feat(ui): add support for top and right panel positions

README.md

@@ -107,7 +107,7 @@ https://github.com/user-attachments/assets/64c41f01-dffe-4318-bce4-16eec8de356e
 
     -- Explorer panel configuration
     explorer = {
-      position = "left",  -- "left" or "bottom"
+      position = "left",  -- "left", "right", "top", or "bottom"
       hidden = false,  -- Initial visibility state
       width = 40,         -- Width when position is "left" (columns)
       height = 15,        -- Height when position is "bottom" (lines)
@@ -135,7 +135,7 @@ https://github.com/user-attachments/assets/64c41f01-dffe-4318-bce4-16eec8de356e
 
     -- History panel configuration (for :CodeDiff history)
     history = {
-      position = "bottom",  -- "left" or "bottom" (default: bottom)
+      position = "bottom",  -- "left", "right", "top", or "bottom" (default: bottom)
       width = 40,           -- Width when position is "left" (columns)
       height = 15,          -- Height when position is "bottom" (lines)
       initial_focus = "history",  -- Initial focus: "history", "original", or "modified"

lua/codediff/config.lua

@@ -51,7 +51,7 @@ M.defaults = {
 
   -- Explorer panel configuration
   explorer = {
-    position = "left", -- "left" or "bottom"
+    position = "left", -- "left", "right", "top", or "bottom"
     hidden = false, -- Initial visibility state
     width = 40, -- Width when position is "left" (columns)
     height = 15, -- Height when position is "bottom" (lines)
@@ -79,7 +79,7 @@ M.defaults = {
 
   -- History panel configuration (for :CodeDiff history)
   history = {
-    position = "bottom", -- "left" or "bottom" (default: bottom)
+    position = "bottom", -- "left", "right", "top", or "bottom" (default: bottom)
     width = 40, -- Width when position is "left" (columns)
     height = 15, -- Height when position is "bottom" (lines)
     initial_focus = "history", -- Initial focus: "history", "original", or "modified"

lua/codediff/ui/explorer/render.lua

@@ -61,9 +61,9 @@ function M.create(status_result, git_root, tabpage, width, base_revision, target
   local size
   local text_width -- Width for text rendering (always horizontal width)
 
-  if position == "bottom" then
+  if position == "bottom" or position == "top" then
     size = explorer_config.height or 15
-    -- For bottom position, use full window width for text
+    -- For bottom/top position, use full window width for text
     text_width = vim.o.columns
   else
     -- Use provided width or config width or default to 40 columns

lua/codediff/ui/history/render.lua

@@ -105,7 +105,7 @@ function M.create(commits, git_root, tabpage, width, opts)
   local size
   local text_width
 
-  if position == "bottom" then
+  if position == "bottom" or position == "top" then
     size = history_config.height or 15
     text_width = vim.o.columns
   else

lua/codediff/ui/layout.lua

@@ -35,7 +35,7 @@ function M.arrange(tabpage)
 
   -- Step 1: Pin panel size (fixed element)
   if panel_visible then
-    if panel_position == "left" then
+    if panel_position == "left" or panel_position == "right" then
       vim.api.nvim_win_set_width(panel_win, panel_config.width)
     else
       vim.api.nvim_win_set_height(panel_win, panel_config.height)
@@ -51,7 +51,7 @@ function M.arrange(tabpage)
     local sole_win = orig_valid and original_win or (mod_valid and modified_win or nil)
     if sole_win then
       if panel_visible then
-        if panel_position == "left" then
+        if panel_position == "left" or panel_position == "right" then
           vim.api.nvim_win_set_width(panel_win, panel_config.width)
           -- Explicitly set diff window to fill remainder
           local remainder = vim.o.columns - panel_config.width - 1
@@ -117,7 +117,7 @@ function M.arrange(tabpage)
 
   -- Step 5: Re-pin panel size (undo disturbance from step 4)
   if panel_visible then
-    if panel_position == "left" then
+    if panel_position == "left" or panel_position == "right" then
       vim.api.nvim_win_set_width(panel_win, panel_config.width)
     else
       vim.api.nvim_win_set_height(panel_win, panel_config.height)

tests/ui/layout_spec.lua

@@ -260,6 +260,82 @@ describe("Layout Manager", function()
     cleanup_mock_session(tabpage)
   end)
 
+  -- =========================================================================
+  -- Case 3b: Explorer right, no result — [orig | mod | expl]
+  -- =========================================================================
+  it("Case 3b: Explorer right — panel gets configured width, diff panes split remainder", function()
+    local panel_width = 35
+    config.options.explorer = { position = "right", width = panel_width }
+
+    vim.cmd("tabnew")
+    local tabpage = vim.api.nvim_get_current_tabpage()
+    local orig_win = vim.api.nvim_get_current_win()
+    local orig_buf = vim.api.nvim_get_current_buf()
+    vim.cmd("vsplit")
+    local mod_win = vim.api.nvim_get_current_win()
+    local mod_buf = vim.api.nvim_get_current_buf()
+
+    local panel = create_panel_split("right", panel_width)
+
+    create_mock_session(tabpage, {
+      mode = "explorer",
+      original_win = orig_win,
+      modified_win = mod_win,
+      original_bufnr = orig_buf,
+      modified_bufnr = mod_buf,
+      panel = panel,
+    })
+
+    layout.arrange(tabpage)
+
+    local panel_w = vim.api.nvim_win_get_width(panel.winid)
+    local orig_w = vim.api.nvim_win_get_width(orig_win)
+    local mod_w = vim.api.nvim_win_get_width(mod_win)
+
+    assert.are.equal(panel_width, panel_w, "Panel should be configured width")
+    assert_width_near(orig_w, mod_w, "Diff panes should be equal width:")
+
+    cleanup_mock_session(tabpage)
+  end)
+
+  -- =========================================================================
+  -- Case 3c: Explorer top, no result — [expl] / [orig | mod]
+  -- =========================================================================
+  it("Case 3c: Explorer top — panel gets configured height, diff panes split full width", function()
+    local panel_height = 12
+    config.options.explorer = { position = "top", height = panel_height }
+
+    vim.cmd("tabnew")
+    local tabpage = vim.api.nvim_get_current_tabpage()
+    local orig_win = vim.api.nvim_get_current_win()
+    local orig_buf = vim.api.nvim_get_current_buf()
+    vim.cmd("vsplit")
+    local mod_win = vim.api.nvim_get_current_win()
+    local mod_buf = vim.api.nvim_get_current_buf()
+
+    local panel = create_panel_split("top", panel_height)
+
+    create_mock_session(tabpage, {
+      mode = "explorer",
+      original_win = orig_win,
+      modified_win = mod_win,
+      original_bufnr = orig_buf,
+      modified_bufnr = mod_buf,
+      panel = panel,
+    })
+
+    layout.arrange(tabpage)
+
+    local panel_h = vim.api.nvim_win_get_height(panel.winid)
+    local orig_w = vim.api.nvim_win_get_width(orig_win)
+    local mod_w = vim.api.nvim_win_get_width(mod_win)
+
+    assert.are.equal(panel_height, panel_h, "Panel should be configured height")
+    assert_width_near(orig_w, mod_w, "Diff panes should be equal width:")
+
+    cleanup_mock_session(tabpage)
+  end)
+
   -- =========================================================================
   -- Case 4: History left, no result — [hist | orig | mod]
   -- =========================================================================
@@ -336,6 +412,82 @@ describe("Layout Manager", function()
     cleanup_mock_session(tabpage)
   end)
 
+  -- =========================================================================
+  -- Case 5b: History right, no result — [orig | mod | hist]
+  -- =========================================================================
+  it("Case 5b: History right — panel gets configured width, diff panes split remainder", function()
+    local panel_width = 30
+    config.options.history = { position = "right", width = panel_width }
+
+    vim.cmd("tabnew")
+    local tabpage = vim.api.nvim_get_current_tabpage()
+    local orig_win = vim.api.nvim_get_current_win()
+    local orig_buf = vim.api.nvim_get_current_buf()
+    vim.cmd("vsplit")
+    local mod_win = vim.api.nvim_get_current_win()
+    local mod_buf = vim.api.nvim_get_current_buf()
+
+    local panel = create_panel_split("right", panel_width)
+
+    create_mock_session(tabpage, {
+      mode = "history",
+      original_win = orig_win,
+      modified_win = mod_win,
+      original_bufnr = orig_buf,
+      modified_bufnr = mod_buf,
+      panel = panel,
+    })
+
+    layout.arrange(tabpage)
+
+    local panel_w = vim.api.nvim_win_get_width(panel.winid)
+    local orig_w = vim.api.nvim_win_get_width(orig_win)
+    local mod_w = vim.api.nvim_win_get_width(mod_win)
+
+    assert.are.equal(panel_width, panel_w, "History panel should be configured width")
+    assert_width_near(orig_w, mod_w, "Diff panes should be equal width:")
+
+    cleanup_mock_session(tabpage)
+  end)
+
+  -- =========================================================================
+  -- Case 5c: History top, no result — [hist] / [orig | mod]
+  -- =========================================================================
+  it("Case 5c: History top — panel gets configured height, diff panes split full width", function()
+    local panel_height = 10
+    config.options.history = { position = "top", height = panel_height }
+
+    vim.cmd("tabnew")
+    local tabpage = vim.api.nvim_get_current_tabpage()
+    local orig_win = vim.api.nvim_get_current_win()
+    local orig_buf = vim.api.nvim_get_current_buf()
+    vim.cmd("vsplit")
+    local mod_win = vim.api.nvim_get_current_win()
+    local mod_buf = vim.api.nvim_get_current_buf()
+
+    local panel = create_panel_split("top", panel_height)
+
+    create_mock_session(tabpage, {
+      mode = "history",
+      original_win = orig_win,
+      modified_win = mod_win,
+      original_bufnr = orig_buf,
+      modified_bufnr = mod_buf,
+      panel = panel,
+    })
+
+    layout.arrange(tabpage)
+
+    local panel_h = vim.api.nvim_win_get_height(panel.winid)
+    local orig_w = vim.api.nvim_win_get_width(orig_win)
+    local mod_w = vim.api.nvim_win_get_width(mod_win)
+
+    assert.are.equal(panel_height, panel_h, "History panel should be configured height")
+    assert_width_near(orig_w, mod_w, "Diff panes should be equal width:")
+
+    cleanup_mock_session(tabpage)
+  end)
+
   -- =========================================================================
   -- Case 6: Explorer left + result bottom — [expl | orig | mod] / [result]
   -- =========================================================================