feat(metadata): enhance metadata extraction with heuristic fallback support

internal/ai/compat/client_test.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"sync/atomic"
 	"testing"
 )
@@ -250,3 +251,93 @@ func TestExtractMetadataUsesReasoningContentWhenContentEmpty(t *testing.T) {
 		t.Fatalf("metadata people = %#v, want [Hein]", metadata.People)
 	}
 }
+
+func TestExtractMetadataFallsBackToHeuristicsWhenModelsFail(t *testing.T) {
+	var calls atomic.Int32
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_ = calls.Add(1)
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{
+				{"message": map[string]any{"content": "not json"}},
+			},
+		})
+	}))
+	defer server.Close()
+
+	client := New(Config{
+		Name:                  "test",
+		BaseURL:               server.URL,
+		APIKey:                "secret",
+		MetadataModel:         "primary",
+		FallbackMetadataModel: "secondary",
+		HTTPClient:            server.Client(),
+		Log:                   discardLogger(),
+	})
+
+	input := "Personal profile - Hein (Warkanum):\n- Born: 23 May 1989\n- Wife: Cindy, born 16 November 1994"
+	metadata, err := client.ExtractMetadata(context.Background(), input)
+	if err != nil {
+		t.Fatalf("ExtractMetadata() error = %v", err)
+	}
+	if calls.Load() != 2 {
+		t.Fatalf("call count = %d, want 2", calls.Load())
+	}
+	if metadata.Type != "person_note" {
+		t.Fatalf("metadata type = %q, want person_note", metadata.Type)
+	}
+	if len(metadata.DatesMentioned) < 2 {
+		t.Fatalf("metadata dates = %#v, want extracted dates", metadata.DatesMentioned)
+	}
+	if len(metadata.People) == 0 || !strings.EqualFold(metadata.People[0], "Cindy") {
+		t.Fatalf("metadata people = %#v, want Cindy", metadata.People)
+	}
+}
+
+func TestExtractMetadataRetriesEmptyResponse(t *testing.T) {
+	var calls atomic.Int32
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		call := calls.Add(1)
+		var req chatCompletionsRequest
+		_ = json.NewDecoder(r.Body).Decode(&req)
+
+		if req.Stream == nil || *req.Stream {
+			t.Fatalf("expected stream=false, got %#v", req.Stream)
+		}
+
+		if call == 1 {
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"choices": []map[string]any{
+					{"message": map[string]any{"content": ""}},
+				},
+			})
+			return
+		}
+
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{
+				{"message": map[string]any{"content": "{\"people\":[],\"action_items\":[],\"dates_mentioned\":[],\"topics\":[\"mcp\"],\"type\":\"observation\",\"source\":\"mcp\"}"}},
+			},
+		})
+	}))
+	defer server.Close()
+
+	client := New(Config{
+		Name:          "test",
+		BaseURL:       server.URL,
+		APIKey:        "secret",
+		MetadataModel: "meta-model",
+		HTTPClient:    server.Client(),
+		Log:           discardLogger(),
+	})
+
+	metadata, err := client.ExtractMetadata(context.Background(), "hello")
+	if err != nil {
+		t.Fatalf("ExtractMetadata() error = %v", err)
+	}
+	if calls.Load() < 2 {
+		t.Fatalf("call count = %d, want >= 2", calls.Load())
+	}
+	if metadata.Type != "observation" {
+		t.Fatalf("metadata type = %q, want observation", metadata.Type)
+	}
+}