#!/usr/bin/env bash
open=0

# tmux requires unrecognized OSC sequences to be wrapped with DCS tmux;
# <sequence> ST, and for all ESCs in <sequence> to be replaced with ESC ESC. It
# only accepts ESC backslash for ST.
function print_osc() {
    if [[ $TERM == screen* || $TERM == tmux* ]] ; then
        printf "\033Ptmux;\033\033]"
    else
        printf "\033]"
    fi
}

# More of the tmux workaround described above.
function print_st() {
    if [[ $TERM == screen* || $TERM == tmux* ]] ; then
        printf "\a\033\\"
    else
        printf "\a"
    fi
}

# set_color key rgb
function set_color() {
    print_osc
    printf '1337;SetColors=%s=%s' "$1" "$2"
    print_st
}

function error() {
    echo "ERROR: $*" 1>&2
}

function show_help() {
    if [ $open = 1 ]; then
      print_st
    fi
    echo "Usage"
    echo ""
    echo "1) To set a specific color to an RGB value:"
    echo "  it2setcolor name color [name color...]" 1>& 2
    echo "For example:"
    echo "  it2setcolor fg fff"
    echo ""
    echo "name is one of:"
    echo "  fg bg bold link selbg selfg curbg curfg underline tab"
    echo "  black red green yellow blue magenta cyan white"
    echo "  br_black br_red br_green br_yellow br_blue br_magenta br_cyan br_white"
    echo ""
    echo "color is of the format:"
    echo "  RGB        (three hex digits, like fff)"
    echo "  RRGGBB     (six hex digits, like f0f0f0)"
    echo "  cs:RGB     (cs is a color space name)"
    echo "  cs:RRGGBB  (cs is a color space name)"
    echo ""
    echo "  The color space names accepted in the color are:"
    echo "    srgb       (sRGB, the default if none is specified)"
    echo "    rgb        (Apple's old device-independent colorspace)"
    echo "    p3         (Apple's fancy large-gamut colorspace)"
    echo ""
    echo "2) To switch to a named color preset:"
    echo "  it2setcolor preset name"
    echo "For example:"
    echo "  it2setcolor preset 'Light Background'"
    echo ""
    echo "3) To reset the current tab's color to the system default:"
    echo "  it2setcolor tab default"
}

# Show help if no arguments and no stdin.
if [ $# -eq 0 ]; then
    show_help
    exit
fi

# Look for command line flags.
while [ $# -gt 0 ]; do
    case "$1" in
    -h|--h|--help)
        show_help
        exit
        ;;
    -*)
        error "Unknown option flag: $1"
        show_help
        exit 1
      ;;
    *)
	if [ $# -lt 2 ]; then
          show_help
          exit
        fi
        if [ $open = 0 ]; then
          open=1
          print_osc
          printf '1337;SetColors='
        else
          printf ","
        fi
        # name is not checked for validity because we'd like this to work with future colors, too.
        printf "%s=%s" "$1" "$2"
        shift
        ;;
    esac
    shift
done

if [ $open = 1 ]; then
  print_st
else
  show_help
fi

exit 0