[ -z "$BASH_VERSION" ] && return

__contains_word () {
        local w word=$1; shift
        for w in "$@"; do
                [[ $w = "$word" ]] && return
        done
}

_xdg-app() {
        local cur prev
        local cur=${COMP_WORDS[COMP_CWORD]}
        local prev=${COMP_WORDS[COMP_CWORD-1]}

        if [[ $cur == "=" ]] && [[ "$prev" = -* ]]; then
           cur=""
        elif [[ $prev == "=" ]]  && [[ "${COMP_WORDS[COMP_CWORD-2]}" = -* ]]; then
                prev=${COMP_WORDS[COMP_CWORD-2]}
        fi

        local i verb comps mode
        local remote name
        local dir cmd sdk loc

        local -A VERBS=(
                [ALL]='add-remote modify-remote delete-remote ls-remote list-remotes install-runtime update-runtime uninstall-runtime list-runtimes install-app update-app uninstall-app list-apps run override enter export-file build-init build build-finish build-export repo-update make-app-current dump-runtime'
                [MODE]='add-remote modify-remote delete-remote ls-remote list-remotes install-runtime update-runtime uninstall-runtime list-runtimes install-app update-app uninstall-app list-apps make-app-current dump-runtime'
                [PERMS]='run override build build-finish'
                [UNINSTALL]='uninstall-runtime uninstall-app'
                [ARCH]='build-init install-runtime install-app run uninstall-runtime uninstall-app update-runtime update-app make-app-current'
                [USER_AND_SYSTEM]='run list-remotes list-apps list-runtimes'
        )

        local -A OPTS=(
                [GENERAL]='--help --verbose --version'
                [MODE]='--user --system'
                [ARCH]='--arch='
                [PERMS]='--share= --unshare= --socket= --nosocket= --device= --nodevice= --filesystem= --env= --own-name= --talk-name= --persist='
                [ADD_REMOTE]='--no-gpg-verify --if-not-exists --title= --gpg-import= --gpg-key='
                [MODIFY_REMOTE]='--no-gpg-verify --gpg-verify --title= --gpg-import= --gpg-key='
                [LIST_REMOTES]='--show-details'
                [LS_REMOTE]='--show-details --runtimes --apps --updates'
                [UNINSTALL]='--keep-ref --force-remove'
                [RUN]='--command= --branch= --devel --runtime='
                [BUILD_INIT]='--arch= --var='
                [BUILD]='--runtime'
                [BUILD_FINISH]='--command= --allow'
                [BUILD_EXPORT]='--subject= --body='
                [EXPORT_FILE]='--app= --allow-write --allow-delete --allow-grant-permission --unique --transient'

                [ARG]='--arch --command --branch --var --share --unshare  --socket --nosocket --device --nodevice --subject --body --title --runtime --filesystem'
        )

        for ((i=0; i < COMP_CWORD; i++)); do
                if [[ "${COMP_WORDS[i]}" = -* ]]; then
                        continue
                fi
                if  __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                        continue
                fi
                if __contains_word "${COMP_WORDS[i]}" ${VERBS[*]} &&
                   test -z $first_verb; then
                        first_verb=${COMP_WORDS[i]}
                fi
        done

        if __contains_word "--user" ${COMP_WORDS[*]}; then
            if __contains_word "--system" ${COMP_WORDS[*]}; then
                mode="--user --system"
            else
                mode="--user"
            fi
        else
            if __contains_word "--system" ${COMP_WORDS[*]}; then
                mode=--system
            else
                if __contains_word "$first_verb" ${VERBS[USER_AND_SYSTEM]}; then
                    mode="--user --system"
                else
                    mode="--system"
                fi
            fi
        fi

        if __contains_word "$prev" ${OPTS[ARG]}; then
                case $prev in
                        --arch)
                                comps='x86_64 i686'
                                ;;
                        --command)
                                comps=$(compgen -A command)
                                ;;
                        --var|--runtime)
                                comps=$(xdg-app $mode list-runtimes)
                                ;;
                        --share|--noshare)
                                comps='network ipc'
                                ;;
                        --device|--nodevice)
                                comps='dri'
                                ;;
                        --socket|--nosocket)
                                comps='x11 wayland pulseaudio system-bus session-bus'
                                ;;
                        --branch|--subject|--body|--title)
                                comps=''
                                ;;
                        --filesystem)
                                comps='host home xdg-desktop xdg-documents xdg-download xdg-music xdg-pictures xdg-public-share xdg-templates xdg-videos'
                                ;;
                esac
                COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
                return 0
        fi

        for ((i=0; i < COMP_CWORD; i++)); do
                if [[ "${COMP_WORDS[i]}" = -* ]]; then
                        continue
                fi
                if  __contains_word "${COMP_WORDS[i-1]}" ${OPTS[ARG]}; then
                        continue
                fi
                if __contains_word "${COMP_WORDS[i]}" ${VERBS[*]} &&
                   test -z $verb; then
                        verb=${COMP_WORDS[i]}
                elif [[ $verb = install-* ]]; then
                        if [[ -z $remote ]]; then
                                remote=${COMP_WORDS[i]}
                        elif [[ -z $name ]]; then
                                name=${COMP_WORDS[i]}
                        fi
                elif [[ $verb =~ (update-*|uninstall-*|run) ]]; then
                        if [[ -z $name ]]; then
                                name=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = build-init ]]; then
                        if [[ -z $dir ]]; then
                                dir=${COMP_WORDS[i]}
                        elif [[ -z $sdk ]]; then
                                sdk=${COMP_WORDS[i]}
                        elif [[ -z $name ]]; then
                                name=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = build ]]; then
                        if [[ -z $dir ]]; then
                                dir=${COMP_WORDS[i]}
                        elif [[ -z $cmd ]]; then
                                cmd=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = build-finish ]]; then
                        if [[ -z $dir ]]; then
                                dir=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = build-export ]]; then
                        if [[ -z $loc ]]; then
                                loc=${COMP_WORDS[i]}
                        elif [[ -z $dir ]]; then
                                dir=${COMP_WORDS[i]}
                        elif [[ -z $name ]]; then
                                name=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = repo-update ]]; then
                        if [[ -z $loc ]]; then
                                loc=${COMP_WORDS[i]}
                        fi
                elif [[ $verb = export-file ]]; then
                        if [[ -z $file ]]; then
                                file=${COMP_WORDS[i]}
                        fi
                fi
        done

        if [[ -z $verb ]]; then
                comps="${VERBS[*]}"

        elif [[ "$cur" = -* ]]; then
                comps="${OPTS[GENERAL]}"
                if __contains_word "$verb" ${VERBS[MODE]}; then
                        comps="$comps ${OPTS[MODE]}"
                fi
                if __contains_word "$verb" ${VERBS[PERMS]}; then
                        comps="$comps ${OPTS[PERMS]}"
                fi
                if [ "$verb" = "list-remotes" ]; then
                        comps="$comps ${OPTS[LIST_REMOTES]}"
                fi
                if __contains_word "$verb" ${VERBS[ARCH]}; then
                        comps="$comps ${OPTS[ARCH]}"
                fi
                if __contains_word "$verb" ${VERBS[UNINSTALL]}; then
                        comps="$comps ${OPTS[UNINSTALL]}"
                fi
                if [ "$verb" = "run" ]; then
                        comps="$comps ${OPTS[RUN]}"
                fi
                if [ "$verb" = "export-file" ]; then
                        comps="$comps ${OPTS[EXPORT_FILE]}"
                fi
                if [ "$verb" = "ls-remote" ]; then
                        comps="$comps ${OPTS[LS_REMOTE]}"
                fi
                if [ "$verb" = "build-init" ]; then
                        comps="$comps ${OPTS[BUILD_INIT]}"
                fi
                if [ "$verb" = "build" ]; then
                        comps="$comps ${OPTS[BUILD]}"
                fi
                if [ "$verb" = "build-finish" ]; then
                        comps="$comps ${OPTS[BUILD_FINISH]}"
                fi
                if [ "$verb" = "build-export" ]; then
                        comps="$comps ${OPTS[BUILD_EXPORT]}"
                fi
                if [ "$verb" = "repo-update" ]; then
                        comps="$comps ${OPTS[REPO_UPDATE]}"
                fi
                if [ "$verb" = "add-remote" ]; then
                        comps="$comps ${OPTS[ADD_REMOTE]}"
                fi
                if [ "$verb" = "modify-remote" ]; then
                        comps="$comps ${OPTS[MODIFY_REMOTE]}"
                fi
        else
                case "$verb" in
                add-remote|modify-remote|delete-remote|ls-remote)
                        comps=$(xdg-app $mode list-remotes)
                ;;

                install-runtime)
                        if [[ -z $remote ]]; then
                                comps=$(xdg-app $mode list-remotes)
                        elif [[ -z $name ]]; then
                                comps=$(xdg-app $mode repo-contents $remote --runtimes)
                        else
                                comps='' # FIXME: branches
                        fi
                ;;

                list-remotes|list-runtimes|list-apps)
                        comps=''
                        ;;

                update-runtime|uninstall-runtime|dump-runtime)
                        if [[ -z $name ]]; then
                                comps=$(xdg-app $mode list-runtimes)
                        else
                                comps='' # FIXME: branches
                        fi
                ;;

                install-app)
                        if [[ -z $remote ]]; then
                                comps=$(xdg-app $mode list-remotes)
                        elif [[ -z $name ]]; then
                                comps=$(xdg-app $mode repo-contents $remote --apps)
                        else
                                comps='' # FIXME: branches
                        fi
                ;;

                update-app|uninstall-app)
                        if [[ -z $name ]]; then
                                comps=$(xdg-app $mode list-apps)
                        else
                                comps='' # FIXME: branches
                        fi
                        ;;

                run|override)
                        if [[ -z $name ]]; then
                                comps=$(xdg-app $mode list-apps)
                        fi
                        ;;


                build-init)
                        if [[ -z $dir ]]; then
                                comps=''
                                compopt -o dirnames
                        elif [[ -z $sdk ]]; then
                                comps="$(xdg-app list-runtimes) $(xdg-app --user list-runtimes)"
                        elif [[ -z $name ]]; then
                                comps="$(xdg-app list-runtimes) $(xdg-app --user list-runtimes)"
                        else
                                comps='' # FIXME: branches
                        fi
                        ;;

                build)
                        if [[ -z $dir ]]; then
                                comps=''
                                compopt -o dirnames
                        elif [[ -z $cmd ]]; then
                                comps=''
                                compopt -o bashdefault
                        fi
                        ;;

                build-finish)
                        if [[ -z $dir ]]; then
                                comps=''
                                compopt -o dirnames
                        fi
                        ;;

                build-export)
                        if [[ -z $loc ]]; then
                                comps=''
                                compopt -o dirnames
                        elif [[ -z $dir ]]; then
                                comps=''
                                compopt -o dirnames
                        fi
                        ;;

                repo-update)
                        if [[ -z $loc ]]; then
                                comps=''
                                compopt -o dirnames
                        fi
                        ;;

                export-file)
                        if [[ -z $file ]]; then
                                comps=''
                                compopt -o dirnames
                        fi
                        ;;

                esac
        fi

        COMPREPLY=( $(compgen -W '$comps' -- "$cur") )
        [[ $COMPREPLY == *= ]] && compopt -o nospace
        return 0
}

complete -F _xdg-app xdg-app
