bash completion for alembic (pythonic db structure migration tool based on sqlAlchemy)

alembic-completion.bash

#/usr/bin/env bash

comment_show_last_detailed=1
comment_show_last_position=0

_simple_alembic_completions() {
    local WORDS="branches current downgrade edit heads history init list_templates merge revision show stamp upgrade"

    #echo -e "\e[1m[${#COMP_WORDS[@]}]\e[0m" >&2

    if [[ "${#COMP_WORDS[@]}" < 3 ]]; then
	COMPREPLY=($(compgen -W "${WORDS[@]}" "${COMP_WORDS[1]}"))
    else
	#echo -e "\e[2m[${COMP_WORDS[1]}\e[0m" >&2
	local ALM_PARAMETERS=( '--help' )
	case "${COMP_WORDS[1]}" in
	    'history' )
		ALM_PARAMETERS+=( '--rev-range' '--indicate-current' '--verbose') ;;
	    'downgrade' ) ;&
	    'upgrade' )
		ALM_PARAMETERS+=( '--sql' '--tag' ) ;;
	    'heads' )
		ALM_PARAMETERS+=( '--resolve-dependencies' '--verbose' ) ;;
	    'init' )
		ALM_PARAMETERS+=( '--package' '--template' ) ;;
	    'merge' )
		ALM_PARAMETERS+=( '--message' '--branch-label' '--rev-id' ) ;;
	    'show' ) ;&
	    'edit' )
		;;
	    'branches' ) ;&
	    'current' )
		ALM_PARAMETERS+=( '--verbose' ) ;;
	    'revision' )
		ALM_PARAMETERS+=( '--message' '--autogenerate' '--sql' '--head' '--splice' '--branch-label' '--version-path VERSION' '--rev-id' '--depends-on') ;;
	    'stamp' )
		ALM_PARAMETERS+=( '--sql' '--tag' '--purge' ) ;;
	esac

	# echo -e "\e[2m[lastComplete:${COMP_WORDS[-2]}]\e[0m" >&2

	# based on last completed parameter - support next arbitrary param
	case "${COMP_WORDS[-2]}" in
	    # standalone parameters
	    '--help' ) ;&
	    '--verbose' ) ;&
	    '--resolve-dependencies' ) ;&
	    '--package' ) ;&
	    '--sql' ) ;&
	    '--autogenerate' ) ;&
	    '--splice' ) ;&
	    '--purge' )
		# NOOP
		;;

	    # parameters with user provided values
	    --* ) 
		ALM_PARAMETERS=()
		;;
	esac

	backup_parameters=( ${ALM_PARAMETERS[@]} )

	if [ -z "${COMP_WORDS[-1]}" ] && [[ ${#COMP_WORDS[@]} > 2 ]]; then
	    # echo 'empty last compword' >&2
	    case "${COMP_WORDS[1]}" in
		'upgrade' ) ;&
		'stamp' ) ;&
		'show' ) ;&
		'downgrade' )
		    local raw_history="$(alembic history | sed -E 's/^[^ ]+ -> ([^ ]+.+)$/\1/')"
		    #echo -e "\n${raw_history}"

		    if [ $comment_show_last_detailed = 0 ] &&
			   [ $comment_show_last_position = $COMP_POINT ]; then
			echo -e "\n${raw_history}"
			comment_show_last_detailed=1
			ALM_PARAMETERS=( ${backup_parameters[@]} )
		    else
			ALM_PARAMETERS=( $(echo "${raw_history}" | sed -E 's/^([^ ]+).+$/\1/' ) )
			comment_show_last_detailed=0
		    fi
		    comment_show_last_position=$COMP_POINT
		    ;;
	    esac
	fi

	if [[ "${#ALM_PARAMETERS[@]}" != '0' ]]; then
	    COMPREPLY=($(compgen -W "$(echo "${ALM_PARAMETERS[@]}")" -- "${COMP_WORDS[-1]}"))
	    #echo -e "\e[35;2m[doing params]\e[0m" >&2
	fi
    fi
    #echo -e "\e[33;2mCOMPREPLY: ${COMPREPLY[@]}\e[0m" >&2
}

complete -F _simple_alembic_completions alembic