#!/usr/bin/env bash

# Use this to copy audio from the left channel to the right. This does not re-encode the video.

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

if [[ $1 == "" ]]; then
    printf "${BOLD}${RED}Usage: copy-left-audio-channel-to-right <filename> <optional output name>${NORMAL}\n"
    exit 1
fi

filename=$(basename -- "$1")
extension="${filename##*.}"
filename="${filename%.*}"

output_name="$2"

if [[ $output_name == "" ]]; then
    output="${filename}_repaired_audio.$extension"
else
    output="${output_name}.$extension"
fi

printf "\n${YELLOW}${BOLD}Copy left audio channeel to right channel in $filename.$extension | output: $output${NORMAL}\n"

ffmpeg -y -stats -loglevel level+error -i "$filename.$extension" -c:v copy -af "pan=stereo|c0=c0|c1=c0" -map 0 "$output"

printf "\n${GREEN}${BOLD}Done copying left audio channel to right channel in $filename.$extension | output: $output${NORMAL}\n\n"