add calculator plugin (#104)

* feat: add calculator plugin

* add MIT license

* fix(calculator): typo

* fix(calculator): wrong PANEL_ID

* remove LICENSE

calculator/bar.luau

@@ -0,0 +1,94 @@
+--!nonstrict
+
+local PANEL_ID = "yuuto/calculator:panel"
+
+local result = "0"
+local expression = ""
+local hasError = false
+
+local function maxLength()
+	local value = noctalia.getConfig("max_bar_length")
+	if type(value) ~= "number" then
+		return 9
+	end
+	return math.clamp(math.floor(value), 3, 20)
+end
+
+local function compact(text)
+	local limit = maxLength()
+	if #text <= limit then
+		return text
+	end
+	return text:sub(1, math.max(1, limit - 1)) .. "~"
+end
+
+local function badge()
+	if noctalia.getConfig("show_bar_value") == false then
+		return ""
+	end
+	if hasError then
+		return noctalia.tr("state.error")
+	end
+	if result == "" or result == "0" then
+		return ""
+	end
+	return compact(result)
+end
+
+local function render()
+	local container = barWidget.isVertical() and ui.column or ui.row
+	local text = badge()
+	local color = hasError and "error" or "on_surface"
+
+	barWidget.setTooltip(expression ~= "" and expression or noctalia.tr("bar.tooltip"))
+
+	local children = {
+		ui.glyph({ name = "calculator", color = color }),
+	}
+
+	if text ~= "" and not barWidget.isVertical() then
+		table.insert(children, ui.label({ text = text, fontWeight = "bold", color = color }))
+	end
+
+	barWidget.render(container({ gap = 6, align = "center" }, children))
+end
+
+function update()
+	render()
+end
+
+noctalia.state.watch("calc.result", function(value)
+	if type(value) == "string" then
+		result = value
+		render()
+	end
+end)
+
+noctalia.state.watch("calc.expression", function(value)
+	if type(value) == "string" then
+		expression = value
+		render()
+	end
+end)
+
+noctalia.state.watch("calc.error", function(value)
+	hasError = value == true
+	render()
+end)
+
+function onClick()
+	noctalia.togglePanel(PANEL_ID)
+end
+
+function onRightClick()
+	noctalia.state.set("calc.result", "0")
+	noctalia.state.set("calc.expression", "")
+	noctalia.state.set("calc.last_expression", "")
+	noctalia.state.set("calc.error", false)
+end
+
+function onIpc(event, _payload)
+	if event == "toggle" then
+		noctalia.togglePanel(PANEL_ID)
+	end
+end