feat: add oil.nvim support for file selection (#27)

* feat: add oil.nvim support for file selection

- Add oil.nvim integration to support file selection with @-mention
- Support both visual selection and single file under cursor
- Handle directories, files, and symbolic links properly
- Add comprehensive unit tests for oil.nvim integration
- Update README documentation to include oil.nvim support

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: add missing oil.nvim filetype checks for window selection

- Add oil filetype check in diff.lua's _find_main_editor_window()
- Add oil filetype check in open_file.lua's find_main_editor_window()
- Add oil filetype check in init.lua's ClaudeCodeSend command

These changes ensure oil.nvim buffers are properly excluded when
searching for main editor windows, preventing diff views and file
opens from appearing in the oil explorer window.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: remove unnecessary variable

* fix: run formatter

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: Peeeaje

README.md

@@ -99,15 +99,15 @@ That's it! For more configuration options, see [Advanced Setup](#advanced-setup)
 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
+- **In nvim-tree/neo-tree/oil.nvim 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
+- **Multiple files**: Select multiple files (using tree plugin's selection features or visual selection in oil.nvim) and press `<leader>as`
+- **Smart detection**: Automatically detects whether you're in nvim-tree, neo-tree, or oil.nvim
 - **Error handling**: Clear feedback if no files are selected or if tree plugins aren't available
 
 ### Direct File Addition

lua/claudecode/diff.lua

@@ -49,6 +49,7 @@ local function find_main_editor_window()
         or filetype == "neo-tree-popup"
         or filetype == "ClaudeCode"
         or filetype == "NvimTree"
+        or filetype == "oil"
         or filetype == "aerial"
         or filetype == "tagbar"
       )

lua/claudecode/init.lua

@@ -409,6 +409,7 @@ function M._create_commands()
 
     local is_tree_buffer = current_ft == "NvimTree"
       or current_ft == "neo-tree"
+      or current_ft == "oil"
       or string.match(current_bufname, "neo%-tree")
       or string.match(current_bufname, "NvimTree")
 

lua/claudecode/integrations.lua

@@ -1,6 +1,6 @@
 ---
 -- Tree integration module for ClaudeCode.nvim
--- Handles detection and selection of files from nvim-tree and neo-tree
+-- Handles detection and selection of files from nvim-tree, neo-tree, and oil.nvim
 -- @module claudecode.integrations
 local M = {}
 
@@ -14,6 +14,8 @@ function M.get_selected_files_from_tree()
     return M._get_nvim_tree_selection()
   elseif current_ft == "neo-tree" then
     return M._get_neotree_selection()
+  elseif current_ft == "oil" then
+    return M._get_oil_selection()
   else
     return nil, "Not in a supported tree buffer (current filetype: " .. current_ft .. ")"
   end
@@ -178,4 +180,85 @@ function M._get_neotree_selection()
   return {}, "No file found under cursor"
 end
 
+--- Get selected files from oil.nvim
+--- Supports both visual selection and single file under cursor
+--- @return table files List of file paths
+--- @return string|nil error Error message if operation failed
+function M._get_oil_selection()
+  local success, oil = pcall(require, "oil")
+  if not success then
+    return {}, "oil.nvim not available"
+  end
+
+  local bufnr = vim.api.nvim_get_current_buf() --[[@as number]]
+  local files = {}
+
+  -- Check if we're in visual mode
+  local mode = vim.fn.mode()
+  if mode == "V" or mode == "v" or mode == "\22" then
+    -- Visual mode: use the common visual range function
+    local visual_commands = require("claudecode.visual_commands")
+    local start_line, end_line = visual_commands.get_visual_range()
+
+    -- Get current directory once
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if not dir_ok or not current_dir then
+      return {}, "Failed to get current directory"
+    end
+
+    -- Process each line in the visual selection
+    for line = start_line, end_line do
+      local entry_ok, entry = pcall(oil.get_entry_on_line, bufnr, line)
+      if entry_ok and entry and entry.name then
+        -- Skip parent directory entries
+        if entry.name ~= ".." and entry.name ~= "." then
+          local full_path = current_dir .. entry.name
+          -- Handle various entry types
+          if entry.type == "file" or entry.type == "link" then
+            table.insert(files, full_path)
+          elseif entry.type == "directory" then
+            -- Ensure directory paths end with /
+            table.insert(files, full_path:match("/$") and full_path or full_path .. "/")
+          else
+            -- For unknown types, return the path anyway
+            table.insert(files, full_path)
+          end
+        end
+      end
+    end
+
+    if #files > 0 then
+      return files, nil
+    end
+  else
+    -- Normal mode: get file under cursor with error handling
+    local ok, entry = pcall(oil.get_cursor_entry)
+    if not ok or not entry then
+      return {}, "Failed to get cursor entry"
+    end
+
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if not dir_ok or not current_dir then
+      return {}, "Failed to get current directory"
+    end
+
+    -- Process the entry
+    if entry.name and entry.name ~= ".." and entry.name ~= "." then
+      local full_path = current_dir .. entry.name
+      -- Handle various entry types
+      if entry.type == "file" or entry.type == "link" then
+        return { full_path }, nil
+      elseif entry.type == "directory" then
+        -- Ensure directory paths end with /
+        return { full_path:match("/$") and full_path or full_path .. "/" }, nil
+      else
+        -- For unknown types, return the path anyway
+        return { full_path }, nil
+      end
+    end
+  end
+
+  return {}, "No file found under cursor"
+end
+
 return M

lua/claudecode/tools/open_file.lua

@@ -75,6 +75,7 @@ local function find_main_editor_window()
         or filetype == "neo-tree-popup"
         or filetype == "ClaudeCode"
         or filetype == "NvimTree"
+        or filetype == "oil"
         or filetype == "aerial"
         or filetype == "tagbar"
       )

lua/claudecode/visual_commands.lua

@@ -174,6 +174,13 @@ function M.get_tree_state()
     end
 
     return nvim_tree_api, "nvim-tree"
+  elseif current_ft == "oil" then
+    local oil_success, oil = pcall(require, "oil")
+    if not oil_success then
+      return nil, nil
+    end
+
+    return oil, "oil"
   else
     return nil, nil
   end
@@ -346,6 +353,34 @@ function M.get_files_from_visual_selection(visual_data)
       end
     end
     files = unique_files
+  elseif tree_type == "oil" then
+    local oil = tree_state
+    local bufnr = vim.api.nvim_get_current_buf()
+
+    -- Get current directory once
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if dir_ok and current_dir then
+      -- Access the process_oil_entry function through a module method
+      for line = start_pos, end_pos do
+        local entry_ok, entry = pcall(oil.get_entry_on_line, bufnr, line)
+        if entry_ok and entry and entry.name then
+          -- Skip parent directory entries
+          if entry.name ~= ".." and entry.name ~= "." then
+            local full_path = current_dir .. entry.name
+            -- Handle various entry types
+            if entry.type == "file" or entry.type == "link" then
+              table.insert(files, full_path)
+            elseif entry.type == "directory" then
+              -- Ensure directory paths end with /
+              table.insert(files, full_path:match("/$") and full_path or full_path .. "/")
+            else
+              -- For unknown types, return the path anyway
+              table.insert(files, full_path)
+            end
+          end
+        end
+      end
+    end
   end
 
   return files, nil