/* Blerg is (C) 2011 The Dominion of Awesome, and is distributed under a
 * BSD-style license.  Please see the COPYING file for details.
 */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include "subscription.h"
#include "stringbucket.h"
#include "util.h"
#include "config.h"
#include "configuration.h"

int subscription_add(const char *from, const char *to) {
	char filename[FILENAME_MAX];
	struct stringbucket * sb;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscriptions", blergconf.data_path, from);
	sb = stringbucket_open(filename);
	stringbucket_add(sb, to);
	stringbucket_close(sb);

	snprintf(filename, FILENAME_MAX, "%s/%s/subscribers", blergconf.data_path, to);
	sb = stringbucket_open(filename);
	stringbucket_add(sb, from);
	stringbucket_close(sb);

	return 1;
}

int subscription_remove(const char *from, const char *to) {
	char filename[FILENAME_MAX];
	struct stringbucket * sb;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscriptions", blergconf.data_path, from);
	sb = stringbucket_open(filename);
	stringbucket_delete(sb, to);
	stringbucket_close(sb);

	snprintf(filename, FILENAME_MAX, "%s/%s/subscribers", blergconf.data_path, to);
	sb = stringbucket_open(filename);
	stringbucket_delete(sb, from);
	stringbucket_close(sb);

	return 1;
}

void subscription_notify_add_item(char *to, void *stuff) {
	char filename[FILENAME_MAX];

	snprintf(filename, FILENAME_MAX, "%s/%s/subscription_feed", blergconf.data_path, to);
	int fd = open(filename, O_WRONLY | O_APPEND | O_CREAT, 0600);
	write(fd, stuff, sizeof(struct blergref));
	close(fd);
}

int subscription_notify(const char *author, uint64_t record) {
	char filename[FILENAME_MAX];
	struct blergref r;

	strncpy(r.author, author, 32);
	r.record = record;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscribers", blergconf.data_path, author);
	struct stringbucket * sb = stringbucket_open(filename);
	stringbucket_iterate(sb, subscription_notify_add_item, &r);
	stringbucket_close(sb);

	return 1;
}

struct blergref * subscription_list(const char *author, uint64_t offset, int *count, int direction) {
	char filename[FILENAME_MAX];
	struct stat st;
	struct blergref * slist;
	struct blergref * retlist;
	uint64_t n_subscription_records;

	if (!valid_name(author))
		return NULL;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscription_feed", blergconf.data_path, author);

	int feed_fd = open(filename, O_RDONLY);
	if (feed_fd == -1) {
		perror("Could not open subscription feed");
		goto subscription_list_open_failed;
	}

	fstat(feed_fd, &st);
	if (st.st_size == 0) {
		fprintf(stderr, "Feed is empty\n");
		goto subscription_list_map_failed;
	}
	n_subscription_records = st.st_size / sizeof(struct blergref);
	if (*count > n_subscription_records - offset)
		*count = n_subscription_records - offset;
	if (offset > n_subscription_records) {
		fprintf(stderr, "Cannot access subscription record beyond end\n");
		goto subscription_list_map_failed;
		close(feed_fd);
		return NULL;
	}

	slist = (struct blergref *) mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, feed_fd, 0);
	if (slist == MAP_FAILED) {
		perror("Could not mmap tag_file");
		goto subscription_list_map_failed;
	}
	retlist = (struct blergref *) malloc(sizeof(struct blergref) * *count);
	if (retlist == NULL) {
		perror("Could not allocate memory for subscription feed list");
		goto subscription_list_malloc_failed;
	}
	
	switch(direction) {
	case 1:
		memcpy(retlist, slist + offset, sizeof(struct blergref) * *count);
		break;
	case -1:
		memcpy(retlist, slist + (n_subscription_records - *count - offset), sizeof(struct blergref) * *count);
	}

	munmap(slist, st.st_size);
	close(feed_fd);
	return retlist;

subscription_list_malloc_failed:
	munmap(slist, st.st_size);
subscription_list_map_failed:
	close(feed_fd);
subscription_list_open_failed:
	*count = 0;
	return NULL;
}

int is_subscribed(const char *from, const char *to) {
	char filename[FILENAME_MAX];
	struct stringbucket * sb;
	int ret = 0;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscriptions", blergconf.data_path, from);
	sb = stringbucket_open(filename);
	if (stringbucket_find(sb, to) != -1)
		ret = 1;
	stringbucket_close(sb);

	return ret;
}

int subscription_count_items(const char *user) {
	char filename[FILENAME_MAX];
	struct stat st;

	if (!valid_name(user))
		return -1;

	snprintf(filename, FILENAME_MAX, "%s/%s/subscription_feed", blergconf.data_path, user);

	if (access(filename, R_OK) != 0)
		return 0;
	stat(filename, &st);
	return st.st_size / sizeof(struct blergref);
}