package paddingx

import (
	"bytes"
	"testing"
)

func TestPadAndUnpadPKCS7(t *testing.T) {
	plain := []byte("hello-world")
	padded, err := Pad(plain, 16, PKCS7)
	if err != nil {
		t.Fatalf("Pad PKCS7 failed: %v", err)
	}
	if len(padded)%16 != 0 {
		t.Fatalf("padded length should be block aligned, got %d", len(padded))
	}
	got, err := Unpad(padded, 16, PKCS7)
	if err != nil {
		t.Fatalf("Unpad PKCS7 failed: %v", err)
	}
	if !bytes.Equal(got, plain) {
		t.Fatalf("roundtrip mismatch, got %x want %x", got, plain)
	}
}

func TestPadAndUnpadPKCS5Compatibility(t *testing.T) {
	plain := []byte("DES-plaintext")
	padded, err := Pad(plain, 8, PKCS5)
	if err != nil {
		t.Fatalf("Pad PKCS5 failed: %v", err)
	}
	got, err := Unpad(padded, 8, PKCS5)
	if err != nil {
		t.Fatalf("Unpad PKCS5 failed: %v", err)
	}
	if !bytes.Equal(got, plain) {
		t.Fatalf("roundtrip mismatch, got %x want %x", got, plain)
	}
}

func TestPadAndUnpadZero(t *testing.T) {
	plain := []byte("abc\x00\x00")
	padded, err := Pad(plain, 8, ZERO)
	if err != nil {
		t.Fatalf("Pad ZERO failed: %v", err)
	}
	got, err := Unpad(padded, 8, ZERO)
	if err != nil {
		t.Fatalf("Unpad ZERO failed: %v", err)
	}
	if !bytes.Equal(got, []byte("abc")) {
		t.Fatalf("zero unpadding mismatch, got %q", got)
	}
}

func TestPadAndUnpadANSIX923(t *testing.T) {
	plain := []byte("ansi-x923")
	padded, err := Pad(plain, 16, ANSIX923)
	if err != nil {
		t.Fatalf("Pad ANSIX923 failed: %v", err)
	}
	got, err := Unpad(padded, 16, ANSIX923)
	if err != nil {
		t.Fatalf("Unpad ANSIX923 failed: %v", err)
	}
	if !bytes.Equal(got, plain) {
		t.Fatalf("roundtrip mismatch, got %x want %x", got, plain)
	}
}

func TestPadUnsupportedMode(t *testing.T) {
	if _, err := Pad([]byte("x"), 8, "UNKNOWN"); err == nil {
		t.Fatalf("expected error for unsupported mode")
	}
}

func TestUnpadInvalidPKCS7(t *testing.T) {
	_, err := Unpad([]byte{1, 2, 3, 4}, 4, PKCS7)
	if err == nil {
		t.Fatalf("expected invalid PKCS7 padding error")
	}
}

func TestPKCS5Helpers(t *testing.T) {
	plain := []byte("1234567")
	padded := PKCS5Padding(plain)
	got, err := PKCS5Unpadding(padded)
	if err != nil {
		t.Fatalf("PKCS5Unpadding failed: %v", err)
	}
	if !bytes.Equal(got, plain) {
		t.Fatalf("PKCS5 helper mismatch, got %x want %x", got, plain)
	}
}