ps1 bash module

ps1.sh

#!/usr/bin/env bash
#
# Copyright (C) 2024 Luis López <[email protected]>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
# USA.
#

# Bash 'strict-mode'
# set -o errexit
# set -o errtrace
# set -o nounset
# set -o pipefail

# export IFS=$'\n'

# Basic usage:
# ```
# $ source ps1.sh
# $ export PS1=$(ps1_get_prompt)
# ```

function ps1_get_prompt() {
    local color="${1:-yes}"

    if [[ "$color" = yes ]]; then
        # Wrap color codes inside \[ and \]
        # https://superuser.com/questions/376790/how-can-i-fix-my-custom-ps1-to-wrap-a-long-command-over-multiple-lines-instead-o

        local PS1_ICON="${PS1_ICON:-$(ps1_get_icon "$(hostname -s)")}"
        local PS1_COLOR='\['"${PS1_COLOR:-$(ps1_get_color "$(hostname -s)")}"'\]'

        local PATH_PORTION_COLOR='\[\033[01;34m\]'
        local COLOR_RESET='\[\033[00m\]'

        local PS1_USER_HOST_PORTION="${PS1_COLOR}"'\u@\h'"${COLOR_RESET}"
        local PS1_PATH_PORTION="${PATH_PORTION_COLOR}"'\w'"${COLOR_RESET}"

        echo "${PS1_ICON} ${PS1_USER_HOST_PORTION}:${PS1_PATH_PORTION}\$ "
    else
        printf '\u@\h:\w\$ '
    fi
}

function ps1_get_color() {
    local hostname="${1:-$(hostname -s)}"
    hostname="${hostname/.*/}"

    if [[ "$(uname -s)" == "Darwin" ]]; then
        hashfunc=$(type -p md5)
    else
        hashfunc=$(type -p md5sum)
    fi

    local hash
    hash=$("$hashfunc" <<<"$hostname")
    hash=${hash/ */}

    if [[ $TERM == *256* ]]; then
        _ps1_hash_to_rgb_color "$hash"
    else
        _ps1_hash_to_15bit_color "$hash"
    fi
}

function ps1_get_icon() {
    local hostname="${1:-$(hostname -s)}"
    hostname="${hostname/.*/}"

    local -a icons=(😸 🐶 ✨ 🔥 💀 ⭐ 🐵 🦄 🦁 🐴 🫎 🦊 🐮 🐷 🐗 🐻 🦥 🦦 🚀)
    local hashfunc hash

    if [[ "$(uname -s)" == "Darwin" ]]; then
        hashfunc=$(type -p md5)
    else
        hashfunc=$(type -p md5sum)
    fi
    hash="$("$hashfunc" <<<"$hostname")"
    hash="${hash/ */}"

    sum=0
    for letter in $(echo "$hash" | sed -e 's,\.,,g' -e 's,\(.\),\1 ,g'); do
        sum=$((sum + $((16#$letter))))
    done

    len=$((${#icons[@]} + 1))
    idx=sum%$len

    echo "${icons[$idx]}"
}

function _ps1_hash_to_15bit_color() {
    local hash="$1"
    local bright=${hash:0:12}
    local color=${hash:20:12}

    printf '\033[%d;%dm' \
        $(($(printf '%d' "0x${bright}") % 3)) \
        $(($(($(printf '%d' "0x${color}") % 5)) + 32))
}

function _ps1_hash_to_rgb_color() {
    local hash="$1"
    local R=${hash:0:8}
    local G=${hash:12:8}
    local B=${hash:24:8}

    printf '\033[38;2;%d;%d;%dm' \
        $(($(printf '%d' "0x${R}") % 256)) \
        $(($(printf '%d' "0x${G}") % 256)) \
        $(($(printf '%d' "0x${B}") % 256))
}