nickcolors.lua

-- generates a string to be used as weechat.color.chat_nick_colors value
-- when using 256 color terminals; includes all hues, skips #000000 (16)
--
-- arguments: <min_saturation>:<max_saturation> <min_value>:<max_value>
-- as in HSV, the 4 values are between 0 and 1

-- enable if you want grayscale (232-255) to be included
local include_gray = false
-- base weechat nick colors (maps to 0-15)
local base_colors = "cyan,magenta,green,brown,lightblue,default,"
                    .. "lightcyan,lightmagenta,lightgreen,blue"

local usage = function()
    print(
        "usage: "
        .. (arg[0] or "nickcolors.lua")
        .. " min_saturation:max_saturation min_value:max_value"
    )
    os.exit(1)
end

local get_sv = function(r, g, b)
    local minv = math.min(r, math.min(g, b))
    local maxv = math.max(r, math.max(g, b))
    return {
        (maxv - minv) / maxv, maxv / 0xFF
    }
end

local generate_colors = function()
    local r = {}
    local steps = { 0x00, 0x5F, 0x87, 0xAF, 0xD7, 0xFF }
    for i = 1, #steps do
        for j = 1, #steps do
            for k = 1, #steps do
                r[#r + 1] = get_sv(steps[i], steps[j], steps[k])
            end
        end
    end
    if include_gray then
        for i = 0x08, 0xEE, 0xA do
            r[#r + 1] = { 0, i / 0xFF }
        end
    end
    return r
end

local colors = generate_colors()
local sat, val = arg[1], arg[2]

if not sat or not val then
    usage()
end

local min_sat, max_sat = sat:match("(.+):(.+)")
if not min_sat then
    usage()
end

local min_val, max_val = val:match("(.+):(.+)")
if not min_val then
    usage()
end

min_sat, max_sat = tonumber(min_sat), tonumber(max_sat)
min_val, max_val = tonumber(min_val), tonumber(max_val)

if not (min_sat and max_sat and min_val and max_val) then
    usage()
end

local out_color = function(n)
    os.execute("tput setab " .. n .. "; printf \"," .. n .. "\"")
end

os.execute("printf \"" .. base_colors .. "\"")
-- skip black (color 16), hence 2
for i = 2, #colors do
    local s, v = unpack(colors[i])
    if s >= min_sat and s <= max_sat and v >= min_val and v <= max_val then
        out_color(i + 15)
    end
end
os.execute("echo")