fix(nvim): smooth scroll ignores lines in closed folds

1 files changed, 26 insertions, 13 deletions

diff --git a/plugin/50-smooth_scroll.lua b/plugin/50-smooth_scroll.lua
index 84824a3..3c2ef05 100644
--- a/plugin/50-smooth_scroll.lua
+++ b/plugin/50-smooth_scroll.lua
@@ -4,24 +4,37 @@ local Dir = {
 }
 
 local function smooth_scroll(dir)
-	local view, start_pos, buf_line_count, win_height =
-		vim.fn.winsaveview(),
-		vim.api.nvim_win_get_cursor(0),
-		vim.api.nvim_buf_line_count(0),
-		vim.api.nvim_win_get_height(0)
+	local at_boundary
+	if dir == Dir.DOWN then
+		at_boundary = function()
+			return vim.fn.line("w$") == vim.api.nvim_buf_line_count(0)
+		end
+	else
+		at_boundary = function()
+			return vim.fn.line("w0") == 1
+		end
+	end
+	-- bail at boundaries: <C-e>/<C-y> would no-op but j/k would still walk the cursor
+	if at_boundary() then
+		return
+	end
+	local win_height = vim.api.nvim_win_get_height(0)
 	local duration, sleep_duration = 100, 16 -- 60 fps
-	local max_distance = dir == Dir.DOWN and buf_line_count - start_pos[1] or start_pos[1] - 1
-	local distance = math.min(max_distance, math.floor(win_height / 2))
+	local distance = math.floor(win_height / 2)
 	local steps_number = math.ceil(duration / sleep_duration) -- We want a movement every `sleep_duration` msec
 	local step = distance / steps_number
+	local keys = dir == Dir.DOWN and "\\<C-e>j" or "\\<C-y>k"
+	local prev = 0
 	for i = 1, steps_number do
+		local cur = math.ceil(step * i)
+		local delta = cur - prev
+		prev = cur
 		vim.defer_fn(function()
-			local offset = math.ceil(step * i) * (dir == Dir.DOWN and 1 or -1)
-			local new_pos = { start_pos[1] + offset, start_pos[2] }
-			vim.api.nvim_win_set_cursor(0, new_pos)
-			local new_topline = math.max(1, view.topline + offset)
-			if buf_line_count - new_topline >= win_height then -- don't move viewport beyond eof (DOWN) or first line (UP)
-				vim.fn.winrestview({ lnum = view.lnum + offset, topline = new_topline }) -- move viewport
+			for _ = 1, delta do
+				if at_boundary() then
+					return
+				end
+				vim.cmd('exec "normal! ' .. keys .. '"')
 			end
 		end, sleep_duration * i)
 	end