scripts/log-hours.sh

function log-hours {
	case $1 in
		on)
			shift
			if [ $# -eq 0 ]
			then
				LAST_MESSAGE="$(grep 'BEGIN' \
						"${HOME}/.log-hours" |
					tail -1 |
					cut -f 3-)"
				echo -e "Reporting beginning of work with" \
					"message\n\t${LAST_MESSAGE}"
				log-hours_on "${LAST_MESSAGE}"
			else
				log-hours_on $*
			fi
			;;
		off)
			shift
			log-hours_off $*
			;;
		total)
			shift
			if [ $# -gt 0 ]
			then
				log-hours_total $*
			else
				log-hours_total $(date -I)
			fi
			;;
		today)
			TODAY="$(date -I)"
			log-hours_total "${TODAY}"
			;;
		yesterday)
			YESTERDAY="$(grep -v "$(date -I)" \
					     "${HOME}/.log-hours" |
				tail -1 |
				awk '{print $2}' |
				cut -d'T' -f1)"
			log-hours_total "${YESTERDAY}"
			;;
		edit)
			"${EDITOR}" "${HOME}/.log-hours"
			;;
		*)
			echo '[ERROR] '"'$1'"' is not a valid command.' >&2
			return 1
			;;
	esac
	return 0
}

function log-hours_on {
	echo -e "BEGIN\t$(date -Imin)\t$*" >> "${HOME}/.log-hours"
}

function log-hours_off {
	echo -e "END\t$(date -Imin)\t$*" >> "${HOME}/.log-hours"
}

function log-hours_total {
	if DATE=$(date -I -d "$*" 2>/dev/null)
	then
		printf "Date:\t${DATE}\n"
		grep "${DATE}" "${HOME}/.log-hours" |
		awk -f <(cat <<-'EOF'
			BEGIN {
				begin = 0
				i = 0
				cut_cmd = "cut -f3-"
			}
			/^\<BEGIN\>/ {
				to_epoch = ("date -d \"" $2 "\" +\"%s\"")
				if (begin == 0) {
					to_epoch | getline begin
					print $0 |& cut_cmd
					close(cut_cmd, "to")
					cut_cmd |& getline task_title
					task_titles[i] = task_title
				}
				close(to_epoch)
				close(cut_cmd)
			}

			/^\<END\>/ {
				to_epoch = ("date -d \"" $2 "\" +\"%s\"")
				if (begin != 0) {
					to_epoch | getline end
					total += (end - begin)
					task_hours[i] = (end - begin) / 3600.0
					sum_rounded += round(task_hours[i], 0.25)
					i++;
					begin = 0
				}
				else {
					print "ERROR: an END is found at", $2,
					      "but it is doesn't have an",
					      "equivalent BEGIN."
					begin = 0
				}
				close(to_epoch)
			}

			END {
				if (FNR == 0) {
					print "WARNING: zero lines to process."
				}
				absolute = total / 3600.0
				printf "Hours (absolute):\t%.2f\n", absolute
				rounded = round(absolute, 0.25)
				printf "Hours (rounded sum):\t%.2f\n", rounded
				printf "Hours (sum of rounded):\t%.2f\n", sum_rounded
				for (j = 0; j < i; j++) {
					printf "\t%.2f\t%.2f\t%s\n", task_hours[j], round(task_hours[j], 0.25), task_titles[j]
					#printf "\t%.2f\t%s\n", task_hours[j], task_titles[j]
				}
			}

			function abs(value) {
				if (value < 0) {
					return (-1 * value);
				}
				return value;
			}

			function sgn(x) {
				return (x < 0)? (-1) : 1;
			}
			
			function ceil(x) {
				return (x == int(x)) ? x : int(x + 1)
			}

			function floor(x) {
				return int(x)
			}

			function round(value, precision,  value_to_round) {
				# Unified the round (half [1]) away from zero [2] with the
				# rounding to a specified multiple [3].
				#
				# [1]: https://en.wikipedia.org/wiki/Rounding#Round_half_away_from_zero
				# [2]: https://en.wikipedia.org/wiki/Rounding#Round_away_from_zero
				# [3]: https://en.wikipedia.org/wiki/Rounding#Rounding_to_a_specified_multiple
				if (precision == 0) {
					precision = 1.0
				}
				else {
					value_to_round = value / (precision * 1.0)
				}
				# round half away from zero [1]
				#return (sgn(value) * floor(abs(value_to_round) + 0.5) * precision)
				# round away from zero [2]
				return (sgn(value) * ceil(abs(value_to_round)) * precision)
			}
			EOF
		)
	else
		echo "ERROR: '$*' is not a valid date. Try writing it" \
		     "according to the ISO 8601 format."
	fi
}

function log-hours_complete {
	if [ $3 == "on" ]
	then
		COMPREPLY=$(grep 'BEGIN' ~/.log-hours |
			    cut -f3- |
			    sort |
			    uniq -c |
			    sed 's/^\s*//' |
			    sort -t' ' -k1nr -k2 |
			    cut -d' ' -f2- |
			    fzy)
	fi
}

# Bash completion for `log-hours on`
complete -o nospace -F log-hours_complete log-hours

function weeks-task {
	seq $(( "$(date +'%u')" - 1 )) -1 0 |
	while read ENTRY
	do
		egrep $'BEGIN\t'"$(date -I --date="$ENTRY days ago")" ~/.log-hours # filters only this week's entries
	done |
	cut -f 3- | # take just the logged entries
	sed -e 's/^[[:blank:]]*//' -e 's/[[:blank:]]*$//' | # trimming the entries
	awk 'entry[$0]++ == 0' # print only the first appearance of the entry
}

function weeks-hours {
	MATCH_WORD="absolute"

	if [ -n "$1" ]
	then
		case $1 in
			absolute)
				MATCH_WORD="absolute"
				;;
			rounded)
				MATCH_WORD="rounded sum"
				;;
			sum-rounded)
				MATCH_WORD="sum of rounded"
				;;
			*)
				echo '[ERROR] '"'$1'"' is not a valid' \
				     'command.' >&2
				return 1
				;;
		esac
	fi
	
	seq $(( "$(date +'%u')" - 1 )) -1 0 |
	while read ENTRY; do
		log-hours total "$(date -I --date="$ENTRY days ago")"
	done |
	sed '/'"${MATCH_WORD}"'/{s/^.*\t//;p};/./d' |
	tr '\n' '+' |
	sed 's/+$/\n/' |
	bc
}

function redmine {
	COMMAND=${*:-yesterday}
	CONTENT=$(log-hours ${COMMAND})

	# Print header.
	echo "${CONTENT}" |
	sed -ne '/^[^[:blank:]]/{p}'

	# Unify hours per task.
	echo "${CONTENT}" |
	egrep '^[[:blank:]]' |
	awk -F '\t' '
	{
		precise[$4] = precise[$4] + $2
		rounded[$4] = rounded[$4] + $3
	}

	END {
		for (t in precise) {
			printf("\t%0.2f\t%0.2f\t%s\n", precise[t], rounded[t], t)
		}
	}' |
	sort -t $'\t' -k4
}