/*

Copyright (c) 2013, Steven Siloti
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the distribution.
    * Neither the name of the author nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

*/

#include <libtorrent/config.hpp>
#include <libtorrent/hasher.hpp>
#include <libtorrent/kademlia/get_item.hpp>
#include <libtorrent/kademlia/node.hpp>

#if TORRENT_USE_ASSERTS
#include <libtorrent/bencode.hpp>
#endif

namespace libtorrent { namespace dht
{

void get_item::got_data(lazy_entry const* v,
	char const* pk,
	boost::uint64_t seq,
	char const* sig)
{
	std::pair<char const*, int> salt(m_salt.c_str(), m_salt.size());

	sha1_hash incoming_target = item_target_id(v->data_section(), salt, pk);
	if (incoming_target != m_target) return;

	if (pk && sig)
	{
		if (m_data.empty() || m_data.seq() < seq)
		{
			if (!m_data.assign(v, salt, seq, pk, sig))
				return;
		}
	}
	else if (m_data.empty())
	{
		m_data.assign(v);
		bool put_requested = m_data_callback(m_data);
		if (put_requested)
		{
#if TORRENT_USE_ASSERTS
			std::vector<char> buffer;
			bencode(std::back_inserter(buffer), m_data.value());
			TORRENT_ASSERT(m_target == hasher(&buffer[0], buffer.size()).final());
#endif
			m_nodes_callback = boost::bind(&get_item::put, this, _1);
		}
		else
		{
			// There can only be one true immutable item with a given id
			// Now that we've got it and the user doesn't want to do a put
			// there's no point in continuing to query other nodes
			abort();
		}
	}
}

get_item::get_item(
	node_impl& node
	, node_id target
	, data_callback const& dcallback)
	: find_data(node, target, nodes_callback())
	, m_data_callback(dcallback)
{
}

char const* get_item::name() const { return "get"; }

observer_ptr get_item::new_observer(void* ptr
	, udp::endpoint const& ep, node_id const& id)
{
	observer_ptr o(new (ptr) get_item_observer(this, ep, id));
#if TORRENT_USE_ASSERTS
	o->m_in_constructor = false;
#endif
	return o;
}

bool get_item::invoke(observer_ptr o)
{
	if (m_done)
	{
		m_invoke_count = -1;
		return false;
	}

	entry e;
	e["y"] = "q";
	entry& a = e["a"];

	e["q"] = "get";
	a["target"] = m_target.to_string();

	return m_node.m_rpc.invoke(e, o->target_ep(), o);
}

void get_item::done()
{
	if (m_data.is_mutable() || m_data.empty())
	{
		bool put_requested = m_data_callback(m_data);
		if (put_requested)
		{
#if TORRENT_USE_ASSERTS
			if (m_data.is_mutable())
			{
				TORRENT_ASSERT(m_target == hasher(m_data.pk(), item_pk_len).final());
			}
			else
			{
				std::vector<char> buffer;
				bencode(std::back_inserter(buffer), m_data.value());
				TORRENT_ASSERT(m_target == hasher(&buffer[0], buffer.size()).final());
			}
#endif
			m_nodes_callback = boost::bind(&get_item::put, this, _1);
		}
	}
	find_data::done();
}

void get_item::put(std::vector<std::pair<node_entry, std::string> > const& v)
{
#ifdef TORRENT_DHT_VERBOSE_LOGGING
	TORRENT_LOG(node) << "sending put [ v: " << m_data.value()
		<< " seq: " << (m_data.is_mutable() ? m_data.seq() : -1)
		<< " nodes: " << v.size() << " ]" ;
#endif

	// create a dummy traversal_algorithm
	boost::intrusive_ptr<traversal_algorithm> algo(
		new traversal_algorithm(m_node, (node_id::min)()));

	// store on the first k nodes
	for (std::vector<std::pair<node_entry, std::string> >::const_iterator i = v.begin()
		, end(v.end()); i != end; ++i)
	{
#ifdef TORRENT_DHT_VERBOSE_LOGGING
		TORRENT_LOG(node) << "  put-distance: " << (160 - distance_exp(m_target, i->first.id));
#endif

		void* ptr = m_node.m_rpc.allocate_observer();
		if (ptr == 0) return;
		observer_ptr o(new (ptr) announce_observer(algo, i->first.ep(), i->first.id));
#if TORRENT_USE_ASSERTS
		o->m_in_constructor = false;
#endif
		entry e;
		e["y"] = "q";
		e["q"] = "put";
		entry& a = e["a"];
		a["v"] = m_data.value();
		a["token"] = i->second;
		if (m_data.is_mutable())
		{
			a["k"] = std::string(m_data.pk(), item_pk_len);
			a["seq"] = m_data.seq();
			a["sig"] = std::string(m_data.sig(), item_sig_len);
		}
		m_node.m_rpc.invoke(e, i->first.ep(), o);
	}
}

void get_item_observer::reply(msg const& m)
{
	char const* pk = NULL;
	char const* sig = NULL;
	boost::uint64_t seq = 0;

	lazy_entry const* r = m.message.dict_find_dict("r");
	if (!r)
	{
#ifdef TORRENT_DHT_VERBOSE_LOGGING
		TORRENT_LOG(traversal) << "[" << m_algorithm.get() << "] missing response dict";
#endif
		return;
	}

	lazy_entry const* k = r->dict_find_string("k");
	if (k && k->string_length() == item_pk_len)
		pk = k->string_ptr();

	lazy_entry const* s = r->dict_find_string("sig");
	if (s && s->string_length() == item_sig_len)
		sig = s->string_ptr();

	lazy_entry const* q = r->dict_find_int("seq");
	if (q)
		seq = q->int_value();
	else if (pk && sig)
		return;

	lazy_entry const* v = r->dict_find("v");
	if (v)
	{
		static_cast<get_item*>(m_algorithm.get())->got_data(v, pk, seq, sig);
	}

	find_data_observer::reply(m);
}

} } // namespace libtorrent::dht