#!/bin/bash

###############################################################################
# Script Name: add-mp3-cover.sh
#
# Description:
#   Embeds album artwork into MP3 files using either ffmpeg or lame.
#
#   By default, the script processes all MP3 files in the current directory.
#   Alternatively, a single MP3 file can be specified.
#
#   When using ffmpeg:
#     - Preserves existing audio stream.
#     - Embeds the supplied image as the front album cover.
#     - Writes ID3v2.3-compatible metadata.
#
#   When using lame:
#     - Uses the --ti option to attach album artwork.
#
# Requirements:
#   - ffmpeg (recommended)
#   - or lame
#   - Cover image located in:
#       /home/lucas/Downloads/
#
# Usage:
#   Process all MP3 files:
#       ./add-mp3-cover.sh cover.jpg
#
#   Process a specific MP3 file:
#       ./add-mp3-cover.sh cover.jpg song.mp3
#
# Examples:
#   Add cover.jpg to every MP3 in current directory:
#       ./add-mp3-cover.sh cover.jpg
#
#   Add cover.png to a specific track:
#       ./add-mp3-cover.sh cover.png "My Song.mp3"
#
# Notes:
#   - Original files are replaced with updated versions.
#   - ffmpeg mode is enabled by default.
#   - Cover image is read from /home/lucas/Downloads/.
#
###############################################################################

FFMPEG="true"

if [ "$2" == "" ]; then

    # Process all MP3 files in current directory
    for file in *.mp3; do

        if [[ "${FFMPEG}" == "true" ]]; then

            ffmpeg \
                -i "$file" \
                -i "/home/lucas/Downloads/$1" \
                -map 0:0 \
                -map 1:0 \
                -c copy \
                -id3v2_version 3 \
                -metadata:s:v title="Album cover" \
                -metadata:s:v comment="Cover (front)" \
                "$file.mp3"

        else

            lame --ti "/home/lucas/Downloads/$1" "$file"

        fi

        mv "$file.mp3" "$file"

    done

else

    # Process a specific MP3 file
    for file in "$2"; do

        if [[ "${FFMPEG}" == "true" ]]; then

            ffmpeg \
                -i "$file" \
                -i "/home/lucas/Downloads/$1" \
                -map 0:0 \
                -map 1:0 \
                -c copy \
                -id3v2_version 3 \
                -metadata:s:v title="Album cover" \
                -metadata:s:v comment="Cover (front)" \
                "$file.mp3"

        else

            lame --ti "/home/lucas/Downloads/$1" "$file"

        fi

        mv "$file.mp3" "$file"

    done

fi