perf: improve performance

lua/helm-ls/conceal.lua

@@ -5,75 +5,133 @@ local lsp = vim.lsp
 local api = vim.api
 local ns_id = api.nvim_create_namespace("conceal_ns")
 
-M.conceal_templates_with_hover = function()
+-- Debounce timer
+local debounce_timer = nil
+
+-- Cache to store hover results
+local hover_cache = {}
+
+-- Function to check if the cursor is on the same line as the node
+local function is_cursor_on_line(start_row)
+  local cursor_row = unpack(api.nvim_win_get_cursor(0))
+  return (cursor_row - 1) == start_row
+end
+
+-- Function to extract hover text from the LSP result
+local function extract_hover_text(contents)
+  local markdown_lines = lsp.util.convert_input_to_markdown_lines(contents)
+  markdown_lines = lsp.util.trim_empty_lines(markdown_lines)
+
+  if vim.tbl_isempty(markdown_lines) then
+    return nil
+  end
+
+  return markdown_lines[3] or markdown_lines[2] or markdown_lines[1]
+end
+
+-- Function to pad hover text to match the length of the original text
+local function pad_text(hover_text, original_length)
+  if #hover_text < original_length then
+    hover_text = hover_text .. string.rep(" ", original_length - #hover_text)
+  end
+  return hover_text
+end
+
+-- Helper function to request hover information from the LSP
+local function request_hover(bufnr, line, col, callback)
+  lsp.buf_request(bufnr, "textDocument/hover", {
+    textDocument = lsp.util.make_text_document_params(),
+    position = { line = line, character = col },
+  }, callback)
+end
+
+-- Helper function to set an extmark with the hover result
+local function set_extmark(bufnr, start_row, start_col, end_row, end_col, hover_text, original_text)
+  hover_text = pad_text(hover_text, #original_text)
+
+  -- Set conceal for the syntax element
+  api.nvim_buf_set_extmark(bufnr, ns_id, start_row, start_col, {
+    end_row = end_row,
+    end_col = end_col,
+    virt_text = { { hover_text, "Conceal" } },
+    virt_text_pos = "overlay",
+    hl_mode = "blend",
+    virt_text_hide = true,
+  })
+end
+
+-- Function to handle LSP hover requests and apply concealment
+local function apply_concealment(bufnr, start_row, start_col, end_row, end_col, node)
+  local original_text = vim.treesitter.get_node_text(node, bufnr)
+  -- Use cached hover result if available
+  local hover_text = hover_cache[original_text]
+  if hover_text then
+    set_extmark(bufnr, start_row, start_col, end_row, end_col, hover_text, original_text)
+  else
+    request_hover(bufnr, end_row, end_col - 1, function(err, result, ctx, _)
+      if err or not result or not result.contents then
+        return
+      end
+
+      hover_text = extract_hover_text(result.contents)
+      hover_cache[original_text] = hover_text
+
+      set_extmark(bufnr, start_row, start_col, end_row, end_col, hover_text, original_text)
+    end)
+  end
+end
+
+-- Main function to conceal templates with hover
+local conceal_templates_with_hover = function()
   local bufnr = api.nvim_get_current_buf()
   local parser = vim.treesitter.get_parser(bufnr, vim.bo.filetype)
   local root = parser:parse()[1]:root()
 
-  -- Define the Tree-sitter query for the syntax you want to conceal
   local query = vim.treesitter.query.parse(
     vim.bo.filetype,
     [[
     ((selector_expression)  ["}}" "|" ]) @selector
   ]]
   )
 
-  for _, match in query:iter_matches(root, bufnr, 0, -1) do
+  -- Get the range of visible lines in the current window
+  local start_line = vim.fn.line("w0") - 1 -- Convert to 0-based index
+  local end_line = vim.fn.line("w$") - 1   -- Convert to 0-based index
+
+  print("start_line: " .. start_line)
+  print("end_line: " .. end_line)
+
+  for _, match in query:iter_matches(root, bufnr, start_line, end_line) do
     for id, node in pairs(match) do
       local start_row, start_col, end_row, end_col = node:range()
 
-      local cursor_row = unpack(api.nvim_win_get_cursor(0))
-      if cursor_row - 1 == start_row then
+      if is_cursor_on_line(start_row) then
         return
       end
 
-      -- Request hover information from the LSP
-      lsp.buf_request(bufnr, "textDocument/hover", {
-        textDocument = lsp.util.make_text_document_params(),
-        position = { line = end_row, character = end_col - 1 },
-      }, function(err, result, ctx, _)
-        if err or not result or not result.contents then
-          return
-        end
-
-        local markdown_lines = lsp.util.convert_input_to_markdown_lines(result.contents)
-        markdown_lines = lsp.util.trim_empty_lines(markdown_lines)
-        if vim.tbl_isempty(markdown_lines) then
-          return
-        end
-
-        local original_text = vim.treesitter.get_node_text(node, bufnr)
-
-        local hover_text = markdown_lines[1] -- Using the first line of the hover result
-        if #markdown_lines >= 3 then
-          hover_text = markdown_lines[3]     -- If there are more lines, use the third one
-        end
-
-        -- Pad the hover text with spaces if it's shorter than the original text
-        if #hover_text < #original_text then
-          hover_text = hover_text .. string.rep(" ", #original_text - #hover_text)
-        end
-
-        -- Set conceal for the syntax element
-        api.nvim_buf_set_extmark(bufnr, ns_id, start_row, start_col, {
-          end_row = end_row,
-          end_col = end_col,
-          virt_text = { { hover_text, "Conceal" } }, -- Replace node content with the hover result
-          virt_text_pos = "overlay",                 -- Overlay the text, replacing the original content
-          hl_mode = "blend",                         -- Blend with the existing text's highlight
-          virt_text_hide = true,                     -- Hide virt_text when selected
-        })
-      end)
+      apply_concealment(bufnr, start_row, start_col, end_row, end_col, node)
     end
   end
 end
 
-M.clear_extmark_if_cursor_on_line = function()
+-- Debounced function call
+local function debounce_conceal_templates_with_hover()
+  if debounce_timer then
+    debounce_timer:stop()
+  end
+  debounce_timer = vim.defer_fn(function()
+    conceal_templates_with_hover()
+  end, 500) -- 200ms debounce time
+end
+
+-- Function to clear extmarks on the cursor's current line
+local clear_extmark_if_cursor_on_line = function()
   local bufnr = api.nvim_get_current_buf()
   local cursor_row = unpack(api.nvim_win_get_cursor(0))
 
-  -- Clear the extmark for the line where the cursor is located
   api.nvim_buf_clear_namespace(bufnr, ns_id, cursor_row - 1, cursor_row)
 end
 
+M.conceal_templates_with_hover = conceal_templates_with_hover
+M.clear_extmark_if_cursor_on_line = clear_extmark_if_cursor_on_line
 return M