From 0ce43c45a75fcac011eede0ab13bd245afc15775 Mon Sep 17 00:00:00 2001
From: dab246 <tdvu@linagora.com>
Date: Wed, 3 Aug 2022 16:25:28 +0700
Subject: [PATCH] TF-786 Converting a series of URL strings to HTML links

---
 core/lib/utils/linkify_html.dart | 79 ++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 core/lib/utils/linkify_html.dart

diff --git a/core/lib/utils/linkify_html.dart b/core/lib/utils/linkify_html.dart
new file mode 100644
index 000000000..9c5a56988
--- /dev/null
+++ b/core/lib/utils/linkify_html.dart
@@ -0,0 +1,79 @@
+
+import 'package:collection/collection.dart';
+import 'package:core/utils/app_logger.dart';
+
+class LinkifyHtml {
+
+  String generateLinkify(String inputText) {
+    var replacedText = _linkifyUrlAddress(inputText);
+    replacedText = _linkifyMailToAddress(replacedText);
+    return replacedText;
+  }
+
+  RegExp _generateRegExp(String pattern) {
+    return RegExp(pattern, multiLine: true, caseSensitive: false);
+  }
+
+  /// URLs starting with http://, https://, ftp://, or "www." without //.
+  String _linkifyUrlAddress(String inputText) {
+    var replacedText = inputText;
+
+    // URLs starting with http://, https://, ftp://
+    final regexLinkWithHttp = _generateRegExp(r'(\b(https?|ftp):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])');
+
+    final listUrlMatch = regexLinkWithHttp.allMatches(replacedText)
+        .map((regexMatch) => regexMatch.group(1))
+        .whereNotNull()
+        .toSet();
+
+    log('ConvertUrlStringToHtmlLinksTransformers::_linkifyUrlAddress(): listUrlMatch: $listUrlMatch');
+
+    if (listUrlMatch.isNotEmpty) {
+      listUrlMatch.forEach((link) {
+        replacedText = replacedText.replaceAll(
+            link,
+            '<a href="$link" target="_blank">$link</a>');
+      });
+    }
+
+    // URLs starting with "www." without // before it or it'd re-link the ones done above.
+    final regexLinkWithWWW = _generateRegExp(r'(^|[^\/])(www\.[\S]+(\b|\$))');
+
+    final listLinkMatch = regexLinkWithWWW.allMatches(replacedText)
+        .map((regexMatch) => regexMatch.group(2))
+        .whereNotNull()
+        .toSet();
+    log('ConvertUrlStringToHtmlLinksTransformers::_linkifyUrlAddress(): listLinkMatch: $listLinkMatch');
+
+    if (listLinkMatch.isNotEmpty) {
+      listLinkMatch.forEach((link) {
+        replacedText = replacedText.replaceAll(
+            link,
+            '<a href="https://$link" target="_blank">$link</a>');
+      });
+    }
+
+    return replacedText;
+  }
+
+  /// Change email addresses to mailto:: links.
+  String _linkifyMailToAddress(String inputText) {
+    final regexMailTo = _generateRegExp(r'(([a-zA-Z0-9\-\_\.])+@[a-zA-Z\_]+?(\.[a-zA-Z]{2,6})+)');
+
+    final listEmailAddressMatch = regexMailTo.allMatches(inputText)
+        .map((regexMatch) => regexMatch.group(1))
+        .whereNotNull()
+        .toSet();
+
+    log('ConvertUrlStringToHtmlLinksTransformers::generateLinkifyHtml(): listEmailAddressMatch: $listEmailAddressMatch');
+
+    if (listEmailAddressMatch.isNotEmpty) {
+      listEmailAddressMatch.forEach((emailAddress) {
+        inputText = inputText.replaceAll(
+            emailAddress,
+            '<a href="mailto:$emailAddress">$emailAddress</a>');
+      });
+    }
+    return inputText;
+  }
+}
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