using System;
using System.Collections.Generic;
using System.Linq;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Presentation;
using D = DocumentFormat.OpenXml.Drawing;

namespace BetterEN5.Services.Conversion;

public class PptxImporter
{
    public DocumentModel Import(string pptxPath)
    {
        var doc = new DocumentModel();

        using var presentation = PresentationDocument.Open(pptxPath, false);
        var presPart = presentation.PresentationPart!;
        var pres = presPart.Presentation;

        var slideSize = pres.SlideSize!;
        doc.SlideWidth = slideSize.Cx!.Value;
        doc.SlideHeight = slideSize.Cy!.Value;

        int slideIndex = 0;
        foreach (var slideId in pres.SlideIdList!.ChildElements.OfType<SlideId>())
        {
            slideIndex++;
            var slidePart = presPart.GetPartById(slideId.RelationshipId!) as SlidePart;
            if (slidePart == null) continue;

            var slide = slidePart.Slide;
            var slideModel = new SlideModel
            {
                Name = $"Slide{slideIndex}",
                Width = doc.SlideWidth,
                Height = doc.SlideHeight
            };

            ParseSlideElements(slidePart, slide, slideModel, doc);

            doc.Slides.Add(slideModel);
        }

        return doc;
    }

    private void ParseSlideElements(SlidePart slidePart, Slide slide, SlideModel slideModel, DocumentModel doc)
    {
        if (slide.CommonSlideData?.ShapeTree == null) return;

        foreach (var element in slide.CommonSlideData.ShapeTree.ChildElements)
        {
            switch (element)
            {
                case Picture pic:
                    ParsePicture(slidePart, pic, slideModel);
                    break;
                case Shape shape:
                    ParseShape(shape, slideModel);
                    break;
            }
        }
    }

    private void ParsePicture(SlidePart slidePart, Picture pic, SlideModel slideModel)
    {
        var blipFill = pic.BlipFill;
        if (blipFill?.Blip == null) return;

        var embed = blipFill.Blip.Embed?.Value;
        if (string.IsNullOrEmpty(embed)) return;

        var imagePart = slidePart.GetPartById(embed) as ImagePart;
        if (imagePart == null) return;

        using var stream = imagePart.GetStream();
        var data = new byte[stream.Length];
        stream.Read(data, 0, data.Length);

        var transform = pic.ShapeProperties?.Transform2D;
        var img = new ImageElement
        {
            Data = data,
            ContentType = imagePart.ContentType,
            FileName = $"image{slideModel.Elements.Count + 1}{GetExtension(imagePart.ContentType)}",
            X = transform?.Offset?.X?.Value ?? 0,
            Y = transform?.Offset?.Y?.Value ?? 0,
            Width = transform?.Extents?.Cx?.Value ?? 0,
            Height = transform?.Extents?.Cy?.Value ?? 0
        };
        slideModel.Elements.Add(img);
    }

    private void ParseShape(Shape shape, SlideModel slideModel)
    {
        var textBody = shape.TextBody;
        if (textBody == null) return;

        var text = string.Concat(
            textBody.Descendants<D.Text>().Select(t => t.Text));
        if (string.IsNullOrWhiteSpace(text)) return;

        var transform = shape.ShapeProperties?.Transform2D;
        var textElem = new TextElement
        {
            Text = text.Trim(),
            X = transform?.Offset?.X?.Value ?? 0,
            Y = transform?.Offset?.Y?.Value ?? 0,
            Width = transform?.Extents?.Cx?.Value ?? 0,
            Height = transform?.Extents?.Cy?.Value ?? 0
        };

        var firstRun = textBody.Descendants<D.Run>().FirstOrDefault();
        if (firstRun?.RunProperties != null)
        {
            var rp = firstRun.RunProperties;
            textElem.FontSize = (rp.FontSize?.Value ?? 1800) / 100.0;
            textElem.IsBold = rp.Bold?.Value ?? false;

            var solidFill = rp.GetFirstChild<D.SolidFill>();
            if (solidFill?.RgbColorModelHex?.Val?.Value != null)
                textElem.FontColor = $"#{solidFill.RgbColorModelHex.Val.Value}";
            else if (solidFill?.SchemeColor?.Val?.Value != null)
                textElem.FontColor = $"#{solidFill.SchemeColor.Val}";
        }

        slideModel.Elements.Add(textElem);
    }

    private static string GetExtension(string contentType)
    {
        return contentType switch
        {
            "image/png" => ".png",
            "image/jpeg" => ".jpg",
            "image/gif" => ".gif",
            "image/bmp" => ".bmp",
            "image/tiff" => ".tiff",
            _ => ".bin"
        };
    }
}