- Added comprehensive state management with conditional states, priority-based resolution, and property overrides

- Added responsive.lua with fluent builder API (:when()/:apply()/:otherwise()) for creating responsive layouts that react to parent size or custom conditions
- All elements now use getResolved() to check active states, enabling multiple responsive rules to coexist

src/plugins/responsive.lua

@@ -0,0 +1,157 @@
+local errorManager = require("errorManager")
+---@configDefault false
+
+--- This is the responsive plugin. It provides a fluent builder API for creating responsive states with an intuitive when/apply/otherwise syntax.
+---@class BaseElement
+local BaseElement = {}
+
+--- Creates a responsive builder for defining responsive states
+--- @shortDescription Creates a responsive state builder
+--- @param self BaseElement The element to create the builder for
+--- @return ResponsiveBuilder builder The responsive builder instance
+function BaseElement:responsive()
+    local builder = {
+        _element = self,
+        _rules = {},
+        _currentStateName = nil,
+        _currentCondition = nil,
+        _stateCounter = 0
+    }
+
+    --- Defines a condition for responsive behavior
+    --- @param condition string|function The condition as string expression or function
+    --- @return ResponsiveBuilder self For method chaining
+    function builder:when(condition)
+        if self._currentCondition then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("Previous when() must be followed by apply() before starting a new when()")
+        end
+
+        self._stateCounter = self._stateCounter + 1
+        self._currentStateName = "__responsive_" .. self._stateCounter
+        self._currentCondition = condition
+
+        return self
+    end
+
+    --- Applies properties when the current condition is met
+    --- @param properties table The properties to apply {property = value, ...}
+    --- @return ResponsiveBuilder self For method chaining
+    function builder:apply(properties)
+        if not self._currentCondition then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("apply() must follow a when() call")
+        end
+
+        if type(properties) ~= "table" then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("apply() requires a table of properties")
+        end
+
+        self._element:registerResponsiveState(
+            self._currentStateName,
+            self._currentCondition,
+            100
+        )
+
+        for propName, value in pairs(properties) do
+            local capitalizedName = propName:sub(1,1):upper() .. propName:sub(2)
+            local setter = "set" .. capitalizedName .. "State"
+
+            if self._element[setter] then
+                self._element[setter](self._element, self._currentStateName, value)
+            else
+                errorManager.header = "Responsive Builder Error"
+                errorManager.error("Unknown property: " .. propName)
+            end
+        end
+
+        table.insert(self._rules, {
+            stateName = self._currentStateName,
+            condition = self._currentCondition,
+            properties = properties
+        })
+
+        self._currentCondition = nil
+        self._currentStateName = nil
+
+        return self
+    end
+
+    --- Defines a fallback condition (else case)
+    --- @param properties table The properties to apply when no other conditions match
+    --- @return ResponsiveBuilder self For method chaining
+    function builder:otherwise(properties)
+        if self._currentCondition then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("otherwise() cannot be used after when() without apply()")
+        end
+
+        if type(properties) ~= "table" then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("otherwise() requires a table of properties")
+        end
+
+        self._stateCounter = self._stateCounter + 1
+        local otherwiseStateName = "__responsive_otherwise_" .. self._stateCounter
+
+        local otherRules = {}
+        for _, rule in ipairs(self._rules) do
+            table.insert(otherRules, rule.condition)
+        end
+
+        local otherwiseCondition
+        if type(otherRules[1]) == "string" then
+            local negatedExprs = {}
+            for _, cond in ipairs(otherRules) do
+                table.insert(negatedExprs, "not (" .. cond .. ")")
+            end
+            otherwiseCondition = table.concat(negatedExprs, " and ")
+        else
+            otherwiseCondition = function(elem)
+                for _, cond in ipairs(otherRules) do
+                    if cond(elem) then
+                        return false
+                    end
+                end
+                return true
+            end
+        end
+
+        self._element:registerResponsiveState(
+            otherwiseStateName,
+            otherwiseCondition,
+            50
+        )
+
+        for propName, value in pairs(properties) do
+            local capitalizedName = propName:sub(1,1):upper() .. propName:sub(2)
+            local setter = "set" .. capitalizedName .. "State"
+
+            if self._element[setter] then
+                self._element[setter](self._element, otherwiseStateName, value)
+            else
+                errorManager.header = "Responsive Builder Error"
+                errorManager.error("Unknown property: " .. propName)
+            end
+        end
+
+        return self
+    end
+
+    --- Completes the builder (optional, for clarity)
+    --- @return BaseElement element The original element
+    function builder:done()
+        if self._currentCondition then
+            errorManager.header = "Responsive Builder Error"
+            errorManager.error("Unfinished when() without apply()")
+        end
+        return self._element
+    end
+
+    return builder
+end
+
+return {
+    BaseElement = BaseElement
+}