bugfix

internal/infra/llm/fake.go

@@ -64,3 +64,62 @@ func (f *FakeClient) Stream(ctx context.Context, modelID string, req Request) (<
 func (f *FakeClient) CountTokens(ctx context.Context, modelID string, req Request) (int, error) {
 	return f.TokenCount, nil
 }
+
+// FakeEmbedder is a deterministic Embedder for tests. Each input maps to a
+// fixed-length vector derived from its bytes, so identical text always yields the
+// same vector (lets tests assert idempotency / ranking without a real endpoint).
+type FakeEmbedder struct {
+	Dims   int   // output dimension; defaults to PlatformEmbeddingDims when 0
+	Err    error // if non-nil, Embed returns it
+	mu     sync.Mutex
+	Calls  int
+	Inputs []string // accumulated inputs across calls (for assertions)
+}
+
+// NewFakeEmbedder constructs a FakeEmbedder with the platform dimension.
+func NewFakeEmbedder() *FakeEmbedder { return &FakeEmbedder{Dims: PlatformEmbeddingDims} }
+
+var _ Embedder = (*FakeEmbedder)(nil)
+
+func (e *FakeEmbedder) dims() int {
+	if e.Dims > 0 {
+		return e.Dims
+	}
+	return PlatformEmbeddingDims
+}
+
+// EmbedDims returns the configured dimension.
+func (e *FakeEmbedder) EmbedDims(string) int { return e.dims() }
+
+// Embed returns one deterministic vector per input. The vector is a normalized
+// projection of a small hash of the input across the dimension, so distinct
+// inputs are distinguishable and identical inputs are identical.
+func (e *FakeEmbedder) Embed(_ context.Context, _ string, inputs []string) ([][]float32, error) {
+	e.mu.Lock()
+	e.Calls++
+	e.Inputs = append(e.Inputs, inputs...)
+	err := e.Err
+	e.mu.Unlock()
+	if err != nil {
+		return nil, err
+	}
+	d := e.dims()
+	out := make([][]float32, len(inputs))
+	for i, s := range inputs {
+		v := make([]float32, d)
+		// Seed from a stable rolling hash of the bytes.
+		var h uint32 = 2166136261
+		for _, b := range []byte(s) {
+			h ^= uint32(b)
+			h *= 16777619
+		}
+		for j := 0; j < d; j++ {
+			h ^= uint32(j) * 2654435761
+			h *= 16777619
+			// Map to [-1,1).
+			v[j] = float32(int32(h)) / float32(1<<31)
+		}
+		out[i] = v
+	}
+	return out, nil
+}