using System.Reflection;
using PdfSharpCore.Fonts;

namespace GB5Shared.Export.NativePdf
{
    /// <summary>
    /// PdfSharpCore's <c>XGraphics</c> needs an explicit <see cref="IFontResolver"/> on platforms
    /// without Windows GDI font enumeration (confirmed: no such implementation existed anywhere in this
    /// repo before this). Every requested font family is routed to Lato — SIL Open Font License 1.1
    /// (see <c>Fonts/Lato-OFL-LICENSE.txt</c>), embedded directly as resources in this project rather
    /// than referenced from the QuestPDF package that incidentally also ships it, so this resolver keeps
    /// working even if QuestPDF is later removed for its own, unrelated commercial-licensing reasons.
    /// Only Regular/Bold/Italic are embedded (no BoldItalic) — bold+italic requests fall back to Bold.
    /// </summary>
    public sealed class LatoFontResolver : IFontResolver
    {
        public string DefaultFontName => "Lato";

        public byte[] GetFont(string faceName)
        {
            var resourceName = faceName switch
            {
                "Lato#Bold" => "GB5Shared.Export.NativePdf.Fonts.Lato-Bold.ttf",
                "Lato#Italic" => "GB5Shared.Export.NativePdf.Fonts.Lato-Italic.ttf",
                _ => "GB5Shared.Export.NativePdf.Fonts.Lato-Regular.ttf",
            };

            using var stream = typeof(LatoFontResolver).Assembly.GetManifestResourceStream(resourceName)
                ?? throw new InvalidOperationException($"Embedded font resource '{resourceName}' not found.");
            using var ms = new MemoryStream();
            stream.CopyTo(ms);
            return ms.ToArray();
        }

        public FontResolverInfo ResolveTypeface(string familyName, bool isBold, bool isItalic)
        {
            if (isBold) return new FontResolverInfo("Lato#Bold");
            if (isItalic) return new FontResolverInfo("Lato#Italic");
            return new FontResolverInfo("Lato#Regular");
        }
    }
}