local socket = require "socket"

local server = require "net.server"

local url_parse = require "socket.url".parse;

local connlisteners_start = require "net.connlisteners".start;

local connlisteners_get = require "net.connlisteners".get;

local listener;

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

local tonumber, tostring, pairs = tonumber, tostring, pairs;

local urlencode = function (s) return s and (s:gsub("%W", function (c) return string.format("%%%x", c:byte()); end)); end

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

local http_servers = {};

module "httpserver"

local default_handler;

local function expectbody(reqt)

    return reqt.method == "POST";

end

local function send_response(request, response)

	-- Write status line

	local resp;

	if response.body then

		log("debug", "Sending response to %s", request.id);

		resp = { "HTTP/1.0 ", response.status or "200 OK", "\r\n"};

		local h = response.headers;

		if h then

			for k, v in pairs(h) do

				t_insert(resp, k);

				t_insert(resp, ": ");

				t_insert(resp, v);

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

			end

		end

		if response.body and not (h and h["Content-Length"]) then

			t_insert(resp, "Content-Length: ");

			t_insert(resp, #response.body);

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

		end

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

		if response.body and request.method ~= "HEAD" then

			t_insert(resp, response.body);

		end

	else

		-- Response we have is just a string (the body)

		log("debug", "Sending response to %s: %s", request.id, response);

		resp = { "HTTP/1.0 200 OK\r\n" };

		t_insert(resp, "Connection: close\r\n");

		t_insert(resp, "Content-Length: ");

		t_insert(resp, #response);

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

		t_insert(resp, response);

	end

	request.write(t_concat(resp));

	if not request.stayopen then

		request:destroy();

	end

end

local function call_callback(request, err)

	if request.handled then return; end

	request.handled = true;

	local callback = request.callback;

	if not callback and request.path then

		local path = request.url.path;

		local base = path:match("^/([^/?]+)");

		if not base then

			base = path:match("^http://[^/?]+/([^/?]+)");

		end

		callback = (request.server and request.server.handlers[base]) or default_handler;

		if callback == default_handler then

			log("debug", "Default callback for this request (base: "..tostring(base)..")")

		end

	end

	if callback then

		if err then

			log("debug", "Request error: "..err);

			if not callback(nil, err, request) then

				destroy_request(request);

			end

			return;

		end

		local response = callback(request.method, request.body and t_concat(request.body), request);

		if response then

			if response == true and not request.destroyed then

				-- Keep connection open, we will reply later

				log("warn", "Request %s left open, on_destroy is %s", request.id, tostring(request.on_destroy));

			elseif response ~= true then

				-- Assume response

				send_response(request, response);

				destroy_request(request);

			end

		else

			log("debug", "Request handler provided no response, destroying request...");

			-- No response, close connection

			destroy_request(request);

		end

	end

end

local function request_reader(request, data, startpos)

	if not data then

		if request.body then

			call_callback(request);

		else

			-- Error.. connection was closed prematurely

			call_callback(request, "connection-closed");

		end

		-- Here we force a destroy... the connection is gone, so we can't reply later

		destroy_request(request);

		return;

	end

	if request.state == "body" then

		log("debug", "Reading body...")

		if not request.body then request.body = {}; request.havebodylength, request.bodylength = 0, tonumber(request.headers["content-length"]); end

		if startpos then

			data = data:sub(startpos, -1)

		end

		t_insert(request.body, data);

		if request.bodylength then

			request.havebodylength = request.havebodylength + #data;

			if request.havebodylength >= request.bodylength then

				-- We have the body

				call_callback(request);

			end

		end

	elseif request.state == "headers" then

		log("debug", "Reading headers...")

		local pos = startpos;

		local headers = request.headers or {};

		for line in data:gmatch("(.-)\r\n") do

			startpos = (startpos or 1) + #line + 2;

			local k, v = line:match("(%S+): (.+)");

			if k and v then

				headers[k:lower()] = v;

--				log("debug", "Header: "..k:lower().." = "..v);

			elseif #line == 0 then

				request.headers = headers;

				break;

			else

				log("debug", "Unhandled header line: "..line);

			end

		end

		if not expectbody(request) then 

			call_callback(request);

			return;

		end

		-- Reached the end of the headers

		request.state = "body";

		if #data > startpos then

			return request_reader(request, data:sub(startpos, -1));

		end

	elseif request.state == "request" then

		log("debug", "Reading request line...")

		local method, path, http, linelen = data:match("^(%S+) (%S+) HTTP/(%S+)\r\n()", startpos);

		if not method then

			return call_callback(request, "invalid-status-line");

		end

		request.method, request.path, request.httpversion = method, path, http;

		request.url = url_parse(request.path);

		log("debug", method.." request for "..tostring(request.path) .. " on port "..request.handler.serverport());

		if request.onlystatus then

			if not call_callback(request) then

				return;

			end

		end

		request.state = "headers";

		if #data > linelen then

			return request_reader(request, data:sub(linelen, -1));

		end

	end

end

-- The default handler for requests

default_handler = function (method, body, request)

	log("debug", method.." request for "..tostring(request.path) .. " on port "..request.handler.serverport());

	return { status = "404 Not Found", 

			headers = { ["Content-Type"] = "text/html" },

			body = "<html><head><title>Page Not Found</title></head><body>Not here :(</body></html>" };

end

function new_request(handler)

	return { handler = handler, conn = handler.socket, 

			write = handler.write, state = "request", 

			server = http_servers[handler.serverport()],

			send = send_response,

			destroy = destroy_request,

			id = tostring{}:match("%x+$")

			 };

end

function destroy_request(request)

	log("debug", "Destroying request %s", request.id);

	listener = listener or connlisteners_get("httpserver");

	if not request.destroyed then

		request.destroyed = true;

		if request.on_destroy then

			log("debug", "Request has destroy callback");

			request.on_destroy(request);

		else

			log("debug", "Request has no destroy callback");

		end

		request.handler.close()

		if request.conn then

			listener.disconnect(request.conn, "closed");

		end

	end

end

function new(params)

	local http_server = http_servers[params.port];

	if not http_server then

		http_server = { handlers = {} };

		http_servers[params.port] = http_server;

		-- We weren't already listening on this port, so start now

		connlisteners_start("httpserver", params);

	end

	if params.base then

		http_server.handlers[params.base] = params.handler;

	end

end

_M.request_reader = request_reader;

_M.send_response = send_response;

_M.urlencode = urlencode;

return _M;