lazygit.nvim/lua/lazygit/window.lua

local api = vim.api

local function get_window_pos()
  local floating_window_scaling_factor = vim.g.lazygit_floating_window_scaling_factor

  -- Why is this required?
  -- vim.g.lazygit_floating_window_scaling_factor returns different types if the value is an integer or float
  if type(floating_window_scaling_factor) == 'table' then
    floating_window_scaling_factor = floating_window_scaling_factor[false]
  end

  local status, plenary = pcall(require, 'plenary.window.float')
  if status and vim.g.lazygit_floating_window_use_plenary and vim.g.lazygit_floating_window_use_plenary ~= 0 then
    local ret = plenary.percentage_range_window(
      floating_window_scaling_factor,
      floating_window_scaling_factor,
      { winblend = vim.g.lazygit_floating_window_winblend }
    )
    return nil, nil, nil, nil, ret.win_id, ret.bufnr
  end

  local height = math.ceil(vim.o.lines * floating_window_scaling_factor) - 1
  local width = math.ceil(vim.o.columns * floating_window_scaling_factor)
  local row = math.ceil(vim.o.lines - height) / 2
  local col = math.ceil(vim.o.columns - width) / 2
  return width, height, row, col
end

--- open floating window with nice borders
local function open_floating_window()
  local width, height, row, col, plenary_win, plenary_buf = get_window_pos()
  if plenary_win and plenary_buf then
    return plenary_win, plenary_buf
  end

  local border_opts = {
    style = 'minimal',
    relative = 'editor',
    row = row - 1,
    col = col - 1,
    width = width + 2,
    height = height + 2,
  }

  local opts = { style = 'minimal', relative = 'editor', row = row, col = col, width = width, height = height }

  local topleft, top, topright, right, botright, bot, botleft, left
  local window_chars = vim.g.lazygit_floating_window_border_chars
  if type(window_chars) == 'table' and #window_chars == 8 then
    topleft, top, topright, right, botright, bot, botleft, left = unpack(window_chars)
  else
    topleft, top, topright, right, botright, bot, botleft, left = '╭', '─', '╮', '│', '╯', '─', '╰', '│'
  end

  local border_lines = { topleft .. string.rep(top, width) .. topright }
  local middle_line = left .. string.rep(' ', width) .. right
  for _ = 1, height do
    table.insert(border_lines, middle_line)
  end
  table.insert(border_lines, botleft .. string.rep(bot, width) .. botright)

  -- create a unlisted scratch buffer for the border
  local border_buffer = api.nvim_create_buf(false, true)

  -- set border_lines in the border buffer from start 0 to end -1 and strict_indexing false
  api.nvim_buf_set_lines(border_buffer, 0, -1, true, border_lines)
  -- create border window
  local border_window = api.nvim_open_win(border_buffer, true, border_opts)
  vim.api.nvim_set_hl(0, "LazyGitBorder", { link = "Normal", default = true })
  vim.cmd('set winhl=NormalFloat:LazyGitBorder')

  -- create a unlisted scratch buffer
  if LAZYGIT_BUFFER == nil or vim.fn.bufwinnr(LAZYGIT_BUFFER) == -1 then
    LAZYGIT_BUFFER = api.nvim_create_buf(false, true)
  else
    LAZYGIT_LOADED = true
  end

  vim.cmd('setlocal signcolumn=no')
  -- create file window, enter the window, and use the options defined in opts
  local win = api.nvim_open_win(LAZYGIT_BUFFER, true, opts)

  vim.bo[LAZYGIT_BUFFER].filetype = 'lazygit'

  vim.cmd('setlocal bufhidden=hide')
  vim.cmd('setlocal nocursorcolumn')
  vim.cmd('setlocal signcolumn=no')
  vim.api.nvim_set_hl(0, "LazyGitFloat", { link = "Normal", default = true })
  vim.cmd('setlocal winhl=NormalFloat:LazyGitFloat')
  vim.cmd('set winblend=' .. vim.g.lazygit_floating_window_winblend)

  -- use autocommand to ensure that the border_buffer closes at the same time as the main buffer
  local cmd = [[autocmd WinLeave <buffer> silent! execute 'hide']]
  vim.cmd(cmd)
  cmd = [[autocmd WinLeave <buffer> silent! execute 'silent bdelete! %s']]
  vim.cmd(cmd:format(border_buffer))
  vim.api.nvim_create_autocmd('VimResized', {
    callback = function()
      vim.defer_fn(function()
        if not vim.api.nvim_win_is_valid(border_window) then
          return
        end
        local new_width, new_height, new_row, new_col = get_window_pos()
        api.nvim_win_set_config(border_window,
          { width = new_width + 2, height = new_height + 2, relative = 'editor', row = new_row - 1, col = new_col - 1, })
        api.nvim_win_set_config(win,
          { width = new_width, height = new_height, relative = 'editor', row = new_row, col = new_col, })
      end, 20)
    end
  })

  return win, LAZYGIT_BUFFER
end

return {
  open_floating_window = open_floating_window,
}