using System.IO.Compression;
using System.Text;
using GhostImageManager.Models;

namespace GhostImageManager.Services;

public class ImageExportService
{
    public byte[] ExportToCsv(List<GhostImage> images)
    {
        var sb = new StringBuilder();
        sb.AppendLine("Dateiname;Relativer Pfad;URL;Größe Bytes;Größe;Dimensionen;Letzte Änderung;Verwaist;Verwendet in Posts");

        foreach (var image in images)
        {
            var posts = string.Join(" | ", image.UsedInPosts.Select(p => $"{p.Title} ({(p.IsFeatureImage ? "Feature" : "Content")})"));
            sb.AppendLine($"{EscapeCsv(image.FileName)};{EscapeCsv(image.RelativePath)};{EscapeCsv(image.Url)};{image.FileSize};{image.FormattedFileSize};{image.Dimensions};{image.LastModified:yyyy-MM-dd HH:mm};{image.IsOrphaned};{EscapeCsv(posts)}");
        }

        return Encoding.UTF8.GetBytes(sb.ToString());
    }

    public byte[] ExportToTxt(List<GhostImage> images)
    {
        var sb = new StringBuilder();
        sb.AppendLine("Ghost Image Export");
        sb.AppendLine($"Erstellt am: {DateTime.Now:yyyy-MM-dd HH:mm}");
        sb.AppendLine($"Anzahl Bilder: {images.Count}");
        sb.AppendLine($"Verwaiste Bilder: {images.Count(i => i.IsOrphaned)}");
        sb.AppendLine(new string('-', 80));

        foreach (var image in images)
        {
            sb.AppendLine($"Datei: {image.FileName}");
            sb.AppendLine($"URL: {image.Url}");
            sb.AppendLine($"Pfad: {image.RelativePath}");
            sb.AppendLine($"Verwaist: {(image.IsOrphaned ? "Ja" : "Nein")}");
            if (image.UsedInPosts.Any())
            {
                sb.AppendLine("Verwendet in:");
                foreach (var post in image.UsedInPosts)
                {
                    sb.AppendLine($"  - {post.Title} ({(post.IsFeatureImage ? "Feature" : "Content")})");
                }
            }
            sb.AppendLine();
        }

        return Encoding.UTF8.GetBytes(sb.ToString());
    }

    public async Task<byte[]> ExportToZipAsync(List<GhostImage> images)
    {
        using var ms = new MemoryStream();
        using (var archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
        {
            foreach (var image in images)
            {
                if (!File.Exists(image.FilePath))
                    continue;

                var entry = archive.CreateEntry(image.RelativePath.Replace("/", "\\"));
                await using (var entryStream = entry.Open())
                {
                    await using var fileStream = File.OpenRead(image.FilePath);
                    await fileStream.CopyToAsync(entryStream);
                }
            }
        }

        return ms.ToArray();
    }

    private static string EscapeCsv(string value)
    {
        if (string.IsNullOrEmpty(value))
            return "";

        if (value.Contains(';') || value.Contains('"') || value.Contains('\n'))
        {
            return $"\"{value.Replace("\"", "\"\"")}\"";
        }

        return value;
    }
}