#include <libetpan/libetpan.h>
#include <stdlib.h>
#include <sys/stat.h>

static void check_error(int r, char * msg)
{
	if (r == MAILIMAP_NO_ERROR)
		return;
  if (r == MAILIMAP_NO_ERROR_AUTHENTICATED)
		return;
  if (r == MAILIMAP_NO_ERROR_NON_AUTHENTICATED)
		return;
	
	fprintf(stderr, "%s\n", msg);
	exit(EXIT_FAILURE);
}

static char * get_msg_att_msg_content(struct mailimap_msg_att * msg_att, size_t * p_msg_size)
{
	clistiter * cur;
	
  /* iterate on each result of one given message */
	for(cur = clist_begin(msg_att->att_list) ; cur != NULL ; cur = clist_next(cur)) {
		struct mailimap_msg_att_item * item;
		
		item = clist_content(cur);
		if (item->att_type != MAILIMAP_MSG_ATT_ITEM_STATIC) {
			continue;
		}
		
    if (item->att_data.att_static->att_type != MAILIMAP_MSG_ATT_BODY_SECTION) {
			continue;
    }
		
		* p_msg_size = item->att_data.att_static->att_data.att_body_section->sec_length;
		return item->att_data.att_static->att_data.att_body_section->sec_body_part;
	}
	
	return NULL;
}

static char * get_msg_content(clist * fetch_result, size_t * p_msg_size)
{
	clistiter * cur;
	
  /* for each message (there will be probably only on message) */
	for(cur = clist_begin(fetch_result) ; cur != NULL ; cur = clist_next(cur)) {
		struct mailimap_msg_att * msg_att;
		size_t msg_size;
		char * msg_content;
		
		msg_att = clist_content(cur);
		msg_content = get_msg_att_msg_content(msg_att, &msg_size);
		if (msg_content == NULL) {
			continue;
		}
		
		* p_msg_size = msg_size;
		return msg_content;
	}
	
	return NULL;
}

static void fetch_msg(struct mailimap * imap, uint32_t uid)
{
	struct mailimap_set * set;
	struct mailimap_section * section;
	char filename[512];
	size_t msg_len;
	char * msg_content;
	FILE * f;
	struct mailimap_fetch_type * fetch_type;
	struct mailimap_fetch_att * fetch_att;
	int r;
	clist * fetch_result;
	struct stat stat_info;
	
	snprintf(filename, sizeof(filename), "download/%u.eml", (unsigned int) uid);
	r = stat(filename, &stat_info);
	if (r == 0) {
		// already cached
		printf("%u is already fetched\n", (unsigned int) uid);
		return;
	}
	
	set = mailimap_set_new_single(uid);
	fetch_type = mailimap_fetch_type_new_fetch_att_list_empty();
	section = mailimap_section_new(NULL);
	fetch_att = mailimap_fetch_att_new_body_peek_section(section);
	mailimap_fetch_type_new_fetch_att_list_add(fetch_type, fetch_att);

	r = mailimap_uid_fetch(imap, set, fetch_type, &fetch_result);
	check_error(r, "could not fetch");
	printf("fetch %u\n", (unsigned int) uid);
	
	msg_content = get_msg_content(fetch_result, &msg_len);
	if (msg_content == NULL) {
		fprintf(stderr, "no content\n");
		mailimap_fetch_list_free(fetch_result);
		return;
	}
	
	f = fopen(filename, "w");
	if (f == NULL) {
		fprintf(stderr, "could not write\n");
		mailimap_fetch_list_free(fetch_result);
		return;
	}
	
	fwrite(msg_content, 1, msg_len, f);
	fclose(f);
	
	printf("%u has been fetched\n", (unsigned int) uid);
	
	mailimap_fetch_list_free(fetch_result);
}

static uint32_t get_uid(struct mailimap_msg_att * msg_att)
{
	clistiter * cur;
	
  /* iterate on each result of one given message */
	for(cur = clist_begin(msg_att->att_list) ; cur != NULL ; cur = clist_next(cur)) {
		struct mailimap_msg_att_item * item;
		
		item = clist_content(cur);
		if (item->att_type != MAILIMAP_MSG_ATT_ITEM_STATIC) {
			continue;
		}
		
		if (item->att_data.att_static->att_type != MAILIMAP_MSG_ATT_UID) {
			continue;
		}
		
		return item->att_data.att_static->att_data.att_uid;
	}
	
	return 0;
}

static void fetch_messages(struct mailimap * imap)
{
	struct mailimap_set * set;
	struct mailimap_fetch_type * fetch_type;
	struct mailimap_fetch_att * fetch_att;
	clist * fetch_result;
	clistiter * cur;
	int r;
	
	/* as improvement UIDVALIDITY should be read and the message cache should be cleaned
	   if the UIDVALIDITY is not the same */
	
	set = mailimap_set_new_interval(1, 0); /* fetch in interval 1:* */
	fetch_type = mailimap_fetch_type_new_fetch_att_list_empty();
	fetch_att = mailimap_fetch_att_new_uid();
	mailimap_fetch_type_new_fetch_att_list_add(fetch_type, fetch_att);

	r = mailimap_fetch(imap, set, fetch_type, &fetch_result);
	check_error(r, "could not fetch");
	
  /* for each message */
	for(cur = clist_begin(fetch_result) ; cur != NULL ; cur = clist_next(cur)) {
		struct mailimap_msg_att * msg_att;
		uint32_t uid;
		
		msg_att = clist_content(cur);
		uid = get_uid(msg_att);
		if (uid == 0)
			continue;

		fetch_msg(imap, uid);
	}

	mailimap_fetch_list_free(fetch_result);
}

int main(int argc, char ** argv)
{
	struct mailimap * imap;
	int r;
	
	/*
	./imap-sample mygmailaccount@gmail.com mygmailpassword
	*/
	if (argc < 3) {
		fprintf(stderr, "usage: imap-sample [gmail-email-address] [password]\n");
		exit(EXIT_FAILURE);
	}
	
	mkdir("download", 0700);
	
	imap = mailimap_new(0, NULL);
	r = mailimap_ssl_connect(imap, "imap.gmail.com", 993);
	fprintf(stderr, "connect: %i\n", r);
	check_error(r, "could not connect to server");
	
	r = mailimap_login(imap, argv[1], argv[2]);
	check_error(r, "could not login");
	
	r = mailimap_select(imap, "INBOX");
	check_error(r, "could not select INBOX");
	
	fetch_messages(imap);
	
	mailimap_logout(imap);
	mailimap_free(imap);
	
	exit(EXIT_SUCCESS);
}