_comp_cmd_yt-dlp() {
    # Not using "$2" and "$3" to partially workaround YouTube keyword completions.
    local have_bashcomp=0 cur="${COMP_WORDS[COMP_CWORD]}" prev="${COMP_WORDS[COMP_CWORD - 1]}"

    # Long options with equals and YouTube keyword completions
    # do not work without bash-completion.
    if declare -F _comp_initialize &> /dev/null; then
        have_bashcomp=1
        # Unused variables assigned by _comp_initialize.
        # shellcheck disable=SC2034
        local words cword comp_args was_split
        # ':' must be excluded from COMP_WORDBREAKS to handle :yt* keywords
        _comp_initialize -n : -s -- "$@" || return
    fi

    local filedir_action
    case "$prev" in
        YT_DLP_FILE_OPTS_CASE )
            filedir_action='file'
            ;;

        YT_DLP_DIR_OPTS_CASE )
            filedir_action='directory'
            ;;

        * )
            ;;
    esac

    local compreply_lines
    if [[ "$filedir_action" ]]; then
        if (( "$have_bashcomp" )); then
            if [[ "$filedir_action" = directory ]]; then
                _comp_compgen_filedir -d
            else
                _comp_compgen_filedir
            fi
        else
            # macOS Bash does not have compopt.
            if type compopt &>/dev/null; then
                compopt -o filenames
            fi
            compreply_lines="$(compgen -A "$filedir_action" -- "$cur")"
        fi
    elif [[ "$cur" = :* ]]; then
        # Adding keywords one by one since macOS Bash
        # can't initialise a local array from brace expansions.
        local k keywords
        for k in :ytnotif{,ication}{,s} \
                 :ytfav{,o{,u}rite}{,s} \
                 :ytwatchlater \
                 :ytrec{,ommended} \
                 :ytsub{,scription}{,s} \
                 :ythis{,tory}; do
            keywords+=("$k")
        done
        if (( "$have_bashcomp" )); then
            _comp_compgen -- -W "${keywords[*]}"
            _comp_ltrim_colon_completions "$cur"
        else
            compreply_lines="$(compgen -W "${keywords[*]}" -- "$cur")"
            compreply_lines="${compreply_lines//:/}"
        fi
    else
        local -r opts=( YT_DLP_OPTS_ARRAY )
        if type compopt &> /dev/null; then
            compopt -o nosort
        fi
        if (( "$have_bashcomp" )); then
            _comp_compgen -- -W "${opts[*]}"
        else
            compreply_lines="$(compgen -W "${opts[*]}" -- "$cur")"
        fi
    fi

    if [[ "$have_bashcomp" != 1 && "$compreply_lines" ]]; then
        COMPREPLY=()
        local line
        while IFS='' read -r line; do
            COMPREPLY+=("$line")
        done <<< "$compreply_lines"
    fi
} \
    && complete -F _comp_cmd_yt-dlp yt-dlp