package vector

import (
	"context"
	"errors"
	"os"
	"testing"
)

func TestNewPG_InvalidURL_异常(t *testing.T) {
	t.Parallel()
	if _, err := NewPG(context.Background(), "   ", 4, testLogger()); !errors.Is(err, ErrInvalidPGURL) {
		t.Fatalf("NewPG(blank url) err = %v, want ErrInvalidPGURL", err)
	}
}

func TestNewPG_InvalidDim_异常(t *testing.T) {
	t.Parallel()
	// dim is validated before any connection is opened, so no network I/O here.
	if _, err := NewPG(context.Background(), "postgres://host/db", 0, testLogger()); !errors.Is(err, ErrInvalidDim) {
		t.Fatalf("NewPG(dim 0) err = %v, want ErrInvalidDim", err)
	}
}

func TestPGVectorLiteral(t *testing.T) {
	t.Parallel()
	tests := []struct {
		name string
		v    Vector
		want string
	}{
		{name: "single", v: Vector{1}, want: "[1]"},
		{name: "three", v: Vector{1.5, 2, -0.25}, want: "[1.5,2,-0.25]"},
		{name: "empty", v: Vector{}, want: "[]"},
	}
	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			if got := pgVectorLiteral(tt.v); got != tt.want {
				t.Fatalf("pgVectorLiteral(%v) = %q, want %q", tt.v, got, tt.want)
			}
		})
	}
}

// TestPG_RequiresEnv runs a real PostgreSQL+pgvector round trip when DB_PG_URL
// is set, and skips otherwise. There is no PG server in this environment by
// default, so the pgvector-backed Add/Search path is validated end-to-end only
// when the operator supplies a live database with the pgvector extension. The
// SQLite path (the default) is fully covered by the sqlite_test.go suite.
func TestPG_RequiresEnv(t *testing.T) {
	url := os.Getenv("DB_PG_URL")
	if url == "" {
		t.Skip("DB_PG_URL not set; skipping real PostgreSQL+pgvector integration test")
	}

	ctx := context.Background()
	idx, err := NewPG(ctx, url, 4, testLogger())
	if err != nil {
		t.Fatalf("NewPG: %v", err)
	}
	idx.withEmbedder(&mockEmbedder{dim: 4})
	defer func() { _ = idx.Close() }()

	if err := idx.Add(ctx, "a", Vector{1, 0, 0, 0}); err != nil {
		t.Fatalf("Add a: %v", err)
	}
	if err := idx.Add(ctx, "b", Vector{0, 1, 0, 0}); err != nil {
		t.Fatalf("Add b: %v", err)
	}

	hits, err := idx.Search(ctx, Vector{1, 0, 0, 0}, 1)
	if err != nil {
		t.Fatalf("Search: %v", err)
	}
	if len(hits) != 1 || hits[0].ID != "a" {
		t.Fatalf("pg top hit = %+v, want single a", hits)
	}
	if hits[0].Score < 0.99 {
		t.Fatalf("pg a score = %v, want ~1.0", hits[0].Score)
	}

	// The embedder is wired, so Index.Embed is usable.
	vs, err := idx.Embed(ctx, []string{"hello"})
	if err != nil {
		t.Fatalf("Embed: %v", err)
	}
	if len(vs) != 1 || len(vs[0]) != 4 {
		t.Fatalf("Embed => %d vectors, want one 4-dim", len(vs))
	}
}