#!/bin/bash

# Simple M3U to CUE Converter Script
# Converts M3U playlist files to basic CUE format

# Function to display usage
show_usage() {
    echo "Usage: $0 [OPTIONS] <input.m3u> [output.cue]"
    echo ""
    echo "Options:"
    echo "  -t, --title TITLE    Set playlist title (default: derived from filename)"
    echo "  -r, --relative       Use relative paths (strip directory paths)"
    echo "  -h, --help           Show this help message"
    echo ""
    echo "Examples:"
    echo "  $0 Mix.m3u"
    echo "  $0 Mix.m3u Mix.cue"
    echo "  $0 --title \"My Playlist\" --relative Mix.m3u"
}

# Default options
PLAYLIST_TITLE=""
USE_RELATIVE_PATHS=false
INPUT_FILE=""
OUTPUT_FILE=""

# Parse command line arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        -t|--title)
            PLAYLIST_TITLE="$2"
            shift 2
            ;;
        -r|--relative)
            USE_RELATIVE_PATHS=true
            shift
            ;;
        -h|--help)
            show_usage
            exit 0
            ;;
        -*)
            echo "Unknown option: $1"
            show_usage
            exit 1
            ;;
        *)
            if [ -z "$INPUT_FILE" ]; then
                INPUT_FILE="$1"
            elif [ -z "$OUTPUT_FILE" ]; then
                OUTPUT_FILE="$1"
            else
                echo "Too many arguments"
                show_usage
                exit 1
            fi
            shift
            ;;
    esac
done

# Check if input file is provided
if [ -z "$INPUT_FILE" ]; then
    echo "Error: Input M3U file is required"
    show_usage
    exit 1
fi

# Check if input file exists
if [ ! -f "$INPUT_FILE" ]; then
    echo "Error: Input file '$INPUT_FILE' not found"
    exit 1
fi

# Set default output file if not provided
if [ -z "$OUTPUT_FILE" ]; then
    OUTPUT_FILE="${INPUT_FILE%.*}.cue"
fi

# Set default playlist title if not provided
if [ -z "$PLAYLIST_TITLE" ]; then
    PLAYLIST_TITLE=$(basename "$INPUT_FILE" .m3u)
fi

# Function to extract filename from path
get_filename() {
    local filepath="$1"
    if [ "$USE_RELATIVE_PATHS" = true ]; then
        basename "$filepath"
    else
        echo "$filepath"
    fi
}

# Function to determine file format from extension
get_file_format() {
    local filepath="$1"
    local ext="${filepath##*.}"
    ext=$(echo "$ext" | tr '[:upper:]' '[:lower:]')
    
    case "$ext" in
        "flac") echo "FLAC" ;;
        "wav") echo "WAVE" ;;
        "mp3") echo "MP3" ;;
        "ogg") echo "OGG" ;;
        *) echo "BINARY" ;;
    esac
}

echo "Converting M3U to CUE format..."
echo "Input:  $INPUT_FILE"
echo "Output: $OUTPUT_FILE"
echo ""

# Start writing CUE file
{
    echo "TITLE \"$PLAYLIST_TITLE\""
} > "$OUTPUT_FILE"

# Process M3U file
track_num=1
processed_files=0

while IFS= read -r line || [ -n "$line" ]; do
    # Skip empty lines and all comment lines
    if [ -z "$line" ] || [[ "$line" == "#"* ]]; then
        continue
    fi
    
    # Process file path
    filepath="$line"
    filename=$(get_filename "$filepath")
    file_format=$(get_file_format "$filepath")
    
    # Add track to CUE file
    {
        echo "FILE \"$filename\" $file_format"
        printf "  TRACK %02d AUDIO\n" $track_num
        echo "    INDEX 01 00:00:00"
    } >> "$OUTPUT_FILE"
    
    echo "  Track $track_num: $filename"
    
    ((track_num++))
    ((processed_files++))
done < "$INPUT_FILE"

echo ""
echo "Conversion completed successfully!"
echo "Processed $processed_files tracks"
echo "CUE file saved as: $OUTPUT_FILE"

# Validate output
if [ -f "$OUTPUT_FILE" ] && [ -s "$OUTPUT_FILE" ]; then
    echo "Output file validation: OK"
    exit 0
else
    echo "Error: Output file was not created properly"
    exit 1
fi