Added sharing a BeyondFacts Lab session with the research team (#1196)

app/MindWork AI Studio/Assistants/BeyondFactsLab/BflShareMail.cs

@@ -0,0 +1,93 @@
+namespace AIStudio.Assistants.BeyondFactsLab;
+
+/// <summary>
+/// Prepares the mail with which a person sends a shared session to the research team of the BeyondFacts Lab.
+/// </summary>
+/// <remarks>
+/// The lab writes no mail itself: a mailto link opens the mail program of the person with the address, the subject,
+/// and a short text, and the person attaches the exported file and sends it, from their own address. The link holds
+/// nothing of the session, since mail programs accept only short links; the runtime opens it outside the app.
+/// </remarks>
+public static class BflShareMail
+{
+    private static string TB(string fallbackEN) => Tools.PluginSystem.I18N.I.T(fallbackEN, typeof(BflShareMail).Namespace, nameof(BflShareMail));
+
+    /// <summary>
+    /// The address of the research team.
+    /// </summary>
+    /// <remarks>
+    /// A placeholder until the research team names its address; it is replaced before the release which brings the
+    /// lab, as the lab is a prototype until then.
+    /// </remarks>
+    public const string RECIPIENT = "xxx@xxx.xxx";
+
+    /// <summary>
+    /// The longest link the lab hands to a mail program. Some programs on Windows refuse longer ones.
+    /// </summary>
+    public const int MAX_URI_LENGTH = 1_800;
+
+    /// <summary>
+    /// The line break of a mailto link, which RFC 6068 demands as CR LF.
+    /// </summary>
+    private const string LINE_BREAK = "\r\n";
+
+    /// <summary>
+    /// Gets the subject of the mail, in the language of the app.
+    /// </summary>
+    /// <remarks>
+    /// The mail speaks to the research team, not to the person, so neither the subject nor the text addresses anybody:
+    /// the form of address the person chose for the lab does not fit the research team.
+    /// </remarks>
+    public static string Subject => TB("A shared session of the BeyondFacts Lab");
+
+    /// <summary>
+    /// Gets the text of the mail, in the language of the app.
+    /// </summary>
+    public static string Body => TB("""
+        Hello,
+
+        attached is a session of the BeyondFacts Lab, which I share for the research on the lab. Before I exported it, AI Studio removed the personal details it recognized.
+
+        Kind regards
+        """);
+
+    /// <summary>
+    /// Creates the link which opens the mail to the research team.
+    /// </summary>
+    public static string CreateUri() => CreateUri(RECIPIENT, Subject, Body);
+
+    /// <summary>
+    /// Creates a mailto link, with everything encoded as RFC 6068 demands.
+    /// </summary>
+    /// <remarks>
+    /// A link longer than MAX_URI_LENGTH loses the end of its text, at a word, so that no mail program refuses it.
+    /// </remarks>
+    /// <param name="recipient">The address.</param>
+    /// <param name="subject">The subject.</param>
+    /// <param name="body">The text, with line breaks of any kind.</param>
+    /// <returns>The link.</returns>
+    public static string CreateUri(string recipient, string subject, string body)
+    {
+        var at = recipient.LastIndexOf('@');
+        var address = at < 0 ? Uri.EscapeDataString(recipient) : $"{Uri.EscapeDataString(recipient[..at])}@{Uri.EscapeDataString(recipient[(at + 1)..])}";
+        var prefix = $"mailto:{address}?subject={Uri.EscapeDataString(subject.ReplaceLineEndings(" "))}";
+
+        var text = body.Trim().ReplaceLineEndings("\n");
+        var uri = Compose(prefix, text);
+        while (uri.Length > MAX_URI_LENGTH && text.Length > 0)
+        {
+            var cut = text.LastIndexOfAny([' ', '\n']);
+            text = cut > 0 ? text[..cut].TrimEnd() : string.Empty;
+            uri = Compose(prefix, text);
+        }
+
+        return uri;
+    }
+
+    /// <summary>
+    /// Puts the link together from its beginning and its text.
+    /// </summary>
+    /// <param name="prefix">The link up to its subject.</param>
+    /// <param name="text">The text, with LF line breaks.</param>
+    private static string Compose(string prefix, string text) => text.Length is 0 ? prefix : $"{prefix}&body={Uri.EscapeDataString(text.Replace("\n", LINE_BREAK))}";
+}