#!/bin/bash source-this-script
[ "$BASH_VERSION" ] || return

_todo()
{
    local cur prev opts
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"

    local -r OPTS="-@ -@@ -+ -++ -d -f -h -p -P -PP -a -n -t -v -vv -V -x"
    local -r COMMANDS="\
        add a addto addm append app archive command del  \
        rm depri dp do help list ls listall lsa listcon  \
        lsc listfile lf listpri lsp listproj lsprj move \
        mv prepend prep pri p replace report shorthelp"

    # Add custom commands from add-ons, if installed.
    local allCommands="$COMMANDS $('ls' ${TODO_ACTIONS_DIR:-$HOME/.todo.actions.d}/ 2>/dev/null)"

    local completions
    if [ $COMP_CWORD -eq 1 ]; then
        completions="$allCommands $OPTS"
    else
        case "$prev" in
            command)
                completions=$COMMANDS;;
            -*) completions="$allCommands $OPTS";;
            *)  case "$cur" in
                    +*) completions=$(TODOTXT_VERBOSE=0 todo.sh command listproj);;
                    @*) completions=$(TODOTXT_VERBOSE=0 todo.sh command listcon);;
                    *)  if [[ "$cur" =~ ^[0-9]+$ ]]; then
                            local item=$(TODOTXT_VERBOSE=0 todo.sh -@ -+ -p -x command ls "^ *${cur} " | head -n 1)

                            # Remove the (padded) task number; we prepend the
                            # user-provided $cur.
                            item=${item#* }

                            # Remove the timestamp prepended by the -t option;
                            # there's no todo.txt option for that yet.
                            item=${item#[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] }

                            # Append task text as a shell comment. This
                            # completion can be a safety check before a
                            # destructive todo.txt operation.
                            [ "$item" ] && COMPREPLY[0]="$cur # $item"
                            return 0
                        else
                            return 0
                        fi
                        ;;
                esac
                ;;
        esac
    fi

    COMPREPLY=( $( compgen -W "$completions" -- $cur ))
    return 0
}
complete -F _todo todo.sh
# If you define an alias (e.g. "t") to todo.sh, you need to explicitly enable
# completion for it, too:
#complete -F _todo t