decouple UI from server

Add a mediator that sits between the sidebar and the server that handles
sending messages

Author: tomgeorge

lua/eca/init.lua

@@ -168,7 +168,7 @@ function M._init(id)
   local sidebar = M.sidebars[id]
 
   if not sidebar then
-    sidebar = Sidebar.new(id)
+    sidebar = Sidebar.new(id, M.mediator)
     M.sidebars[id] = sidebar
   end
   M.current = { sidebar = sidebar }
@@ -241,11 +241,9 @@ function M.setup(opts)
   H.keymaps()
   H.signs()
 
-  -- Initialize status bar
-
   -- Initialize the ECA server with callbacks
   M.server = Server.new()
-
+  M.mediator = require("eca.mediator").new(M.server)
   -- Start server automatically in background
   vim.defer_fn(function()
     M.server:start()

lua/eca/sidebar.lua

@@ -8,6 +8,7 @@ local Split = require("nui.split")
 ---@class eca.Sidebar
 ---@field public id integer The tab ID
 ---@field public containers table<string, NuiSplit> The nui containers
+---@field mediator eca.Mediator mediator to send server requests to
 ---@field private _initialized boolean Whether the sidebar has been initialized
 ---@field private _current_response_buffer string Buffer for accumulating streaming response
 ---@field private _is_streaming boolean Whether we're currently receiving a streaming response
@@ -34,10 +35,12 @@ local UI_ELEMENTS_HEIGHT = 2 -- Reserve space for statusline and tabline
 local SAFETY_MARGIN = 2 -- Extra margin to prevent "Not enough room" errors
 
 ---@param id integer Tab ID
+---@param mediator eca.Mediator
 ---@return eca.Sidebar
-function M.new(id)
+function M.new(id, mediator)
   local instance = setmetatable({}, M)
   instance.id = id
+  instance.mediator = mediator
   instance.containers = {}
   instance._initialized = false
   instance._current_response_buffer = ""
@@ -1163,7 +1166,7 @@ function M:_send_message(message)
   if eca.server and eca.server:is_running() then
     -- Include active contexts in the message
     local contexts = self:get_contexts()
-    eca.server:send_request("chat/prompt", {
+    self.mediator:send("chat/prompt", {
       chatId = self.id,
       requestId = tostring(os.time()),
       message = message,

lua/eca/types.lua

@@ -22,6 +22,10 @@
 
 ---@alias eca.ToolCallDetails eca.FileChangedDetails
 
+---TODO: flesh these out
+---@alias eca.MessageParams table
+---@alias eca.Message table
+
 ---@class eca.FileChangedDetails
 ---@field type 'fileChange'
 ---@field path string the file path of this file change