fix: synchronize the size of the floating window and split window (#151)

lua/avante/floating_window.lua

@@ -12,6 +12,9 @@ api.nvim_set_hl(namespace, "FloatBorder", { link = "Normal" })
 ---@field buf_options table | nil
 ---@field win_options table | nil
 ---@field float_options table | nil
+---@field on_mount_handlers table | nil
+---@field on_unmount_handlers table | nil
+---@field augroup integer | nil
 local FloatingWindow = {}
 FloatingWindow.__index = FloatingWindow
 
@@ -37,9 +40,128 @@ function FloatingWindow.new(opts)
   instance.buf_options = opts.buf_options or {}
   instance.win_options = opts.win_options or {}
   instance.float_options = opts.float_options or {}
+  instance.on_mount_handlers = {}
+  instance.on_unmount_handlers = {}
+  instance.augroup = nil
   return instance
 end
 
+---@param split_winid integer
+---@param opts opts
+---@return FloatingWindow
+function FloatingWindow.from_split_win(split_winid, opts)
+  local split_win_width = api.nvim_win_get_width(split_winid)
+  local split_win_height = api.nvim_win_get_height(split_winid)
+
+  local calc_floating_win_size = function(width, height)
+    return {
+      width = math.max(width - 2, 0),
+      height = math.max(height - 3, 0),
+    }
+  end
+
+  local floating_win_size = calc_floating_win_size(split_win_width, split_win_height)
+
+  local float_opts_ = vim.tbl_deep_extend("force", {
+    relative = "win",
+    win = split_winid,
+    width = floating_win_size.width,
+    height = floating_win_size.height,
+    row = 1,
+    col = 0,
+    style = "minimal",
+    border = { " ", " ", " ", " ", " ", " ", " ", " " },
+  }, opts.float_options or {})
+
+  local win_opts_ = vim.tbl_deep_extend("force", {}, opts.win_options or {})
+
+  local buf_opts_ = vim.tbl_deep_extend("force", {}, opts.buf_options or {})
+
+  local floating_win = FloatingWindow({
+    buf_options = buf_opts_,
+    win_options = win_opts_,
+    float_options = float_opts_,
+  })
+
+  floating_win:on_mount(function(winid)
+    api.nvim_create_autocmd("WinResized", {
+      group = floating_win.augroup,
+      callback = function()
+        if not api.nvim_win_is_valid(split_winid) or not api.nvim_win_is_valid(winid) then
+          return
+        end
+
+        local current_width = api.nvim_win_get_width(winid)
+        local current_height = api.nvim_win_get_height(winid)
+
+        if current_width == floating_win_size.width and current_height == floating_win_size.height then
+          return
+        end
+
+        floating_win_size.width = current_width
+        floating_win_size.height = current_height
+
+        api.nvim_win_set_height(split_winid, current_height + 3)
+        api.nvim_win_set_width(split_winid, current_width + 2)
+      end,
+    })
+
+    api.nvim_create_autocmd("WinResized", {
+      group = floating_win.augroup,
+      callback = function()
+        if not api.nvim_win_is_valid(split_winid) or not api.nvim_win_is_valid(winid) then
+          return
+        end
+
+        local current_split_win_width = api.nvim_win_get_width(split_winid)
+        local current_split_win_height = api.nvim_win_get_height(split_winid)
+
+        if current_split_win_width == split_win_width and current_split_win_height == split_win_height then
+          return
+        end
+
+        split_win_width = current_split_win_width
+        split_win_height = current_split_win_height
+
+        local current_floating_win_size = calc_floating_win_size(current_split_win_width, current_split_win_height)
+
+        local old_floating_win_options = api.nvim_win_get_config(winid)
+        local new_floating_win_options = vim.tbl_deep_extend("force", old_floating_win_options, {
+          width = current_floating_win_size.width,
+          height = current_floating_win_size.height,
+        })
+        api.nvim_win_set_config(winid, new_floating_win_options)
+      end,
+    })
+  end)
+
+  return floating_win
+end
+
+function FloatingWindow:__gc()
+  self:unmount()
+end
+
+function FloatingWindow:__tostring()
+  return "FloatingWindow"
+end
+
+function FloatingWindow:__eq(other)
+  return self.winid == other.winid
+end
+
+---@param handler fun(number, number): nil
+---@return nil
+function FloatingWindow:on_mount(handler)
+  table.insert(self.on_mount_handlers, handler)
+end
+
+---@param handler fun(nuber, nubmer): nil
+---@return nil
+function FloatingWindow:on_unmount(handler)
+  table.insert(self.on_unmount_handlers, handler)
+end
+
 ---@return nil
 function FloatingWindow:mount()
   self.bufnr = api.nvim_create_buf(false, true)
@@ -50,15 +172,30 @@ function FloatingWindow:mount()
 
   self.winid = api.nvim_open_win(self.bufnr, self.enter, self.float_options)
 
+  self.augroup = api.nvim_create_augroup("avante_floating_window_" .. tostring(self.winid), { clear = true })
+
   for option, value in pairs(self.win_options) do
     api.nvim_set_option_value(option, value, { win = self.winid })
   end
 
   api.nvim_win_set_hl_ns(self.winid, namespace)
+
+  for _, handler in ipairs(self.on_mount_handlers) do
+    handler(self.winid, self.bufnr)
+  end
 end
 
 ---@return nil
 function FloatingWindow:unmount()
+  for _, handler in ipairs(self.on_unmount_handlers) do
+    handler(self.winid, self.bufnr)
+  end
+
+  if self.augroup ~= nil then
+    pcall(api.nvim_delete_augroup, self.augroup)
+    self.augroup = nil
+  end
+
   if self.bufnr and api.nvim_buf_is_valid(self.bufnr) then
     api.nvim_buf_delete(self.bufnr, { force = true })
     self.bufnr = nil