#!/usr/bin/env bash

# getHash returns the hash of a given file.
function getHash() {
    echo $(xxd -p -l20 -s 653 ${1})
}

# getActivationBytes returns the bytes needed to decrypt a given hash. 
function getActivationBytes() {
    json=$(curl -A 'Christian Colglazier' https://aax.api.j-kit.me/api/v2/activation/${1})
    echo $(echo $json | jq '.activationBytes' | tr -d '"')
}

# createConfig creates a config file.
function createConfig() {
    hash=$(getHash ${2})
    bytes=$(getActivationBytes $hash)
    echo "activationBytes=${bytes}" >> ${1}
}

# checkAudibleFile checks if a given file is valid and if not exits the program.
function checkAudibleFile() {
    if [ ! -f ${1} ]; then
	echo "${1}" not found
	exit 1
    fi
}

function removeDRM() {
    ffmpeg -activation_bytes ${2} -i ${1} -c copy "$(basename ${1} | cut -f 1 -d '.').m4b"
}

function getChapterJSON() {
    echo $(ffprobe -i ${1} -print_format json -show_chapters -loglevel error -sexagesimal)
}

function getMetadataJSON() {
    echo $(ffprobe -show_format -print_format json ${1} | jq '.format.tags')
}

function getTitle() {
    echo $(echo ${1} | jq '.title')
}

settingsFile='./settings.conf'

audibleFile=${1}
checkAudibleFile $audibleFile

# Check for config file
if [ ! -f $settingsFile ]; then
    echo 'No config file'
    createConfig $settingsFile $audibleFile
fi

# Load settings
. $settingsFile

metadataJSON=$(getMetadataJSON $audibleFile)
json=$(getMetadataJSON $audibleFile)
removeDRM $audibleFile $activationBytes