# Completion script for hledger.
# Created using a Makefile and real hledger.

# No set -e because this file is sourced and is not supposed to quit the current shell.
set -o pipefail

# TODO grep "^$wordToComplete" is (functional) not safe to use if the word
# contains regex special chars. But it might be no problem because of
# COMP_WORDBREAKS.

# Working with bash arrays is nasty compared to editing a text file. Consider
# for example grepping an array or mapping a substitution on it.
# Therefore, we create temp files in RAM for completion suggestions (see below).

readonly HLEDGER_COMPLETION_TEMPDIR=$(mktemp -d)

hledgerCompletionFunction() {
    #declare cmd=$1
    declare wordToComplete=$2
    declare precedingWord=$3

    declare subcommand
    for subcommand in "${COMP_WORDS[@]}"; do
	if grep -Fxqe "$subcommand" "$HLEDGER_COMPLETION_TEMPDIR/commands.txt"; then
	    COMPREPLY+=( $(grep -h "^$wordToComplete" -- "$HLEDGER_COMPLETION_TEMPDIR/options-$subcommand.txt") )
	    break
	fi
	subcommand=
    done

    if [[ -z $subcommand ]]; then

	declare completeFiles filenameSoFar
	case $precedingWord in
	    -f|--file|--rules-file)
		completeFiles=1
		filenameSoFar=$wordToComplete
		;;
	    =)
		completeFiles=1
		filenameSoFar=$wordToComplete
		;;
	esac

	if [[ -n $completeFiles ]]; then
	    #COMP_WORDBREAKS='= '
	    declare -a files
	    # This does not work because assignment to 'files' in the "pipe
	    # subshell" has no effect!
	    #compgen -df | grep "^$filenameSoFar" | readarray -t files
	    readarray -t files < <(compgen -df | grep "^$filenameSoFar")
	    COMPREPLY=( "${files[@]}" )

	else
	    COMPREPLY+=( $(grep -h "^$wordToComplete" -- "$HLEDGER_COMPLETION_TEMPDIR/commands.txt" "$HLEDGER_COMPLETION_TEMPDIR/generic-options.txt") )
	fi

    else

	# Almost all subcommands accept [QUERY]
	# -> always add accounts to completion list

	# TODO Get ledger file from -f --file arguments from COMP_WORDS and pass it to
	# the 'hledger accounts' call. Note that --rules-file - if present - must also
	# be passed!

	declare -a accounts
	readarray -t accounts < <(hledger accounts --flat | grep "^$wordToComplete")
	COMPREPLY+=( "${accounts[@]}" )
	# Special characters (e.g. '-', ':') are allowed in account names.
	# Account names with spaces must be still be quoted (e.g. '"Expens')
	# for completion. Setting COMP_WORDBREAKS='' would not help here!
	COMP_WORDBREAKS=' '

    fi

}

# Register completion function for hledger:
complete -F hledgerCompletionFunction hledger

# Include lists of commands and options generated by the Makefile using the
# m4 macro processor.
# Included files must have exactly one newline at EOF to prevent weired errors.

cat <<TEXT > "$HLEDGER_COMPLETION_TEMPDIR/commands.txt"
include(`commands.txt')dnl
TEXT

cat <<TEXT > "$HLEDGER_COMPLETION_TEMPDIR/generic-options.txt"
include(`generic-options.txt')dnl
TEXT

include(`foreach2.m4')

foreach(`cmd', (include(`commands-list.txt')), `
cat <<TEXT > "$HLEDGER_COMPLETION_TEMPDIR/options-cmd.txt"
include(options-cmd.txt)dnl
TEXT
')