Infinity scroll progress

druid/extended/infinity_list.lua

@@ -15,17 +15,22 @@ function M:init(data_list, scroll, grid, create_function)
     self.grid = grid
     self.scroll:bind_grid(grid)
 
-    self.data = data_list
+    --- Current visual elements indexes
     self.top_index = 1
     self.last_index = 1
 
+    self._data = {}
+    self._data_first_index = false
+    self._data_last_index = false
+    self._data_length = 0
+
     self.create_function = create_function
 
-    self.nodes = {}
-    self.components = {}
+    self._data_visual = {}
 
-    self:_refresh()
     self.scroll.on_scroll:subscribe(self._check_elements, self)
+
+    self:set_data(data_list)
 end
 
 
@@ -35,41 +40,72 @@ end
 
 
 function M:set_data(data_list)
-    self.data = data_list
+    self._data = data_list
+    self:_update_data_info()
     self:_refresh()
 end
 
 
-function M:add(data, index)
-    table.insert(self.data, index, data)
-    self:_refresh()
+function M:add(data, index, shift_policy)
+    index = index or self._data_last_index + 1
+    shift_policy = shift_policy or const.SHIFT.RIGHT
+
+    if self._data[index] then
+        if shift_policy == const.SHIFT.RIGHT then
+            for i = self._data_last_index, index, -1 do
+                self._data[i + 1] = self._data[i]
+            end
+        end
+        if shift_policy == const.SHIFT.LEFT then
+            for i = self._data_first_index, index do
+                self._data[i - 1] = self._data[i]
+            end
+        end
+    end
+    self._data[index] = data
+    self:_update_data_info()
+    self:_check_elements()
 end
 
 
 function M:remove(index, shift_policy)
-    table.remove(self.data, index)
+    table.remove(self._data, index)
     self:_refresh()
 end
 
 
+function M:remove_by_data(data, shift_policy)
+    local index = helper.contains(self._data, data)
+    if index then
+        table.remove(self._data, index)
+        self:_refresh()
+    end
+end
+
+
 function M:clear()
-    self.data = {}
+    self._data = {}
     self:_refresh()
 end
 
 
 function M:get_first_index()
-    return self.top_index
+    return self._data_first_index
 end
 
 
 function M:get_last_index()
-    return self.last_index
+    return self._data_last_index
+end
+
+
+function M:get_length()
+    return self._data_length
 end
 
 
 function M:get_index(data)
-    for index, value in pairs(self.data) do
+    for index, value in pairs(self._data) do
         if value == data then
             return index
         end
@@ -79,40 +115,41 @@ end
 
 
 function M:scroll_to_index(index)
-    self.top_index = helper.clamp(index, 1, #self.data)
+    self.top_index = helper.clamp(index, 1, #self._data)
     self:_refresh()
     self.scroll.on_scroll:trigger(self:get_context(), self)
 end
 
 
 function M:_add_at(index)
-    if self.nodes[index] then
+    if self._data_visual[index] then
         self:_remove_at(index)
     end
 
-    local node, instance = self.create_function(self.data[index], index)
+    local node, instance = self.create_function(self._data[index], index)
     self.grid:add(node, index, const.SHIFT.NO_SHIFT)
-    self.nodes[index] = node
-    self.components[index] = instance
+    self._data_visual[index] = {
+        node = node,
+        component = instance
+    }
 end
 
 
 function M:_remove_at(index)
     self.grid:remove(index, const.SHIFT.NO_SHIFT)
 
-    local node = self.nodes[index]
+    local node = self._data_visual[index].node
     gui.delete_node(node)
-    self.nodes[index] = nil
 
-    if self.components[index] then
-        self.druid:remove(self.components[index])
-        self.components[index] = nil
+    if self._data_visual[index].component then
+        self.druid:remove(self._data_visual[index].component)
     end
+    self._data_visual[index] = nil
 end
 
 
 function M:_refresh()
-    for index, _ in pairs(self.nodes) do
+    for index, _ in pairs(self._data_visual) do
         self:_remove_at(index)
     end
     self:_check_elements()
@@ -120,8 +157,8 @@ end
 
 
 function M:_check_elements()
-    for index, node in pairs(self.nodes) do
-        if self.scroll:is_node_in_view(node) then
+    for index, data in pairs(self._data_visual) do
+        if self.scroll:is_node_in_view(data.node) then
             self.top_index = index
             self.last_index = index
         end
@@ -130,7 +167,7 @@ function M:_check_elements()
     self:_check_elements_from(self.top_index - 1, -1)
     self:_check_elements_from(self.top_index, 1)
 
-    for index, node in pairs(self.nodes) do
+    for index, data in pairs(self._data_visual) do
         self.top_index = math.min(self.top_index or index, index)
         self.last_index = math.max(self.last_index or index, index)
     end
@@ -140,20 +177,20 @@ end
 function M:_check_elements_from(index, step)
     local is_outside = false
     while not is_outside do
-        if not self.data[index] then
+        if not self._data[index] then
             break
         end
 
-        if not self.nodes[index] then
+        if not self._data_visual[index] then
             self:_add_at(index)
         end
 
-        if not self.scroll:is_node_in_view(self.nodes[index]) then
+        if not self.scroll:is_node_in_view(self._data_visual[index].node) then
             is_outside = true
 
             -- remove nexts:
             local remove_index = index + step
-            while self.nodes[remove_index] do
+            while self._data_visual[remove_index] do
                 self:_remove_at(remove_index)
                 remove_index = remove_index + step
             end
@@ -164,4 +201,22 @@ function M:_check_elements_from(index, step)
 end
 
 
+function M:_update_data_info()
+    self._data_first_index = false
+    self._data_last_index = false
+    self._data_length = 0
+
+    for index, data in pairs(self._data) do
+        self._data_first_index = math.min(self._data_first_index or index, index)
+        self._data_last_index = math.max(self._data_last_index or index, index)
+        self._data_length = self._data_length + 1
+    end
+
+    if self._data_length == 0 then
+        self._data_first_index = 1
+        self._data_last_index = 1
+    end
+end
+
+
 return M