//
// This code is part of Document Solutions for PDF demos.
// Copyright (c) MESCIUS inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Pdf.TextMap;
using GrapeCity.Documents.Pdf.Text;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Pdf.Spec;
using System.Collections.Immutable;
using System.Collections.Generic;
using System.Linq;

namespace DsPdfWeb.Demos
{
    // This sample loads an existing PDF, enumerates the fonts used in it,
    // determines whether each font is embedded, and prints the list of fonts
    // along with their embedding status on the first page of the resulting PDF,
    // followed by the original document.
    // 
    // Note: The check for whether a font is embedded is reliable.
    // However, determining whether an embedded font is a full font or a subset
    // is heuristic and may not be accurate for all PDFs.
    public class FontEmbeddingStatus
    {
        public int CreatePDF(Stream stream)
        {
            // This function checks whether a font is embedded, and if it is,
            // also tries to determine whether it is a subset or a complete font.
            // For embedded subsets, the name usually contains a prefix ending with '+'
            // which we strip from the name for display (as does Acrobat).
            (FontEmbedMode, string) GetFontInfo(GrapeCity.Documents.Pdf.Text.Font font)
            {
                if (font.IsEmbedded)
                {
                    int p = font.BaseFont.IndexOf('+');
                    if (p > 0)
                        return (FontEmbedMode.EmbedSubset, font.BaseFont[(p + 1)..]);
                    else
                        return (FontEmbedMode.EmbedFullFont, font.BaseFont);
                }
                return (FontEmbedMode.NotEmbed, font.BaseFont);
            }
            string EmbedModeToString(FontEmbedMode fem)
            {
                if (fem == FontEmbedMode.EmbedFullFont)
                    return "Embedded font";
                else if (fem == FontEmbedMode.EmbedSubset)
                    return "Embedded subset";
                else
                    return "Not embedded";
            }

            const string pdfName = "C1Olap-QuickStart.pdf";
            var fs = File.OpenRead(Path.Combine("Resources", "PDFs", pdfName));
            var doc = new GcPdfDocument();
            doc.Load(fs);

            var page = doc.Pages.Insert(0);
            var g = page.Graphics;
            var tl = g.CreateTextLayout();
            tl.AppendLine($"Fonts used in {pdfName}, and their embedding status:\n");
            // List fonts and their embedding states:
            var ff = doc.GetFonts().ToImmutableArray().Select(f_ => GetFontInfo(f_)).DistinctBy(fi_ => fi_.Item2).OrderBy(fi_ => fi_.Item2);
            foreach (var fi in ff)
                tl.AppendLine($"- \"{fi.Item2}\": {EmbedModeToString(fi.Item1)}");

            tl.MarginAll = g.Resolution;
            g.DrawTextLayout(tl, Point.Empty);
            
            doc.Save(stream);
            return doc.Pages.Count;
        }
    }
}