Changes for DST

cmd/handlers.c

@@ -19,8 +19,8 @@
 #endif
 #include <ip_addr.h>
 #include "esp-link/cgi.h"
-
 #include "config.h"
+#include <cgiservices.h>
 
 #ifdef CMD_DBG
 #define DBG(format, ...) do { os_printf(format, ## __VA_ARGS__); } while(0)
@@ -199,6 +199,8 @@ cmdWifiStatus(CmdPacket *cmd) {
 // Command handler for time
 static void ICACHE_FLASH_ATTR
 cmdGetTime(CmdPacket *cmd) {
+  cgiServicesCheckDST();	// This can cause DST to change, so the sntp call to return 0.
+
   cmdResponseStart(CMD_RESP_V, sntp_get_current_timestamp(), 0);
   cmdResponseEnd();
   return;

esp-link/cgiservices.c

@@ -8,6 +8,8 @@
 #ifdef SYSLOG
 #include "syslog.h"
 #endif
+#include "time.h"
+#include "cgiservices.h"
 
 #ifdef CGISERVICES_DBG
 #define DBG(format, ...) do { os_printf(format, ## __VA_ARGS__); } while(0)
@@ -26,6 +28,10 @@ char* flash_maps[7] = {
 
 static ETSTimer reassTimer;
 
+// Daylight Savings Time support
+static ETSTimer dstTimer;
+static bool old_dst;
+
 // Cgi to update system info (name/description)
 int ICACHE_FLASH_ATTR cgiSystemSet(HttpdConnData *connData) {
   if (connData->conn == NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
@@ -96,6 +102,144 @@ int ICACHE_FLASH_ATTR cgiSystemInfo(HttpdConnData *connData) {
   return HTTPD_CGI_DONE;
 }
 
+static bool ICACHE_FLASH_ATTR isDSTEurope(struct tm *tp) {
+  int mon = tp->tm_mon + 1;
+
+  if (mon < 3 || tp->tm_mon > 11) return false;
+  if (mon > 3 && tp->tm_mon < 11) return true;
+
+  int previousSunday = tp->tm_mday - tp->tm_wday;
+
+  if (mon == 10) {
+    if (previousSunday < 25)
+      return true;
+    if (tp->tm_wday > 0)
+      return false;
+    if (tp->tm_hour < 2)
+      return true;
+    return false;
+  }
+  if (mon == 3) {
+    if (previousSunday < 25)
+      return false;
+    if (tp->tm_wday > 0)
+      return true;
+    if (tp->tm_hour < 2)
+      return false;
+    return true;
+  }
+
+  return true;
+}
+
+static bool ICACHE_FLASH_ATTR isDSTUSA(struct tm *tp) {
+  int month = tp->tm_mon + 1;
+
+  // January, february, and december are out.
+  if (month < 3 || month > 11)
+    return false;
+
+  // April to October are in
+  if (month > 3 && month < 11)
+    return true;
+
+  int previousSunday = tp->tm_mday - tp->tm_wday;
+
+  // In march, we are DST if our previous sunday was on or after the 8th.
+  if (month == 3)
+    return previousSunday >= 8;
+
+  // In november we must be before the first sunday to be dst.
+  // That means the previous sunday must be before the 1st.
+  return previousSunday <= 0;
+}
+
+/*
+ * When adding more regions, this must be extended.
+ * If someone needs a half hour timezone, then it might be better to change
+ * the return type to int instead of bool.
+ * It could then mean the number of minutes to add.
+ */
+static bool ICACHE_FLASH_ATTR isDST(struct tm *tp) {
+  switch (flashConfig.dst_mode) {
+  case DST_EUROPE:
+    return isDSTEurope(tp);
+  case DST_USA:
+    return isDSTUSA(tp);
+  case DST_NONE:
+  default:
+    return false;
+  }
+}
+
+static ICACHE_FLASH_ATTR char *dstMode2text(int dm) {
+  switch(dm) {
+  case DST_EUROPE:
+    return "Europe";
+  case DST_USA:
+    return "USA";
+  case DST_NONE:
+  default:
+    return "None";
+  }
+}
+
+
+#if 1
+/*
+ * For debugging only
+ * This function is called yet another timeout after changing the timezone offset.
+ * This is the only way to report the time correctly if we're in DST.
+ */
+static void ICACHE_FLASH_ATTR dstDelayed2() {
+  time_t ts = sntp_get_current_timestamp();
+  if (ts < 10000)
+    return;
+  struct tm *tp = gmtime(&ts);
+
+  os_printf("dstDelayed (dst) : date %04d-%02d-%02d time %02d:%02d:%02d\n",
+    tp->tm_year + 1900, tp->tm_mon + 1, tp->tm_mday, tp->tm_hour, tp->tm_min, tp->tm_sec);
+}
+#endif
+
+/*
+ * This gets called a while after initializing SNTP.
+ * The assumption is we will now know the date/time so we can determine whether we're in
+ * a Daylight Savings Time period.
+ * And then set the time offset accordingly.
+ */
+static void ICACHE_FLASH_ATTR dstDelayed() {
+  time_t ts = sntp_get_current_timestamp();
+  if (ts < 10000)
+    return;		// FIX ME failed to obtain time. Now what ?
+
+  struct tm *tp = gmtime(&ts);
+
+  bool dst = isDST(tp);
+
+  os_printf("dstDelayed : date %04d-%02d-%02d time %02d:%02d:%02d, wday = %d, DST = %s (%s)\n",
+    tp->tm_year + 1900, tp->tm_mon + 1, tp->tm_mday, tp->tm_hour, tp->tm_min, tp->tm_sec,
+    tp->tm_wday, dst ? "true" : "false", dstMode2text(flashConfig.dst_mode));
+
+  old_dst = dst;
+
+  // Only change the timezone offset if we're in DST
+  if (dst) {
+    // Changing timezone offset requires a SNTP stop/start.
+    sntp_stop();
+    if (! sntp_set_timezone(flashConfig.timezone_offset + 1))
+      os_printf("sntp_set_timezone(%d) failed\n", flashConfig.timezone_offset + 1);
+    sntp_init();
+
+#if 1
+    // FIX ME for debugging only
+    os_timer_disarm(&dstTimer);
+    os_timer_setfn(&dstTimer, dstDelayed2, NULL);
+    os_timer_arm(&dstTimer, 5000, 0);		// wait 5 seconds
+#endif
+  }
+}
+
 void ICACHE_FLASH_ATTR cgiServicesSNTPInit() {
   if (flashConfig.sntp_server[0] != '\0') {
     sntp_stop();
@@ -103,7 +247,58 @@ void ICACHE_FLASH_ATTR cgiServicesSNTPInit() {
       sntp_setservername(0, flashConfig.sntp_server);
       sntp_init();
     }
-    DBG("SNTP timesource set to %s with offset %d\n", flashConfig.sntp_server, flashConfig.timezone_offset);
+    old_dst = false;
+
+    // If we support daylight savings time, delay setting the timezone until we know the date/time
+    if (flashConfig.dst_mode != 0) {
+      os_timer_disarm(&dstTimer);
+      os_timer_setfn(&dstTimer, dstDelayed, NULL);
+      os_timer_arm(&dstTimer, 5000, 0);		// wait 5 seconds
+
+      DBG("SNTP timesource set to %s with offset %d, awaiting DST info\n",
+        flashConfig.sntp_server, flashConfig.timezone_offset);
+    } else {
+      DBG("SNTP timesource set to %s with offset %d\n",
+        flashConfig.sntp_server, flashConfig.timezone_offset);
+    }
+  }
+}
+
+/*
+ * Check whether to change DST, at every CMD_GET_TIME call.
+ *
+ * If we need to change, then the next call to sntp_get_current_timestamp() will return 0
+ * so a retry will be required. The apps already had to cope with such situations, I believe.
+ */
+void ICACHE_FLASH_ATTR cgiServicesCheckDST() {
+  if (flashConfig.dst_mode == 0)
+    return;
+
+  time_t ts = sntp_get_current_timestamp();
+  if (ts < 10000)
+    return;		// FIX ME failed to obtain time. Now what ?
+
+  struct tm *tp = gmtime(&ts);
+  bool dst = isDST(tp);
+
+  if (dst != old_dst) {
+    // Just calling this would be easy but too slow, we already know the new DST setting.
+    // cgiServicesSNTPInit();
+
+    old_dst = dst;
+
+    int add = dst ? 1 : 0;
+    sntp_stop();
+    if (! sntp_set_timezone(flashConfig.timezone_offset + add))
+      os_printf("sntp_set_timezone(%d) failed\n", flashConfig.timezone_offset + add);
+    sntp_init();
+
+#if 1
+    // FIX ME for debugging only
+    os_timer_disarm(&dstTimer);
+    os_timer_setfn(&dstTimer, dstDelayed2, NULL);
+    os_timer_arm(&dstTimer, 5000, 0);		// wait 5 seconds
+#endif
   }
 }
 
@@ -124,7 +319,8 @@ int ICACHE_FLASH_ATTR cgiServicesInfo(HttpdConnData *connData) {
       "\"timezone_offset\": %d, "
       "\"sntp_server\": \"%s\", "
       "\"mdns_enable\": \"%s\", "
-      "\"mdns_servername\": \"%s\""
+      "\"mdns_servername\": \"%s\", "
+      "\"dst_mode\": \"%d\" "
     " }",
 #ifdef SYSLOG
     flashConfig.syslog_host,
@@ -136,7 +332,13 @@ int ICACHE_FLASH_ATTR cgiServicesInfo(HttpdConnData *connData) {
     flashConfig.timezone_offset,
     flashConfig.sntp_server,
     flashConfig.mdns_enable ? "enabled" : "disabled",
-    flashConfig.mdns_servername
+    flashConfig.mdns_servername,
+#if 0
+    flashConfig.dst_mode ?
+      (flashConfig.dst_mode == DST_EUROPE ? "Europe" : "USA")
+      : "None"
+#endif
+    flashConfig.dst_mode
     );
 
   jsonHeader(connData, 200);
@@ -172,6 +374,10 @@ int ICACHE_FLASH_ATTR cgiServicesSet(HttpdConnData *connData) {
   sntp |= getStringArg(connData, "sntp_server", flashConfig.sntp_server, sizeof(flashConfig.sntp_server));
   if (sntp < 0) return HTTPD_CGI_DONE;
 
+  sntp |= getUInt8Arg(connData, "dst_mode", &flashConfig.dst_mode);
+  os_printf("DSTMODE %d\n", flashConfig.dst_mode);
+  if (sntp < 0) return HTTPD_CGI_DONE;
+
   if (sntp > 0) {
     cgiServicesSNTPInit();
   }

esp-link/cgiservices.h

@@ -3,10 +3,17 @@
 
 #include "httpd.h"
 
+// Need to be in sync with html/services.html
+#define	DST_NONE	0
+#define	DST_EUROPE	1
+#define	DST_USA		2
+
 int cgiSystemSet(HttpdConnData *connData);
 int cgiSystemInfo(HttpdConnData *connData);
 
 void cgiServicesSNTPInit();
+void cgiServicesCheckDST();
+
 int cgiServicesInfo(HttpdConnData *connData);
 int cgiServicesSet(HttpdConnData *connData);
 

esp-link/cgiwifi.h

@@ -2,6 +2,7 @@
 #define CGIWIFI_H
 
 #include "httpd.h"
+#include "cmd.h"
 
 enum { wifiIsDisconnected, wifiIsConnected, wifiGotIP };
 typedef void(*WifiStateChangeCb)(uint8_t wifiStatus);

esp-link/config.c

@@ -34,6 +34,7 @@ FlashConfig flashDefault = {
   .data_bits	= EIGHT_BITS,
   .parity	= NONE_BITS,
   .stop_bits	= ONE_STOP_BIT,
+  .dst_mode     = 0,
 };
 
 typedef union {

esp-link/config.h

@@ -41,6 +41,7 @@ typedef struct {
   int8_t   data_bits;
   int8_t   parity;
   int8_t   stop_bits;
+  uint8_t  dst_mode;
 } FlashConfig;
 extern FlashConfig flashConfig;