rename and simplification

modules/Context.lua

@@ -0,0 +1,151 @@
+---@class Context
+local Context = {
+  -- Top-level elements
+  topElements = {},
+
+  -- Base scale configuration
+  baseScale = nil, -- {width: number, height: number}
+
+  -- Current scale factors
+  scaleFactors = { x = 1.0, y = 1.0 },
+
+  -- Default theme name
+  defaultTheme = nil,
+
+  -- Currently focused element (for keyboard input)
+  _focusedElement = nil,
+
+  -- Active event element (for current frame)
+  _activeEventElement = nil,
+
+  -- Cached viewport dimensions
+  _cachedViewport = { width = 0, height = 0 },
+
+  -- Immediate mode state
+  _immediateMode = false,
+  _frameNumber = 0,
+  _currentFrameElements = {},
+  _immediateModeState = nil, -- Will be initialized if immediate mode is enabled
+  _frameStarted = false,
+  _autoBeganFrame = false,
+
+  -- Z-index ordered element tracking for immediate mode
+  _zIndexOrderedElements = {}, -- Array of elements sorted by z-index (lowest to highest)
+}
+
+--- Get current scale factors
+---@return number, number -- scaleX, scaleY
+function Context.getScaleFactors()
+  return Context.scaleFactors.x, Context.scaleFactors.y
+end
+
+--- Register an element in the z-index ordered tree (for immediate mode)
+---@param element Element The element to register
+function Context.registerElement(element)
+  if not Context._immediateMode then
+    return
+  end
+
+  table.insert(Context._zIndexOrderedElements, element)
+end
+
+--- Clear frame elements (called at start of each immediate mode frame)
+function Context.clearFrameElements()
+  Context._zIndexOrderedElements = {}
+end
+
+--- Sort elements by z-index (called after all elements are registered)
+function Context.sortElementsByZIndex()
+  -- Sort elements by z-index (lowest to highest)
+  -- We need to consider parent-child relationships and z-index
+  table.sort(Context._zIndexOrderedElements, function(a, b)
+    -- Calculate effective z-index considering parent hierarchy
+    local function getEffectiveZIndex(elem)
+      local z = elem.z or 0
+      local parent = elem.parent
+      while parent do
+        z = z + (parent.z or 0) * 1000 -- Parent z-index has much higher weight
+        parent = parent.parent
+      end
+      return z
+    end
+
+    return getEffectiveZIndex(a) < getEffectiveZIndex(b)
+  end)
+end
+
+--- Check if a point is inside an element's bounds, respecting scroll and clipping
+---@param element Element The element to check
+---@param x number Screen X coordinate
+---@param y number Screen Y coordinate
+---@return boolean True if point is inside element bounds
+local function isPointInElement(element, x, y)
+  local bx = element.x
+  local by = element.y
+  local bw = element._borderBoxWidth or (element.width + element.padding.left + element.padding.right)
+  local bh = element._borderBoxHeight or (element.height + element.padding.top + element.padding.bottom)
+
+  -- Walk up parent chain to check clipping and apply scroll offsets
+  local current = element.parent
+  while current do
+    local overflowX = current.overflowX or current.overflow
+    local overflowY = current.overflowY or current.overflow
+
+    -- Check if parent clips content (overflow: hidden, scroll, auto)
+    if overflowX == "hidden" or overflowX == "scroll" or overflowX == "auto" or overflowY == "hidden" or overflowY == "scroll" or overflowY == "auto" then
+      local parentX = current.x + current.padding.left
+      local parentY = current.y + current.padding.top
+      local parentW = current.width
+      local parentH = current.height
+
+      if x < parentX or x > parentX + parentW or y < parentY or y > parentY + parentH then
+        return false -- Point is clipped by parent
+      end
+    end
+
+    current = current.parent
+  end
+
+  return x >= bx and x <= bx + bw and y >= by and y <= by + bh
+end
+
+--- Get the topmost element at a screen position
+---@param x number Screen X coordinate
+---@param y number Screen Y coordinate
+---@return Element|nil The topmost element at the position, or nil if none
+function Context.getTopElementAt(x, y)
+  if not Context._immediateMode then
+    return nil
+  end
+
+  -- Helper function to find the first interactive ancestor (including self)
+  local function findInteractiveAncestor(elem)
+    local current = elem
+    while current do
+      -- An element is interactive if it has an onEvent handler, themeComponent, or is editable
+      if current.onEvent or current.themeComponent or current.editable then
+        return current
+      end
+      current = current.parent
+    end
+    return nil
+  end
+
+  -- Traverse from highest to lowest z-index (reverse order)
+  for i = #Context._zIndexOrderedElements, 1, -1 do
+    local element = Context._zIndexOrderedElements[i]
+
+    if isPointInElement(element, x, y) then
+      local interactive = findInteractiveAncestor(element)
+      if interactive then
+        return interactive
+      end
+      -- This preserves backward compatibility for non-interactive overlays
+      return element
+    end
+  end
+
+  return nil
+end
+
+return Context