local function termopen(opts)
  opts = opts or {}

  -- setup the buffer
  local buf = vim.api.nvim_create_buf(false, true)
  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
  vim.api.nvim_set_option_value('modifiable', false, { buf = buf })

  -- setup keymappings
  vim.keymap.set('n', 'q', '<cmd>close<cr>', { buffer = buf })
  vim.keymap.set('n', '<esc>', '<cmd>close<cr>', { buffer = buf })

  -- setup the window
  local w = math.ceil(vim.o.columns * 1.0)
  local h = math.ceil(vim.o.lines * 0.4)
  local win = vim.api.nvim_open_win(buf, true, {
    style = 'minimal',
    relative = 'editor',
    width = w,
    height = h,
    row = math.ceil(vim.o.lines - h),
    col = vim.o.columns,
    border = { ' ', '─', ' ', ' ', ' ', '─', ' ', ' ' },
  })
  vim.api.nvim_set_current_win(win)

  -- spawn the command
  vim.fn.termopen(opts.cmd, {
    on_exit = function()
      if vim.api.nvim_win_is_valid(win) then
        vim.api.nvim_win_close(win, true)
      end
    end,
  })

  -- put into insert mode
  vim.cmd.startinsert()
end

-- provide user commands
vim.api.nvim_create_user_command('Termopen', function(a)
  termopen({ cmd = a.fargs })
end, { nargs = '*' })

-- alias
vim.api.nvim_create_user_command('T', function(a)
  termopen({ cmd = a.fargs })
end, { nargs = '*' })

-- helper to spawn &makeprg
vim.api.nvim_create_user_command('Make', function(a)
  local cmd = vim.split(vim.o.makeprg, ' ')
  cmd = vim.tbl_map(function(p)
    p, _ = string.gsub(p, [[%$%*]], a.args)
    p, _ = vim.fn.expand(p)
    return p
  end, cmd)
  termopen({ cmd = cmd })
end, { nargs = '*' })