using System.Security.Cryptography;
using TheCr3w.Shared.Models;

namespace TheCr3w.Shared.External;

public class FileDiffItem
{
    public string Path { get; set; } = string.Empty;
    public string Action { get; set; } = "update"; // add, update, delete
    public long FileSizeBytes { get; set; }
    public string LocalSha256 { get; set; } = string.Empty;
    public string? RemoteSha256 { get; set; }
}

public class SyncPreviewResult
{
    public int FilesToAdd { get; set; }
    public int FilesToUpdate { get; set; }
    public int FilesToDelete { get; set; }
    public long TotalTransferBytes { get; set; }
    public List<FileDiffItem> DiffDetails { get; set; } = new();
}

public interface IExternalDeploymentService
{
    SyncPreviewResult ComputeSyncPreview(Dictionary<string, (string Sha256, long Size)> localFiles, Dictionary<string, string> remoteFiles);
    bool ValidateHostKey(string actualFingerprint, string? expectedFingerprint);
}

public class ExternalDeploymentService : IExternalDeploymentService
{
    public SyncPreviewResult ComputeSyncPreview(
        Dictionary<string, (string Sha256, long Size)> localFiles, 
        Dictionary<string, string> remoteFiles)
    {
        var result = new SyncPreviewResult();

        foreach (var (path, (sha256, size)) in localFiles)
        {
            if (!remoteFiles.TryGetValue(path, out var remoteSha))
            {
                result.FilesToAdd++;
                result.TotalTransferBytes += size;
                result.DiffDetails.Add(new FileDiffItem
                {
                    Path = path,
                    Action = "add",
                    FileSizeBytes = size,
                    LocalSha256 = sha256
                });
            }
            else if (!string.Equals(sha256, remoteSha, StringComparison.OrdinalIgnoreCase))
            {
                result.FilesToUpdate++;
                result.TotalTransferBytes += size;
                result.DiffDetails.Add(new FileDiffItem
                {
                    Path = path,
                    Action = "update",
                    FileSizeBytes = size,
                    LocalSha256 = sha256,
                    RemoteSha256 = remoteSha
                });
            }
        }

        foreach (var (remotePath, remoteSha) in remoteFiles)
        {
            if (!localFiles.ContainsKey(remotePath))
            {
                result.FilesToDelete++;
                result.DiffDetails.Add(new FileDiffItem
                {
                    Path = remotePath,
                    Action = "delete",
                    RemoteSha256 = remoteSha
                });
            }
        }

        return result;
    }

    public bool ValidateHostKey(string actualFingerprint, string? expectedFingerprint)
    {
        if (string.IsNullOrWhiteSpace(expectedFingerprint))
            return false; // Rygorystyczny brak automatycznego akceptowania nieznanych kluczy

        return string.Equals(actualFingerprint.Trim(), expectedFingerprint.Trim(), StringComparison.OrdinalIgnoreCase);
    }
}