From ca991ae9dddcb38d6ce5e2b17cdc41aa17006357 Mon Sep 17 00:00:00 2001
From: Thibault Deckers <thibault.deckers@gmail.com>
Date: Tue, 18 Jan 2022 11:36:18 +0900
Subject: [PATCH] #158 fallback for weird timestamps

---
 lib/model/entry.dart                          | 15 +-------
 .../metadata/metadata_fetch_service.dart      |  8 ++---
 lib/utils/time_utils.dart                     | 36 ++++++++++++-------
 3 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/lib/model/entry.dart b/lib/model/entry.dart
index 0b6f72511..16f5cb237 100644
--- a/lib/model/entry.dart
+++ b/lib/model/entry.dart
@@ -349,20 +349,7 @@ class AvesEntry {
   DateTime? _bestDate;
 
   DateTime? get bestDate {
-    if (_bestDate == null) {
-      try {
-        if ((_catalogDateMillis ?? 0) > 0) {
-          _bestDate = DateTime.fromMillisecondsSinceEpoch(_catalogDateMillis!);
-        } else if ((sourceDateTakenMillis ?? 0) > 0) {
-          _bestDate = DateTime.fromMillisecondsSinceEpoch(sourceDateTakenMillis!);
-        } else if ((dateModifiedSecs ?? 0) > 0) {
-          _bestDate = DateTime.fromMillisecondsSinceEpoch(dateModifiedSecs! * 1000);
-        }
-      } catch (e, stack) {
-        // date millis may be out of range
-        reportService.recordError(e, stack);
-      }
-    }
+    _bestDate ??= dateTimeFromMillis(_catalogDateMillis) ?? dateTimeFromMillis(sourceDateTakenMillis) ?? dateTimeFromMillis((dateModifiedSecs ?? 0) * 1000);
     return _bestDate;
   }
 
diff --git a/lib/services/metadata/metadata_fetch_service.dart b/lib/services/metadata/metadata_fetch_service.dart
index b3e93e5fa..c483486b2 100644
--- a/lib/services/metadata/metadata_fetch_service.dart
+++ b/lib/services/metadata/metadata_fetch_service.dart
@@ -7,6 +7,7 @@ import 'package:aves/model/panorama.dart';
 import 'package:aves/services/common/service_policy.dart';
 import 'package:aves/services/common/services.dart';
 import 'package:aves/services/metadata/xmp.dart';
+import 'package:aves/utils/time_utils.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
@@ -238,12 +239,7 @@ class PlatformMetadataFetchService implements MetadataFetchService {
         'field': field.toExifInterfaceTag(),
       });
       if (result is int) {
-        try {
-          return DateTime.fromMillisecondsSinceEpoch(result);
-        } catch (e, stack) {
-          // date millis may be out of range
-          await reportService.recordError(e, stack);
-        }
+        return dateTimeFromMillis(result, isUtc: false);
       }
     } on PlatformException catch (e, stack) {
       if (!entry.isMissingAtPath) {
diff --git a/lib/utils/time_utils.dart b/lib/utils/time_utils.dart
index c49e427b4..b3699462f 100644
--- a/lib/utils/time_utils.dart
+++ b/lib/utils/time_utils.dart
@@ -1,4 +1,4 @@
-import 'package:aves/services/common/services.dart';
+import 'package:flutter/foundation.dart';
 
 extension ExtraDateTime on DateTime {
   bool isAtSameYearAs(DateTime? other) => year == other?.year;
@@ -18,6 +18,26 @@ extension ExtraDateTime on DateTime {
 
 final epoch = DateTime.fromMillisecondsSinceEpoch(0, isUtc: true);
 
+// Overflowing timestamps that are supposed to be in milliseconds
+// will be retried after stripping extra digits.
+const _millisMaxDigits = 13; // 13 digits can go up to 2286/11/20
+
+DateTime? dateTimeFromMillis(int? millis, {bool isUtc = false}) {
+  if (millis == null || millis == 0) return null;
+  try {
+    return DateTime.fromMillisecondsSinceEpoch(millis, isUtc: isUtc);
+  } catch (e) {
+    // `DateTime`s can represent time values that are at a distance of at most 100,000,000
+    // days from epoch (1970-01-01 UTC): -271821-04-20 to 275760-09-13.
+    debugPrint('failed to build DateTime from timestamp in millis=$millis');
+  }
+  final digits = '$millis'.length;
+  if (digits > _millisMaxDigits) {
+    millis = int.tryParse('$millis'.substring(0, _millisMaxDigits));
+    return dateTimeFromMillis(millis, isUtc: isUtc);
+  }
+}
+
 final _unixStampMillisPattern = RegExp(r'\d{13}');
 final _unixStampSecPattern = RegExp(r'\d{10}');
 final _plainPattern = RegExp(r'(\d{8})([_-\s](\d{6})([_-\s](\d{3}))?)?');
@@ -31,12 +51,7 @@ DateTime? parseUnknownDateFormat(String? s) {
     if (stampMillisString != null) {
       final stampMillis = int.tryParse(stampMillisString);
       if (stampMillis != null) {
-        try {
-          return DateTime.fromMillisecondsSinceEpoch(stampMillis, isUtc: false);
-        } catch (e, stack) {
-          // date millis may be out of range
-          reportService.recordError(e, stack);
-        }
+        return dateTimeFromMillis(stampMillis, isUtc: false);
       }
     }
   }
@@ -47,12 +62,7 @@ DateTime? parseUnknownDateFormat(String? s) {
     if (stampSecString != null) {
       final stampSec = int.tryParse(stampSecString);
       if (stampSec != null) {
-        try {
-          return DateTime.fromMillisecondsSinceEpoch(stampSec * 1000, isUtc: false);
-        } catch (e, stack) {
-          // date millis may be out of range
-          reportService.recordError(e, stack);
-        }
+        return dateTimeFromMillis(stampSec * 1000, isUtc: false);
       }
     }
   }