#include "common.h"
#include <unistd.h>

typedef struct itc_message_s itc_message;
struct itc_message_s {
	int number;
	void *data;

	itc_message *older, *newer;
};

typedef struct {
	itc_message *newest, *oldest;
	SDL_mutex *mutex;

} itc_chan;


void itc_chan_create(itc_chan *chan)
{
	memset(chan, 0, sizeof(itc_chan));

	chan->mutex = SDL_CreateMutex();
	assert(chan->mutex);
}

void itc_chan_destroy(itc_chan *chan)
{
	// todo: free queue

	SDL_DestroyMutex(chan->mutex);
}

void itc_chan_push(itc_chan *chan, int number, void *data)
{
	itc_message *msg;

	msg = calloc(1, sizeof(itc_message));
	assert(msg);

	msg->number = number;
	msg->data = data;

	SDL_LockMutex(chan->mutex);
	
	if (!chan->oldest) {      
		chan->oldest = msg;
		chan->newest = msg;
	} else {
		/*
		 *   head <---> ... <---> tail
		 *
		 */

		chan->newest->newer = msg;
		msg->older = chan->newest;
		chan->newest = msg;
	}

	SDL_UnlockMutex(chan->mutex);
}

int itc_chan_pop(itc_chan *chan, int *number, void **data)
{
	itc_message *msg;

	SDL_LockMutex(chan->mutex);

	if (!chan->oldest) {
		SDL_UnlockMutex(chan->mutex);
		return 1;
	}

	msg = chan->oldest;

	if (msg->newer) {
		msg->newer->older = NULL;
		chan->oldest = msg->newer;
	} else {
		chan->newest = NULL;
		chan->oldest = NULL;
	}

	SDL_UnlockMutex(chan->mutex);

	*number = msg->number;
	*data = msg->data;
	free(msg);

	return 0;
}



itc_chan gulg_chan;

int gulgulator(void *unused)
{
	int cmd_num;
	void *cmd_data;

	while (1) {
		while (!itc_chan_pop(&gulg_chan, &cmd_num, &cmd_data)) {
			printf("gulgulator: pop %i %p\n", cmd_num, cmd_data);
		}

		usleep(100 * 1000);
	}
}

void itc_test(void)
{
	SDL_Thread *thread;
	char line[512];

	itc_chan_create(&gulg_chan);
	thread = SDL_CreateThread(gulgulator, "gulgulator", NULL);

	while (1) {
		int cmd_num;

		printf("> ");
		fflush(stdout);

		if (!fgets(line, sizeof(line), stdin))
			break;

		cmd_num = atoi(line);

		printf("main: push %i %p\n", cmd_num, 0xDEADBEEF);
		itc_chan_push(&gulg_chan, cmd_num, (void*)0xDEADBEEF);
	}

	printf("EOF\n");

	SDL_WaitThread(thread, NULL);
}