fix: improve vertical split behavior for claude terminal

Previously the window split command resized the current editor window rather than the claude window. This led to a weird behavior where asking for a vertical split made the window much shorter.

This change fixes this by:
1. Adding a unified split_ratio config option (with backward compatibility for height_ratio)
2. Properly detecting vertical splits via window position
3. Applying the appropriate resize command for each split type

Author: stephenprater

lua/claude-code/config.lua

@@ -8,7 +8,7 @@ local M = {}
 
 --- ClaudeCodeWindow class for window configuration
 -- @table ClaudeCodeWindow
--- @field height_ratio number Percentage of screen height for the terminal window
+-- @field split_ratio number Percentage of screen for the terminal window (height for horizontal, width for vertical splits)
 -- @field position string Position of the window: "botright", "topleft", "vertical", etc.
 -- @field enter_insert boolean Whether to enter insert mode when opening Claude Code
 -- @field hide_numbers boolean Hide line numbers in the terminal window
@@ -49,7 +49,8 @@ local M = {}
 M.default_config = {
   -- Terminal window settings
   window = {
-    height_ratio = 0.3, -- Percentage of screen height for the terminal window
+    split_ratio = 0.3, -- Percentage of screen for the terminal window (height or width)
+    height_ratio = 0.3, -- DEPRECATED: Use split_ratio instead
     position = 'botright', -- Position of the window: "botright", "topleft", "vertical", etc.
     enter_insert = true, -- Whether to enter insert mode when opening Claude Code
     hide_numbers = true, -- Hide line numbers in the terminal window
@@ -90,11 +91,11 @@ local function validate_config(config)
   end
 
   if
-    type(config.window.height_ratio) ~= 'number'
-    or config.window.height_ratio <= 0
-    or config.window.height_ratio > 1
+    type(config.window.split_ratio) ~= 'number'
+    or config.window.split_ratio <= 0
+    or config.window.split_ratio > 1
   then
-    return false, 'window.height_ratio must be a number between 0 and 1'
+    return false, 'window.split_ratio must be a number between 0 and 1'
   end
 
   if type(config.window.position) ~= 'string' then
@@ -187,6 +188,14 @@ end
 --- @param silent? boolean Set to true to suppress error notifications (for tests)
 --- @return ClaudeCodeConfig
 function M.parse_config(user_config, silent)
+  -- Handle backward compatibility first
+  if user_config and user_config.window then
+    if user_config.window.height_ratio and not user_config.window.split_ratio then
+      -- Copy height_ratio to split_ratio for backward compatibility
+      user_config.window.split_ratio = user_config.window.height_ratio
+    end
+  end
+
   local config = vim.tbl_deep_extend('force', {}, M.default_config, user_config or {})
 
   local valid, err = validate_config(config)

lua/claude-code/terminal.lua

@@ -15,6 +15,36 @@ M.terminal = {
   saved_updatetime = nil,
 }
 
+--- Create a split window according to the specified position configuration
+--- @param position string Window position configuration
+--- @param config table Plugin configuration containing window settings
+--- @param existing_bufnr number|nil Buffer number of existing buffer to show in the split (optional)
+--- @private
+local function create_split(position, config, existing_bufnr)
+  local is_vertical = position:match('vsplit') or position:match('vertical')
+
+  -- Create the window with the user's specified command
+  -- If the command already contains 'split' or 'vsplit', use it as is
+  if position:match('split') then
+    vim.cmd(position)
+  else
+    -- Otherwise append 'split'
+    vim.cmd(position .. ' split')
+  end
+
+  -- If we have an existing buffer to display, switch to it
+  if existing_bufnr then
+    vim.cmd('buffer ' .. existing_bufnr)
+  end
+
+  -- Resize the window appropriately based on split type
+  if is_vertical then
+    vim.cmd('vertical resize ' .. math.floor(vim.o.columns * config.window.split_ratio))
+  else
+    vim.cmd('resize ' .. math.floor(vim.o.lines * config.window.split_ratio))
+  end
+end
+
 --- Set up function to force insert mode when entering the Claude Code window
 --- @param claude_code table The main plugin module
 function M.force_insert_mode(claude_code)
@@ -48,18 +78,15 @@ function M.toggle(claude_code, config, git)
       end
     else
       -- Claude Code buffer exists but is not visible, open it in a split
-      vim.cmd(config.window.position .. ' split')
-      vim.cmd('resize ' .. math.floor(vim.o.lines * config.window.height_ratio))
-      vim.cmd('buffer ' .. bufnr)
+      create_split(config.window.position, config, bufnr)
       -- Force insert mode more aggressively
       vim.schedule(function()
         vim.cmd 'stopinsert | startinsert'
       end)
     end
   else
     -- Claude Code is not running, start it in a new split
-    vim.cmd(config.window.position .. ' split')
-    vim.cmd('resize ' .. math.floor(vim.o.lines * config.window.height_ratio))
+    create_split(config.window.position, config)
 
     -- Determine if we should use the git root directory
     local cmd = 'terminal ' .. config.command

tests/spec/config_spec.lua

@@ -15,28 +15,43 @@ describe('config', function()
     it('should merge user config with default config', function()
       local user_config = {
         window = {
-          height_ratio = 0.5,
+          split_ratio = 0.5,
         },
       }
       local result = config.parse_config(user_config, true) -- silent mode
-      assert.are.equal(0.5, result.window.height_ratio)
+      assert.are.equal(0.5, result.window.split_ratio)
 
       -- Other values should be set to defaults
       assert.are.equal('botright', result.window.position)
       assert.are.equal(true, result.window.enter_insert)
     end)
 
     it('should validate config values', function()
-      -- This config has an invalid height_ratio (should be between 0 and 1)
+      -- This config has an invalid split_ratio (should be between 0 and 1)
       local invalid_config = {
         window = {
-          height_ratio = 2,
+          split_ratio = 2,
         },
       }
 
       -- When validation fails, it should return the default config
       local result = config.parse_config(invalid_config, true) -- silent mode
-      assert.are.equal(config.default_config.window.height_ratio, result.window.height_ratio)
+      assert.are.equal(config.default_config.window.split_ratio, result.window.split_ratio)
+    end)
+    
+    it('should maintain backward compatibility with height_ratio', function()
+      -- Config using the legacy height_ratio instead of split_ratio
+      local legacy_config = {
+        window = {
+          height_ratio = 0.7,
+          -- split_ratio not specified
+        },
+      }
+
+      local result = config.parse_config(legacy_config, true) -- silent mode
+      
+      -- split_ratio should be set to the height_ratio value
+      assert.are.equal(0.7, result.window.split_ratio)
     end)
   end)
 end)

tests/spec/terminal_spec.lua

@@ -70,7 +70,7 @@ describe('terminal module', function()
       command = 'claude',
       window = {
         position = 'botright',
-        height_ratio = 0.5,
+        split_ratio = 0.5,
         enter_insert = true,
         hide_numbers = true,
         hide_signcolumn = true,