create debug Neovim plugin for lsp-devtools and server logs (#292)

Author: joshuadavidthomas

.lazy.lua

@@ -12,4 +12,189 @@ vim.api.nvim_create_autocmd({ "BufRead", "BufNewFile" }, {
   end,
 })
 
-return {}
+local M = {}
+
+M.state = {
+  wins = {},
+  bufs = {},
+  timers = { devtools = nil, logs = nil },
+  devtools = { job = nil, lines = {} },
+}
+
+local function strip_ansi(str)
+  return str:gsub("\27%[[0-9;]*m", "")
+end
+
+local function create_buffer(opts)
+  local buf = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_set_current_buf(buf)
+  vim.bo.modifiable = true
+  vim.bo.buftype = "nofile"
+  vim.bo.filetype = opts.filetype or "text"
+
+  local win = vim.api.nvim_get_current_win()
+  vim.wo.number = opts.number ~= nil and opts.number or false
+  vim.wo.relativenumber = false
+  vim.wo.list = false
+  vim.wo.wrap = opts.wrap or false
+
+  return buf, win
+end
+
+local function auto_scroll(bufnr, line_count)
+  local wins = vim.fn.win_findbuf(bufnr)
+  for _, win in ipairs(wins) do
+    vim.api.nvim_win_set_cursor(win, { line_count, 0 })
+  end
+end
+
+function M.ensure_devtools_running()
+  if M.state.devtools.job then
+    return
+  end
+
+  M.state.devtools.lines = {}
+  M.state.devtools.job = vim.fn.jobstart("just dev devtools record", {
+    stdout_buffered = false,
+    on_stdout = function(_, data)
+      if not data then
+        return
+      end
+      local cleaned = vim.tbl_map(strip_ansi, data)
+      local filtered = vim.tbl_filter(function(line)
+        return line ~= ""
+      end, cleaned)
+      for _, line in ipairs(filtered) do
+        table.insert(M.state.devtools.lines, line)
+      end
+    end,
+    on_exit = function()
+      M.state.devtools.job = nil
+    end,
+  })
+end
+
+function M.update_devtools(bufnr, start_idx)
+  if not vim.api.nvim_buf_is_valid(bufnr) then
+    return #M.state.devtools.lines
+  end
+
+  local new_lines = vim.list_slice(M.state.devtools.lines, start_idx + 1)
+  if #new_lines > 0 then
+    vim.api.nvim_buf_set_lines(bufnr, -1, -1, false, new_lines)
+    auto_scroll(bufnr, vim.api.nvim_buf_line_count(bufnr))
+  end
+
+  return #M.state.devtools.lines
+end
+
+function M.update_logs(bufnr)
+  local log_file = vim.fn.system("ls -t /tmp/djls.log.* 2>/dev/null | head -1"):gsub("%s+$", "")
+
+  if log_file == "" then
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, { "Waiting for server logs..." })
+    return
+  end
+
+  local lines = vim.fn.readfile(log_file)
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
+  auto_scroll(bufnr, #lines)
+end
+
+function M.close()
+  for _, timer in pairs(M.state.timers) do
+    if timer then
+      timer:stop()
+    end
+  end
+  M.state.timers = { devtools = nil, logs = nil }
+
+  for _, win in ipairs(M.state.wins) do
+    if vim.api.nvim_win_is_valid(win) then
+      vim.api.nvim_win_close(win, true)
+    end
+  end
+  for _, buf in ipairs(M.state.bufs) do
+    if vim.api.nvim_buf_is_valid(buf) then
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end
+  end
+
+  M.state.wins = {}
+  M.state.bufs = {}
+end
+
+function M.open()
+  M.ensure_devtools_running()
+
+  local main_win = vim.api.nvim_get_current_win()
+
+  vim.cmd("vsplit")
+  vim.cmd("wincmd l")
+  vim.cmd("vertical resize 80")
+
+  -- Top: lsp-devtools
+  local devtools_buf, devtools_win = create_buffer({ filetype = "json" })
+  if #M.state.devtools.lines > 0 then
+    vim.api.nvim_buf_set_lines(devtools_buf, 0, -1, false, M.state.devtools.lines)
+  end
+
+  local last_line_count = #M.state.devtools.lines
+  M.state.timers.devtools = vim.uv.new_timer()
+  M.state.timers.devtools:start(
+    100,
+    100,
+    vim.schedule_wrap(function()
+      last_line_count = M.update_devtools(devtools_buf, last_line_count)
+    end)
+  )
+
+  table.insert(M.state.wins, devtools_win)
+  table.insert(M.state.bufs, devtools_buf)
+
+  -- Bottom: server logs
+  vim.cmd("split")
+  vim.cmd("wincmd j")
+  local log_buf, log_win = create_buffer({ filetype = "log", wrap = true })
+
+  M.update_logs(log_buf)
+  M.state.timers.logs = vim.uv.new_timer()
+  M.state.timers.logs:start(
+    500,
+    500,
+    vim.schedule_wrap(function()
+      M.update_logs(log_buf)
+    end)
+  )
+
+  table.insert(M.state.wins, log_win)
+  table.insert(M.state.bufs, log_buf)
+
+  vim.api.nvim_set_current_win(main_win)
+end
+
+function M.toggle()
+  if #M.state.wins > 0 then
+    M.close()
+  else
+    M.open()
+  end
+end
+
+vim.api.nvim_create_autocmd("VimLeavePre", {
+  callback = function()
+    if M.state.devtools.job then
+      vim.fn.jobstop(M.state.devtools.job)
+    end
+  end,
+})
+
+vim.api.nvim_create_user_command("DjlsDebugToggle", M.toggle, {})
+vim.keymap.set("n", "<leader>dd", M.toggle, { desc = "Toggle DJLS debug windows" })
+
+return {
+  {
+    "fei6409/log-highlight.nvim",
+    opts = {},
+  },
+}