/*
 *  Copyright (c) 2026 Kaiy Ragur
 *
 *  This Source Code Form is subject to the terms of the Mozilla Public
 *  License, v. 2.0. If a copy of the MPL was not distributed with this
 *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
package e2ee_test

import (
	"bytes"
	"crypto/ed25519"
	"io"
	"testing"

	"github.com/neilalexander/yggmail/internal/utils"
	"github.com/neilalexander/yggmail/internal/utils/age"
	"github.com/neilalexander/yggmail/internal/utils/e2ee"
)

func TestFullE2EECycle(t *testing.T) {
	_, senderPriv, _ := ed25519.GenerateKey(nil)
	senderPub := senderPriv.Public().(ed25519.PublicKey)
	_, recipientPriv, _ := ed25519.GenerateKey(nil)
	recipientPub := recipientPriv.Public().(ed25519.PublicKey)

	_, domainPriv, _ := ed25519.GenerateKey(nil)
	domainPub := domainPriv.Public().(ed25519.PublicKey)

	senderAddr := utils.CreateAddress(senderPub, domainPub) // например: userkey@domainkey

	original := []byte("From: " + senderAddr + "\r\nSubject: test\r\n\r\nHello world! Это тест.")

	encryptedReader, err := e2ee.EncryptFilter(
		bytes.NewReader(original),
		senderAddr,
		[]ed25519.PublicKey{recipientPub},
		func(data []byte) ([]byte, error) {
			return ed25519.Sign(senderPriv, data), nil
		},
		func(w io.Writer, rcpt ...ed25519.PublicKey) (io.WriteCloser, error) {
			r, err := age.Recipient(rcpt...)
			if err != nil {
				return nil, err
			}
			return age.EncryptArmor(w, r...)
		},
	)
	if err != nil {
		t.Fatal("EncryptFilter failed:", err)
	}

	encryptedBytes, _ := io.ReadAll(encryptedReader)
	encryptedReader.Close()

	stored := bytes.NewReader(encryptedBytes)

	decryptor := func(r io.Reader) (io.Reader, error) {
		id, err := age.Identity(recipientPriv)
		if err != nil {
			return nil, err
		}
		return age.DecryptArmor(r, id)
	}

	decrypted, err := e2ee.DecryptFilter(stored, decryptor)
	if err != nil {
		t.Fatal("DecryptFilter failed:", err)
	}

	result, _ := io.ReadAll(decrypted)
	decrypted.Close()

	if !bytes.Contains(result, []byte("Hello world! Это тест.")) {
		t.Fatalf("Decryption failed, got:\n%s", string(result))
	}

	if !bytes.Contains(result, []byte("Subject: test")) {
		t.Fatalf("Original headers lost, got:\n%s", string(result))
	}

	t.Log("Full E2EE cycle OK. Decrypted body preview:\n", string(result[:200]))
}