Complete copilot chat integration with lua-tiktoken support

flake.nix

@@ -19,6 +19,10 @@
       url = "github:moyiz/git-dev.nvim";
       flake = false;
     };
+    lua-tiktoken = {
+      url = "github:gptlang/lua-tiktoken";
+      flake = false;
+    };
   };
 
   outputs =

full.nix

@@ -4,11 +4,13 @@ let
   themeryModule = import ./plugins/optional/themery-nvim.nix { inherit inputs pkgs; };
   # Import the git-dev module with inputs passed through
   gitDevModule = import ./plugins/optional/git-dev-nvim.nix { inherit inputs pkgs; };
+  # Import the copilot module with inputs passed through
+  copilotModule = import ./plugins/optional/copilot.nix { inherit inputs pkgs; };
 in
 {
   imports = [
     ./minimal.nix
-    ./plugins/optional/copilot.nix
+    copilotModule
     themeryModule
     gitDevModule
   ];

plugins/optional/copilot.nix

@@ -1,5 +1,12 @@
 # https://github.com/CopilotC-Nvim/CopilotChat.nvim
-{ pkgs, ... }:
+{ inputs, pkgs, ... }:
+let
+  # Build lua-tiktoken from source for enhanced token counting
+  lua-tiktoken = pkgs.vimUtils.buildVimPlugin {
+    name = "lua-tiktoken";
+    src = inputs.lua-tiktoken;
+  };
+in
 {
   config.vim = {
     assistant.copilot = {
@@ -8,11 +15,84 @@
         panel.layout.position = "right";
       };
     };
-    extraPlugins.copilotChat = {
-      package = pkgs.vimPlugins.CopilotChat-nvim;
-      setup = ''
-        require('copilotChat')
-      '';
+
+    # Add tiktoken as an extra package for enhanced token counting
+    extraPackages = with pkgs; [
+      # Try to include tiktoken-related packages
+      (python3Packages.tiktoken or null)
+    ];
+
+    extraPlugins = {
+      copilotChat = {
+        package = pkgs.vimPlugins.CopilotChat-nvim;
+        setup = ''
+          require('CopilotChat').setup({
+            -- Chat integration settings
+            debug = false,
+            show_help = "yes",
+
+            -- Window settings for chat
+            window = {
+              layout = 'float',
+              relative = 'cursor',
+              width = 1,
+              height = 0.4,
+              row = 1
+            },
+
+            -- Mappings
+            mappings = {
+              complete = {
+                detail = 'Use @<Tab> or /<Tab> for options.',
+                insert ='<Tab>',
+              },
+              close = {
+                normal = 'q',
+                insert = '<C-c>'
+              },
+              reset = {
+                normal ='<C-l>',
+                insert = '<C-l>'
+              },
+              submit_prompt = {
+                normal = '<CR>',
+                insert = '<C-s>'
+              },
+              accept_diff = {
+                normal = '<C-y>',
+                insert = '<C-y>'
+              },
+              show_diff = {
+                normal = 'gd'
+              },
+              show_system_prompt = {
+                normal = 'gp'
+              },
+              show_user_selection = {
+                normal = 'gs'
+              },
+            },
+          })
+
+          -- Add keymaps for quick access
+          vim.keymap.set('n', '<leader>cc', '<cmd>CopilotChat<CR>', { desc = 'Open Copilot Chat' })
+          vim.keymap.set('v', '<leader>cc', '<cmd>CopilotChatVisual<CR>', { desc = 'Open Copilot Chat with selection' })
+          vim.keymap.set('n', '<leader>ce', '<cmd>CopilotChatExplain<CR>', { desc = 'Explain code' })
+          vim.keymap.set('n', '<leader>ct', '<cmd>CopilotChatTests<CR>', { desc = 'Generate tests' })
+          vim.keymap.set('n', '<leader>cr', '<cmd>CopilotChatReview<CR>', { desc = 'Review code' })
+          vim.keymap.set('n', '<leader>cf', '<cmd>CopilotChatFixDiagnostic<CR>', { desc = 'Fix diagnostic' })
+          vim.keymap.set('n', '<leader>co', '<cmd>CopilotChatOptimize<CR>', { desc = 'Optimize code' })
+        '';
+      };
+
+      # Add lua-tiktoken for enhanced token counting
+      luaTiktoken = {
+        package = lua-tiktoken;
+        setup = ''
+          -- lua-tiktoken provides more accurate token counting for chat contexts
+          -- CopilotChat will automatically use it if available
+        '';
+      };
     };
   };
 }