using System;
using System.Collections.Generic;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using Paca.Mobile.Core;
using Paca.Tests.Infrastructure;
using Xunit;

namespace Paca.Tests.Core;

/// <summary>
/// Gate 171 ~ 174: 기기 교체 및 무결성 보장을 위한 Paca Vault 스냅샷 백업 & 복원 엔진 기계적 검증
/// </summary>
public class PacaVaultBackupRestoreGateTests
{
    [Fact]
    public void Gate171_VaultSnapshot_Creation_And_Integrity()
    {
        var favorites = new List<string> { "https://youtu.be/abc", "https://x.com/def" };
        var queueUrls = new List<string> { "https://chzzk.naver.com/video/1" };

        var snapshot = PacaVaultSnapshot.Create("device-alpha", favorites, queueUrls);

        Assert.Equal("device-alpha", snapshot.SourceDeviceId);
        Assert.Equal(2, snapshot.Favorites.Count);
        Assert.Single(snapshot.QueueUrls);
        Assert.True(snapshot.VerifyChecksum());

        // 조작된 스냅샷 체크섬 검증 실패
        var tampered = snapshot with { Favorites = new List<string> { "https://malicious.com" } };
        Assert.False(tampered.VerifyChecksum());
    }

    [Fact]
    public void Gate172_VaultSnapshot_Corrupted_ThrowsException()
    {
        var invalidJson = "{\"SourceDeviceId\":\"x\",\"Checksum\":\"invalid-hash\"}";

        Assert.ThrowsAny<Exception>(() =>
        {
            var snapshot = JsonSerializer.Deserialize<PacaVaultSnapshot>(invalidJson);
            if (snapshot == null || !snapshot.VerifyChecksum())
            {
                throw new InvalidDataException("Checksum verification failed");
            }
        });
    }

    [Fact]
    public void Gate173_VaultRestorer_Merge_Strategy()
    {
        var currentFavorites = new List<string> { "https://youtu.be/1", "https://youtu.be/2" };
        var backupFavorites = new List<string> { "https://youtu.be/2", "https://youtu.be/3" };

        var merged = VaultRestorer.MergeLists(currentFavorites, backupFavorites);

        // 중복 제거되어 1, 2, 3 총 3개 존재 확인
        Assert.Equal(3, merged.Count);
        Assert.Contains("https://youtu.be/1", merged);
        Assert.Contains("https://youtu.be/2", merged);
        Assert.Contains("https://youtu.be/3", merged);
    }

    [Fact]
    public void Gate174_ServerHost_VaultEndpoints_Registered()
    {
        var serverHostPath = Path.Combine(SourceTree.Root, "src", "Paca.Server", "ServerHost.cs");
        Assert.True(File.Exists(serverHostPath), "ServerHost.cs must exist");

        var code = File.ReadAllText(serverHostPath);

        Assert.Contains("/api/vault/backup", code);
        Assert.Contains("/api/vault/restore", code);
    }
}