Show recoverable panel and editor feedback

src/tui.zig

@@ -65,6 +65,7 @@ pub const Client = struct {
     leader: leader_mod.Leader,
     viewport: Viewport,
     saved_bytes: ?[]u8 = null,
+    message: ?[]const u8 = null,
     quit: bool = false,
 
     pub fn init(allocator: std.mem.Allocator, viewport: Viewport) !Client {
@@ -96,6 +97,10 @@ pub const Client = struct {
         if (std.mem.startsWith(u8, line, "panel_open ")) return self.applyProtocolCommand(line);
         if (std.mem.startsWith(u8, line, "list_open ")) return self.applyProtocolCommand(line);
         if (std.mem.startsWith(u8, line, "list_filter ")) return self.applyProtocolCommand(line);
+        if (std.mem.startsWith(u8, line, "message ")) {
+            self.message = line[8..];
+            return;
+        }
         if (std.mem.eql(u8, line, "list_down")) return self.applyProtocol("command list_down");
         if (std.mem.eql(u8, line, "list_up")) return self.applyProtocol("command list_up");
         if (std.mem.eql(u8, line, "list_select")) return self.applyProtocol("command list_select");
@@ -149,7 +154,9 @@ pub const Client = struct {
         }
 
         const leader_status = self.leader.status();
-        const status = if (leader_status.len != 0)
+        const status = if (self.message) |message|
+            try std.fmt.allocPrint(allocator, "{s}", .{message})
+        else if (leader_status.len != 0)
             try std.fmt.allocPrint(
                 allocator,
                 "{s}{s}{s}",
@@ -206,11 +213,14 @@ pub const Client = struct {
             try out.append(allocator, '\n');
         }
 
-        const status = try std.fmt.allocPrint(
-            allocator,
-            "panel {d}/{d}  x close",
-            .{ snap.active_panel_index.? + 1, snap.panel_depth },
-        );
+        const status = if (self.message) |message|
+            try std.fmt.allocPrint(allocator, "{s}", .{message})
+        else
+            try std.fmt.allocPrint(
+                allocator,
+                "panel {d}/{d}  x close",
+                .{ snap.active_panel_index.? + 1, snap.panel_depth },
+            );
         defer allocator.free(status);
         try appendVisibleCells(allocator, &out, status, self.viewport.width);
         return out.toOwnedSlice(allocator);
@@ -293,7 +303,19 @@ pub const Client = struct {
     fn applyProtocol(self: *Client, line: []const u8) !void {
         const response = try protocol.handleLine(self.allocator, &self.session, line);
         defer self.allocator.free(response);
-        if (std.mem.startsWith(u8, response, "err ")) return Error.ProtocolRejected;
+        if (std.mem.startsWith(u8, response, "err ")) {
+            self.message = protocolErrorMessage(response);
+            return Error.ProtocolRejected;
+        }
+        self.message = null;
+    }
+
+    fn protocolErrorMessage(response: []const u8) []const u8 {
+        if (std.mem.indexOf(u8, response, "invalid panel title") != null) return "error: invalid panel title";
+        if (std.mem.indexOf(u8, response, "no panel open") != null) return "error: no panel open";
+        if (std.mem.indexOf(u8, response, "invalid list") != null) return "error: invalid list";
+        if (std.mem.indexOf(u8, response, "active panel is not list") != null) return "error: active panel is not list";
+        return "error: command failed";
     }
 
     fn resize(self: *Client, payload: []const u8) !void {
@@ -310,6 +332,7 @@ pub const Client = struct {
         const copy = try self.allocator.dupe(u8, snap.bytes);
         if (self.saved_bytes) |old| self.allocator.free(old);
         self.saved_bytes = copy;
+        self.message = "saved";
     }
 };
 
@@ -665,3 +688,52 @@ test "adversarial: list no-match state and invalid actions recover" {
     try client.handleTraceLine("list_cancel");
     try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("list_down"));
 }
+
+test "regular: save status appears near editor status line" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 20, .height = 4 });
+    defer client.deinit();
+
+    try client.handleTraceLine("open abc");
+    try client.handleTraceLine("key space");
+    try client.handleTraceLine("key s");
+    const frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(frame);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "saved") != null);
+    try assertLinesFit(frame, 20);
+}
+
+test "regular: empty generic panel shows local empty state" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 22, .height = 4 });
+    defer client.deinit();
+
+    try client.handleTraceLine("panel_open help");
+    const frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(frame);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "help: no content yet") != null);
+    try assertLinesFit(frame, 22);
+}
+
+test "adversarial: protocol errors render recoverable local message" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 24, .height = 4 });
+    defer client.deinit();
+
+    try client.handleTraceLine("open abc");
+    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("panel_open bad title"));
+    const frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(frame);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "error: invalid panel") != null);
+    try assertLinesFit(frame, 24);
+}
+
+test "adversarial: long feedback messages are clipped to viewport width" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 16, .height = 4 });
+    defer client.deinit();
+
+    try client.handleTraceLine("open abc");
+    try client.handleTraceLine("message this-message-is-way-too-long-for-the-phone-width");
+    const frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(frame);
+    try assertLinesFit(frame, 16);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "this-message-is-") != null);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "phone-width") == null);
+}