absvim/lua/autocmds.lua

local autocmd = vim.api.nvim_create_autocmd -- Create autocommand
---- Toggle between line numbers and relative line numbers
local _group = vim.api.nvim_create_augroup("LineNumber", { clear = true })

local function relativeln(target)
  if vim.b.lnstatus == nil then
    vim.b.lnstatus = "number"
  end

  if vim.b.lnstatus ~= "nonumber" then
    if target == "number" then
      vim.o.number = true
      vim.o.relativenumber = false
    else
      vim.o.number = true
      vim.o.relativenumber = true
    end
  else
    vim.o.number = false
  end
end

autocmd("InsertEnter", {
  pattern = "*",
  callback = function()
    relativeln("number")
  end,
  once = false,
  group = _group,
})
autocmd("InsertLeave", {
  pattern = "*",
  callback = function()
    relativeln("relativenumber")
  end,
  once = false,
  group = _group,
})

autocmd("FocusLost", {
  pattern = "*",
  callback = function()
    relativeln("number")
  end,
  once = false,
  group = _group,
})
autocmd("CursorMoved", {
  pattern = "*",
  callback = function()
    relativeln("relativenumber")
  end,
  once = false,
  group = _group,
})

function Toggleln()
  if vim.b.lnstatus == nil then
    vim.b.lnstatus = "number"
  end

  if vim.b.lnstatus == "number" then
    vim.o.number = false
    vim.o.relativenumber = false
    vim.b.lnstatus = "nonumber"
  else
    vim.o.number = true
    vim.o.relativenumber = true
    vim.b.lnstatus = "number"
  end
end

---- trim whitespace on save
autocmd("BufWritePre", {
  pattern = "*",
  callback = function()
    vim.cmd([[:%s/\s\+$//e]])
  end,
  once = false,
  group = _group,
})

-- change tmux title
autocmd("BufReadPost", {
  pattern = "*",
  callback = function()
    vim.cmd([[call system("tmux rename-window '" . expand("%:t") . "'")]])
  end,
  once = false,
  group = _group,
})
autocmd("FileReadPost", {
  pattern = "*",
  callback = function()
    vim.cmd([[call system("tmux rename-window '" . expand("%:t") . "'")]])
  end,
  once = false,
  group = _group,
})

autocmd("BufNewFile", {
  pattern = "*",
  callback = function()
    vim.cmd([[call system("tmux rename-window '" . expand("%:t") . "'")]])
  end,
  once = false,
  group = _group,
})
autocmd("BufEnter", {
  pattern = "*",
  callback = function()
    vim.cmd([[call system("tmux rename-window '" . expand("%:t") . "'")]])
  end,
  once = false,
  group = _group,
})

-- auto close nvimtree
autocmd('BufEnter', {
  command = "if winnr('$') == 1 && bufname() == 'NvimTree_' . tabpagenr() | quit | endif",
  nested = true,
})


-- dont show line numbers for nvimtree buffers
autocmd("BufEnter",
  {
    pattern = { "NvimTree*" },
    callback = function()
      vim.b.lnstatus = "nonumber"
    end
  })

-- Disable the statusline, tabline and cmdline while the alpha dashboard is open
autocmd('User', {
  pattern = 'AlphaReady',
  desc = 'disable status, tabline and cmdline for alpha',
  callback = function()
    vim.go.laststatus = 1
    vim.opt.showtabline = 1
    vim.opt.cmdheight = 1
  end,
})
autocmd('BufUnload', {
  buffer = 0,
  desc = 'enable status, tabline and cmdline after alpha',
  callback = function()
    vim.go.laststatus = 2
    vim.opt.showtabline = 2
    vim.opt.cmdheight = 1
  end,
})

-- syntax fix
vim.cmd("syntax sync fromstart")