local M = {}

function M.lookup()
	local keywords = vim.fn.getreg("*") -- receive yanked text
	local url = "https://dl.acm.org/action/doSearch?AllField=" .. keywords
	url, empty = url:gsub(" ", "+")

	-- Setup a http socket and request
	local command = string.format("curl -s '%s'", url)

	-- Execute the curl command and capture its output
	local handle = io.popen(command)
	local response = ""
	if handle ~= nil then
		response = handle:read("*a")
		handle:close()
	else
		response = ""
	end

	-- select doi links from response
	local b = 1
	local doi_links = {}
	while true do
		local x, y = response:find("doi/[a-zA-Z]+/10.[0-9]+/[0-9.]+", b, false)

		-- stop if no further occurrences are found
		if x == nil or y == nil then
			break
		end

		-- save substring to doi_links
		doi_links:insert(response:sub(x, y))
		b = y
	end

	print("Keywords: " .. keywords)
	print("URL: " .. url)
	print("Links: " .. #doi_links)
end

return M