books_functions

# shellcheck shell=bash disable=SC2154

# UTITLITIES

# find tool, returns the first|one|found, exit with error message if none found
find_tool () {
        IFS='|' read -ra tools <<< "$*"
        
        found=0
                
        for tool in "${tools[@]}"; do
                if [[ -n $(which "$tool") ]]; then
                        found=1
                        break
                fi
        done
        
        if [[ "$found" -eq 0 ]]; then
                if [[ ${#tools[@]} -gt 1 ]]; then
                        exit_with_error "missing programs: $*; install at least one of these: ${tools[*]} and try again"
                else
                        exit_with_error "missing program: $1; please install and try again"
                fi                  
        fi   
                          
        echo "$tool"
}

url_available () {
        url="$1"
        dl_tool=$(find_tool "curl|wget")
                    
        case "$dl_tool" in
                curl)
                        ${torsocks:-} curl --output /dev/null --silent --fail -r 0-0 "$url"
                        ;;
                wget)
                        ${torsocks:-} wget -q --spider "$url"
                        ;;
                *)
                        exit_with_error "unknown download tool ${dl_tool}"
                        ;;
        esac
}

add_cron_job () {
        job="$*"

        (crontab -l ; echo "*/1 * * * * $job") 2>/dev/null | sort | uniq | crontab -
}

# leave <br> and <pre> to enable some simple formatting tasks
strip_html () {
        #echo "$*"|sed -e 's/<br>/\n/g;s/<[^>]*>//g;s/\n/<br>/g'
        echo "$*"
}

is_true () {
        val="${1,,}"
        if [[ "${val:0:1}" == "y" || "$val" -gt 0 ]]; then
                true
        else
                false
        fi
}

# dummmy cleanup function
cleanup () {
	true
}

# echo error message to stderr and terminate main
exit_with_error () {
        echo -e "$(basename "$0"): $*" >&2

        kill -s TERM "$TOP_PID"
}

trap_error () {
	cleanup

        exit 1
}

trap_clean () {
	cleanup

        exit
}

_log () {
	msg="$*"
	logdir="${XDG_STATE_HOME:-$HOME/.state}/books"
	logfile=$(basename "$0").log
	mkdir -p "$logdir"
	echo "$(date -Iseconds): $msg" >> "$logdir/$logfile"
}

log_err () {
	_log "E: $*"
}

log_warn () {
	_log "W: $*"
}

log_info () {
	_log "I: $*"
}

log_debug () {
	_log "D: $*"
}

# DATABASE
dbx () {
        db="$1"
        shift

	mysql=$(find_tool "mysql")

        if [ $# -gt 0 ]; then
                "$mysql" -N -Bsss -h "$dbhost" -P "$dbport" -u "$dbuser" "$db" -e "$*"
        else
                "$mysql" -N -Bsss -h "$dbhost" -P "$dbport" -u "$dbuser" "$db"
        fi
}

# LOCKING

exlock () {
	cmd="$1"

	lockfile="/var/lock/$(basename "$0")"
	lockfd=99

	flock=$(find_tool "flock")

	case "$cmd" in
		prepare)
			eval "exec $lockfd<>\"$lockfile\""
			trap 'exlock nolock' EXIT
			;;

		now)
			$flock -xn $lockfd
			;;

		lock)
			$flock -x $lockfd
			;;

		shlock)
			$flock -s $lockfd
			;;

		unlock)
			$flock -u $lockfd
			;;

		nolock)
			$flock -u $lockfd
			$flock -xn $lockfd && rm -f "$lockfile"
			trap_clean
			;;

		*)
			exit_with_error "unknown lock command: $cmd"
			;;
	esac
}