package research

import (
	"encoding/base64"
	"net/url"
	"strings"
	"testing"
)

func TestCursorValidation(t *testing.T) {
	f := Filters{Query: "graph", Sort: "title", SearchIn: "text", PageSize: 8}
	f.Cursor = encodeCursor(f, position{ID: 9223372036854775807, Key: "duplicate\x01title"}, true)
	p, err := decodeCursor(f)
	if err != nil || !p.Before || p.ID != 9223372036854775807 || p.Key != "duplicate\x01title" {
		t.Fatalf("roundtrip %+v %v", p, err)
	}
	if _, err := parseFilters("q=graph&sort=title&cursor=" + url.QueryEscape(f.Cursor)); err != nil {
		t.Fatal(err)
	}
	for _, raw := range []string{"!", strings.Repeat("a", 32769), base64.RawURLEncoding.EncodeToString([]byte(`{"v":2}`)), f.Cursor + "="} {
		bad := f
		bad.Cursor = raw
		if _, err := decodeCursor(bad); err == nil {
			t.Fatal("accepted invalid cursor")
		}
	}
	for _, change := range []func(*Filters){func(f *Filters) { f.Query = "other" }, func(f *Filters) { f.Sort = "recent" }, func(f *Filters) { f.PageSize = 9 }, func(f *Filters) { f.SearchIn = "author" }, func(f *Filters) { f.Topic = "cs.AI" }} {
		bad := f
		change(&bad)
		if _, err := decodeCursor(bad); err == nil {
			t.Fatal("accepted mismatched filter")
		}
	}
}