local t_insert, t_remove, t_concat = table.insert, table.remove, table.concat;

local parser_new = require "net.http.parser".new;

local events = require "util.events".new();

local addserver = require "net.server".addserver;

local log = require "util.logger".init("http.server");

local os_date = os.date;

local pairs = pairs;

local s_upper = string.upper;

local setmetatable = setmetatable;

local xpcall = xpcall;

local debug = debug;

local tostring = tostring;

local codes = require "net.http.codes";

local _G = _G;

local legacy_httpserver = require "net.httpserver";

local _M = {};

local sessions = {};

local handlers = {};

local listener = {};

local function is_wildcard_event(event)

	return event:sub(-2, -1) == "/*";

end

local function is_wildcard_match(wildcard_event, event)

	return wildcard_event:sub(1, -2) == event:sub(1, #wildcard_event-1);

end

local event_map = events._event_map;

setmetatable(events._handlers, {

	__index = function (handlers, curr_event)

		if is_wildcard_event(curr_event) then return; end -- Wildcard events cannot be fired

		-- Find all handlers that could match this event, sort them

		-- and then put the array into handlers[curr_event] (and return it)

		local matching_handlers_set = {};

		local handlers_array = {};

		for event, handlers_set in pairs(event_map) do

			if event == curr_event or

			is_wildcard_event(event) and is_wildcard_match(event, curr_event) then

				for handler, priority in pairs(handlers_set) do

					matching_handlers_set[handler] = { (select(2, event:gsub("/", "%1"))), is_wildcard_event(event) and 0 or 1, priority };

					table.insert(handlers_array, handler);

				end

			end

		end

		if #handlers_array == 0 then return; end

		table.sort(handlers_array, function(b, a)

			local a_score, b_score = matching_handlers_set[a], matching_handlers_set[b];

			for i = 1, #a_score do

				if a_score[i] ~= b_score[i] then -- If equal, compare next score value

					return a_score[i] < b_score[i];

				end

			end

			return false;

		end);

		handlers[curr_event] = handlers_array;

		return handlers_array;

	end;

	__newindex = function (handlers, curr_event, handlers_array)

		if handlers_array == nil

		and is_wildcard_event(curr_event) then

			-- Invalidate all matching

			for event in pairs(handlers) do

				if is_wildcard_match(curr_event, event) then

					handlers[event] = nil;

				end

			end

		end

	end;

});

local handle_request;

local _1, _2, _3;

local function _handle_request() return handle_request(_1, _2, _3); end

local function _traceback_handler(err) log("error", "Traceback[http]: %s: %s", tostring(err), debug.traceback()); end

function listener.onconnect(conn)

	local secure = conn:ssl() and true or nil;

	local pending = {};

	local waiting = false;

	local function process_next(last_response)

		--if waiting then log("debug", "can't process_next, waiting"); return; end

		if sessions[conn] and #pending > 0 then

			local request = t_remove(pending);

			--log("debug", "process_next: %s", request.path);

			waiting = true;

			--handle_request(conn, request, process_next);

			_1, _2, _3 = conn, request, process_next;

			if not xpcall(_handle_request, _traceback_handler) then

				conn:write("HTTP/1.0 503 Internal Server Error\r\n\r\nAn error occured during the processing of this request.");

				conn:close();

			end

		else

			--log("debug", "ready for more");

			waiting = false;

		end

	end

	local function success_cb(request)

		--log("debug", "success_cb: %s", request.path);

		request.secure = secure;

		t_insert(pending, request);

		if not waiting then

			process_next();

		end

	end

	local function error_cb(err)

		log("debug", "error_cb: %s", err or "<nil>");

		-- FIXME don't close immediately, wait until we process current stuff

		-- FIXME if err, send off a bad-request response

		sessions[conn] = nil;

		conn:close();

	end

	sessions[conn] = parser_new(success_cb, error_cb);

end

function listener.ondisconnect(conn)

	local open_response = conn._http_open_response;

	if open_response and open_response.on_destroy then

		open_response.finished = true;

		open_response:on_destroy();

	end

	sessions[conn] = nil;

end

function listener.onincoming(conn, data)

	sessions[conn]:feed(data);

end

local headerfix = setmetatable({}, {

	__index = function(t, k)

		local v = "\r\n"..k:gsub("_", "-"):gsub("%f[%w].", s_upper)..": ";

		t[k] = v;

		return v;

	end

});

function _M.hijack_response(response, listener)

	error("TODO");

end

function handle_request(conn, request, finish_cb)

	--log("debug", "handler: %s", request.path);

	local headers = {};

	for k,v in pairs(request.headers) do headers[k:gsub("-", "_")] = v; end

	request.headers = headers;

	request.conn = conn;

	local date_header = os_date('!%a, %d %b %Y %H:%M:%S GMT'); -- FIXME use

	local conn_header = request.headers.connection;

	local keep_alive = conn_header == "Keep-Alive" or (request.httpversion == "1.1" and conn_header ~= "close");

	local response = {

		request = request;

		status_code = 200;

		headers = { date = date_header, connection = (keep_alive and "Keep-Alive" or "close") };

		conn = conn;

		send = _M.send_response;

		finish_cb = finish_cb;

	};

	conn._http_open_response = response;

	if not request.headers.host then

		response.status_code = 400;

		response.headers.content_type = "text/html";

		response:send("<html><head>400 Bad Request</head><body>400 Bad Request: No Host header.</body></html>");

	else

		local host = request.headers.host;

		if host then

			host = host:match("[^:]*"):lower();

			local event = request.method.." "..host..request.path:match("[^?]*");

			local payload = { request = request, response = response };

			--log("debug", "Firing event: %s", event);

			local result = events.fire_event(event, payload);

			if result ~= nil then

				if result ~= true then

					local code, body = 200, "";

					local result_type = type(result);

					if result_type == "number" then

						response.status_code = result;

					elseif result_type == "string" then

						body = result;

					elseif result_type == "table" then

						body = result.body;

						result.body = nil;

						for k, v in pairs(result) do

							response[k] = v;

						end

					end

					response:send(body);

				end

				return;

			end

		end

		-- if handler not called, return 404

		response.status_code = 404;

		response.headers.content_type = "text/html";

		response:send("<html><head><title>404 Not Found</title></head><body>404 Not Found: No such page.</body></html>");

	end

end

function _M.send_response(response, body)

	if response.finished then return; end

	response.finished = true;

	response.conn._http_open_response = nil;

	local status_line = "HTTP/"..response.request.httpversion.." "..(response.status or codes[response.status_code]);

	local headers = response.headers;

	body = body or "";

	headers.content_length = #body;

	local output = { status_line };

	for k,v in pairs(headers) do

		t_insert(output, headerfix[k]..v);

	end

	t_insert(output, "\r\n\r\n");

	t_insert(output, body);

	response.conn:write(t_concat(output));

	if response.on_destroy then

		response:on_destroy();

		response.on_destroy = nil;

	end

	if headers.connection == "Keep-Alive" then

		response:finish_cb();

	else

		response.conn:close();

	end

end

function _M.add_handler(event, handler, priority)

	events.add_handler(event, handler, priority);

end

function _M.remove_handler(event, handler)

	events.remove_handler(event, handler);

end

function _M.listen_on(port, interface, ssl)

	addserver(interface or "*", port, listener, "*a", ssl);

end

_M.listener = listener;

_M.codes = codes;

_M._events = events;

return _M;