package index_test

import (
	"testing"
	"time"

	"github.com/archivmail/internal/index"
)

// newXapianIndex creates a temporary Xapian index for testing.
func newXapianIndex(t *testing.T) index.Indexer {
	t.Helper()
	idx, err := index.New(t.TempDir(), 100, "xapian")
	if err != nil {
		t.Skip("xapian not available:", err)
	}
	t.Cleanup(func() { idx.Close() })
	return idx
}

func seedDocs(t *testing.T, idx index.Indexer) {
	t.Helper()
	docs := []index.MailDocument{
		{
			ID:      "aaa111",
			From:    "alice@example.com",
			To:      "bob@example.com",
			Subject: "Invoice Q1-2026",
			Body:    "Please find attached the invoice for January.",
			Date:    time.Date(2026, 1, 15, 10, 0, 0, 0, time.UTC),
			Size:    1024,
		},
		{
			ID:      "bbb222",
			From:    "bob@example.com",
			To:      "alice@example.com charlie@example.com",
			Subject: "Meeting Agenda",
			Body:    "Agenda for the quarterly review meeting.",
			Date:    time.Date(2026, 2, 1, 9, 0, 0, 0, time.UTC),
			Size:    512,
		},
		{
			ID:            "ccc333",
			From:          "charlie@example.com",
			To:            "alice@example.com",
			Subject:       "Offer with attachment",
			Body:          "Please review the attached offer document.",
			AttachNames:   "offer.pdf",
			HasAttachment: true,
			Date:          time.Date(2026, 3, 1, 14, 0, 0, 0, time.UTC),
			Size:          8192,
		},
	}
	for _, d := range docs {
		if err := idx.IndexSync(d); err != nil {
			t.Fatalf("IndexSync %s: %v", d.ID, err)
		}
	}
}

func TestIndexAndSearchFulltext(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	result, err := idx.Search(index.SearchRequest{Query: "invoice", PageSize: 10})
	if err != nil {
		t.Fatalf("Search: %v", err)
	}
	if result.Total == 0 {
		t.Error("expected at least 1 hit for 'invoice'")
	}
	if result.Hits[0].ID != "aaa111" {
		t.Errorf("top hit = %q, want aaa111", result.Hits[0].ID)
	}
}

func TestSearchMatchAll(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	result, err := idx.Search(index.SearchRequest{PageSize: 25})
	if err != nil {
		t.Fatalf("Search all: %v", err)
	}
	if result.Total != 3 {
		t.Errorf("expected 3 total hits, got %d", result.Total)
	}
}

func TestSearchFromFilter(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	result, err := idx.Search(index.SearchRequest{
		From:     "alice@example.com",
		PageSize: 25,
	})
	if err != nil {
		t.Fatalf("Search from: %v", err)
	}
	if result.Total != 1 {
		t.Errorf("expected 1 hit from alice, got %d", result.Total)
	}
}

func TestSearchDateRange(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	from := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
	to := time.Date(2026, 2, 1, 23, 59, 59, 0, time.UTC)
	result, err := idx.Search(index.SearchRequest{
		DateFrom: &from,
		DateTo:   &to,
		PageSize: 25,
	})
	if err != nil {
		t.Fatalf("Search date range: %v", err)
	}
	if result.Total != 2 {
		t.Errorf("expected 2 hits in Jan-Feb 2026, got %d", result.Total)
	}
}

func TestSearchOwnEmail(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	// charlie@example.com sent 1 mail and received 1 mail = should see 2
	result, err := idx.Search(index.SearchRequest{
		OwnEmail: "charlie@example.com",
		PageSize: 25,
	})
	if err != nil {
		t.Fatalf("Search OwnEmail: %v", err)
	}
	if result.Total < 1 {
		t.Errorf("charlie should see at least 1 mail, got %d", result.Total)
	}
}

func TestSearchPagination(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	page0, _ := idx.Search(index.SearchRequest{PageSize: 2, Page: 0})
	page1, _ := idx.Search(index.SearchRequest{PageSize: 2, Page: 1})

	if len(page0.Hits) != 2 {
		t.Errorf("page 0: expected 2 hits, got %d", len(page0.Hits))
	}
	if len(page1.Hits) != 1 {
		t.Errorf("page 1: expected 1 hit, got %d", len(page1.Hits))
	}
	// No overlap
	if page0.Hits[0].ID == page1.Hits[0].ID {
		t.Error("pagination returned duplicate results")
	}
}

func TestDelete(t *testing.T) {
	idx := newXapianIndex(t)
	seedDocs(t, idx)

	if err := idx.Delete("aaa111"); err != nil {
		t.Fatalf("Delete: %v", err)
	}

	result, _ := idx.Search(index.SearchRequest{Query: "invoice", PageSize: 10})
	for _, h := range result.Hits {
		if h.ID == "aaa111" {
			t.Error("deleted document still in results")
		}
	}
}

func TestUnknownBackend(t *testing.T) {
	_, err := index.New(t.TempDir(), 10, "elasticsearch")
	if err == nil {
		t.Error("expected error for unknown backend")
	}
}

func TestXapianNotCompiledError(t *testing.T) {
	_, err := index.New(t.TempDir(), 10, "xapian")
	// Without -tags xapian this must return a helpful error
	if err == nil {
		t.Log("xapian compiled in — skipping stub error test")
	} else {
		t.Logf("xapian stub error (expected): %v", err)
	}
}