local st = require "util.stanza";

local url_escape = require "util.http".urlencode;

local base_url = "https://"..module.host.."/";

local render_html_template = require"util.interpolation".new("%b{}", st.xml_escape, {

	urlescape = url_escape;

	lower = string.lower;

	classname = function (s) return (s:gsub("%W+", "-")); end;

	relurl = function (s)

		if s:match("^%w+://") then

			return s;

		end

		return base_url.."/"..s;

	end;

});

local render_url = require "util.interpolation".new("%b{}", url_escape, {

	urlescape = url_escape;

	noscheme = function (url)

		return (url:gsub("^[^:]+:", ""));

	end;

});

local site_name = module:get_option_string("site_name", module.host);

local site_apps;

-- Enable/disable built-in invite pages

local external_only = module:get_option_boolean("invites_page_external", false);

local http_files;

if not external_only then

	-- Load HTTP-serving dependencies

	if prosody.shutdown then -- not if running under prosodyctl

		module:depends("http");

		http_files = module:depends("http_files");

	end

	-- Calculate automatic base_url default

	base_url = module.http_url and module:http_url();

	-- Load site apps info

	module:depends("register_apps");

	site_apps = module:shared("register_apps/apps");

end

local invites = module:depends("invites");

-- Point at eg https://github.com/ge0rg/easy-xmpp-invitation

-- This URL must always be absolute, as it is shared standalone

local invite_url_template = module:get_option_string("invites_page", base_url and (base_url.."?{invite.token}") or nil);

-- This URL is relative to the invite page, or can be absolute

local register_url_template = module:get_option_string("invites_registration_page", "register?t={invite.token}&c={app.id}");

local function add_landing_url(invite)

	if not invite_url_template then return; end

	-- TODO: we don't currently have a landing page for subscription-only invites,

	-- so the user will only receive a URI. The client should be able to handle this

	-- by automatically falling back to a client-specific landing page, per XEP-0401.

	if not invite.allow_registration then return; end

	invite.landing_page = render_url(invite_url_template, { host = module.host, invite = invite });

end

module:hook("invite-created", add_landing_url);

if external_only then

	return;

end

local function render_app_urls(apps, invite_vars)

	local rendered_apps = {};

	for _, unrendered_app in ipairs(apps) do

		local app = setmetatable({}, { __index = unrendered_app });

		local template_vars = { app = app, invite = invite_vars, base_url = base_url };

		if app.magic_link_format then

			-- Magic link generally links directly to third-party

			app.proceed_url = render_url(app.magic_link_format or app.link or "#", template_vars);

		elseif app.supports_preauth_uri then

			-- Proceed to a page that guides the user to download, and then

			-- click the URI button

			app.proceed_url = render_url("{base_url!}/setup/{app.id}?{invite.token}", template_vars);

		else

			-- Manual means proceed to web registration, but include app id

			-- so it can show post-registration instructions

			app.proceed_url = render_url(register_url_template, template_vars);

		end

		table.insert(rendered_apps, app);

	end

	return rendered_apps;

end

function serve_invite_page(event)

	local invite_page_template = assert(module:load_resource("html/invite.html")):read("*a");

	local invalid_invite_page_template = assert(module:load_resource("html/invite_invalid.html")):read("*a");

	event.response.headers["Content-Type"] = "text/html; charset=utf-8";

	local invite = invites.get(event.request.url.query);

	if not invite then

		return render_html_template(invalid_invite_page_template, {

			site_name = site_name;

			static = base_url.."/static";

		});

	end

	local template_vars = {

		site_name = site_name;

		token = invite.token;

		uri = invite.uri;

		type = invite.type;

		jid = invite.jid;

		inviter = invite.inviter;

		static = base_url.."/static";

	};

	template_vars.apps = render_app_urls(site_apps, template_vars);

	local invite_page = render_html_template(invite_page_template, template_vars);

	event.response.headers["Link"] = ([[<%s>; rel="alternate"]]):format(template_vars.uri);

	return invite_page;

end

function serve_setup_page(event, app_id)

	local invite_page_template = assert(module:load_resource("html/client.html")):read("*a");

	local invalid_invite_page_template = assert(module:load_resource("html/invite_invalid.html")):read("*a");

	event.response.headers["Content-Type"] = "text/html; charset=utf-8";

	local invite = invites.get(event.request.url.query);

	if not invite then

		return render_html_template(invalid_invite_page_template, {

			site_name = site_name;

			static = base_url.."/static";

		});

	end

	local template_vars = {

		site_name = site_name;

		apps = site_apps;

		token = invite.token;

		uri = invite.uri;

		type = invite.type;

		jid = invite.jid;

		static = base_url.."/static";

	};

	template_vars.app = render_app_urls({ site_apps[app_id] }, template_vars)[1];

	local invite_page = render_html_template(invite_page_template, template_vars);

	return invite_page;

end

local mime_map = {

	png = "image/png";

	svg = "image/svg+xml";

	js  = "application/javascript";

};

module:provides("http", {

	route = {

		["GET"] = serve_invite_page;

		["GET /setup/*"] = serve_setup_page;

		["GET /static/*"] = http_files and http_files.serve({ path = module:get_directory().."/static", mime_map = mime_map });

	};

});