local base64 = require "util.encodings".base64;
local sha1 = require "util.hashes".sha1;
local st = require "util.stanza";

local sm_bind_resource = require "core.sessionmanager".bind_resource;

local xmlns_bind2 = "urn:xmpp:bind2:1";
local xmlns_sasl2 = "urn:xmpp:sasl:1";

-- Advertise what we can do

module:hook("stream-features", function(event)
	local origin, features = event.origin, event.features;

	if origin.type ~= "c2s_unauthed" then
		return;
	end

	local inline = st.stanza("inline", { xmlns = xmlns_bind2 });
	module:fire_event("advertise-bind-features", { origin = origin, features = inline });
	features:add_direct_child(inline);
end, 1);

module:hook("advertise-sasl-features", function(event)
	event.features:tag("bind", { xmlns = xmlns_bind2 }):up();
end, 1);

-- Helper to actually bind a resource to a session

local function do_bind(session, bind_request)
	local resource;

	local client_id_tag = bind_request:get_child("client-id");
	local client_id = client_id_tag and client_id_tag:get_text() or session.client_id;
	if client_id and client_id ~= "" then
		local tag = client_id_tag and client_id_tag.attr.tag or "client";
		resource = ("%s~%s"):format(tag, base64.encode(sha1(client_id):sub(1, 9)));
	end

	local success, err_type, err, err_msg = sm_bind_resource(session, resource);
	if not success then
		session.log("debug", "Resource bind failed: %s", err_msg or err);
		return nil, { type = err_type, condition = err, text = err_msg };
	end

	session.log("debug", "Resource bound: %s", session.full_jid);
	return st.stanza("bound", { xmlns = xmlns_bind2 })
		:text_tag("jid", session.full_jid)
end

-- Enable inline features requested by the client

local function enable_features(session, bind_request, bind_result)
	local features = bind_request:get_child("features");
	if not features then return; end
	module:fire_event("enable-bind-features", {
		session = session;
		features = features;
		result = bind_result;
	});
end

-- SASL 2 integration

module:hook_tag(xmlns_sasl2, "authenticate", function (session, auth)
	-- Cache action for future processing (after auth success)
	session.sasl2_bind_request = auth:child_with_ns(xmlns_bind2);
end, 100);

module:hook("sasl2/c2s/success", function (event)
	local session = event.session;

	local bind_request = session.sasl2_bind_request;
	if not bind_request then return; end -- No bind requested
	session.sasl2_bind_request = nil;

	local sm_success = event.sasl2_sm_success;
	if sm_success and sm_success.type == "resumed" then
		return; -- No need to bind a resource
	end

	local bind_result, err = do_bind(session, bind_request);
	if not bind_result then
		bind_result = st.stanza("failed", { xmlns = xmlns_bind2 })
			:add_error(err);
	else
		enable_features(session, bind_request, bind_result);
	end

	event.success:add_child(bind_result);
end, 100);

-- Inline features

module:hook("advertise-bind-features", function (event)
	local features = event.features;
	features:tag("feature", { var = "urn:xmpp:carbons:2" }):up();
	features:tag("feature", { var = "urn:xmpp:csi:0" }):up();
end);

module:hook("enable-bind-features", function (event)
	local session, features = event.session, event.features;

	-- Carbons
	session.want_carbons = not not features:get_child("enable", "urn:xmpp:carbons:2");

	-- CSI
	local csi_state_tag = features:child_with_ns("urn:xmpp:csi:0");
	if csi_state_tag then
		session.state = csi_state_tag.name;
	end
end, 10);