#!/bin/sh

error_log=.fix_gopro_filenames_error.log

if ! touch $error_log; then
    printf '%b\n' "\e[1;31mERROR\e[1;37m:\e[0m Unable to write to current directory." >&2
    exit 1
fi
printf '%s\n' 'Searching for GoPro video files...'
FILES=$(ls -1 | grep -E '^GX[0-9]{6}.MP4$')
if [ -z "$FILES" ]; then
    printf '%b\n' "\e[1;31mERROR\e[1;37m:\e[0m No GoPro files with default names found in current directory." >&2
    exit 1
fi
printf '%b\n' "\nFound:\n$FILES\n"
printf '%s' "Do you want to continue renaming these files? (y/N) "
read -n 1 response
if [ "$response" != "y" ] && [ "$response" != "Y" ]; then
    printf '\n%s\n' "Aborted."
    exit 1
fi
printf '\n%s\n' "Continuing..."

printf '%s\n' $FILES | while read -r i; do
    sq=$(printf '%s\n' $i | awk '{print substr($0, 3, 2)}')
    vn=$(printf '%s\n' $i | awk '{print substr($0, 5, 4)}')
    oname="GX${sq}${vn}.MP4"
    nname="GX${vn}_${sq}.MP4"

    printf '%b' "Renaming \e[1;33m${oname}\e[0m to \e[1;32m${nname}\e[0m... "
    if mv $oname $nname 2>>$error_log; then
        printf '%b\n' "\e[1mDONE\e[0m"
    else
        printf '%b\n' "\e[1;31mFAIL\e[0m"
    fi
done

if [ -s $error_log ]; then
    printf '%b\n' " !!!\e[1;31m    ERRORS ENCOUNTERED:    \e[0m!!!\n------------" >&2
    printf '%b\n' "$(cat $error_log)\n------------" >&2
    rm "$error_log"
    exit 3
else
    printf '%b\n' "\e[1;34m  Complete!\e[0m"
    rm "$error_log"
    exit 0
fi