package bookfile

import (
	"archive/zip"
	"bytes"
	"testing"
)

func zipOf(t *testing.T, names ...string) *bytes.Reader {
	t.Helper()
	buf := &bytes.Buffer{}
	zw := zip.NewWriter(buf)
	for i, n := range names {
		w, err := zw.Create(n)
		if err != nil {
			t.Fatal(err)
		}
		w.Write([]byte{byte(i)})
	}
	zw.Close()
	return bytes.NewReader(buf.Bytes())
}

func TestPageIndexSortAndFilter(t *testing.T) {
	r := zipOf(t, "page10.jpg", "page2.jpg", "page1.jpg", "cover.PNG", "meta.xml", "sub/3.webp", "readme.txt")
	idx, err := PageIndex(r, int64(r.Len()))
	if err != nil {
		t.Fatal(err)
	}
	want := []string{"cover.PNG", "page1.jpg", "page2.jpg", "page10.jpg", "sub/3.webp"}
	if len(idx) != len(want) {
		t.Fatalf("got %v", idx)
	}
	for i := range want {
		if idx[i] != want[i] {
			t.Fatalf("got %v want %v", idx, want)
		}
	}
}

func TestPageIndexRejectsSlip(t *testing.T) {
	for _, bad := range []string{"../evil.jpg", "/etc/passwd.jpg", "a\\..\\b.jpg"} {
		r := zipOf(t, bad)
		if _, err := PageIndex(r, int64(r.Len())); err == nil {
			t.Fatalf("entry %q must be rejected", bad)
		}
	}
}

func TestReadEntry(t *testing.T) {
	buf := &bytes.Buffer{}
	zw := zip.NewWriter(buf)
	w, _ := zw.Create("p1.jpg")
	w.Write([]byte("jpegbytes"))
	zw.Close()
	r := bytes.NewReader(buf.Bytes())
	got, err := ReadEntry(r, int64(r.Len()), "p1.jpg")
	if err != nil || string(got) != "jpegbytes" {
		t.Fatalf("%q %v", got, err)
	}
	if _, err := ReadEntry(r, int64(r.Len()), "nope.jpg"); err == nil {
		t.Fatal("missing entry must error")
	}
}

func TestNaturalLess(t *testing.T) {
	pairs := [][2]string{{"2", "10"}, {"a2b", "a10b"}, {"007", "7"}, {"a", "b"}, {"A", "a"}}
	for _, p := range pairs {
		if !NaturalLess(p[0], p[1]) {
			t.Errorf("NaturalLess(%q,%q) want true", p[0], p[1])
		}
		if NaturalLess(p[1], p[0]) {
			t.Errorf("NaturalLess(%q,%q) want false", p[1], p[0])
		}
	}
}

func TestHash(t *testing.T) {
	if Hash(100, 200) == Hash(101, 200) || Hash(100, 200) != Hash(100, 200) {
		t.Fatal("hash broken")
	}
	if len(Hash(1, 2)) != 16 {
		t.Fatal("hash length")
	}
}