local coroutine = coroutine;

local tonumber = tonumber;

local deadroutine = coroutine.create(function() end);

coroutine.resume(deadroutine);

module("httpstream")

local function parser(success_cb, parser_type, options_cb)

	local data = coroutine.yield();

	local function readline()

		local pos = data:find("\r\n", nil, true);

		while not pos do

			data = data..coroutine.yield();

			pos = data:find("\r\n", nil, true);

		end

		local r = data:sub(1, pos-1);

		data = data:sub(pos+2);

		return r;

	end

	local function readlength(n)

		while #data < n do

			data = data..coroutine.yield();

		end

		local r = data:sub(1, n);

		data = data:sub(n + 1);

		return r;

	end

	local function readheaders()

		local headers = {}; -- read headers

		while true do

			local line = readline();

			if line == "" then break; end -- headers done

			local key, val = line:match("^([^%s:]+): *(.*)$");

			if not key then coroutine.yield("invalid-header-line"); end -- TODO handle multi-line and invalid headers

			key = key:lower();

			headers[key] = headers[key] and headers[key]..","..val or val;

		end

		return headers;

	end

	if not parser_type or parser_type == "server" then

		while true do

			-- read status line

			local status_line = readline();

			local method, path, httpversion = status_line:match("^(%S+)%s+(%S+)%s+HTTP/(%S+)$");

			if not method then coroutine.yield("invalid-status-line"); end

			path = path:gsub("^//+", "/"); -- TODO parse url more

			local headers = readheaders();

			-- read body

			local len = tonumber(headers["content-length"]);

			len = len or 0; -- TODO check for invalid len

			local body = readlength(len);

			success_cb({

				method = method;

				path = path;

				httpversion = httpversion;

				headers = headers;

				body = body;

			});

		end

	elseif parser_type == "client" then

		while true do

			-- read status line

			local status_line = readline();

			local httpversion, status_code, reason_phrase = status_line:match("^HTTP/(%S+)%s+(%d%d%d)%s+(.*)$");

			status_code = tonumber(status_code);

			if not status_code then coroutine.yield("invalid-status-line"); end

			local headers = readheaders();

			-- read body

			local have_body = not

				 ( (options_cb and options_cb().method == "HEAD")

				or (status_code == 204 or status_code == 304 or status_code == 301)

				or (status_code >= 100 and status_code < 200) );

			local body;

			if have_body then

				local len = tonumber(headers["content-length"]);

				if headers["transfer-encoding"] == "chunked" then

					body = "";

					while true do

						local chunk_size = readline():match("^%x+");

						if not chunk_size then coroutine.yield("invalid-chunk-size"); end

						chunk_size = tonumber(chunk_size, 16)

						if chunk_size == 0 then break; end

						body = body..readlength(chunk_size);

						if readline() ~= "" then coroutine.yield("invalid-chunk-ending"); end

					end

					local trailers = readheaders();

				elseif len then -- TODO check for invalid len

					body = readlength(len);

				else -- read to end

					repeat

						local newdata = coroutine.yield();

						data = data..newdata;

					until newdata == "";

					body, data = data, "";

				end

			end

			success_cb({

				code = status_code;

				httpversion = httpversion;

				headers = headers;

				body = body;

				-- COMPAT the properties below are deprecated

				responseversion = httpversion;

				responseheaders = headers;

			});

		end

	else coroutine.yield("unknown-parser-type"); end

end

function new(success_cb, error_cb, parser_type, options_cb)

	local co = coroutine.create(parser);

	coroutine.resume(co, success_cb, parser_type, options_cb)

	return {

		feed = function(self, data)

			if not data then

				if parser_type == "client" then coroutine.resume(co, ""); end

				co = deadroutine;

				return error_cb();

			end

			local success, result = coroutine.resume(co, data);

			if result then

				co = deadroutine;

				return error_cb(result);

			end

		end;

	};

end

return _M;