local M = {}

function M.clearcol()
	vim.api.nvim_set_option_value("number", false, { scope = "local" })
	vim.api.nvim_set_option_value("relativenumber", false, { scope = "local" })
	vim.api.nvim_set_option_value("statuscolumn", "", { scope = "local" })
	vim.api.nvim_set_option_value("signcolumn", "no", { scope = "local" })
	vim.api.nvim_set_option_value("equalalways", false, { scope = "global" })
end

function M.save_layout()
	local windows = {}
	for _, win in ipairs(vim.api.nvim_list_wins()) do
		if vim.api.nvim_win_is_valid(win) then
			local bufnr = vim.api.nvim_win_get_buf(win)
			windows[win] = {
				bufnr = bufnr,
				view = vim.fn.winsaveview(),
				width = vim.api.nvim_win_get_width(win),
				height = vim.api.nvim_win_get_height(win),
			}
		end
	end

	return {
		windows = windows,
		current_win = vim.api.nvim_get_current_win(),
		layout = vim.fn.winrestcmd(),
	}
end

function M.restore_layout(state)
	if not state then
		return
	end

	vim.cmd.diffoff()
	vim.cmd(state.layout)

	for win, win_state in pairs(state.windows) do
		if vim.api.nvim_win_is_valid(win) then
			vim.api.nvim_set_current_win(win)
			if vim.api.nvim_get_current_buf() == win_state.bufnr then
				vim.fn.winrestview(win_state.view)
			end
		end
	end

	if vim.api.nvim_win_is_valid(state.current_win) then
		vim.api.nvim_set_current_win(state.current_win)
	end
end

function M.setup_diff_layout(actual_output, expected_output, input_file)
	vim.cmd.diffoff()
	vim.cmd.only()

	local output_lines = vim.split(actual_output, "\n")
	local output_buf = vim.api.nvim_create_buf(false, true)
	vim.api.nvim_buf_set_lines(output_buf, 0, -1, false, output_lines)
	vim.bo[output_buf].filetype = "cpoutput"

	vim.cmd.edit()
	vim.api.nvim_set_current_buf(output_buf)
	vim.cmd.diffthis()
	M.clearcol()

	vim.cmd.vsplit(expected_output)
	vim.cmd.diffthis()
	M.clearcol()

	vim.cmd(("botright split %s"):format(input_file))
	M.clearcol()
	vim.cmd.wincmd("k")
end

return M