module:depends("http");

local st = require "util.stanza";

local json = require "util.json";

local xml = require "util.xml";

local uuid_generate = require "util.uuid".generate;

local timestamp_generate = require "util.datetime".datetime;

local hashes = require "util.hashes";

local from_hex = require "util.hex".from;

local hmacs = {

	sha1 = hashes.hmac_sha1;

	sha256 = hashes.hmac_sha256;

	sha384 = hashes.hmac_sha384;

	sha512 = hashes.hmac_sha512;

};

local pubsub_service = module:depends("pubsub").service;

local error_mapping = {

	["forbidden"] = 403;

	["item-not-found"] = 404;

	["internal-server-error"] = 500;

	["conflict"] = 409;

};

local function publish_payload(node, actor, item_id, payload)

	local post_item = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = item_id, })

		:add_child(payload);

	local ok, err = pubsub_service:publish(node, actor, item_id, post_item);

	module:log("debug", ":publish(%q, true, %q, %s) -> %q", node, item_id, payload:top_tag(), err or "");

	if not ok then

		return error_mapping[err] or 500;

	end

	return 202;

end

local function handle_json(node, actor, data)

	local parsed, err = json.decode(data);

	if not parsed then

		return { status_code = 400; body = tostring(err); }

	end

	if type(parsed) ~= "table" then

		return { status_code = 400; body = "object or array expected"; };

	end

	local wrapper = st.stanza("json", { xmlns="urn:xmpp:json:0" }):text(data);

	return publish_payload(node, actor, data.id or "current", wrapper);

end

local function publish_atom(node, actor, feed)

	for entry in feed:childtags("entry") do

		local item_id = entry:get_child_text("id");

		if not item_id then

			item_id = uuid_generate();

			entry:tag("id"):text(item_id):up();

		end

		if not entry:get_child_text("published") then

			entry:tag("published"):text(timestamp_generate()):up();

		end

		local resp = publish_payload(node, actor, item_id, entry);

		if resp ~= 202 then return resp; end

	end

	return 202;

end

local function handle_xml(node, actor, payload)

	local xmlpayload, err = xml.parse(payload);

	if not xmlpayload then

		module:log("debug", "XML parse error: %s\n%q", err, payload);

		return { status_code = 400, body = tostring(err) };

	end

	if xmlpayload.attr.xmlns == "http://www.w3.org/2005/Atom" and xmlpayload.name == "feed" then

		return publish_atom(node, actor, xmlpayload);

	else

		return publish_payload(node, actor, "current", xmlpayload);

	end

end

local actor_secrets = module:get_option("pubsub_post_secrets");

local function verify_signature(secret, body, signature)

	if not signature then return false; end

	local algo, digest = signature:match("^([^=]+)=(%x+)");

	if not algo then return false; end

	local hmac = hmacs[algo];

	if not algo then return false; end

	return hmac(secret, body) == from_hex(digest);

end

function handle_POST(event, path)

	local request = event.request;

	module:log("debug", "Handling POST: \n%s\n", tostring(request.body));

	local content_type = request.headers.content_type or "application/octet-stream";

	if secret and not verify_signature(secret, request.body, request.headers.x_hub_signature) then

		return 401;

	end

	if not actor then

		return 401;

	end

	if content_type == "application/xml" or content_type:sub(-4) == "+xml" then

		return handle_xml(path, actor, request.body);

	elseif content_type == "application/json" or content_type:sub(-5) == "+json" then

		return handle_json(path, actor, request.body);

	end

	module:log("debug", "Unsupported content-type: %q", content_type);

	return 415;

end

module:provides("http", {

	route = {

		["POST /*"] = handle_POST;

	};

});

function module.load()

	module:log("debug", "Loaded at %s", module:http_url());

end