#pragma warning disable CA1416

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;
using System.IO;
using System.Numerics;
using System.Text;
using System.Text.Json;
using OpenGLTutorial.Rendering.Display;
using static OpenGL.GL;

namespace OpenGLTutorial.Rendering.Objects.Components {
    
    [Serializable]
    public class TextSettings {
        public int GlyphsPerLine { get; set; } = 16;
        public int GlyphLineCount { get; set; } = 16;
        public int GlyphWidth { get; set; } = 30;
        public int GlyphHeight { get; set; } = 48;

        public float CharXSpacing { get; set; } = 0.0f;

        // Used to offset rendering glyphs to bitmap
        public int AtlasOffsetX { get; set; } = -3;
        public int AtlasOffsetY { get; set; } = -1;
        public int FontSize { get; set; } = 35;
        public bool BitmapFont { get; set; } = false;
        public float TexCoordOffset { get; set; } = 0.005f;

        public void Save(string file) {
            string json = JsonSerializer.Serialize(this, new JsonSerializerOptions {WriteIndented = true});
            File.WriteAllText(file, json, Encoding.UTF8);
        }

        public static TextSettings Load(string file) {
            string text = File.ReadAllText(file, Encoding.UTF8);
            return JsonSerializer.Deserialize<TextSettings>(text);
        }
    }
    
    public class TextComponent : IComponent {

        public static TextSettings CompileFont(string fontNameOrUrl, string output, TextSettings settings = null) {
            if (settings is null)
                settings = new TextSettings();
            
            int bitmapWidth = settings.GlyphsPerLine * settings.GlyphWidth;
            int bitmapHeight = settings.GlyphLineCount * settings.GlyphHeight;

            using Bitmap texture = new Bitmap(bitmapWidth, bitmapHeight, PixelFormat.Format32bppArgb);
            Font font;
            if (File.Exists(fontNameOrUrl))
            {
                var collection = new PrivateFontCollection();
                collection.AddFontFile(fontNameOrUrl);
                var fontFamily = new FontFamily(Path.GetFileNameWithoutExtension(fontNameOrUrl), collection);
                font = new Font(fontFamily, settings.FontSize);
            }
            else {
                font = new Font(new FontFamily(fontNameOrUrl), settings.FontSize);
            }

            using (var g = Graphics.FromImage(texture)) {
                if (settings.BitmapFont) {
                    g.SmoothingMode = SmoothingMode.None;
                    g.TextRenderingHint = TextRenderingHint.SingleBitPerPixel;
                }
                else {
                    g.SmoothingMode = SmoothingMode.HighQuality;
                    g.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
                }

                for (int p = 0; p < settings.GlyphLineCount; p++) {
                    for (int n = 0; n < settings.GlyphsPerLine; n++) {
                        char c = (char)(n + p * settings.GlyphsPerLine);
                        g.DrawString(c.ToString(), font, Brushes.White,
                            n * settings.GlyphWidth + settings.AtlasOffsetX,
                            p * settings.GlyphHeight + settings.AtlasOffsetY);
                    }
                }
            }

            texture.Save(output);

            return settings;
        }
        
        public string Text { get; set; }
        public Vector2 Size { get; private set; }
        
        public Color TextColor { get; set; } = Color.White;
        private Shape Shape { get; set; }
        private Texture Texture { get; set; }
        private TextSettings Settings { get; set; }
        private string CurrentText { get; set; }

        public TextComponent(string fontImage, string text, TextSettings settings = null, int renderingMode = GL_STATIC_DRAW) {
            Texture = new Texture(fontImage);
            Shape = new Shape(Shapes.Rectangle, renderingMode);
            Settings = settings is not null ? settings : new TextSettings();
        }
        
        public void Load(GameObject thisObject) {
            Texture.Load();
            Shape.Load();
        }

        public void Update(GameObject thisObject) {
            if (CurrentText == Text) return;
            CurrentText = Text;
            List<float> vertices = new List<float>();
            float x = 0;
            float y = 0;
            float uW = Settings.GlyphWidth / (float)Texture.Width;
            float vH = Settings.GlyphHeight / (float)Texture.Height;
            float w = Settings.GlyphWidth / (float)Settings.GlyphHeight;
            const float h = 1.0f;

            for (int n = 0; n < Text.Length; n++) {
                char idx = Text[n];
                
                if (idx == '\n') {
                    y += 1;
                    x = 0;
                    continue;
                }
                if (idx == '\t') {
                    x += (w + Settings.CharXSpacing) * 4;
                    continue;
                }
                
                float u = (idx % Settings.GlyphsPerLine) * uW + Settings.TexCoordOffset;
                float v = (idx / Settings.GlyphsPerLine) * vH + Settings.TexCoordOffset;

                vertices.AddRange(new[] {
                    x,     y + h, TextColor.R, TextColor.G, TextColor.B, TextColor.A, u,      v + vH,
                    x + w, y + h, TextColor.R, TextColor.G, TextColor.B, TextColor.A, u + uW, v + vH,
                    x,     y,     TextColor.R, TextColor.G, TextColor.B, TextColor.A, u,      v,
                    
                    x + w, y,     TextColor.R, TextColor.G, TextColor.B, TextColor.A, u + uW, v,
                    x + w, y + h, TextColor.R, TextColor.G, TextColor.B, TextColor.A, u + uW, v + vH,
                    x,     y,     TextColor.R, TextColor.G, TextColor.B, TextColor.A, u,      v
                });

                x += w + Settings.CharXSpacing;
            }
            
            Shape.SetVertices(vertices.ToArray());
            Size = new Vector2(x, y);
        }

        public void Destroy(GameObject thisObject) {
            Shape.Delete();
            Texture.Delete();
        }

        public void Render(GameObject thisObject) {
            glEnable(GL_BLEND);
            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            Texture.Use();
            
            glBindVertexArray(Shape.Vao);
            glDrawArrays(GL_TRIANGLES, 0, Shape.GetVertexCount());
            glBindVertexArray(0);

            glBindTexture(GL_TEXTURE_2D, 0);
        }
    }
}