using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Packaging;
using System.Linq;
using System.Xml.Linq;

namespace BetterEN5.Services.Conversion;

public class EnbxWriter
{
    private static readonly XNamespace En = "http://schemas.seewo.com/easinote/2016/document";
    private static readonly XNamespace Dc = "http://purl.org/dc/elements/1.1/";

    public void Write(DocumentModel doc, string outputPath)
    {
        if (File.Exists(outputPath)) File.Delete(outputPath);

        using var package = Package.Open(outputPath, FileMode.Create);

        var docPart = package.CreatePart(
            PackUriHelper.CreatePartUri(new Uri("/document.xml", UriKind.Relative)),
            "application/xml");

        var slideTargets = new List<string>();
        int slideIndex = 0;

        foreach (var slide in doc.Slides)
        {
            slideIndex++;
            var slideName = $"slides/slide{slideIndex}.xml";
            slideTargets.Add(slideName);

            var slidePart = package.CreatePart(
                PackUriHelper.CreatePartUri(new Uri($"/{slideName}", UriKind.Relative)),
                "application/xml");

            int imgIdx = 0;
            foreach (var elem in slide.Elements)
            {
                if (elem is ImageElement img && img.Data != null && img.Data.Length > 0)
                {
                    imgIdx++;
                    var ext = Path.GetExtension(img.FileName);
                    if (string.IsNullOrEmpty(ext)) ext = ".png";
                    var mediaName = $"media/{Guid.NewGuid():N}{ext}";

                    var imagePart = package.CreatePart(
                        PackUriHelper.CreatePartUri(new Uri($"/{mediaName}", UriKind.Relative)),
                        img.ContentType);
                    using (var s = imagePart.GetStream())
                        s.Write(img.Data, 0, img.Data.Length);

                    slidePart.CreateRelationship(
                        PackUriHelper.CreatePartUri(new Uri($"/{mediaName}", UriKind.Relative)),
                        TargetMode.Internal,
                        "http://schemas.seewo.com/easinote/relationships/image",
                        $"r{imgIdx}");

                    img.FileName = mediaName;
                }
            }

            WriteSlideXml(slidePart, slide);
            docPart.CreateRelationship(
                PackUriHelper.CreatePartUri(new Uri($"/{slideName}", UriKind.Relative)),
                TargetMode.Internal,
                "http://schemas.seewo.com/easinote/relationships/slide",
                $"r{slideIndex}");
        }

        WriteDocumentXml(docPart, doc, slideTargets);

        package.CreateRelationship(
            PackUriHelper.CreatePartUri(new Uri("/document.xml", UriKind.Relative)),
            TargetMode.Internal,
            "http://schemas.seewo.com/easinote/relationships/document",
            "rId1");
    }

    private void WriteDocumentXml(PackagePart docPart, DocumentModel doc, List<string> slideTargets)
    {
        var docXml = new XDocument(
            new XElement(En + "Document",
                new XAttribute(XNamespace.Xmlns + "en", En.NamespaceName),
                new XAttribute(XNamespace.Xmlns + "dc", Dc.NamespaceName),
                new XElement(En + "Properties",
                    new XElement(En + "Title", doc.Title),
                    new XElement(En + "Author", doc.Author),
                    new XElement(En + "Created", DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ss")),
                    new XElement(En + "Application", "Better-Seewo"),
                    new XElement(En + "Version", "5.2.4.9855"),
                    new XElement(En + "SlideWidth", doc.SlideWidth),
                    new XElement(En + "SlideHeight", doc.SlideHeight)),
                new XElement(En + "Slides",
                    slideTargets.Select((t, i) =>
                        new XElement(En + "Slide",
                            new XAttribute("RId", $"r{i + 1}"),
                            new XAttribute("Source", t))))));

        using var stream = docPart.GetStream(FileMode.Create);
        docXml.Save(stream);
    }

    private void WriteSlideXml(PackagePart slidePart, SlideModel slide)
    {
        var elems = new List<XElement>();
        int imgIdx = 0;
        foreach (var e in slide.Elements)
        {
            switch (e)
            {
                case TextElement t:
                    elems.Add(new XElement(En + "TextElement",
                        new XAttribute("X", t.X),
                        new XAttribute("Y", t.Y),
                        new XAttribute("Width", t.Width),
                        new XAttribute("Height", t.Height),
                        new XAttribute("FontSize", t.FontSize),
                        new XAttribute("IsBold", t.IsBold),
                        new XAttribute("FontName", t.FontName),
                        new XAttribute("FontColor", t.FontColor),
                        new XElement(En + "Text", t.Text)));
                    break;
                case ImageElement img:
                    imgIdx++;
                    elems.Add(new XElement(En + "ImageElement",
                        new XAttribute("X", img.X),
                        new XAttribute("Y", img.Y),
                        new XAttribute("Width", img.Width),
                        new XAttribute("Height", img.Height),
                        new XAttribute("Source", img.FileName),
                        new XAttribute("RId", $"r{imgIdx}")));
                    break;
            }
        }

        var slideXml = new XDocument(
            new XElement(En + "Slide",
                new XAttribute(XNamespace.Xmlns + "en", En.NamespaceName),
                new XAttribute("Width", slide.Width),
                new XAttribute("Height", slide.Height),
                new XElement(En + "Elements", elems)));

        using var stream = slidePart.GetStream(FileMode.Create);
        slideXml.Save(stream);
    }
}