package embeddings

import (
	"context"
	"math"
	"testing"

	"github.com/missionworkforce/missionmatch/internal/platform/config"
)

func TestDeterministicIsStableAndCorrectDimension(t *testing.T) {
	e := NewDeterministic(384)
	if e.Dimension() != 384 {
		t.Fatalf("dim = %d, want 384", e.Dimension())
	}
	a, _ := e.Embed(context.Background(), "Top Secret cleared Go developer")
	b, _ := e.Embed(context.Background(), "Top Secret cleared Go developer")
	if len(a) != 384 {
		t.Fatalf("len = %d, want 384", len(a))
	}
	for i := range a {
		if a[i] != b[i] {
			t.Fatalf("not deterministic at %d: %v vs %v", i, a[i], b[i])
		}
	}
}

func TestDeterministicVectorsAreNormalized(t *testing.T) {
	e := NewDeterministic(256)
	v, _ := e.Embed(context.Background(), "DISA cloud engineer")
	var ss float64
	for _, f := range v {
		ss += float64(f) * float64(f)
	}
	if math.Abs(math.Sqrt(ss)-1.0) > 1e-4 {
		t.Fatalf("vector not unit-norm: |v| = %f", math.Sqrt(ss))
	}
}

func TestDifferentTextDiffersAndCaseInsensitive(t *testing.T) {
	e := NewDeterministic(128)
	x, _ := e.Embed(context.Background(), "Kubernetes")
	y, _ := e.Embed(context.Background(), "Terraform")
	if equalVec(x, y) {
		t.Fatal("different text must produce different vectors")
	}
	// normalization of input: same text differing only by case/space is identical
	lower, _ := e.Embed(context.Background(), "  kubernetes ")
	upper, _ := e.Embed(context.Background(), "Kubernetes")
	if !equalVec(lower, upper) {
		t.Fatal("case/space-normalized text must produce identical vectors")
	}
}

func TestEmbedBatchMatchesEmbed(t *testing.T) {
	e := NewDeterministic(64)
	texts := []string{"a", "b", "c"}
	batch, _ := e.EmbedBatch(context.Background(), texts)
	if len(batch) != 3 {
		t.Fatalf("batch len = %d, want 3", len(batch))
	}
	for i, txt := range texts {
		one, _ := e.Embed(context.Background(), txt)
		if !equalVec(one, batch[i]) {
			t.Fatalf("batch[%d] != Embed(%q)", i, txt)
		}
	}
}

func TestNewSelectsProvider(t *testing.T) {
	fake, err := New(config.Embeddings{Provider: config.ProviderFake, Dimension: 384})
	if err != nil || fake == nil {
		t.Fatalf("fake provider: %v", err)
	}
	if _, ok := fake.(deterministicEmbedder); !ok {
		t.Fatalf("fake provider should be deterministic, got %T", fake)
	}

	httpE, err := New(config.Embeddings{Provider: config.ProviderOpenAI, Endpoint: "http://x/v1/embeddings", Model: "m", Dimension: 384})
	if err != nil || httpE == nil {
		t.Fatalf("openai provider: %v", err)
	}

	if _, err := New(config.Embeddings{Provider: config.ProviderBedrock, Dimension: 1024}); err == nil {
		t.Fatal("bedrock provider should report not-wired error in core build")
	}
}

func equalVec(a, b []float32) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}