package router

import (
	"context"
	"testing"
)

// TestHashEmbedderCyrillic guards the ru-first floor: a byte-only tokenizer
// drops every Cyrillic word (bytes ≥ 0x80) and embeds Russian to the zero
// vector — cosine 0 across all intents, misrouting every RU utterance. Assert
// non-zero vectors, and that shared Russian words produce more similar vectors
// than disjoint ones (the point of the bag-of-words floor).
func TestHashEmbedderCyrillic(t *testing.T) {
	e := NewHashEmbedder(1024)
	ctx := context.Background()

	nonZero := func(text string) []float32 {
		v, err := e.Embed(ctx, text)
		if err != nil {
			t.Fatalf("embed %q: %v", text, err)
		}
		var sum float64
		for _, x := range v {
			sum += float64(x) * float64(x)
		}
		if sum == 0 {
			t.Fatalf("embed %q → zero vector (tokenizer dropped all tokens)", text)
		}
		return v
	}

	a := nonZero("найди заметку про сервер")
	b := nonZero("найди заметку про роутер") // shares 3 of 4 words
	c := nonZero("перезагрузи компьютер")    // disjoint

	if cosine(a, b) <= cosine(a, c) {
		t.Fatalf("cosine(shared)=%.3f not > cosine(disjoint)=%.3f", cosine(a, b), cosine(a, c))
	}
}