#include "tmate.h"
#include "tmate-protocol.h"

static void on_encoder_buffer_ready(__unused evutil_socket_t fd,
				    __unused short what, void *arg)
{
	struct tmate_encoder *encoder = arg;

	encoder->ev_active = false;
	if (encoder->ready_callback)
		encoder->ready_callback(encoder->userdata, encoder->buffer);
}

static int on_encoder_write(void *userdata, const char *buf, size_t len)
{
	struct tmate_encoder *encoder = userdata;

	if (evbuffer_add(encoder->buffer, buf, len) < 0)
		tmate_fatal("Cannot buffer encoded data");

	if (!encoder->ev_active) {
		event_active(&encoder->ev_buffer, EV_READ, 0);
		encoder->ev_active = true;
	}

	return 0;
}

/* Really sad hack, but we can get away with it */
#define tmate_encoder_from_pk(pk) ((struct tmate_encoder *)pk)

void msgpack_pack_string(msgpack_packer *pk, const char *str)
{
	size_t len = strlen(str);

	msgpack_pack_str(pk, len);
	msgpack_pack_str_body(pk, str, len);
}

void msgpack_pack_boolean(msgpack_packer *pk, bool value)
{
	if (value)
		msgpack_pack_true(pk);
	else
		msgpack_pack_false(pk);
}

void tmate_encoder_init(struct tmate_encoder *encoder,
			tmate_encoder_write_cb *callback,
			void *userdata)
{
	msgpack_packer_init(&encoder->pk, encoder, &on_encoder_write);
	encoder->buffer = evbuffer_new();
	encoder->ready_callback = callback;
	encoder->userdata = userdata;

	if (!encoder->buffer)
		tmate_fatal("Can't allocate buffer");

	event_set(&encoder->ev_buffer, -1,
		  EV_READ | EV_PERSIST, on_encoder_buffer_ready, encoder);

	event_add(&encoder->ev_buffer, NULL);

	encoder->ev_active = false;
}

void tmate_encoder_destroy(struct tmate_encoder *encoder)
{
	/* encoder->pk doesn't need any cleanup */
	evbuffer_free(encoder->buffer);
	event_del(&encoder->ev_buffer);
	memset(encoder, 0, sizeof(*encoder));
}

void tmate_encoder_set_ready_callback(struct tmate_encoder *encoder,
				      tmate_encoder_write_cb *callback,
				      void *userdata)
{
	encoder->ready_callback = callback;
	encoder->userdata = userdata;
	if (encoder->ready_callback)
		encoder->ready_callback(encoder->userdata, encoder->buffer);
}

void tmate_decoder_error(void)
{
	/* TODO Don't kill the session, disconnect */
	tmate_print_stack_trace();
	tmate_fatal("Received a bad message");
}

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

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

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

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

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

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

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

	return val;
}

bool unpack_bool(struct tmate_unpacker *uk)
{
	bool val;

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

	if (uk->argv[0].type != MSGPACK_OBJECT_BOOLEAN)
		tmate_decoder_error();

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

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

	return val;
}

void unpack_buffer(struct tmate_unpacker *uk, const char **buf, size_t *len)
{
	if (uk->argc == 0)
		tmate_decoder_error();

	if (uk->argv[0].type != MSGPACK_OBJECT_STR &&
	    uk->argv[0].type != MSGPACK_OBJECT_BIN)
		tmate_decoder_error();

	*len = uk->argv[0].via.str.size;
	*buf = uk->argv[0].via.str.ptr;

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

char *unpack_string(struct tmate_unpacker *uk)
{
	const char *buf;
	char *alloc_buf;
	size_t len;

	unpack_buffer(uk, &buf, &len);

	alloc_buf = xmalloc(len + 1);
	memcpy(alloc_buf, buf, len);
	alloc_buf[len] = '\0';

	return alloc_buf;
}

void unpack_array(struct tmate_unpacker *uk, struct tmate_unpacker *nested)
{
	if (uk->argc == 0)
		tmate_decoder_error();

	init_unpacker(nested, uk->argv[0]);

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

void tmate_decoder_init(struct tmate_decoder *decoder, tmate_decoder_reader *reader,
			void *userdata)
{
	if (!msgpack_unpacker_init(&decoder->unpacker, TMATE_MAX_MESSAGE_SIZE))
		tmate_fatal("Cannot initialize the unpacker");
	decoder->reader = reader;
	decoder->userdata = userdata;
}

void tmate_decoder_destroy(struct tmate_decoder *decoder)
{
	msgpack_unpacker_destroy(&decoder->unpacker);
	memset(decoder, 0, sizeof(*decoder));
}

void tmate_decoder_get_buffer(struct tmate_decoder *decoder,
			      char **buf, size_t *len)
{
	ssize_t current_size = msgpack_unpacker_message_size(&decoder->unpacker);
	if (!msgpack_unpacker_reserve_buffer(&decoder->unpacker,
					     TMATE_MAX_MESSAGE_SIZE - current_size))
		tmate_fatal("cannot expand decoder buffer");

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

void tmate_decoder_commit(struct tmate_decoder *decoder, size_t len)
{
	struct tmate_unpacker _uk, *uk = &_uk;
	msgpack_unpacked result;

	msgpack_unpacker_buffer_consumed(&decoder->unpacker, len);

	msgpack_unpacked_init(&result);
	while (msgpack_unpacker_next(&decoder->unpacker, &result)) {
		init_unpacker(uk, result.data);
		decoder->reader(decoder->userdata, uk);
	}
	msgpack_unpacked_destroy(&result);
}