package search

import (
	"context"
	"database/sql"
	"io"
	"log/slog"
	"path/filepath"
	"testing"

	"github.com/mithral/vellum/internal/core"
	"github.com/mithral/vellum/migrations"
)

func testDB(t *testing.T) *sql.DB {
	t.Helper()
	db, err := core.OpenDB(filepath.Join(t.TempDir(), "search.db"))
	if err != nil {
		t.Fatalf("OpenDB: %v", err)
	}
	t.Cleanup(func() { _ = db.Close() })
	log := slog.New(slog.NewTextHandler(io.Discard, nil))
	if err := core.Migrate(context.Background(), db, migrations.FS, log); err != nil {
		t.Fatalf("Migrate: %v", err)
	}
	return db
}

func addLibrary(t *testing.T, db *sql.DB, name, kind string) int64 {
	t.Helper()
	var id int64
	err := db.QueryRowContext(context.Background(),
		`INSERT INTO libraries (name, kind, root_path) VALUES (?, ?, ?) RETURNING id`,
		name, kind, "/media/"+name).Scan(&id)
	if err != nil {
		t.Fatal(err)
	}
	return id
}

func addItem(t *testing.T, db *sql.DB, libraryID int64, kind, path, title string) int64 {
	t.Helper()
	var id int64
	err := db.QueryRowContext(context.Background(),
		`INSERT INTO media_items (library_id, kind, path, title, sort_title) VALUES (?, ?, ?, ?, ?) RETURNING id`,
		libraryID, kind, path, title, title).Scan(&id)
	if err != nil {
		t.Fatal(err)
	}
	return id
}

func titles(results []Result) []string {
	out := make([]string, len(results))
	for i, r := range results {
		out[i] = r.Title
	}
	return out
}

func contains(haystack []string, needle string) bool {
	for _, h := range haystack {
		if h == needle {
			return true
		}
	}
	return false
}

func TestQueryFindsItems(t *testing.T) {
	db := testDB(t)
	ctx := context.Background()
	lib := addLibrary(t, db, "ebooks", "ebooks")
	addItem(t, db, lib, "ebooks", "hobbit.epub", "The Hobbit")
	addItem(t, db, lib, "ebooks", "hail.epub", "Project Hail Mary")

	res, err := Query(ctx, db, "hobbit", []int64{lib}, 50)
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	if len(res) != 1 || res[0].Title != "The Hobbit" {
		t.Fatalf("results = %v", titles(res))
	}

	// Multi-term is an implicit AND.
	res, err = Query(ctx, db, "project mary", []int64{lib}, 50)
	if err != nil {
		t.Fatal(err)
	}
	if len(res) != 1 || res[0].Title != "Project Hail Mary" {
		t.Errorf("multi-term results = %v", titles(res))
	}

	// A term that matches nothing.
	res, err = Query(ctx, db, "nonexistent", []int64{lib}, 50)
	if err != nil {
		t.Fatal(err)
	}
	if len(res) != 0 {
		t.Errorf("expected no results, got %v", titles(res))
	}
}

func TestQueryIsScopedToLibraries(t *testing.T) {
	db := testDB(t)
	ctx := context.Background()
	allowed := addLibrary(t, db, "allowed", "ebooks")
	hidden := addLibrary(t, db, "hidden", "ebooks")
	addItem(t, db, allowed, "ebooks", "a.epub", "Shared Word")
	addItem(t, db, hidden, "ebooks", "b.epub", "Shared Word Two")

	res, err := Query(ctx, db, "shared", []int64{allowed}, 50)
	if err != nil {
		t.Fatal(err)
	}
	if len(res) != 1 || res[0].LibraryID != allowed {
		t.Fatalf("scoping failed: %v", titles(res))
	}

	// No libraries means no results, never everything.
	res, err = Query(ctx, db, "shared", nil, 50)
	if err != nil {
		t.Fatal(err)
	}
	if len(res) != 0 {
		t.Errorf("empty library set returned %v", titles(res))
	}
}

func TestQueryHandlesHostileInput(t *testing.T) {
	db := testDB(t)
	ctx := context.Background()
	lib := addLibrary(t, db, "ebooks", "ebooks")
	addItem(t, db, lib, "ebooks", "a.epub", "The Hobbit")

	// None of these may raise an FTS5 syntax error.
	for _, q := range []string{
		`"`, `"unbalanced`, `OR`, `AND NOT`, `foo*`, `-hobbit`, `title:hobbit`,
		`hobbit OR`, `*`, `""`, `NEAR(`, `a"b`, `(); DROP TABLE users;--`,
	} {
		if _, err := Query(ctx, db, q, []int64{lib}, 50); err != nil {
			t.Errorf("Query(%q) errored: %v", q, err)
		}
	}

	// The injection attempt must not have dropped anything.
	var n int
	if err := db.QueryRowContext(ctx, `SELECT count(*) FROM media_items`).Scan(&n); err != nil {
		t.Fatalf("media_items is gone: %v", err)
	}
	if n != 1 {
		t.Errorf("media_items count = %d, want 1", n)
	}
}

func TestIndexStaysInSync(t *testing.T) {
	db := testDB(t)
	ctx := context.Background()
	lib := addLibrary(t, db, "ebooks", "ebooks")

	id := addItem(t, db, lib, "ebooks", "x.epub", "Original Title")
	if res, _ := Query(ctx, db, "original", []int64{lib}, 50); len(res) != 1 {
		t.Fatalf("insert did not reach the index")
	}

	if _, err := db.ExecContext(ctx, `UPDATE media_items SET title = 'Changed Title' WHERE id = ?`, id); err != nil {
		t.Fatal(err)
	}
	if res, _ := Query(ctx, db, "changed", []int64{lib}, 50); len(res) != 1 {
		t.Error("update did not reach the index")
	}
	if res, _ := Query(ctx, db, "original", []int64{lib}, 50); len(res) != 0 {
		t.Error("stale entry survived the update")
	}

	if _, err := db.ExecContext(ctx, `DELETE FROM media_items WHERE id = ?`, id); err != nil {
		t.Fatal(err)
	}
	if res, _ := Query(ctx, db, "changed", []int64{lib}, 50); len(res) != 0 {
		t.Error("delete did not reach the index")
	}
}

func TestMissingItemsAreExcluded(t *testing.T) {
	db := testDB(t)
	ctx := context.Background()
	lib := addLibrary(t, db, "ebooks", "ebooks")
	id := addItem(t, db, lib, "ebooks", "gone.epub", "Vanished Book")

	if _, err := db.ExecContext(ctx, `UPDATE media_items SET missing = 1 WHERE id = ?`, id); err != nil {
		t.Fatal(err)
	}
	res, err := Query(ctx, db, "vanished", []int64{lib}, 50)
	if err != nil {
		t.Fatal(err)
	}
	if len(res) != 0 {
		t.Errorf("missing item appeared in search: %v", titles(res))
	}
}