--- a/Bar.lua	Tue Apr 22 21:33:37 2008 +0000
+++ b/Bar.lua	Thu Apr 24 19:19:42 2008 +0000
@@ -13,7 +13,7 @@
 -- update ReAction revision if this file is newer
 local revision = tonumber(("$Revision$"):match("%d+"))
 if revision > ReAction.revision then
-  Reaction.revision = revision
+  ReAction.revision = revision
 end
 
 ------ BAR CLASS ------
@@ -62,11 +62,16 @@
   local anchor = config.anchor
   f:ClearAllPoints()
   if anchor then
-    local anchorTo
+    local anchorTo = f:GetParent()
     if config.anchorTo then
-      anchorTo = ReAction:GetBar(config.anchorTo) or _G[config.anchorTo]
+      local bar = ReAction:GetBar(config.anchorTo)
+      if bar then
+        anchorTo = bar:GetFrame()
+      else
+        anchorTo = _G[config.anchorTo]
+      end
     end
-    f:SetPoint(anchor, anchorTo, config.relativePoint, config.x or 0, config.y or 0)
+    f:SetPoint(anchor, anchorTo or f:GetParent(), config.relativePoint, config.x or 0, config.y or 0)
   else
     f:SetPoint("CENTER")
   end
@@ -164,7 +169,7 @@
 --
 -- Bar config overlay
 --
-local StoreExtents, RecomputeButtonSize, RecomputeButtonSpacing, RecomputeGrid, ClampToButtons, HideGameTooltip, CreateControls
+local CreateControls
 
 do
   -- upvalue some of these for small OnUpdate performance boost
@@ -176,17 +181,15 @@
   local SetButtonGrid = Bar.SetButtonGrid
   local ApplyAnchor   = Bar.ApplyAnchor
 
-  StoreExtents = function(bar)
+  local function StoreExtents(bar)
     local f = bar.frame
     local point, relativeTo, relativePoint, x, y = f:GetPoint(1)
     relativeTo = relativeTo or f:GetParent()
     local anchorTo
     for name, b in pairs(ReAction.bars) do
-      if b then
-        if b:GetFrame() == relativeTo then
-          anchorTo = name
-          break
-        end
+      if b and b:GetFrame() == relativeTo then
+        anchorTo = name
+        break
       end
     end
     anchorTo = anchorTo or relativeTo:GetName()
@@ -199,7 +202,13 @@
     c.width, c.height = f:GetWidth(), f:GetHeight()
   end
 
-  RecomputeButtonSize = function(bar)
+  local function StoreSize(bar)
+    local f = bar.frame
+    local c = bar.config
+    c.width, c.height = f:GetWidth(), f:GetHeight()
+  end
+
+  local function RecomputeButtonSize(bar)
     local w, h = GetSize(bar)
     local bw, bh = GetButtonSize(bar)
     local r, c, s = GetButtonGrid(bar)
@@ -211,7 +220,7 @@
     SetButtonSize(bar, scale * bw, scale * bh, s)
   end
 
-  RecomputeButtonSpacing = function(bar)
+  local function RecomputeButtonSpacing(bar)
     local w, h = GetSize(bar)
     local bw, bh = GetButtonSize(bar)
     local r, c, s = GetButtonGrid(bar)
@@ -219,7 +228,7 @@
     SetButtonGrid(bar,r,c,min(floor(w/c) - bw, floor(h/r) - bh))
   end
 
-  RecomputeGrid = function(bar)
+  local function RecomputeGrid(bar)
     local w, h = GetSize(bar)
     local bw, bh = GetButtonSize(bar)
     local r, c, s = GetButtonGrid(bar)
@@ -227,16 +236,297 @@
     SetButtonGrid(bar, floor(h/(bh+s)), floor(w/(bw+s)), s)
   end
 
-  ClampToButtons = function(bar)
+  local function ClampToButtons(bar)
     local bw, bh = GetButtonSize(bar)
     local r, c, s = GetButtonGrid(bar)
     SetSize(bar, (bw+s)*c + 1, (bh+s)*r + 1)
   end
 
-  HideGameTooltip = function()
+  local function HideGameTooltip()
     GameTooltip:Hide()
   end
 
+  local anchorInside  = { inside = true }
+  local anchorOutside = { outside = true }
+  local edges = { "BOTTOM", "TOP", "LEFT", "RIGHT" }
+  local oppositeEdges = {
+    TOP = "BOTTOM",
+    BOTTOM = "TOP",
+    LEFT = "RIGHT",
+    RIGHT = "LEFT"
+  }
+  local pointsOnEdge = {
+    BOTTOM = { "BOTTOM", "BOTTOMLEFT",  "BOTTOMRIGHT",  },
+    TOP    = { "TOP",    "TOPLEFT",     "TOPRIGHT",     },
+    RIGHT  = { "RIGHT",  "BOTTOMRIGHT", "TOPRIGHT",     },
+    LEFT   = { "LEFT",   "BOTTOMLEFT",  "TOPLEFT",      },
+  }
+  local edgeSelector = {
+    BOTTOM = 1,  -- select x of x,y
+    TOP    = 1,  -- select x of x,y
+    LEFT   = 2,  -- select y of x,y
+    RIGHT  = 2,  -- select y of x,y  
+  }
+  local snapPoints = {
+    [anchorOutside] = {
+      BOTTOMLEFT  = {"BOTTOMRIGHT","TOPLEFT","TOPRIGHT"},
+      BOTTOM      = {"TOP"},
+      BOTTOMRIGHT = {"BOTTOMLEFT","TOPRIGHT","TOPLEFT"},
+      RIGHT       = {"LEFT"},
+      TOPRIGHT    = {"TOPLEFT","BOTTOMRIGHT","BOTTOMLEFT"},
+      TOP         = {"BOTTOM"},
+      TOPLEFT     = {"TOPRIGHT","BOTTOMLEFT","BOTTOMRIGHT"},
+      LEFT        = {"RIGHT"},
+      CENTER      = {"CENTER"}
+    },
+    [anchorInside] = {
+      BOTTOMLEFT  = {"BOTTOMLEFT"},
+      BOTTOM      = {"BOTTOM"},
+      BOTTOMRIGHT = {"BOTTOMRIGHT"},
+      RIGHT       = {"RIGHT"},
+      TOPRIGHT    = {"TOPRIGHT"},
+      TOP         = {"TOP"},
+      TOPLEFT     = {"TOPLEFT"},
+      LEFT        = {"LEFT"},
+      CENTER      = {"CENTER"}
+    }
+  }
+  local insidePointOffsetFuncs = {
+    BOTTOMLEFT  = function(x, y) return x, y end,
+    BOTTOM      = function(x, y) return 0, y end,
+    BOTTOMRIGHT = function(x, y) return -x, y end,
+    RIGHT       = function(x, y) return -x, 0 end,
+    TOPRIGHT    = function(x, y) return -x, -y end,
+    TOP         = function(x, y) return 0, -y end,
+    TOPLEFT     = function(x, y) return x, -y end,
+    LEFT        = function(x, y) return x, 0 end,
+    CENTER      = function(x, y) return 0, 0 end,
+  }
+  local pointCoordFuncs = {
+    BOTTOMLEFT  = function(f) return f:GetLeft(),  f:GetBottom() end,
+    BOTTOM      = function(f) return nil,          f:GetBottom() end,
+    BOTTOMRIGHT = function(f) return f:GetRight(), f:GetBottom() end,
+    RIGHT       = function(f) return f:GetRight(), nil end,
+    TOPRIGHT    = function(f) return f:GetRight(), f:GetTop() end,
+    TOP         = function(f) return nil,          f:GetTop() end,
+    TOPLEFT     = function(f) return f:GetLeft(),  f:GetTop() end,
+    LEFT        = function(f) return f:GetLeft(),  nil end,
+    CENTER      = function(f) return f:GetCenter() end,
+  }
+  local edgeBoundsFuncs = {
+    BOTTOM = function(f) return f:GetLeft(), f:GetRight() end,
+    LEFT   = function(f) return f:GetBottom(), f:GetTop() end
+  }
+  edgeBoundsFuncs.TOP   = edgeBoundsFuncs.BOTTOM
+  edgeBoundsFuncs.RIGHT = edgeBoundsFuncs.LEFT
+
+
+  -- Returns absolute coordinates x,y of the named point 'p' of frame 'f'
+  local function GetPointCoords( f, p )
+    local x, y = pointCoordFuncs[p](f)
+    if not(x and y) then
+      local cx, cy = f:GetCenter()
+      x = x or cx
+      y = y or cy
+    end
+    return x, y
+  end
+
+
+  -- Returns true if frame 'f1' can be anchored to frame 'f2'
+  local function CheckAnchorable( f1, f2 )
+    -- can't anchor a frame to itself or to nil
+    if f1 == f2 or f2 == nil then
+      return false
+    end
+    
+    -- can always anchor to UIParent
+    if f2 == UIParent then
+      return true
+    end
+    
+    -- also can't do circular anchoring of frames 
+    -- walk the anchor chain, which generally shouldn't be that expensive
+    -- (who nests draggables that deep anyway?)
+    for i = 1, f2:GetNumPoints() do
+      local _, f = f2:GetPoint(i)
+      if not f then f = f2:GetParent() end
+      return CheckAnchorable(f1,f)
+    end
+    
+    return true
+  end
+
+  -- Returns true if frames f1 and f2 specified edges overlap
+  local function CheckEdgeOverlap( f1, f2, e )
+    local l1, u1 = edgeBoundsFuncs[e](f1)
+    local l2, u2 = edgeBoundsFuncs[e](f2)
+    return l1 <= l2 and l2 <= u1 or l2 <= l1 and l1 <= u2
+  end
+
+  -- Returns true if point p1 on frame f1 overlaps edge e2 on frame f2
+  local function CheckPointEdgeOverlap( f1, p1, f2, e2 )
+    local l, u = edgeBoundsFuncs[e2](f2)
+    local x, y = GetPointCoords(f1,p1)
+    x = select(edgeSelector[e2], x, y)
+    return l <= x and x <= u
+  end
+
+  -- Returns the distance between corresponding edges. It is 
+  -- assumed that the passed in edges e1 and e2 are the same or opposites
+  local function GetEdgeDistance( f1, f2, e1, e2 )
+    local x1, y1 = pointCoordFuncs[e1](f1)
+    local x2, y2 = pointCoordFuncs[e2](f2)
+    return math.abs((x1 or y1) - (x2 or y2))
+  end
+
+  local globalSnapTargets = { [UIParent] = anchorInside }
+
+  local function GetClosestFrameEdge(f1,f2,a)
+    local dist, edge, opp
+    if f2:IsVisible() and CheckAnchorable(f1,f2) then
+      for _, e in pairs(edges) do
+        local o = a.inside and e or oppositeEdges[e]
+        if CheckEdgeOverlap(f1,f2,e) then
+          local d = GetEdgeDistance(f1, f2, e, o)
+          if not dist or (d < dist) then
+            dist, edge, opp = d, e, o
+          end
+        end
+      end
+    end
+    return dist, edge, opp
+  end
+
+  local function GetClosestVisibleEdge( f )
+    local r, o, e1, e2
+    local a = anchorOutside
+    for _, b in pairs(ReAction.bars) do
+      local d, e, opp = GetClosestFrameEdge(f,b:GetFrame(),a)
+      if d and (not r or d < r) then
+        r, o, e1, e2 = d, b:GetFrame(), e, opp
+      end
+    end
+    for f2, a2 in pairs(globalSnapTargets) do
+      local d, e, opp = GetClosestFrameEdge(f,f2,a2)
+      if d and (not r or d < r) then
+        r, o, e1, e2, a = d, f2, e, opp, a2
+      end
+    end
+    return o, e1, e2, a
+  end
+
+  local function GetClosestVisiblePoint(f1)
+    local f2, e1, e2, a = GetClosestVisibleEdge(f1)
+    if f2 then
+      local rsq, p, rp, x, y
+      -- iterate pointsOnEdge in order and use < to prefer edge centers to corners
+      for _, p1 in ipairs(pointsOnEdge[e1]) do
+        if CheckPointEdgeOverlap(f1,p1,f2,e2) then
+          for _, p2 in pairs(snapPoints[a][p1]) do
+            local x1, y1 = GetPointCoords(f1,p1)
+            local x2, y2 = GetPointCoords(f2,p2)
+            local dx = x1 - x2
+            local dy = y1 - y2
+            local rsq2 = dx*dx + dy*dy
+            if not rsq or rsq2 < rsq then
+              rsq, p, rp, x, y = rsq2, p1, p2, dx, dy
+            end
+          end
+        end
+      end
+      return f2, p, rp, x, y
+    end
+  end
+
+  local function GetClosestPointSnapped(f1, rx, ry, xOff, yOff)
+    local o, p, rp, x, y = GetClosestVisiblePoint(f1)
+    local s = false
+    
+    local sx, sy = insidePointOffsetFuncs[p](xOff or 0, yOff or 0)
+    local xx, yy = pointCoordFuncs[p](f1)
+    if xx and yy then
+      if math.abs(x) <= rx then
+        x = sx
+        s = true
+      end
+      if math.abs(y) <= ry then
+        y = sy
+        s = true
+      end
+    elseif xx then
+      if math.abs(x) <= rx then
+        x = sx
+        s = true
+        if math.abs(y) <= ry then
+          y = sy
+        end
+      end
+    elseif yy then
+      if math.abs(y) <= ry then
+        y = sy
+        s = true
+        if math.abs(x) <= rx then
+          x = sx
+        end
+      end
+    end
+
+    if x == -0 then x = 0 end
+    if y == -0 then y = 0 end
+    
+    if s then
+      return o, p, rp, math.floor(x), math.floor(y)
+    end
+  end
+
+  local function CreateSnapIndicator()
+    local si = CreateFrame("Frame",nil,UIParent)
+    si:SetFrameStrata("HIGH")
+    si:SetHeight(8)
+    si:SetWidth(8)
+    local tex = si:CreateTexture()
+    tex:SetAllPoints()
+    tex:SetTexture(1.0, 0.82, 0, 0.8)
+    tex:SetBlendMode("ADD")
+    tex:SetDrawLayer("OVERLAY")
+    return si
+  end
+
+  local si1 = CreateSnapIndicator()
+  local si2 = CreateSnapIndicator()
+
+  local function DisplaySnapIndicator( f, rx, ry, xOff, yOff )
+    local o, p, rp, x, y, snap = GetClosestPointSnapped(f, rx, ry, xOff, yOff)
+    if o then
+      si1:ClearAllPoints()
+      si2:ClearAllPoints()
+      si1:SetPoint("CENTER", f, p, 0, 0)
+      local xx, yy = pointCoordFuncs[rp](o)
+      x = math.abs(x) <=rx and xx and 0 or x
+      y = math.abs(y) <=ry and yy and 0 or y
+      si2:SetPoint("CENTER", o, rp, x, y)
+      si1:Show()
+      si2:Show()
+    else
+      if si1:IsVisible() then
+        si1:Hide()
+        si2:Hide()
+      end
+    end
+  end
+
+  local function HideSnapIndicator()
+    if si1:IsVisible() then
+      si1:Hide()
+      si2:Hide()
+    end
+  end
+
+  local function RefreshLayoutEditor()
+    ReAction:CallModuleMethod("ConfigUI","RefreshLayoutEditor")
+  end
+
   CreateControls = function(bar)
     local f = bar.frame
 
@@ -291,9 +581,10 @@
       f:StopMovingOrSizing()
       f.isMoving = false
       f:SetScript("OnUpdate",nil)
-      StoreExtents(bar)
+      StoreSize(bar)
       ClampToButtons(bar)
       ApplyAnchor(bar)
+      RefreshLayoutEditor()
     end
 
     -- edge drag handles
@@ -418,17 +709,50 @@
       function()
         f:StartMoving()
         f.isMoving = true
-        -- TODO: snap indicator update install
+        local w,h = bar:GetButtonSize()
+        f:ClearAllPoints()
+        f:SetScript("OnUpdate", function()
+            if IsShiftKeyDown() then
+              DisplaySnapIndicator(f,w,h)
+            else
+              HideSnapIndicator()
+            end
+          end)
       end
     )
 
+    local function updateDragTooltip()
+      GameTooltip:SetOwner(f, "ANCHOR_TOPRIGHT")
+      GameTooltip:AddLine(bar.name)
+      GameTooltip:AddLine(L["Drag to move"])
+      GameTooltip:AddLine(("|cff00ff00%s|r %s"):format(L["Shift-drag"],L["to anchor to nearby frames"]))
+      GameTooltip:AddLine(("|cff00cccc%s|r %s"):format(L["Right-click"],L["for options"]))
+      local _, a = bar:GetAnchor()
+      if a and a ~= "UIParent" then
+        GameTooltip:AddLine(L["Currently anchored to <%s>"]:format(a))
+      end
+      GameTooltip:Show()
+    end
+
     control:SetScript("OnDragStop",
       function()
         f:StopMovingOrSizing()
         f.isMoving = false
         f:SetScript("OnUpdate",nil)
-        -- TODO: snap frame here
+
+        if IsShiftKeyDown() then
+          local w, h = bar:GetButtonSize()
+          local a, p, rp, x, y = GetClosestPointSnapped(f,w,h)
+          if a then
+            f:ClearAllPoints()
+            f:SetPoint(p,a,rp,x,y)
+          end
+          HideSnapIndicator()
+        end
+
         StoreExtents(bar)
+        RefreshLayoutEditor()
+        updateDragTooltip()
       end
     )
 
@@ -444,13 +768,8 @@
           end
           --]]
         end
-        
-        GameTooltip:SetOwner(f, "ANCHOR_TOPRIGHT")
-        GameTooltip:AddLine(name)
-        GameTooltip:AddLine(L["Drag to move"])
-        --GameTooltip:AddLine(L["Shift-drag for sticky mode"])
-        GameTooltip:AddLine(L["Right-click for options"])
-        GameTooltip:Show()
+
+        updateDragTooltip()
       end
     )