#include <c_types.h>
#include <user_interface.h>
#include <espconn.h>
#include <osapi.h>
#include <mem.h>
#include <time.h>
#include <sys_time.h>

#include "ntp.h"
#include "lwip/def.h"
#include "user_config.h"
#include "driver/uart.h"
//#include "utils.h"

#define OFFSET 2208988800ULL

static ip_addr_t ntp_server_ip = { 0 };

static os_timer_t ntp_timeout;
static struct espconn *pCon, pConDNS;

static struct timeval t_tv = { 0, 0 };

static uint64_t t_offset = 0;
static int16_t ntp_timezone = 0;

void ICACHE_FLASH_ATTR get_cur_time(struct timeval *tv) {
    uint64_t t_curr = get_long_systime() - t_offset + t_tv.tv_usec;
    tv->tv_sec = t_tv.tv_sec + t_curr / 1000000;
    tv->tv_usec = t_curr % 1000000;
}

void ICACHE_FLASH_ATTR set_timezone(int16_t timezone) {
    ntp_timezone = timezone;
}

uint8_t *ICACHE_FLASH_ATTR get_timestr() {
    struct timeval tv;
    static uint8_t buf[10];

    get_cur_time(&tv);
    tv.tv_sec += ntp_timezone * 3600;
    os_sprintf(buf, "%02d:%02d:%02d", (tv.tv_sec / 3600) % 24, (tv.tv_sec / 60) % 60, tv.tv_sec % 60);
    return buf;
}


static uint8_t *days[] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
uint8_t *ICACHE_FLASH_ATTR get_weekday() {
    struct timeval tv;

    get_cur_time(&tv);
    tv.tv_sec += ntp_timezone * 3600;
    return days[((tv.tv_sec / (3600 * 24)) + 3) % 7];
}

void ICACHE_FLASH_ATTR ntp_to_tv(uint8_t ntp[8], struct timeval *tv) {
    uint64_t aux = 0;

    tv->tv_sec = ntohl(*(uint32_t *) ntp) - OFFSET;

    aux = ntohl(*(uint32_t *) & ntp[4]);

    // aux is the NTP fraction (0..2^32-1)
    aux *= 1000000;		// multiply by 1e6 
    aux >>= 32;			// and divide by 2^32
    tv->tv_usec = (uint32_t) aux;
}

LOCAL void ICACHE_FLASH_ATTR ntp_dns_found(const char *name, ip_addr_t * ipaddr, void *arg) {
    struct espconn *pespconn = (struct espconn *)arg;

    if (ipaddr != NULL) {
	os_printf("Got NTP server: %d.%d.%d.%d\r\n", IP2STR(ipaddr));
	// Call the NTP update
	ntp_server_ip.addr = ipaddr->addr;
	ntp_get_time();
    }
}

static void ICACHE_FLASH_ATTR ntp_udp_timeout(void *arg) {

    os_timer_disarm(&ntp_timeout);
    os_printf("NTP timout\r\n");

    // clean up connection
    if (pCon) {
	espconn_delete(pCon);
	os_free(pCon->proto.udp);
	os_free(pCon);
	pCon = 0;
    }
}

static void ICACHE_FLASH_ATTR ntp_udp_recv(void *arg, char *pdata, unsigned short len) {
    ntp_t *ntp;

    struct timeval tv;
    int32_t hh, mm, ss;

    if (!ntp_sync_done())
	os_printf("NTP synced\r\n");

    get_cur_time(&tv);

    // get the according sys_time;
    t_offset = get_long_systime();

    os_timer_disarm(&ntp_timeout);

    // extract ntp time
    ntp = (ntp_t *) pdata;

    ntp_to_tv(ntp->trans_time, &t_tv);

//      os_printf("NTP re-sync - diff: %d usecs\r\n", t_tv.tv_usec-tv.tv_usec);
/*
	ss = t_tv.tv_sec%60;
	mm = (t_tv.tv_sec/60)%60;
	hh = (t_tv.tv_sec/3600)%24;
	os_printf("time: %2d:%02d:%02d\r\n", hh, mm, ss);
	os_printf("Day: %s\r\n", get_weekday());
*/
    // clean up connection
    if (pCon) {
	espconn_delete(pCon);
	os_free(pCon->proto.udp);
	os_free(pCon);
	pCon = 0;
    }
}

void ICACHE_FLASH_ATTR ntp_set_server(uint8_t * ntp_server) {

    ntp_server_ip.addr = 0;

    // invalid arg?
    if (ntp_server == NULL)
	return;

    // ip or DNS name?
    if (UTILS_IsIPV4(ntp_server)) {
	// read address
	UTILS_StrToIP(ntp_server, &ntp_server_ip);
	ntp_get_time();
    } else {
	// call DNS and wait for callback
	espconn_gethostbyname(&pConDNS, ntp_server, &ntp_server_ip, ntp_dns_found);
    }
}

bool ICACHE_FLASH_ATTR ntp_sync_done() {
    return t_offset != 0;
}

void ICACHE_FLASH_ATTR ntp_get_time() {
    ntp_t ntp;

    // either ongoing request or invalid ip?
    if (pCon != 0 || ntp_server_ip.addr == 0)
	return;

    // set up the udp "connection"
    pCon = (struct espconn *)os_zalloc(sizeof(struct espconn));
    pCon->type = ESPCONN_UDP;
    pCon->state = ESPCONN_NONE;
    pCon->proto.udp = (esp_udp *) os_zalloc(sizeof(esp_udp));
    pCon->proto.udp->local_port = espconn_port();
    pCon->proto.udp->remote_port = 123;
    os_memcpy(pCon->proto.udp->remote_ip, &ntp_server_ip, 4);

    // create a really simple ntp request packet
    os_memset(&ntp, 0, sizeof(ntp_t));
    ntp.options = 0b00011011;	// leap = 0, version = 3, mode = 3 (client)

    // set timeout timer
    os_timer_disarm(&ntp_timeout);
    os_timer_setfn(&ntp_timeout, (os_timer_func_t *) ntp_udp_timeout, pCon);
    os_timer_arm(&ntp_timeout, NTP_TIMEOUT_MS, 0);

    // send the ntp request
    espconn_create(pCon);
    espconn_regist_recvcb(pCon, ntp_udp_recv);
    espconn_sent(pCon, (uint8 *) & ntp, sizeof(ntp_t));
}

void ICACHE_FLASH_ATTR set_time_local(uint16_t h, uint16_t m, uint16_t s) {

    // get the according sys_time;
    t_offset = get_long_systime();

    t_tv.tv_sec -= t_tv.tv_sec % (3600 * 24);
    t_tv.tv_sec += (h%24)*3600 + (m%60)*60 + s%60;
    t_tv.tv_usec = 0;
}

bool ICACHE_FLASH_ATTR set_weekday_local(char *day) {
    int i;

    for (i = 0; i<7; i++) {
	if (os_strcmp(day, days[i]) == 0)
	    break;
    }
    if (i>=7)
	return false;

    t_tv.tv_sec = t_tv.tv_sec % (3600 * 24);
    t_tv.tv_sec += (7 + i-3) * (3600 * 24);

    return true;
}