nvim/lua/catppuccin/utils/util.lua

local hsluv = require("catppuccin.utils.hsluv")

local g = vim.g
local o = vim.o

local util = {}

util.bg = "#000000"
util.fg = "#ffffff"
util.day_brightness = 0.3

---@param hex_str string hexadecimal value of a color
local hex_to_rgb = function(hex_str)
	local hex = "[abcdef0-9][abcdef0-9]"
	local pat = "^#(" .. hex .. ")(" .. hex .. ")(" .. hex .. ")$"
	hex_str = string.lower(hex_str)

	assert(string.find(hex_str, pat) ~= nil, "hex_to_rgb: invalid hex_str: " .. tostring(hex_str))

	local red, green, blue = string.match(hex_str, pat)
	return { tonumber(red, 16), tonumber(green, 16), tonumber(blue, 16) }
end

---@param fg string foreground color
---@param bg string background color
---@param alpha number number between 0 and 1. 0 results in bg, 1 results in fg
function util.blend(fg, bg, alpha)
	bg = hex_to_rgb(bg)
	fg = hex_to_rgb(fg)

	local blendChannel = function(i)
		local ret = (alpha * fg[i] + ((1 - alpha) * bg[i]))
		return math.floor(math.min(math.max(0, ret), 255) + 0.5)
	end

	return string.format("#%02X%02X%02X", blendChannel(1), blendChannel(2), blendChannel(3))
end

function util.darken(hex, amount, bg)
	return util.blend(hex, bg or util.bg, math.abs(amount))
end

function util.lighten(hex, amount, fg)
	return util.blend(hex, fg or util.fg, math.abs(amount))
end

function util.brighten(color, percentage)
	local hsl = hsluv.hex_to_hsluv(color)
	local larpSpace = 100 - hsl[3]
	if percentage < 0 then
		larpSpace = hsl[3]
	end
	hsl[3] = hsl[3] + larpSpace * percentage
	return hsluv.hsluv_to_hex(hsl)
end

function util.invertColor(color)
	if color ~= "NONE" then
		local hsl = hsluv.hex_to_hsluv(color)
		hsl[3] = 100 - hsl[3]
		if hsl[3] < 40 then
			hsl[3] = hsl[3] + (100 - hsl[3]) * util.day_brightness
		end
		return hsluv.hsluv_to_hex(hsl)
	end
	return color
end

function util.string_to_color(colors, value, default)
	if not value or value == "" then
		return default
	end

	-- If the value is a hex color code then return it
	local hex = "[abcdef0-9][abcdef0-9]"
	local pat = "^#" .. hex .. hex .. hex .. "$"
	if string.match(value, pat) then
		return value
	end

	local acceptable_colors = { "black", "red", "green", "blue", "magenta", "cyan", "text", "orange", "pink" }
	for _, ac in ipairs(acceptable_colors) do
		if string.match(value, ac) then
			return colors[value]
		end
	end

	-- Did not match anything to return default
	return default
end

function util.highlight(group, color)
	-- Doc: :h highlight-gui
	local style = color.style and "gui=" .. color.style or "gui=NONE"
	local fg = color.fg and "guifg=" .. color.fg or "guifg=NONE"
	local bg = color.bg and "guibg=" .. color.bg or "guibg=NONE"
	local sp = color.sp and "guisp=" .. color.sp or ""
	local blend = color.blend and "blend=" .. color.blend or ""
	local hl = "highlight " .. group .. " " .. style .. " " .. fg .. " " .. bg .. " " .. sp .. " " .. blend

	vim.cmd(hl)
	if color.link then
		vim.cmd("highlight! link " .. group .. " " .. color.link)
	end
end

function util.syntax(tbl)
	for group, colors in pairs(tbl) do
		util.highlight(group, colors)
	end
end

function util.properties(tbl)
	for property, value in pairs(tbl) do
		vim.o[property] = value
	end
end

function util.terminal(cp)
	g.terminal_color_0 = cp.overlay0
	g.terminal_color_8 = cp.overlay1

	g.terminal_color_1 = cp.red
	g.terminal_color_9 = cp.red

	g.terminal_color_2 = cp.green
	g.terminal_color_10 = cp.green

	g.terminal_color_3 = cp.yellow
	g.terminal_color_11 = cp.yellow

	g.terminal_color_4 = cp.blue
	g.terminal_color_12 = cp.blue

	g.terminal_color_5 = cp.pink
	g.terminal_color_13 = cp.pink

	g.terminal_color_6 = cp.sky
	g.terminal_color_14 = cp.sky

	g.terminal_color_7 = cp.text
	g.terminal_color_15 = cp.text
end

function util.load(theme)
	vim.cmd("hi clear")
	if vim.fn.exists("syntax_on") then
		vim.cmd("syntax reset")
	end

	g.colors_name = "catppuccin"

	util.properties(theme.properties)
	util.syntax(theme.base)
	util.syntax(theme.integrations)

	if require("catppuccin.config").options["term_colors"] then
		util.terminal(theme.terminal)
	end
end

return util