Added mailboxes as local data sources (#1022)

app/MindWork AI Studio/Tools/Mail/MailServerPolicy.cs

@@ -0,0 +1,41 @@
+using AIStudio.Settings;
+using AIStudio.Tools.PluginSystem;
+
+namespace AIStudio.Tools.Mail;
+
+/// <summary>
+/// Which mail servers AI Studio may connect to, and whose mailboxes the AI may read.
+/// </summary>
+/// <remarks>
+/// Read anew for every decision rather than kept: both parts come from configuration plugins, which
+/// may change while AI Studio runs.
+/// </remarks>
+/// <param name="AllowsOnlyOrganizationMailServers">Whether the organization allows only its own mail servers, see DataMailboxes.AllowOnlyOrganizationMailServers.</param>
+/// <param name="OrganizationHosts">The hosts of the mail servers which the configuration plugins offer.</param>
+public sealed record MailServerPolicy(bool AllowsOnlyOrganizationMailServers, IReadOnlyList<string> OrganizationHosts)
+{
+    /// <summary>
+    /// Every server: what holds as long as no organization rules otherwise.
+    /// </summary>
+    public static readonly MailServerPolicy ANY_SERVER = new(false, []);
+
+    /// <summary>
+    /// Reads the policy which holds right now.
+    /// </summary>
+    /// <param name="settingsManager">The settings, which hold the switch of the organization.</param>
+    /// <returns>The policy.</returns>
+    public static MailServerPolicy Read(SettingsManager settingsManager) => new(
+        settingsManager.ConfigurationData.MailboxSettings.AllowOnlyOrganizationMailServers,
+        PluginFactory.GetMailboxProviders().Select(provider => provider.Host).ToList());
+
+    /// <summary>
+    /// Whether AI Studio may connect to a server, and the AI read the mailboxes on it.
+    /// </summary>
+    /// <remarks>
+    /// Port and encryption make no difference: a mailbox on the right host but another port is
+    /// still on the server of the organization.
+    /// </remarks>
+    /// <param name="host">The host of the server.</param>
+    /// <returns>True when the server is allowed.</returns>
+    public bool IsAllowed(string host) => !this.AllowsOnlyOrganizationMailServers || this.OrganizationHosts.Any(organizationHost => MailServerHosts.AreSame(organizationHost, host));
+}