feat: add nvim-tree and neotree integration

Makefile

@@ -1,26 +1,18 @@
 .PHONY: check format test clean
 
 # Default target
-all: check format
+all: format check test
 
 # Check for syntax errors
 check:
 	@echo "Checking Lua files for syntax errors..."
-	@find lua -name "*.lua" -type f -exec lua -e "assert(loadfile('{}'))" \;
+	nix develop .#ci -c find lua -name "*.lua" -type f -exec lua -e "assert(loadfile('{}'))" \;
 	@echo "Running luacheck..."
-	@luacheck lua/ tests/ --no-unused-args --no-max-line-length
+	nix develop .#ci -c luacheck lua/ tests/ --no-unused-args --no-max-line-length
 
 # Format all files
 format:
-	@echo "Formatting files..."
-	@if command -v nix >/dev/null 2>&1; then \
-		nix fmt; \
-	elif command -v stylua >/dev/null 2>&1; then \
-		stylua lua/; \
-	else \
-		echo "Neither nix nor stylua found. Please install one of them."; \
-		exit 1; \
-	fi
+	nix fmt
 
 # Run tests
 test:

README.md

@@ -49,8 +49,15 @@ Using [lazy.nvim](https://github.com/folke/lazy.nvim):
   "coder/claudecode.nvim",
   config = true,
   keys = {
+    { "<leader>a", nil, desc = "AI/Claude Code" },
     { "<leader>ac", "<cmd>ClaudeCode<cr>", desc = "Toggle Claude" },
     { "<leader>as", "<cmd>ClaudeCodeSend<cr>", mode = "v", desc = "Send to Claude" },
+    {
+      "<leader>as",
+      "<cmd>ClaudeCodeTreeAdd<cr>",
+      desc = "Add file",
+      ft = { "NvimTree", "neo-tree" },
+    },
   },
 }
 ```
@@ -60,13 +67,80 @@ That's it! For more configuration options, see [Advanced Setup](#advanced-setup)
 ## Usage
 
 1. **Launch Claude**: Run `:ClaudeCode` to open Claude in a split terminal
-2. **Send context**: Select text and run `:'<,'>ClaudeCodeSend` to send it to Claude
+2. **Send context**:
+   - Select text in visual mode and use `<leader>as` to send it to Claude
+   - In `nvim-tree` or `neo-tree`, press `<leader>as` on a file to add it to Claude's context
 3. **Let Claude work**: Claude can now:
    - See your current file and selections in real-time
    - Open files in your editor
    - Show diffs with proposed changes
    - Access diagnostics and workspace info
 
+## Commands
+
+- `:ClaudeCode` - Toggle the Claude Code terminal window
+- `:ClaudeCodeSend` - Send current visual selection to Claude, or add files from tree explorer
+- `:ClaudeCodeTreeAdd` - Add selected file(s) from tree explorer to Claude context (also available via ClaudeCodeSend)
+- `:ClaudeCodeAdd <file-path> [start-line] [end-line]` - Add a specific file or directory to Claude context by path with optional line range
+
+### Tree Integration
+
+The `<leader>as` keybinding has context-aware behavior:
+
+- **In normal buffers (visual mode)**: Sends selected text to Claude
+- **In nvim-tree/neo-tree buffers**: Adds the file under cursor (or selected files) to Claude's context
+
+This allows you to quickly add entire files to Claude's context for review, refactoring, or discussion.
+
+#### Features
+
+- **Single file**: Place cursor on any file and press `<leader>as`
+- **Multiple files**: Select multiple files (using tree plugin's selection features) and press `<leader>as`
+- **Smart detection**: Automatically detects whether you're in nvim-tree or neo-tree
+- **Error handling**: Clear feedback if no files are selected or if tree plugins aren't available
+
+### Direct File Addition
+
+The `:ClaudeCodeAdd` command allows you to add files or directories directly by path, with optional line range specification:
+
+```vim
+:ClaudeCodeAdd src/main.lua
+:ClaudeCodeAdd ~/projects/myproject/
+:ClaudeCodeAdd ./README.md
+:ClaudeCodeAdd src/main.lua 50 100    " Lines 50-100 only
+:ClaudeCodeAdd config.lua 25          " From line 25 to end of file
+```
+
+#### Features
+
+- **Path completion**: Tab completion for file and directory paths
+- **Path expansion**: Supports `~` for home directory and relative paths
+- **Line range support**: Optionally specify start and end lines for files (ignored for directories)
+- **Validation**: Checks that files and directories exist before adding, validates line numbers
+- **Flexible**: Works with both individual files and entire directories
+
+#### Examples
+
+```vim
+" Add entire files
+:ClaudeCodeAdd src/components/Header.tsx
+:ClaudeCodeAdd ~/.config/nvim/init.lua
+
+" Add entire directories (line numbers ignored)
+:ClaudeCodeAdd tests/
+:ClaudeCodeAdd ../other-project/
+
+" Add specific line ranges
+:ClaudeCodeAdd src/main.lua 50 100        " Lines 50 through 100
+:ClaudeCodeAdd config.lua 25              " From line 25 to end of file
+:ClaudeCodeAdd utils.py 1 50              " First 50 lines
+:ClaudeCodeAdd README.md 10 20            " Just lines 10-20
+
+" Path expansion works with line ranges
+:ClaudeCodeAdd ~/project/src/app.js 100 200
+:ClaudeCodeAdd ./relative/path.lua 30
+```
+
 ## How It Works
 
 This plugin creates a WebSocket server that Claude Code CLI connects to, implementing the same protocol as the official VS Code extension. When you launch Claude, it automatically detects Neovim and gains full access to your editor.
@@ -132,8 +206,15 @@ See [DEVELOPMENT.md](./DEVELOPMENT.md) for build instructions and development gu
   },
   config = true,
   keys = {
+    { "<leader>a", nil, desc = "AI/Claude Code" },
     { "<leader>ac", "<cmd>ClaudeCode<cr>", desc = "Toggle Claude" },
     { "<leader>as", "<cmd>ClaudeCodeSend<cr>", mode = "v", desc = "Send to Claude" },
+    {
+      "<leader>as",
+      "<cmd>ClaudeCodeTreeAdd<cr>",
+      desc = "Add file",
+      ft = { "NvimTree", "neo-tree" },
+    },
     { "<leader>ao", "<cmd>ClaudeCodeOpen<cr>", desc = "Open Claude" },
     { "<leader>ax", "<cmd>ClaudeCodeClose<cr>", desc = "Close Claude" },
   },

flake.nix

@@ -40,6 +40,7 @@
           luajitPackages.luacov
           neovim
           treefmt.config.build.wrapper
+          findutils
         ];
 
         # Development packages (additional tools for development)
@@ -49,7 +50,7 @@
           gnumake
           websocat
           jq
-          claude-code
+          # claude-code
         ];
       in
       {

lua/claudecode/diff.lua

@@ -408,6 +408,26 @@ function M._apply_accepted_changes(diff_data, final_content)
 
   require("claudecode.logger").debug("diff", "Writing accepted changes to file:", old_file_path)
 
+  -- Ensure parent directories exist for new files
+  if diff_data.is_new_file then
+    local parent_dir = vim.fn.fnamemodify(old_file_path, ":h")
+    if parent_dir and parent_dir ~= "" and parent_dir ~= "." then
+      require("claudecode.logger").debug("diff", "Creating parent directories for new file:", parent_dir)
+      local mkdir_success, mkdir_err = pcall(vim.fn.mkdir, parent_dir, "p")
+      if not mkdir_success then
+        require("claudecode.logger").error(
+          "diff",
+          "Failed to create parent directories:",
+          parent_dir,
+          "error:",
+          mkdir_err
+        )
+        return
+      end
+      require("claudecode.logger").debug("diff", "Successfully created parent directories:", parent_dir)
+    end
+  end
+
   -- Write the content to the actual file
   local lines = vim.split(final_content, "\n")
   local success, err = pcall(vim.fn.writefile, lines, old_file_path)
@@ -581,8 +601,9 @@ end
 -- @param old_file_path string Path to the original file
 -- @param new_buffer number New file buffer ID
 -- @param tab_name string The diff identifier
+-- @param is_new_file boolean Whether this is a new file (doesn't exist yet)
 -- @return table Info about the created diff layout
-function M._create_diff_view_from_window(target_window, old_file_path, new_buffer, tab_name)
+function M._create_diff_view_from_window(target_window, old_file_path, new_buffer, tab_name, is_new_file)
   require("claudecode.logger").debug("diff", "Creating diff view from window", target_window)
 
   -- If no target window provided, create a new window in suitable location
@@ -608,16 +629,36 @@ function M._create_diff_view_from_window(target_window, old_file_path, new_buffe
     vim.api.nvim_set_current_win(target_window)
   end
 
-  -- Make sure the window shows the file we want to diff
-  -- This handles the case where the buffer exists but isn't in the current window
-  vim.cmd("edit " .. vim.fn.fnameescape(old_file_path))
-
-  -- Store the original buffer for later
-  local original_buffer = vim.api.nvim_win_get_buf(target_window)
+  -- Handle the left side of the diff (original file or empty for new files)
+  local original_buffer
+  if is_new_file then
+    -- Create an empty buffer for new file comparison
+    require("claudecode.logger").debug("diff", "Creating empty buffer for new file diff")
+    local empty_buffer = vim.api.nvim_create_buf(false, true) -- unlisted, scratch
+    vim.api.nvim_buf_set_name(empty_buffer, old_file_path .. " (NEW FILE)")
+    vim.api.nvim_buf_set_lines(empty_buffer, 0, -1, false, {}) -- Empty content
+    vim.api.nvim_buf_set_option(empty_buffer, "buftype", "nofile")
+    vim.api.nvim_buf_set_option(empty_buffer, "modifiable", false)
+    vim.api.nvim_buf_set_option(empty_buffer, "readonly", true)
+
+    -- Set the empty buffer in the target window
+    vim.api.nvim_win_set_buf(target_window, empty_buffer)
+    original_buffer = empty_buffer
+  else
+    -- Make sure the window shows the existing file we want to diff
+    vim.cmd("edit " .. vim.fn.fnameescape(old_file_path))
+    original_buffer = vim.api.nvim_win_get_buf(target_window)
+  end
 
-  -- Enable diff mode on the original file
+  -- Enable diff mode on the original/empty file
   vim.cmd("diffthis")
-  require("claudecode.logger").debug("diff", "Enabled diff mode on original file in window", target_window)
+  require("claudecode.logger").debug(
+    "diff",
+    "Enabled diff mode on",
+    is_new_file and "empty buffer" or "original file",
+    "in window",
+    target_window
+  )
 
   -- Create vertical split for new buffer (proposed changes)
   vim.cmd("vsplit")
@@ -647,6 +688,14 @@ function M._create_diff_view_from_window(target_window, old_file_path, new_buffe
     -- Accept all changes
     local new_content = vim.api.nvim_buf_get_lines(new_buffer, 0, -1, false)
 
+    -- Ensure parent directories exist for new files
+    if is_new_file then
+      local parent_dir = vim.fn.fnamemodify(old_file_path, ":h")
+      if parent_dir and parent_dir ~= "" and parent_dir ~= "." then
+        vim.fn.mkdir(parent_dir, "p")
+      end
+    end
+
     -- Write to file
     vim.fn.writefile(new_content, old_file_path)
 
@@ -747,41 +796,49 @@ function M._setup_blocking_diff(params, resolution_callback)
     params.old_file_path
   )
 
-  -- Step 1: Check if the file exists
+  -- Step 1: Check if the file exists (allow new files)
   local old_file_exists = vim.fn.filereadable(params.old_file_path) == 1
-  if not old_file_exists then
-    error({
-      code = -32000,
-      message = "File access error",
-      data = "Cannot open file: " .. params.old_file_path .. " (file does not exist)",
-    })
-  end
+  local is_new_file = not old_file_exists
 
-  -- Step 2: Find if the file is already open in a buffer
+  require("claudecode.logger").debug(
+    "diff",
+    "File existence check - old_file_exists:",
+    old_file_exists,
+    "is_new_file:",
+    is_new_file,
+    "path:",
+    params.old_file_path
+  )
+
+  -- Step 2: Find if the file is already open in a buffer (only for existing files)
   local existing_buffer = nil
   local target_window = nil
 
-  -- Look for existing buffer with this file
-  for _, buf in ipairs(vim.api.nvim_list_bufs()) do
-    if vim.api.nvim_buf_is_valid(buf) and vim.api.nvim_buf_is_loaded(buf) then
-      local buf_name = vim.api.nvim_buf_get_name(buf)
-      if buf_name == params.old_file_path then
-        existing_buffer = buf
-        require("claudecode.logger").debug("diff", "Found existing buffer", buf, "for file", params.old_file_path)
-        break
+  if old_file_exists then
+    -- Look for existing buffer with this file
+    for _, buf in ipairs(vim.api.nvim_list_bufs()) do
+      if vim.api.nvim_buf_is_valid(buf) and vim.api.nvim_buf_is_loaded(buf) then
+        local buf_name = vim.api.nvim_buf_get_name(buf)
+        if buf_name == params.old_file_path then
+          existing_buffer = buf
+          require("claudecode.logger").debug("diff", "Found existing buffer", buf, "for file", params.old_file_path)
+          break
+        end
       end
     end
-  end
 
-  -- Find window containing this buffer (if any)
-  if existing_buffer then
-    for _, win in ipairs(vim.api.nvim_list_wins()) do
-      if vim.api.nvim_win_get_buf(win) == existing_buffer then
-        target_window = win
-        require("claudecode.logger").debug("diff", "Found window", win, "containing buffer", existing_buffer)
-        break
+    -- Find window containing this buffer (if any)
+    if existing_buffer then
+      for _, win in ipairs(vim.api.nvim_list_wins()) do
+        if vim.api.nvim_win_get_buf(win) == existing_buffer then
+          target_window = win
+          require("claudecode.logger").debug("diff", "Found window", win, "containing buffer", existing_buffer)
+          break
+        end
       end
     end
+  else
+    require("claudecode.logger").debug("diff", "Skipping buffer search for new file:", params.old_file_path)
   end
 
   -- If no existing buffer/window, find a suitable main editor window
@@ -811,7 +868,7 @@ function M._setup_blocking_diff(params, resolution_callback)
     })
   end
 
-  local new_unique_name = tab_name .. " (proposed)"
+  local new_unique_name = is_new_file and (tab_name .. " (NEW FILE - proposed)") or (tab_name .. " (proposed)")
   vim.api.nvim_buf_set_name(new_buffer, new_unique_name)
   vim.api.nvim_buf_set_lines(new_buffer, 0, -1, false, vim.split(params.new_file_contents, "\n"))
 
@@ -820,8 +877,15 @@ function M._setup_blocking_diff(params, resolution_callback)
   vim.api.nvim_buf_set_option(new_buffer, "modifiable", true)
 
   -- Step 4: Set up diff view using the target window
-  require("claudecode.logger").debug("diff", "Creating diff view from window", target_window)
-  local diff_info = M._create_diff_view_from_window(target_window, params.old_file_path, new_buffer, tab_name)
+  require("claudecode.logger").debug(
+    "diff",
+    "Creating diff view from window",
+    target_window,
+    "is_new_file:",
+    is_new_file
+  )
+  local diff_info =
+    M._create_diff_view_from_window(target_window, params.old_file_path, new_buffer, tab_name, is_new_file)
 
   -- Step 5: Register autocmds for user interaction monitoring
   require("claudecode.logger").debug("diff", "Registering autocmds")
@@ -842,6 +906,7 @@ function M._setup_blocking_diff(params, resolution_callback)
     status = "pending",
     resolution_callback = resolution_callback,
     result_content = nil,
+    is_new_file = is_new_file,
   })
   require("claudecode.logger").debug("diff", "Setup completed successfully for", tab_name)
 end