using System.Text;

namespace Sonex.Worker.DatabaseBackup;

internal sealed class DatabaseBackupRunReport
{
    private readonly List<CopyResult> _copyResults = [];

    public DateTime StartedAtUtc { get; } = DateTime.UtcNow;
    public string BackupDirectoryPath { get; set; } = string.Empty;
    public string BackupLogFilePath { get; set; } = string.Empty;
    public long BackupSizeBytes { get; set; }
    public bool BackupSucceeded { get; set; }

    public void RegisterCopyResult(string targetPath, bool success, string details)
    {
        _copyResults.Add(new CopyResult
        {
            TargetPath = targetPath,
            Success = success,
            Details = details
        });
    }

    public string BuildSummary(TimeSpan duration)
    {
        int successfulCopies = _copyResults.Count(static item => item.Success);
        int failedCopies = _copyResults.Count - successfulCopies;

        return
            $"Worker finished. Duration: {duration:hh\\:mm\\:ss}. " +
            $"BackupSuccess={BackupSucceeded}. BackupSize={FormatBytes(BackupSizeBytes)}. " +
            $"CopySuccess={successfulCopies}. CopyFailed={failedCopies}.";
    }

    public string BuildFullReport(TimeSpan duration)
    {
        var sb = new StringBuilder();
        sb.AppendLine(BuildSummary(duration));
        sb.AppendLine($"Backup directory: {BackupDirectoryPath}");
        sb.AppendLine($"Backup log file: {BackupLogFilePath}");

        if (_copyResults.Count == 0)
        {
            sb.AppendLine("Copy targets: none");
            return sb.ToString().TrimEnd();
        }

        sb.AppendLine("Copy targets:");
        foreach (CopyResult copyResult in _copyResults)
        {
            sb.AppendLine(
                $"- Success={copyResult.Success}; Target={copyResult.TargetPath}; Details={copyResult.Details}");
        }

        return sb.ToString().TrimEnd();
    }

    private static string FormatBytes(long bytes)
    {
        if (bytes <= 0)
            return "0 B";

        string[] units = ["B", "KB", "MB", "GB", "TB"];
        double value = bytes;
        int index = 0;
        while (value >= 1024 && index < units.Length - 1)
        {
            value /= 1024;
            index++;
        }

        return $"{value:F2} {units[index]}";
    }

    private sealed class CopyResult
    {
        public string TargetPath { get; init; } = string.Empty;
        public bool Success { get; init; }
        public string Details { get; init; } = string.Empty;
    }
}