#!/bin/sh

fg_16() {
  case $1 in
    0|1|2|3|4|5|6|7)        printf '\e[3%sm' "$1";;
    8|9|10|11|12|13|14|15)  printf '\e[9%sm' "$(($1 - 8))";;
    *)                      ;;
  esac
}

bg_16() {
  case $1 in
    0|1|2|3|4|5|6|7)        printf '\e[4%sm'  "$1";;
    8|9|10|11|12|13|14|15)  printf '\e[10%sm' "$(($1 - 8))";;
    *)                      ;;
  esac
}

fg_256() { printf '\e[38;5;%sm' "$1"; }
bg_256() { printf '\e[48;5;%sm' "$1"; }

fg_rgb() { printf '\e[38;2;%s;%s;%sm' "$1" "$2" "$3"; }
bg_rgb() { printf '\e[48;2;%s;%s;%sm' "$1" "$2" "$3"; }

rgb_from_hex() { printf '%d %d %d' "0x${1:1:2}" "0x${1:3:2}" "0x${1:5:2}"; }

fg_hex() { fg_rgb $(rgb_from_hex "$1"); }
bg_hex() { bg_rgb $(rgb_from_hex "$1"); }

reset()     { printf '\e[0m'; }
fg_reset()  { printf '\e[39m'; }
bg_reset()  { printf '\e[49m'; }

indent()  { printf '      '; }
newline() { printf '%b\n' '\e[0m'; }

indexed_16() {
  echo "16 indexed colors:"
  for i in 0 1; do
    indent
    for j in $(seq 0 7); do
      bg_16 $((8*i + j)); printf '%4s'
    done
    newline
  done
}

indexed_256() {
  echo "256 indexed colors:"

  # 16 standard colors
  for i in 0 1; do
    indent
    for j in $(seq 0 7); do
      bg_256 $((8*i + j)); printf '%9s'
    done
    newline
  done

  # 216 colors
  for i in 0 18; do
    for j in $(seq 0 5); do
      indent
      for k in $(seq $i $(( i + 17 ))); do
        bg_256 $((16 + 36*j + k)); printf '%4s'
      done
      newline
    done
  done

  # 24 grayscale colors
  for i in 0 1; do
    indent
    for j in $(seq 0 11); do
      bg_256 $((232 + 12*i + j)); printf '%6s'
    done
    newline
  done
}

hex_theme() {
  for i in 0 1; do
    indent
    for j in $(seq 0 7); do
      [ $# -gt 0 ] && { bg_hex "$1"; printf '%4s'; shift; }
    done
    newline
  done
}

gruvbox_dark() {
  echo "RGB Gruvbox Dark:"
  hex_theme \
    '#282828' '#cc241d' '#98971a' '#d79921' '#458588' '#b16286' '#689d6a' '#a89984' \
    '#928374' '#fb4934' '#b8bb26' '#fabd2f' '#84a598' '#d3869b' '#8ec07c' '#ebdbb2'
}

gruvbox_light() {
  echo "RGB Gruvbox Light:"
  hex_theme \
    '#fbf1c7' '#cc241d' '#98971a' '#d79921' '#458588' '#b16286' '#689d6a' '#7c6f64' \
    '#928374' '#9d0006' '#79740e' '#b57614' '#076678' '#8f3f71' '#427b58' '#3c3836'
}

solarized() {
  echo "RGB Solarized:"
  hex_theme \
    '#073642' '#dc322f' '#859900' '#b58900' '#268bd2' '#d33682' '#2aa198' '#eee8d5' \
    '#002b36' '#cb4b16' '#586e75' '#657b83' '#839496' '#6c71c4' '#93a1a1' '#fdf6e3'
}

nord() {
  echo "Nord:"
  hex_theme \
    '#2e3440' '#bf616a' '#a3be8c' '#ebcb8b' '#5e81ac' '#b48ead' '#88c0d0' '#e5e9f0' \
    '#434c5e' '#d08770' '#3b4252' '#4c566a' '#81a1c1' '#d8dee9' '#8fbcbb' '#eceff4'
}

main() {
  indexed_16
  echo
  indexed_256
  echo
  gruvbox_dark
  echo
  gruvbox_light
  echo
  solarized
  echo
  nord
}

main