local term_buf = nil

local function open_term_split()
  vim.cmd('botright vsplit')
  local win = vim.api.nvim_get_current_win()
  if term_buf and vim.api.nvim_buf_is_valid(term_buf) then
    vim.api.nvim_win_set_buf(win, term_buf)
  else
    vim.cmd('terminal')
    term_buf = vim.api.nvim_get_current_buf()
  end
  vim.api.nvim_win_set_width(win, math.floor(vim.o.columns * 0.37))
  vim.cmd('startinsert')
end

local function toggle_term()
  -- Check if terminal is already visible in a window
  for _, win in ipairs(vim.api.nvim_list_wins()) do
    if vim.api.nvim_win_get_buf(win) == term_buf then
      vim.api.nvim_win_close(win, false)
      return
    end
  end
  open_term_split()
end

local function open_term_fullscreen()
  if term_buf and vim.api.nvim_buf_is_valid(term_buf) then
    vim.api.nvim_set_current_buf(term_buf)
  else
    vim.cmd('terminal')
    term_buf = vim.api.nvim_get_current_buf()
  end
  vim.cmd('startinsert')
end

local function prev_non_term_buf()
  local cur = vim.api.nvim_get_current_buf()
  local bufs = vim.fn.getbufinfo({ buflisted = 1 })
  local candidates = {}
  for _, info in ipairs(bufs) do
    if info.bufnr ~= cur and vim.bo[info.bufnr].buftype ~= 'terminal' then
      table.insert(candidates, info)
    end
  end
  if #candidates == 0 then
    print('No previous non-terminal buffer')
    return
  end
  table.sort(candidates, function(a, b) return a.lastused > b.lastused end)
  vim.api.nvim_set_current_buf(candidates[1].bufnr)
end

map('n', '<leader>l', prev_non_term_buf,    { desc = 'Go to previous non-terminal buffer' })
map('n', '<C-j>',     toggle_term,          { desc = 'Toggle terminal split' })
map('n', '<C-o>',     open_term_fullscreen, { desc = 'Open terminal fullscreen' })
map('t', '<C-j>',     toggle_term,          { desc = 'Toggle terminal split' })
map('t', '<C-o>',     prev_non_term_buf,    { desc = 'Exit terminal mode' })