From 6ce36a58d6c4e3ca38dcfb53850aa4b0381e4316 Mon Sep 17 00:00:00 2001
From: Guillaume Vernieres <guillaume.vernieres@noaa.gov>
Date: Mon, 13 Nov 2023 16:43:19 -0500
Subject: [PATCH] fix refdate

---
 utils/obsproc/Ghrsst2Ioda.h           | 15 ++++++++++++++-
 utils/obsproc/NetCDFToIodaConverter.h |  1 +
 utils/test/testref/ghrsst2ioda.test   |  2 ++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/utils/obsproc/Ghrsst2Ioda.h b/utils/obsproc/Ghrsst2Ioda.h
index 1d1deebec..64b5ed28b 100644
--- a/utils/obsproc/Ghrsst2Ioda.h
+++ b/utils/obsproc/Ghrsst2Ioda.h
@@ -2,6 +2,7 @@
 
 #include <iostream>
 #include <netcdf>    // NOLINT (using C API)
+#include <regex>
 #include <string>
 #include <vector>
 
@@ -67,12 +68,24 @@ namespace gdasapp {
         }
       }
 
-      // datetime: Read Reference Time
+      // Read the reference time
       std::vector<int32_t> refTime(dimTime);
       ncFile.getVar("time").getVar(refTime.data());
       std::string refDate;
       ncFile.getVar("time").getAtt("units").getValues(refDate);
 
+      // Reformat the reference time
+      std::regex dateRegex(R"(\b\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\b)");
+      std::smatch match;
+      std::regex_search(refDate, match, dateRegex);
+      refDate = match.str();
+      std::tm tmStruct = {};
+      std::istringstream ss(refDate);
+      ss >> std::get_time(&tmStruct, "%Y-%m-%d %H:%M:%S");
+      std::ostringstream isoFormatted;
+      isoFormatted << std::put_time(&tmStruct, "seconds since %Y-%m-%dT%H:%M:%SZ");
+      refDate = isoFormatted.str();
+
       // Read sst_dtime to add to the reference time
       // TODO(AMG): What's below does not read the field the same way python does
       std::vector<int32_t> sstdTime(dimTime*dimLat*dimLon);
diff --git a/utils/obsproc/NetCDFToIodaConverter.h b/utils/obsproc/NetCDFToIodaConverter.h
index 49a372b83..428e2f69d 100644
--- a/utils/obsproc/NetCDFToIodaConverter.h
+++ b/utils/obsproc/NetCDFToIodaConverter.h
@@ -158,6 +158,7 @@ namespace gdasapp {
 
     // Testing
     void testOutput() {
+      oops::Log::test() << referenceDate_ << std::endl;
       oops::Log::test() <<
         gdasapp::testutils::checksum(obsVal_, "obsVal") << std::endl;
       oops::Log::test() <<
diff --git a/utils/test/testref/ghrsst2ioda.test b/utils/test/testref/ghrsst2ioda.test
index 652fd10bc..c8e895e1e 100644
--- a/utils/test/testref/ghrsst2ioda.test
+++ b/utils/test/testref/ghrsst2ioda.test
@@ -1,4 +1,5 @@
 Reading ghrsst_sst_mb_202107010000.nc4
+seconds since 1981-01-01T00:00:00Z
 obsVal:
     Min: 276.708
     Max: 276.9
@@ -24,6 +25,7 @@ datetime:
     Max: 1277942528
     Sum: 23002965504
 Reading ghrsst_sst_mb_202107010100.nc4
+seconds since 1981-01-01T00:00:00Z
 obsVal:
     Min: 281.547
     Max: 281.714