Documents: invite people to a document by email (#56)

InterlinedList/Services/DocumentInviteTarget.cs

@@ -0,0 +1,38 @@
+using InterlinedList.Models;
+
+namespace InterlinedList.Services;
+
+/// <summary>
+/// Binds the shared invite panel to one document's
+/// /api/documents/{id}/invites routes. Mirror image of
+/// <see cref="ListInviteTarget"/> — the sharing model is identical, so the panel
+/// itself needs no document-specific branch.
+/// </summary>
+public sealed class DocumentInviteTarget : IInviteTarget
+{
+    private readonly InterlinedApiClient _api;
+    private readonly string _documentId;
+
+    public DocumentInviteTarget(InterlinedApiClient api, string documentId)
+    {
+        _api = api;
+        _documentId = documentId;
+    }
+
+    public string ResourceNoun => "document";
+
+    public Task<List<EmailInvite>> GetInvitesAsync(CancellationToken ct = default)
+        => _api.GetDocumentInvitesAsync(_documentId, ct);
+
+    public Task<EmailInvite> CreateInviteAsync(
+        string email, string role, DateTimeOffset? expiresAt, CancellationToken ct = default)
+        => _api.CreateDocumentInviteAsync(_documentId, email, role, expiresAt, ct);
+
+    public Task RevokeInviteAsync(string token, CancellationToken ct = default)
+        => _api.DeleteDocumentInviteAsync(_documentId, token, ct);
+
+    public Task<string?> GetOwnerUserIdAsync(CancellationToken ct = default)
+        => _api.GetDocumentOwnerUserIdAsync(_documentId, ct);
+
+    public string InviteUrlFor(string token) => $"{ApiConfig.BaseUrl}documents/invite/{token}";
+}

InterlinedList/Services/IInviteTarget.cs

@@ -57,8 +57,7 @@ public static class InviteTargets
         return kind switch
         {
             InviteTargetKind.List => new ListInviteTarget(api, resourceId),
-            // Document invites land with issue #56 (same endpoints under
-            // /api/documents) and slot in here.
+            InviteTargetKind.Document => new DocumentInviteTarget(api, resourceId),
             _ => null,
         };
     }

InterlinedList/Services/InterlinedApiClient.DocumentInvites.cs

@@ -0,0 +1,84 @@
+using System.Net.Http;
+using System.Text.Json;
+using InterlinedList.Models;
+
+namespace InterlinedList.Services;
+
+/// <summary>
+/// Email invites to a document — the same sharing model as
+/// InterlinedApiClient.ListInvites.cs, and the path the web Share window leads
+/// with. Distinct from the share links and collaborators in
+/// InterlinedApiClient.Documents.cs: a share link is a bearer capability and a
+/// collaborator is an existing account, whereas an invite is bound to an email
+/// address that may not have an account yet.
+///
+/// All three routes are owner-only (a non-owner gets 404 — existence is never
+/// leaked). Creating is subscriber-gated (403 for a free owner); listing and
+/// revoking are not, so an owner whose subscription lapsed can always shut off
+/// access they previously granted.
+///
+/// Verified live 2026-09-16 against a throwaway document, and the payloads are
+/// byte-identical to the list ones — hence the shared <see cref="EmailInvite"/>
+/// wire type:
+/// <code>
+/// GET    /api/documents/{id}/invites            → 200 { "invites": [ … ] }
+/// POST   /api/documents/{id}/invites            → 201 { email, role, expiresAt, url }
+/// DELETE /api/documents/{id}/invites/{token}    → 200 { "revoked": true }
+/// </code>
+/// </summary>
+public sealed partial class InterlinedApiClient
+{
+    public async Task<List<EmailInvite>> GetDocumentInvitesAsync(string documentId, CancellationToken ct = default)
+    {
+        var json = await GetElementAsync($"api/documents/{documentId}/invites", ct);
+        return json.TryGetProperty("invites", out var arr) && arr.ValueKind == JsonValueKind.Array
+            ? arr.Deserialize<List<EmailInvite>>(JsonOptions) ?? new()
+            : new();
+    }
+
+    /// <summary>
+    /// Invite an email address to this document. Re-inviting the same address is
+    /// idempotent server-side: it re-issues a fresh token and resets the invite
+    /// to unclaimed. An invite email carrying the returned url is sent to the
+    /// address best-effort (fire-and-forget), so this is a real outbound email —
+    /// callers should not exercise it against addresses they don't own.
+    ///
+    /// The returned envelope IS live-verified, but it carries no token, so
+    /// callers still re-read <see cref="GetDocumentInvitesAsync"/> afterwards to
+    /// get the token they need for <see cref="DeleteDocumentInviteAsync"/>.
+    /// </summary>
+    public Task<EmailInvite> CreateDocumentInviteAsync(
+        string documentId,
+        string email,
+        string role = ShareRoles.Viewer,
+        DateTimeOffset? expiresAt = null,
+        CancellationToken ct = default)
+        => SendJsonAsync<EmailInvite>(HttpMethod.Post, $"api/documents/{documentId}/invites",
+            new { email, role, expiresAt = expiresAt?.UtcDateTime }, ct);
+
+    public Task DeleteDocumentInviteAsync(string documentId, string token, CancellationToken ct = default)
+        => SendVoidAsync(HttpMethod.Delete,
+            $"api/documents/{documentId}/invites/{Uri.EscapeDataString(token)}", null, ct);
+
+    /// <summary>
+    /// The document owner's user id, read straight off the GET
+    /// /api/documents/{id} "document" envelope (verified live 2026-09-16 — the
+    /// payload carries userId, which <see cref="DocumentSummary"/> does not
+    /// model). Only the true owner can manage sharing — not even a manager-role
+    /// collaborator can — so the share UI compares this against the signed-in
+    /// user rather than assuming the open document is owned. Returns null when
+    /// the field is missing.
+    ///
+    /// Note the envelope key differs from the list equivalent: documents nest
+    /// under "document", lists under "data".
+    /// </summary>
+    public async Task<string?> GetDocumentOwnerUserIdAsync(string documentId, CancellationToken ct = default)
+    {
+        var json = await GetElementAsync($"api/documents/{documentId}", ct);
+        return json.TryGetProperty("document", out var doc)
+               && doc.TryGetProperty("userId", out var userId)
+               && userId.ValueKind == JsonValueKind.String
+            ? userId.GetString()
+            : null;
+    }
+}

InterlinedList/Views/DocumentsView.xaml

@@ -434,6 +434,10 @@
                     Margin="20,0,20,20"
                     Padding="16,12">
                 <StackPanel>
+                    <!-- Invite people by email — leads the Share card, as the web does
+                         (inviting keeps the document private; links are secondary). -->
+                    <local:InvitePanel Kind="Document" TargetId="{Binding SelectedDocument.Id}" Margin="0,0,0,12"/>
+
                     <DockPanel Margin="0,0,0,8">
                         <TextBlock DockPanel.Dock="Left"
                                    Text="Share"