git_commands

#!/bin/bash

# Based on `git help -a` provided by `hub`, show all the available git commands, both native and custom.
#
# git help -a
#     Ref: https://stackoverflow.com/questions/7866353/git-list-all-available-commands

################ Preparation ################
# The line that divides the whole text into two: regular and custom commands
dividing_line_number=$(git help -a | \
	grep -n 'git commands available from elsewhere on your $PATH' |
	sed 's/[^0-9]*//g')

whole_line_number="$(git help -a | wc -l)"

############# Child Functions ###############
function native_commands() {
	git help -a |
		head -n "$dividing_line_number" |
		grep "^  [a-z]" |
		tr ' ' '\n' |
		grep -v "^$" |
		while read line; do
			echo -e "\e[00m$line\e[0m"
		done
}

function custom_commands() {
	git help -a |
		tail -n $(($whole_line_number - $dividing_line_number)) |
		grep "^  [a-z]" |
		tr ' ' "\n" |
		grep -v "^$" |
		while read line; do
			echo -e "\e[94m$line\e[0m"
		done
}

function all_commands() {
	native_commands && custom_commands
}

################ Main ################
function main() {
	list=$("$1" | \
		# -u: unique key to prevent duplicates
		# -k: sort only after the specified character, after 6th character on 1st field
		#     Ref: https://unix.stackexchange.com/questions/157923/sorting-strings-with-ansi-escape-codes
		sort -u -k 1.6)

	# If fzf exists
    # todo: if [[ hash fzf ]] ?
	if type fzf >/dev/null 2>&1; then

		_help_preview="man git-{} || {echo '\n*****************************' && git-{} -h}"
		result=$(echo -e "$list" |
				fzf --ansi --reverse --height=90% --cycle \
					--preview="$_help_preview" \
					--preview-window=right:75%)

		# Execute a git command if a command selected
		[[ -n "$result" ]] && git "$result"

	else
		echo -e "\e[94m'`fzf`' is not detected on '$PATH', defaulting to '`git help -a`' \e[0m \n"
		git help -a
	fi
}

################ Help ################
usage="""\
usage: $(basename "$0") [<options>]

List all available git commands with help using fzf.
Native git commands in white, \e[94mcustom git commands in blue\e[0m.

where:
	-h  show this help text
	-n  list only the native git commands
	-c  list only the custom git commands
	-a  list all commands, which is also default
"""

############# Parse options ##############
while getopts ':hnca:' option; do
	case "$option" in
	h)
		echo -e "$usage"
		exit
		;;
	n)
		main native_commands
		exit
		;;
	c)
		main custom_commands
		exit
		;;
	a)
		main all_commands
		exit
		;;
	:)
		main all_commands
		exit
		;;
	\?)
		printf "illegal option: -%s\n" "$OPTARG" >&2
		echo -e "$usage" >&2
		exit 1
		;;
	esac
done
shift $((OPTIND - 1))

# Default case when no option provided
main all_commands

# Vim: set ft=bash: