package index

import (
	"math"
	"testing"
)

func TestInMemoryVectorIndex_AddSearch(t *testing.T) {
	idx := NewInMemoryVectorIndex()

	idx.Add("a", []float64{1, 0, 0})
	idx.Add("b", []float64{0, 1, 0})
	idx.Add("c", []float64{0, 0, 1})

	if idx.Len() != 3 {
		t.Fatalf("Len = %d, want 3", idx.Len())
	}

	hits := idx.Search([]float64{1, 0, 0}, 3)
	if len(hits) != 3 {
		t.Fatalf("Search: got %d hits, want 3", len(hits))
	}
	if hits[0].ID != "a" {
		t.Errorf("top hit = %q, want %q", hits[0].ID, "a")
	}
	if math.Abs(hits[0].Score-1.0) > 1e-9 {
		t.Errorf("top score = %f, want 1.0", hits[0].Score)
	}
}

func TestInMemoryVectorIndex_Remove(t *testing.T) {
	idx := NewInMemoryVectorIndex()
	idx.Add("a", []float64{1, 0})
	idx.Add("b", []float64{0, 1})

	idx.Remove("a")
	if idx.Len() != 1 {
		t.Fatalf("Len after remove = %d, want 1", idx.Len())
	}

	hits := idx.Search([]float64{0, 1}, 5)
	if len(hits) != 1 || hits[0].ID != "b" {
		t.Errorf("expected only 'b' in results")
	}
}

func TestInMemoryVectorIndex_RemoveByPrefix(t *testing.T) {
	idx := NewInMemoryVectorIndex()
	idx.Add("note1_0", []float64{1, 0})
	idx.Add("note1_1", []float64{0.9, 0.1})
	idx.Add("note2_0", []float64{0, 1})

	idx.RemoveByPrefix("note1_")
	if idx.Len() != 1 {
		t.Fatalf("Len after RemoveByPrefix = %d, want 1", idx.Len())
	}
}

func TestCosine(t *testing.T) {
	tests := []struct {
		a, b []float64
		want float64
	}{
		{[]float64{1, 0}, []float64{1, 0}, 1.0},
		{[]float64{1, 0}, []float64{0, 1}, 0.0},
		{[]float64{1, 0}, []float64{-1, 0}, -1.0},
	}
	for _, tt := range tests {
		got := cosine(tt.a, tt.b)
		if math.Abs(got-tt.want) > 1e-9 {
			t.Errorf("cosine(%v, %v) = %f, want %f", tt.a, tt.b, got, tt.want)
		}
	}
}