#include "tmate.h"

int tmate_sx = -1;
int tmate_sy = -1;

struct tmate_unpacker {
	msgpack_object *argv;
	int argc;
};

static void decoder_error(void)
{
	tmate_fatal("Received a bad message");
}

static void init_unpacker(struct tmate_unpacker *uk,
			  msgpack_object obj)
{
	if (obj.type != MSGPACK_OBJECT_ARRAY)
		decoder_error();

	uk->argv = obj.via.array.ptr;
	uk->argc = obj.via.array.size;
}

static int64_t unpack_int(struct tmate_unpacker *uk)
{
	int64_t val;

	if (uk->argc == 0)
		decoder_error();

	if (uk->argv[0].type != MSGPACK_OBJECT_POSITIVE_INTEGER &&
	    uk->argv[0].type != MSGPACK_OBJECT_NEGATIVE_INTEGER)
		decoder_error();

	val = uk->argv[0].via.i64;

	uk->argv++;
	uk->argc--;

	return val;
}

static void tmate_client_key(struct tmate_unpacker *uk)
{
	struct client *c;
	int key = unpack_int(uk);

	/* Very gross. other clients cannot even detach */

	if (ARRAY_LENGTH(&clients) > 0) {
		c = ARRAY_ITEM(&clients, 0);
		server_client_handle_key(c, key);
	}
}

static void tmate_client_resize(struct tmate_unpacker *uk)
{
	/* A bit gross as well */
	tmate_sx = unpack_int(uk);
	tmate_sy = unpack_int(uk);
	recalculate_sizes();

	/* TODO Handle reconnection cases */
}

static void handle_message(msgpack_object obj)
{
	struct tmate_unpacker _uk;
	struct tmate_unpacker *uk = &_uk;
	int cmd;

	init_unpacker(uk, obj);

	switch (unpack_int(uk)) {
	case TMATE_CLIENT_KEY:		tmate_client_key(uk); break;
	case TMATE_CLIENT_RESIZE:	tmate_client_resize(uk); break;
	default:			decoder_error();
	}
}

void tmate_decoder_commit(struct tmate_decoder *decoder, size_t len)
{
	msgpack_unpacked result;

	msgpack_unpacker_buffer_consumed(&decoder->unpacker, len);

	msgpack_unpacked_init(&result);
	while (msgpack_unpacker_next(&decoder->unpacker, &result)) {
		handle_message(result.data);
	}
	msgpack_unpacked_destroy(&result);

	if (msgpack_unpacker_message_size(&decoder->unpacker) >
						TMATE_MAX_MESSAGE_SIZE) {
		tmate_fatal("Message too big");
	}
}

void tmate_decoder_get_buffer(struct tmate_decoder *decoder,
			      char **buf, size_t *len)
{
	/* rewind the buffer if possible */
	if (msgpack_unpacker_buffer_capacity(&decoder->unpacker) <
						TMATE_MAX_MESSAGE_SIZE) {
		msgpack_unpacker_expand_buffer(&decoder->unpacker, 0);
	}

	*buf = msgpack_unpacker_buffer(&decoder->unpacker);
	*len = msgpack_unpacker_buffer_capacity(&decoder->unpacker);
}

void tmate_decoder_init(struct tmate_decoder *decoder)
{
	if (!msgpack_unpacker_init(&decoder->unpacker, 2*TMATE_MAX_MESSAGE_SIZE))
		tmate_fatal("cannot initialize the unpacker");
}