#include "recv_install_snapshot.h"

#include "../tracing.h"
#include "assert.h"
#include "convert.h"
#include "flags.h"
#include "log.h"
#include "recv.h"
#include "replication.h"

static void installSnapshotSendCb(struct raft_io_send *req, int status)
{
	(void)status;
	raft_free(req);
}

int recvInstallSnapshot(struct raft *r,
			const raft_id id,
			const char *address,
			struct raft_install_snapshot *args)
{
	struct raft_io_send *req;
	struct raft_message message;
	struct raft_append_entries_result *result =
	    &message.append_entries_result;
	int rv;
	int match;
	bool async;

	assert(address != NULL);
	tracef(
	    "self:%llu from:%llu@%s conf_index:%llu last_index:%llu "
	    "last_term:%llu "
	    "term:%llu",
	    r->id, id, address, args->conf_index, args->last_index,
	    args->last_term, args->term);

	result->rejected = args->last_index;
	result->last_log_index = logLastIndex(r->log);
	result->version = RAFT_APPEND_ENTRIES_RESULT_VERSION;
	result->features = RAFT_DEFAULT_FEATURE_FLAGS;

	rv = recvEnsureMatchingTerms(r, args->term, &match);
	if (rv != 0) {
		return rv;
	}

	if (match < 0) {
		tracef("local term is higher -> reject ");
		goto reply;
	}

	/* TODO: this logic duplicates the one in the AppendEntries handler */
	assert(r->state == RAFT_FOLLOWER || r->state == RAFT_CANDIDATE);
	assert(r->current_term == args->term);
	if (r->state == RAFT_CANDIDATE) {
		assert(match == 0);
		tracef("discovered leader -> step down ");
		convertToFollower(r);
	}

	rv = recvUpdateLeader(r, id, address);
	if (rv != 0) {
		return rv;
	}
	r->election_timer_start = r->io->time(r->io);

	rv = replicationInstallSnapshot(r, args, &result->rejected, &async);
	if (rv != 0) {
		tracef("replicationInstallSnapshot failed %d", rv);
		return rv;
	}

	if (async) {
		return 0;
	}

	if (result->rejected == 0) {
		/* Echo back to the leader the point that we reached. */
		result->last_log_index = args->last_index;
	}

reply:
	result->term = r->current_term;

	/* Free the snapshot data. */
	raft_configuration_close(&args->conf);
	raft_free(args->data.base);

	message.type = RAFT_IO_APPEND_ENTRIES_RESULT;
	message.server_id = id;
	message.server_address = address;

	req = raft_malloc(sizeof *req);
	if (req == NULL) {
		return RAFT_NOMEM;
	}
	req->data = r;

	rv = r->io->send(r->io, req, &message, installSnapshotSendCb);
	if (rv != 0) {
		raft_free(req);
		return rv;
	}

	return 0;
}

#undef tracef
