "Converted: $CONVERTED files"
echo "Skipped:   $SKIPPED files (already exist)"
echo ""
echo "Original total: $(format_bytes $TOTAL_ORIGINAL)"
echo "WebP total:     $(format_bytes $TOTAL_WEBP)"

if [ $TOTAL_ORIGINAL -gt 0 ]; then
    SAVINGS=$((TOTAL_ORIGINAL - TOTAL_WEBP))
    PCT=$(echo "scale=1; $SAVINGS * 100 / $TOTAL_ORIGINAL" | bc)
    echo "Space saved:   $(format_bytes $SAVINGS) ($PCT%)"
fi

echo ""
echo "Finished at: $(date)"
echo ""
echo "=== Git LFS Note ==="
echo "The .webp files are NOT added to git."
echo "To track them with Git LFS later, run:"
echo "  git lfs track '*.webp'"
echo "  git add .gitattributes"
echo "  git add *.webp"
echo "  git commit -m 'Add WebP versions'"