#!/bin/bash

# Configuration
SOURCE_DIR="/mnt/zpool0_nfs/cios_www"
DEST_DIR="/home/paulmataruso/TORRENT_BACKUP_GOLD"
TORRENT_WATCH_DIR="/home/paulmataruso/TORRENT_WATCH"
TRACKER_URL="http://tracker.dhitechnical.com:6969/announce"

# 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 print colored output
print_status() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

print_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

print_header() {
    echo -e "${BLUE}================================${NC}"
    echo -e "${BLUE}$1${NC}"
    echo -e "${BLUE}================================${NC}"
}

# Check if transmission-create is installed
check_dependencies() {
    if ! command -v transmission-create &> /dev/null; then
        print_error "transmission-create is not installed. Please install transmission-cli package."
        print_status "On Ubuntu/Debian: sudo apt-get install transmission-cli"
        print_status "On CentOS/RHEL: sudo yum install transmission-cli"
        print_status "On Arch: sudo pacman -S transmission-cli"
        exit 1
    fi
}

# Validate destination directories exist
check_dest_dirs() {
    if [ ! -d "$DEST_DIR" ]; then
        print_error "Destination directory does not exist: $DEST_DIR"
        exit 1
    fi
    
    if [ ! -d "$TORRENT_WATCH_DIR" ]; then
        print_error "Torrent watch directory does not exist: $TORRENT_WATCH_DIR"
        exit 1
    fi
}

# Calculate optimal piece size based on folder size
calculate_piece_size() {
    local folder_path="$1"
    local size_bytes=$(du -sb "$folder_path" | cut -f1)
    
    # Convert to MB for easier comparison
    local size_mb=$((size_bytes / 1024 / 1024))
    
    # Piece size mapping based on folder size
    # < 100 MB: 16 KB pieces
    # 100 MB - 1 GB: 32 KB pieces  
    # 1 GB - 10 GB: 64 KB pieces
    # 10 GB - 100 GB: 128 KB pieces
    # > 100 GB: 256 KB pieces
    
    if [ $size_mb -lt 100 ]; then
        echo "16"
    elif [ $size_mb -lt 1024 ]; then
        echo "32"
    elif [ $size_mb -lt 10240 ]; then
        echo "64"
    elif [ $size_mb -lt 102400 ]; then
        echo "128"
    else
        echo "256"
    fi
}

# Format size for display
format_size() {
    local size_bytes="$1"
    if [ $size_bytes -gt 1073741824 ]; then
        echo "$(($size_bytes / 1073741824)) GB"
    elif [ $size_bytes -gt 1048576 ]; then
        echo "$(($size_bytes / 1048576)) MB"
    elif [ $size_bytes -gt 1024 ]; then
        echo "$(($size_bytes / 1024)) KB"
    else
        echo "$size_bytes bytes"
    fi
}

# Create torrent file for a single folder
create_torrent() {
    local folder_path="$1"
    local folder_name=$(basename "$folder_path")
    local torrent_file="$DEST_DIR/${folder_name}.torrent"
    
    # Calculate folder size and optimal piece size
    local size_bytes=$(du -sb "$folder_path" | cut -f1)
    local size_formatted=$(format_size $size_bytes)
    local piece_size=$(calculate_piece_size "$folder_path")
    
    print_status "Creating torrent for: $folder_name (Size: $size_formatted, Piece size: ${piece_size}KB)"
    
    # Create torrent file
    transmission-create \
        --tracker "$TRACKER_URL" \
        --outfile "$torrent_file" \
        --piece-size "$piece_size" \
        --comment "Created by torrent creation script - Piece size: ${piece_size}KB" \
        "$folder_path"
    
    if [ $? -eq 0 ]; then
        print_status "✓ Torrent created: $torrent_file"
        
        # Copy torrent file to watch directory
        local watch_torrent_file="$TORRENT_WATCH_DIR/${folder_name}.torrent"
        cp "$torrent_file" "$watch_torrent_file"
        chown 1000:1000 "$watch_torrent_file"
        print_status "✓ Torrent copied to watch directory: $watch_torrent_file"
        
        # Extract magnet link
        local magnet_link=$(transmission-show --magnet "$torrent_file")
        if [ $? -eq 0 ]; then
            local magnet_file="$DEST_DIR/${folder_name}.magnet"
            echo "$magnet_link" > "$magnet_file"
            print_status "✓ Magnet link saved: $magnet_file"
        else
            print_warning "Could not extract magnet link for: $folder_name"
        fi
    else
        print_error "Failed to create torrent for: $folder_name"
    fi
}

# Main function
main() {
    print_header "Torrent Creation Script"
    
    # Check dependencies
    check_dependencies
    
    # Validate source directory
    if [ ! -d "$SOURCE_DIR" ]; then
        print_error "Source directory does not exist: $SOURCE_DIR"
        exit 1
    fi
    
    print_status "Source directory: $SOURCE_DIR"
    print_status "Destination directory: $DEST_DIR"
    print_status "Torrent watch directory: $TORRENT_WATCH_DIR"
    print_status "Tracker URL: $TRACKER_URL"
    
    # Validate destination directories
    check_dest_dirs
    
    # Get list of folders in source directory
    local folders=($(find "$SOURCE_DIR" -maxdepth 1 -type d -not -name "$(basename "$SOURCE_DIR")"))
    
    if [ ${#folders[@]} -eq 0 ]; then
        print_warning "No folders found in source directory"
        exit 0
    fi
    
    print_status "Found ${#folders[@]} folders to process"
    
    # Process each folder
    local count=0
    for folder in "${folders[@]}"; do
        count=$((count + 1))
        print_status "Processing folder $count of ${#folders[@]}: $(basename "$folder")"
        create_torrent "$folder"
        echo
    done
    
    print_header "Summary"
    print_status "Processed ${#folders[@]} folders"
    print_status "Torrent files saved to: $DEST_DIR"
    print_status "Torrent files copied to: $TORRENT_WATCH_DIR"
    print_status "Magnet files saved to: $DEST_DIR"
    
    # List created files
    echo
    print_status "Created files:"
    ls -la "$DEST_DIR"/*.torrent 2>/dev/null | wc -l | xargs echo "  Torrent files in backup:"
    ls -la "$TORRENT_WATCH_DIR"/*.torrent 2>/dev/null | wc -l | xargs echo "  Torrent files in watch:"
    ls -la "$DEST_DIR"/*.magnet 2>/dev/null | wc -l | xargs echo "  Magnet files:"
}

# Run main function
main "$@"