darcula_nvim/nvim/lua/darcula/lsp/lightbulb.lua

-- The MIT License (MIT)
--
-- Copyright © 2026 Scott E. Graves <scott.e.graves@protonmail.com>
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software
-- and associated documentation files (the “Software”), to deal in the Software without restriction,
-- including without limitation the rights to use, copy, modify, merge, publish, distribute,
-- sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
-- furnished to do so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in all copies or
-- substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
-- BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-- NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
--
local M = {}

local namespace = vim.api.nvim_create_namespace("DarculaLightbulb")
local requests = {}
local revisions = {}

local config = {
  priority = 10,
  sign = {
    enabled = true,
    text = "💡",
    hl = "DiagnosticSignInfo"
  },
  virtual_text = {
    enabled = false,
    text = "💡",
    hl = "DiagnosticVirtualTextInfo"
  }
}

local function cancel_request(bufnr)
  local cancel = requests[bufnr]
  requests[bufnr] = nil
  if cancel then
    pcall(cancel)
  end
end

local function clear_indicator(bufnr)
  if vim.api.nvim_buf_is_valid(bufnr) then
    vim.api.nvim_buf_clear_namespace(bufnr, namespace, 0, -1)
  end
end

local function render(bufnr, line)
  clear_indicator(bufnr)
  if not vim.api.nvim_buf_is_valid(bufnr) then
    return
  end

  line = math.max(0, math.min(line, vim.api.nvim_buf_line_count(bufnr) - 1))

  vim.api.nvim_buf_set_extmark(
    bufnr,
    namespace,
    line,
    0,
    {
      strict = false,
      priority = config.priority,
      sign_text = config.sign.enabled and config.sign.text or nil,
      sign_hl_group = config.sign.enabled and config.sign.hl or nil,
      virt_text = config.virtual_text.enabled and
        {{config.virtual_text.text, config.virtual_text.hl}} or
        nil,
      virt_text_pos = config.virtual_text.enabled and "eol" or nil,
      hl_mode = config.virtual_text.enabled and "combine" or nil
    }
  )
end

function M.clear(bufnr)
  bufnr = bufnr or vim.api.nvim_get_current_buf()
  revisions[bufnr] = (revisions[bufnr] or 0) + 1
  cancel_request(bufnr)
  clear_indicator(bufnr)
end

function M.update()
  local bufnr = vim.api.nvim_get_current_buf()
  local win = vim.api.nvim_get_current_win()
  local cursor = vim.api.nvim_win_get_cursor(win)
  local line = cursor[1] - 1
  local revision = (revisions[bufnr] or 0) + 1
  revisions[bufnr] = revision

  cancel_request(bufnr)

  local clients = vim.lsp.get_clients(
    {bufnr = bufnr, method = "textDocument/codeAction"}
  )
  if #clients == 0 then
    clear_indicator(bufnr)
    return
  end

  local diagnostics = vim.lsp.diagnostic.from(
    vim.diagnostic.get(bufnr, {lnum = line})
  )

  requests[bufnr] = vim.lsp.buf_request_all(
    bufnr,
    "textDocument/codeAction",
    function(client)
      local params = vim.lsp.util.make_range_params(win, client.offset_encoding)
      params.context = {diagnostics = diagnostics}
      return params
    end,
    function(responses)
      if
        revisions[bufnr] ~= revision or
          not vim.api.nvim_buf_is_valid(bufnr)
       then
        return
      end
      requests[bufnr] = nil

      local has_actions = false
      for _, response in pairs(responses) do
        if response.result ~= nil and not vim.tbl_isempty(response.result) then
          has_actions = true
          break
        end
      end

      if has_actions then
        render(bufnr, line)
      else
        clear_indicator(bufnr)
      end
    end
  )
end

function M.setup(opts)
  config = vim.tbl_deep_extend("force", config, opts or {})

  local group = vim.api.nvim_create_augroup("DarculaLightbulb", {clear = true})
  vim.api.nvim_create_autocmd(
    {"CursorHold", "CursorHoldI"},
    {
      callback = M.update,
      group = group
    }
  )
  vim.api.nvim_create_autocmd(
    "WinLeave",
    {
      callback = function(args)
        M.clear(args.buf)
      end,
      group = group
    }
  )
  vim.api.nvim_create_autocmd(
    "BufWipeout",
    {
      callback = function(args)
        cancel_request(args.buf)
        requests[args.buf] = nil
        revisions[args.buf] = nil
      end,
      group = group
    }
  )
end

return M