welcome.lua

local M = {}

-- Default welcome message
local welcome_lines = {
  '',
  '  ███╗   ██╗███████╗ ██████╗ ██╗   ██╗██╗███╗   ███╗',
  '  ████╗  ██║██╔════╝██╔═══██╗██║   ██║██║████╗ ████║',
  '  ██╔██╗ ██║█████╗  ██║   ██║██║   ██║██║██╔████╔██║',
  '  ██║╚██╗██║██╔══╝  ██║   ██║╚██╗ ██╔╝██║██║╚██╔╝██║',
  '  ██║ ╚████║███████╗╚██████╔╝ ╚████╔╝ ██║██║ ╚═╝ ██║',
  '  ╚═╝  ╚═══╝╚══════╝ ╚═════╝   ╚═══╝  ╚═╝╚═╝     ╚═╝',
  '',
  '              Welcome to Neovim!',
  '',
  '           Press any key to continue...',
  '',
}

local function should_show_welcome()
  local buffers = vim.api.nvim_list_bufs()

  for _, buf in ipairs(buffers) do
    if vim.api.nvim_buf_is_loaded(buf) then
      local name = vim.api.nvim_buf_get_name(buf)
      local buftype = vim.bo[buf].buftype
      local lines = vim.api.nvim_buf_get_lines(buf, 0, -1, false)

      if buftype == '' and vim.bo[buf].buflisted then
        if name ~= '' or (#lines > 1 or (#lines == 1 and lines[1] ~= '')) then return false end
      end
    end
  end

  return true
end

local function create_welcome_buffer()
  local buf = vim.api.nvim_create_buf(false, true)

  vim.bo[buf].buftype = 'nofile'
  vim.bo[buf].bufhidden = 'wipe'
  vim.bo[buf].swapfile = false
  vim.bo[buf].buflisted = false
  vim.bo[buf].modifiable = false

  -- Calculate centering
  local win_height = vim.api.nvim_win_get_height(0)
  local win_width = vim.api.nvim_win_get_width(0)
  local content_height = #welcome_lines
  local start_row = math.max(0, math.floor((win_height - content_height) / 2))

  -- Find the longest line for consistent centering
  local max_width = 0
  for _, line in ipairs(welcome_lines) do
    max_width = math.max(max_width, vim.fn.strdisplaywidth(line))
  end

  -- Calculate horizontal padding for the entire block
  local horizontal_padding = math.max(0, math.floor((win_width - max_width) / 2))

  -- Add empty lines to center vertically
  local centered_lines = {}
  for _ = 1, start_row do
    table.insert(centered_lines, '')
  end

  -- Add each line with consistent horizontal padding (but not for empty lines)
  for _, line in ipairs(welcome_lines) do
    if line == '' then
      table.insert(centered_lines, '') -- Keep empty lines truly empty
    else
      table.insert(centered_lines, string.rep(' ', horizontal_padding) .. line)
    end
  end

  vim.bo[buf].modifiable = true
  vim.api.nvim_buf_set_lines(buf, 0, -1, false, centered_lines)

  return buf
end

local function close_welcome()
  local buf = vim.api.nvim_get_current_buf()

  if vim.bo[buf].buftype == 'nofile' and vim.bo[buf].bufhidden == 'wipe' then vim.cmd('enew') end
end

local function setup_welcome_listener(buf)
  local listener_id

  listener_id = vim.on_key(function(key)
    if vim.api.nvim_get_current_buf() == buf then
      vim.on_key(nil, listener_id)
      vim.defer_fn(close_welcome, 1)
    end
  end)

  -- Clean up listener if buffer is deleted
  vim.api.nvim_create_autocmd('BufDelete', {
    buffer = buf,
    callback = function() vim.on_key(nil, listener_id) end,
    once = true,
  })
end

function M.show_welcome()
  if not should_show_welcome() then return end

  local buf = create_welcome_buffer()
  vim.api.nvim_set_current_buf(buf)

  setup_welcome_listener(buf)

  local win = vim.api.nvim_get_current_win()

  local original_opts = {}
  local opts_to_hide = {
    number = false,
    relativenumber = false,
    signcolumn = 'no',
    foldcolumn = '0',
    statuscolumn = '',
  }

  for opt, new_value in pairs(opts_to_hide) do
    original_opts[opt] = vim.wo[win][opt]
    vim.wo[win][opt] = new_value
  end

  vim.opt.guicursor = 'a:hor1-Cursor'

  vim.api.nvim_create_autocmd('BufLeave', {
    buffer = buf,
    callback = function()
      vim.opt.guicursor = ''
      for opt, original_value in pairs(original_opts) do
        vim.wo[win][opt] = original_value
      end
    end,
    once = true,
  })
end

function M.setup(opts)
  opts = opts or {}

  if opts.message then welcome_lines = opts.message end

  vim.api.nvim_create_autocmd('VimEnter', {
    callback = function() M.show_welcome() end,
  })
end

return M