#!/usr/bin/env bash

if which tput >/dev/null 2>&1; then
    ncolors=$(tput colors)
fi
if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
    RED="$(tput setaf 1)"
    GREEN="$(tput setaf 2)"
    YELLOW="$(tput setaf 3)"
    BLUE="$(tput setaf 4)"
    MAGENTA="$(tput setaf 5)"
    CYAN="$(tput setaf 6)"
    BOLD="$(tput bold)"
    NORMAL="$(tput sgr0)"
else
    RED=""
    GREEN=""
    YELLOW=""
    BLUE=""
    MAGENTA=""
    CYAN=""
    BOLD=""
    NORMAL=""
fi

transcode="$1"
filename=$(basename -- "$2")
format="$3"
bitrate="$4"

if [[ $1 == "" || $2 == "" || $3 == "" ]]; then
    printf "${BOLD}${RED}Usage: $0 <transcode? 0|1 (needed when container doesn't contain format)> <filename> <format (mp3, m4a, aac, etc)> <optional: bitrate. Uses 64k when not specified, 0 = variable (e.g. 0, 64, 128, etc)>${NORMAL}\n"
    exit 1
fi

extension="${filename##*.}"
filename="${filename%.*}"
output_name="$filename.$format"

if [[ $bitrate == "" ]]; then
    bitrate="64"
fi

printf "\n${YELLOW}${BOLD}Extracting audio from '$filename.$extension' | bitrate: ${bitrate}k | output: $output_name${NORMAL}\n"

if [[ $transcode == "1" ]]; then
    # Transcode audio
    ffmpeg -i "$filename.$extension" -b:a ${bitrate}k -ac 2 -ar 44100 -map a "$output_name"
else
    # Grab the audio stream from the video.
    ffmpeg -i "$filename.$extension" -vn -acodec copy "$output_name"
fi

printf "\n${GREEN}${BOLD}Done extracting audio from '$filename.$extension' | output name '$output_name'${NORMAL}\n\n"