// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.

using namespace ircd;

static void
send_join__response(client &,
                    const m::resource::request &,
                    const m::event &,
                    const m::room::state &,
                    const m::room::auth::chain &,
                    json::stack::object &out);

static m::resource::response
put__send_join(client &,
               const m::resource::request &);

mapi::header
IRCD_MODULE
{
	"Federation :Send join event"
};

const string_view
send_join_description
{R"(

Inject a join event into a room originating from a server without any joined
users in that room.

)"};

m::resource
send_join_resource
{
	"/_matrix/federation/v1/send_join/",
	{
		send_join_description,
		resource::DIRECTORY
	}
};

m::resource
send_join_resource_v2
{
	"/_matrix/federation/v2/send_join/",
	{
		send_join_description,
		resource::DIRECTORY
	}
};

m::resource::method
method_put
{
	send_join_resource, "PUT", put__send_join,
	{
		method_put.VERIFY_ORIGIN
	}
};

m::resource::method
method_put_v2
{
	send_join_resource_v2, "PUT", put__send_join,
	{
		method_put.VERIFY_ORIGIN
	}
};

m::resource::response
put__send_join(client &client,
               const m::resource::request &request)
{
	const bool v1
	{
		startswith(request.head.path, "/_matrix/federation/v1/")
	};

	if(request.parv.size() < 1)
		throw m::NEED_MORE_PARAMS
		{
			"room_id path parameter required"
		};

	m::room::id::buf room_id
	{
		url::decode(room_id, request.parv[0])
	};

	if(request.parv.size() < 2)
		throw m::NEED_MORE_PARAMS
		{
			"event_id path parameter required"
		};

	m::event::id::buf event_id
	{
		url::decode(event_id, request.parv[1])
	};

	const m::event event
	{
		request, event_id
	};

	if(!check_id(event))
		throw m::BAD_REQUEST
		{
			"ID of event in request does not match path parameter %s",
			string_view{event_id},
		};

	if(at<"room_id"_>(event) != room_id)
		throw m::error
		{
			http::NOT_MODIFIED, "M_MISMATCH_ROOM_ID",
			"ID of room in request body does not match path parameter."
		};

	if(json::get<"type"_>(event) != "m.room.member")
		throw m::error
		{
			http::NOT_MODIFIED, "M_INVALID_TYPE",
			"Event type must be m.room.member"
		};

	if(unquote(json::get<"content"_>(event).get("membership")) != "join")
		throw m::error
		{
			http::NOT_MODIFIED, "M_INVALID_CONTENT_MEMBERSHIP",
			"Event content.membership state must be 'join'."
		};

	if(json::get<"origin"_>(event) != request.origin)
		throw m::error
		{
			http::NOT_MODIFIED, "M_MISMATCH_ORIGIN",
			"Event origin must be you."
		};

	if(m::room::server_acl::enable_write && !m::room::server_acl::check(room_id, request.node_id))
		throw m::ACCESS_DENIED
		{
			"You are not permitted by the room's server access control list."
		};

	m::vm::opts vmopts;
	vmopts.fetch = false;
	m::vm::eval eval
	{
		event, vmopts
	};

	const m::room::state state
	{
		room_id
	};

	const m::room::auth::chain auth_chain
	{
		m::head_idx(room_id)
	};

	m::resource::response::chunked response
	{
		client, http::OK
	};

	json::stack out
	{
		response.buf, response.flusher()
	};

	if(v1)
	{
		json::stack::array top
		{
			out
		};

		// First element is the 200
		top.append(json::value(200L));

		// Second element is the object
		json::stack::object data
		{
			top
		};

		send_join__response(client, request, event, state, auth_chain, data);
		return std::move(response);
	}

	json::stack::object top
	{
		out
	};

	// Top element is the object
	send_join__response(client, request, event, state, auth_chain, top);
	return std::move(response);
}

void
send_join__response(client &client,
                    const m::resource::request &request,
                    const m::event &event,
                    const m::room::state &state,
                    const m::room::auth::chain &auth_chain,
                    json::stack::object &data)
{
	// Required. The resident server's DNS name.
	json::stack::member
	{
		data, "origin", my_host()
	};

	// auth_chain
	if(request.query.get<bool>("auth_chain", true))
	{
		json::stack::array auth_chain_a
		{
			data, "auth_chain"
		};

		auth_chain.for_each(m::event::closure_idx_bool{[&auth_chain_a]
		(const m::event::idx &event_idx)
		{
			const m::event::fetch event
			{
				std::nothrow, event_idx
			};

			if(event.valid)
				auth_chain_a.append(event);

			return true;
		}});
	}

	// auth_chain_ids (non-spec)
	if(request.query.get<bool>("auth_chain_ids", false))
	{
		json::stack::array auth_chain_a
		{
			data, "auth_chain_ids"
		};

		auth_chain.for_each(m::event::closure_idx_bool{[&auth_chain_a]
		(const m::event::idx &event_idx)
		{
			const auto &event_id
			{
				m::event_id(std::nothrow, event_idx)
			};

			if(event_id)
				auth_chain_a.append(event_id);

			return true;
		}});
	}

	// state
	if(request.query.get<bool>("state", true))
	{
		json::stack::array state_a
		{
			data, "state"
		};

		state.for_each([&state_a]
		(const m::event &event)
		{
			state_a.append(event);
		});
	}

	// state_ids (non-spec)
	if(request.query.get<bool>("state_ids", false))
	{
		json::stack::array state_ids
		{
			data, "state_ids"
		};

		state.for_each(m::event::id::closure{[&state_ids]
		(const m::event::id &event_id)
		{
			state_ids.append(event_id);
			return true;
		}});
	}
}