bash

#!/usr/bin/env bash

__fastfetch_complete_help()
{
    local __ff_helps=(
        "color"
        "format"
        "load-config"
        "os-format"
        "host-format"
        "kernel-format"
        "packages-format"
        "shell-format"
        "resolution-format"
        "de-format"
        "wm-format"
        "theme-format"
        "icons-format"
        "font-format"
        "terminal-format"
        "terminal-font-format"
        "cpu-format"
        "gpu-format"
        "memory-format"
        "disk-format"
        "battery-format"
        "locale-format"
    )
    COMPREPLY=($(compgen -W "${__ff_helps[*]}" -- "$CURRENT_WORD"))
}

__fastfetch_complete_bool()
{
    COMPREPLY=($(compgen -W "true false" -- "$CURRENT_WORD"))
}

__fastfetch_complete_string()
{
    if [[ $CURRENT_WORD != "" ]]; then
        COMPREPLY=("$CURRENT_WORD")
    fi
}

__fastfetch_complete_path()
{
    COMPREPLY=($(compgen -A file -- "$CURRENT_WORD"))
}

__fastfetch_complete_logo()
{
    COMPREPLY=($(compgen -W "$(fastfetch --list-logos)" -- "$CURRENT_WORD"))
}

__fastfetch_complete_option()
{
    local FF_OPTIONS_ALL=(
        "${FF_OPTIONS_BOOL[@]}"
        "${FF_OPTIONS_STRING[@]}"
        "${FF_OPTIONS_PATH[@]}"
        "${FF_OPTIONS_LOGO[@]}"
    )

    if [[ $WORD_COUND -lt 3 ]]; then
        FF_OPTIONS_ALL+=(
            "${FF_OPTIONS_SINGLE[@]}"
            "${FF_OPTIONS_HELP[@]}"
        )
    fi

    for ff_word in ${COMP_WORDS[@]}; do
        if [[ $ff_word == $CURRENT_WORD ]]; then
            break
        fi

        FF_OPTIONS_ALL=("${FF_OPTIONS_ALL[@]/$ff_word}")
    done

    COMPREPLY=($(compgen -W "${FF_OPTIONS_ALL[*]}" -- "$CURRENT_WORD"))
}

__fastfetch_previous_matches()
{
    for ff_option in "$@"; do
        if [[ $ff_option == "$PREVIOUS_WORD" ]]; then
            return 0
        fi
    done
    return 1
}

__fastfetch_completion()
{
    local CURRENT_WORD="${COMP_WORDS[$COMP_CWORD]}"
    local PREVIOUS_WORD="${COMP_WORDS[$COMP_CWORD - 1]}"
    local WORD_COUND="${#COMP_WORDS[@]}"

    local FF_OPTIONS_SINGLE=(
        "-v"
        "--version"
        "--list-logos"
        "--print-logos"
        "--print-default-config"
        "--print-default-structure"
        "--print-available-modules"
        "--print-available-presets"
    )

    local FF_OPTIONS_HELP=(
        "-h"
        "--help"
    )

    local FF_OPTIONS_BOOL=(
        "-r"
        "--recache"
        "--nocache"
        "--show-errors"
        "--color-logo"
        "--print-remaining-logo"
        "--multithreading"
        "--allow-slow-operations"
        "--disable-linewrap"
        "--hide-cursor"
    )

    local FF_OPTIONS_STRING=(
        "-c"
        "--color"
        "--spacing"
        "-s"
        "--separator"
        "-x"
        "--offsetx"
        "--structure"
        "--set"
        "--os-format"
        "--os-key"
        "--host-format"
        "--host-key"
        "--kernel-format"
        "--kernel-key"
        "--uptime-format"
        "--uptime-key"
        "--packages-format"
        "--packages-key"
        "--shell-format"
        "--shell-key"
        "--resolution-format"
        "--resolution-key"
        "--de-format"
        "--de-key"
        "--wm-format"
        "--wm-key"
        "--wm-theme-format"
        "--wm-theme-key"
        "--theme-format"
        "--theme-key"
        "--icons-format"
        "--icons-key"
        "--font-format"
        "--font-key"
        "--cursor-format"
        "--cursor-key"
        "--terminal-format"
        "--terminal-key"
        "--terminal-font-format"
        "--terminal-font-key"
        "--cpu-format"
        "--cpu-key"
        "--gpu-format"
        "--gpu-key"
        "--memory-format"
        "--memory-key"
        "--disk-format"
        "--disk-key"
        "--battery-format"
        "--battery-key"
        "--locale-format"
        "--locale-key"
        "--disk-folders"
        "--disk-key"
    )

    local FF_OPTIONS_PATH=(
        "--lib-PCI"
        "--lib-X11"
        "--lib-Xrandr"
        "--lib-gio"
        "--lib-DConf"
        "--lib-wayland"
        "--lib-XFConf"
        "--lib-SQLite"
        "--battery-dir"
        "--load-config"
    )

    local FF_OPTIONS_LOGO=(
        "-l"
        "--logo"
    )

    if __fastfetch_previous_matches "${FF_OPTIONS_SINGLE[@]}"; then
        return
    elif [[ $WORD_COUND -gt 3 && ( ${COMP_WORDS[$COMP_CWORD - 2]} == "--help" || ${COMP_WORDS[$COMP_CWORD - 2]} == "-h" ) ]]; then
        return
    elif [[ $CURRENT_WORD == "-"* ]]; then
        __fastfetch_complete_option
    elif __fastfetch_previous_matches "${FF_OPTIONS_HELP[@]}"; then
        __fastfetch_complete_help
    elif __fastfetch_previous_matches "${FF_OPTIONS_BOOL[@]}"; then
        __fastfetch_complete_bool
    elif __fastfetch_previous_matches "${FF_OPTIONS_STRING[@]}"; then
        __fastfetch_complete_string
    elif __fastfetch_previous_matches "${FF_OPTIONS_PATH[@]}"; then
        __fastfetch_complete_path
    elif __fastfetch_previous_matches "${FF_OPTIONS_LOGO[@]}"; then
        __fastfetch_complete_logo
    else
        __fastfetch_complete_option
    fi
}

complete -F __fastfetch_completion fastfetch