#!/bin/bash

# Script to minimize PNG images with progress bar
# Usage: ./minimize-png.sh [colors] file1.png file2.png ...
# Usage: ./minimize-png.sh [colors] *.png
# Works as Nemo script with selected files
# Default colors: 256

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Function to get colors from user via dialog (for Nemo)
get_colors_dialog() {
    local colors=256
    
    # Try zenity
    if command -v zenity &> /dev/null; then
        colors=$(zenity --entry \
            --title="PNG Color Reduction" \
            --text="Enter number of colors (8-256):" \
            --entry-text="256" \
            2>/dev/null)
        
        # Check if user cancelled or entered invalid value
        if [ $? -ne 0 ] || [ -z "$colors" ]; then
            echo "256"
            return
        fi
    else
        # No dialog available, use default
        echo "256"
        return
    fi
    
    # Validate colors
    if [[ "$colors" =~ ^[0-9]+$ ]] && [ "$colors" -ge 8 ] && [ "$colors" -le 256 ]; then
        echo "$colors"
    else
        echo "256"
    fi
}

# Function to check if pngquant is installed
check_pngquant() {
    if ! command -v pngquant &> /dev/null; then
        echo -e "${RED}Error: pngquant is not installed.${NC}"
        echo -e "${YELLOW}Install pngquant with:${NC}"
        echo "  Ubuntu/Debian: sudo apt-get install pngquant"
        echo "  CentOS/RHEL: sudo yum install pngquant"
        echo "  Arch: sudo pacman -S pngquant"
        exit 1
    fi
}

# Main function
main() {
    local colors=256
    local file_args=()
    local colors_was_explicit=false
    
    # Parse arguments
    for arg in "$@"; do
        if [[ "$arg" =~ ^[0-9]+$ ]] && [ "$arg" -ge 8 ] && [ "$arg" -le 256 ]; then
            colors="$arg"
            colors_was_explicit=true
        else
            # Add all non-numeric arguments as potential file paths
            file_args+=("$arg")
        fi
    done
    
    # Check pngquant
    check_pngquant
    
    # Create output directory
    local output_dir="min"
    if [ ! -d "$output_dir" ]; then
        mkdir -p "$output_dir"
        echo -e "${GREEN}Created output directory: $output_dir${NC}"
    fi
    
    # Get files to process
    local png_files=()
    
    # If we have file arguments, process them
    if [ ${#file_args[@]} -gt 0 ]; then
        # Process file arguments (expand patterns and check files)
        for pattern in "${file_args[@]}"; do
            # Use shell expansion for patterns like *.png
            for file in $pattern; do
                if [[ -f "$file" ]] && [[ "$file" =~ \.(png|PNG)$ ]]; then
                    png_files+=("$file")
                fi
            done
        done
    else
        echo -e "${RED}Error: No files specified.${NC}"
        echo -e "${YELLOW}Usage from terminal: $0 [colors] file1.png file2.png ...${NC}"
        echo -e "${YELLOW}Usage from terminal: $0 [colors] *.png${NC}"
        echo -e "${YELLOW}Or select files in Nemo and run as script${NC}"
        exit 1
    fi
    
    if [ ${#png_files[@]} -eq 0 ]; then
        echo -e "${YELLOW}No PNG files found to process.${NC}"
        exit 0
    fi
    
    local total_files=${#png_files[@]}
    local total_size_before=0
    local total_size_after=0
    
    # Detect if running from Nemo (file manager) or terminal
    local use_gui=false
    local colors_from_dialog=false
    local original_colors=$colors
    
    # Only use GUI if:
    # 1. Colors wasn't explicitly set 
    # 2. We're likely running from Nemo (NEMO_SCRIPT_SELECTED_FILE_PATHS is set)
    # 3. zenity is available
    if [ "$colors_was_explicit" = false ] && [ -n "$NEMO_SCRIPT_SELECTED_FILE_PATHS" ] && command -v zenity &> /dev/null; then
        local dialog_colors
        dialog_colors=$(get_colors_dialog)
        if [ -n "$dialog_colors" ]; then
            colors="$dialog_colors"
            colors_from_dialog=true
            use_gui=true
        fi
    fi
    
    # Show initial info only for terminal
    if [ "$use_gui" = false ]; then
        echo -e "${GREEN}PNG minimization started${NC}"
        echo -e "${BLUE}Colors set to: ${colors}${NC}"
        echo -e "${BLUE}Files to process: ${total_files}${NC}"
        echo -e "${BLUE}Output directory: ${output_dir}${NC}"
        echo ""
    fi
    
    # Calculate total size before compression
    for file in "${png_files[@]}"; do
        if [ -f "$file" ]; then
            size=$(stat -f%z "$file" 2>/dev/null || stat -c%s "$file" 2>/dev/null)
            total_size_before=$((total_size_before + size))
        fi
    done
    
    # Process each file with appropriate progress display
    local count=0
    if [ "$use_gui" = true ]; then
        # Use zenity progress bar for GUI
        (
            for file in "${png_files[@]}"; do
                if [ -f "$file" ]; then
                    count=$((count + 1))
                    filename=$(basename "$file")
                    output_file="${output_dir}/${filename}"
                    
                    echo "# Minimizing $filename... ($count/$total_files)"
                    
                    # Minimize the file
                    pngquant --output "$output_file" --force "$colors" "$file"
                    
                    echo "$((count * 100 / total_files))"
                fi
            done
        ) | zenity --progress --title="PNG Minimization" --text="Initializing..." --percentage=0 --auto-close
        
        # Check if user cancelled
        if [ $? -ne 0 ]; then
            zenity --error --text="Minimization was cancelled."
            exit 1
        fi
    else
        # Use terminal progress bar
        for file in "${png_files[@]}"; do
            if [ -f "$file" ]; then
                count=$((count + 1))
                filename=$(basename "$file")
                output_file="${output_dir}/${filename}"
                
                # Show terminal progress
                local percentage=$((count * 100 / total_files))
                printf "\r${BLUE}[%3d%%] Processing $filename ($count/$total_files)${NC}" "$percentage"
                
                # Minimize the file
                pngquant --output "$output_file" --force "$colors" "$file"
            fi
        done
        echo "" # New line after progress
    fi
    
    # Calculate total size after compression
    for file in "${png_files[@]}"; do
        filename=$(basename "$file")
        output_file="${output_dir}/${filename}"
        if [ -f "$output_file" ]; then
            size=$(stat -f%z "$output_file" 2>/dev/null || stat -c%s "$output_file" 2>/dev/null)
            total_size_after=$((total_size_after + size))
        fi
    done
    
    # Calculate statistics
    local saved_bytes=$((total_size_before - total_size_after))
    local saved_percentage=0
    if [ "$total_size_before" -gt 0 ]; then
        saved_percentage=$((saved_bytes * 100 / total_size_before))
    fi
    
    # Convert bytes to readable format with automatic KB/MB selection
    local size_before_display
    local size_after_display
    local saved_display
    local unit_before="MB"
    local unit_after="MB"
    local unit_saved="MB"
    
    # Check if sizes are less than 1MB to display in KB
    if [ "$total_size_before" -lt 1048576 ]; then
        size_before_display=$((total_size_before / 1024))
        unit_before="KB"
    else
        size_before_display=$((total_size_before / 1024 / 1024))
    fi
    
    if [ "$total_size_after" -lt 1048576 ]; then
        size_after_display=$((total_size_after / 1024))
        unit_after="KB"
    else
        size_after_display=$((total_size_after / 1024 / 1024))
    fi
    
    if [ "$saved_bytes" -lt 1048576 ]; then
        saved_display=$((saved_bytes / 1024))
        unit_saved="KB"
    else
        saved_display=$((saved_bytes / 1024 / 1024))
    fi
    
    # Show final report
    if [ "$use_gui" = true ]; then
        # Show report with zenity
        local report_message="✓ Minimization completed!\n\n"
        report_message+="Files processed: ${total_files}\n"
        report_message+="Original size: ${size_before_display} ${unit_before}\n"
        report_message+="Minimized size: ${size_after_display} ${unit_after}\n"
        report_message+="Space saved: ${saved_display} ${unit_saved} (${saved_percentage}%)\n"
        report_message+="Colors used: ${colors}\n"
        report_message+="Output directory: ${output_dir}/"
        
        zenity --info --title="PNG Minimization Complete" --text="$report_message"
    else
        # Show report in terminal
        echo ""
        echo -e "${GREEN}✓ Minimization completed!${NC}"
        echo ""
        echo -e "${BLUE}Statistics:${NC}"
        echo -e "  Files processed: ${total_files}"
        echo -e "  Original size: ${size_before_display} ${unit_before}"
        echo -e "  Minimized size: ${size_after_display} ${unit_after}"
        echo -e "  Space saved: ${saved_display} ${unit_saved} (${saved_percentage}%)"
        echo -e "  Colors used: ${colors}"
        echo -e "  Output directory: ${output_dir}/"
    fi
}

# Show help if requested
if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    echo -e "${GREEN}Script to minimize PNG images${NC}"
    echo ""
    echo -e "${YELLOW}Usage:${NC}"
    echo "  $0 [colors] file1.png file2.png ..."
    echo "  $0 [colors] *.png"
    echo "  Or select files in Nemo file manager and run as script"
    echo ""
    echo -e "${YELLOW}Parameters:${NC}"
    echo "  colors     Number of colors (8-256, default: 256)"
    echo "  files      PNG files to minimize"
    echo ""
    echo -e "${YELLOW}Examples:${NC}"
    echo "  $0 image1.png image2.png    # Minimize specific files with 256 colors"
    echo "  $0 128 *.png                # Minimize all PNG files with 128 colors"
    echo "  $0 64 graphics/*.png        # Minimize PNG files in graphics folder"
    echo ""
    echo -e "${BLUE}Note: Minimized images will be saved in the 'min' subdirectory${NC}"
    echo -e "${BLUE}      When used as Nemo script, a dialog will ask for colors${NC}"
    echo -e "${BLUE}      Requires pngquant for PNG optimization${NC}"
    exit 0
fi

# Execute main
main "$@"