feat: implement ufo properly

lua/config/options.lua

@@ -5,3 +5,9 @@ vim.opt.swapfile = false
 vim.opt.backup = false
 vim.opt.writebackup = false
 vim.opt.spelllang = {}
+
+-- fold config
+vim.o.foldcolumn = "1" -- '0' is not bad
+vim.o.foldlevel = 99   -- Using ufo provider need a large value, feel free to decrease the value
+vim.o.foldlevelstart = 99
+vim.o.foldenable = true

lua/plugins/visualize/fold.lua

@@ -1,8 +1,49 @@
+local handler = function(virtText, lnum, endLnum, width, truncate)
+	local newVirtText = {}
+	local suffix = (" 󰁂 %d "):format(endLnum - lnum)
+	local sufWidth = vim.fn.strdisplaywidth(suffix)
+	local targetWidth = width - sufWidth
+	local curWidth = 0
+	for _, chunk in ipairs(virtText) do
+		local chunkText = chunk[1]
+		local chunkWidth = vim.fn.strdisplaywidth(chunkText)
+		if targetWidth > curWidth + chunkWidth then
+			table.insert(newVirtText, chunk)
+		else
+			chunkText = truncate(chunkText, targetWidth - curWidth)
+			local hlGroup = chunk[2]
+			table.insert(newVirtText, { chunkText, hlGroup })
+			chunkWidth = vim.fn.strdisplaywidth(chunkText)
+			-- str width returned from truncate() may less than 2nd argument, need padding
+			if curWidth + chunkWidth < targetWidth then
+				suffix = suffix .. (" "):rep(targetWidth - curWidth - chunkWidth)
+			end
+			break
+		end
+		curWidth = curWidth + chunkWidth
+	end
+	table.insert(newVirtText, { suffix, "MoreMsg" })
+	return newVirtText
+end
 return {
 	"kevinhwang91/nvim-ufo",
 	dependencies = "kevinhwang91/promise-async",
 	event = "BufReadPre",
+	config = function()
+		local capabilities = vim.lsp.protocol.make_client_capabilities()
+		capabilities.textDocument.foldingRange = {
+			dynamicRegistration = false,
+			lineFoldingOnly = true,
+		}
+		local language_servers = require("lspconfig").util.available_servers()
+		for _, ls in ipairs(language_servers) do
+			require("lspconfig")[ls].setup({
+				capabilities = capabilities,
+			})
+		end
+	end,
 	opts = {
+		fold_virt_text_handler = handler,
 		provider_selector = function(bufnr, filetype, buftype)
 			return { "treesitter", "indent" }
 		end,