// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;
using System.Drawing;
#if ANDROID
using Android.Graphics;
#endif

namespace ClassicalSharp.Gui.Widgets {
	public sealed partial class TextGroupWidget : Widget {
		
		public void SetText(int index, string text) {
			gfx.DeleteTexture(ref Textures[index]);
			DrawTextArgs args = new DrawTextArgs(text, font, true);
			linkData[index] = default(LinkData);
			LinkFlags prevFlags = index > 0 ? linkData[index - 1].flags : 0;
			
			if (!String.IsNullOrEmpty(text)) {
				Texture tex = NextToken(text, 0, ref prevFlags) == -1 ? DrawSimple(ref args) :
					DrawAdvanced(ref args, index, text);
				game.Drawer2D.ReducePadding(ref tex, Utils.Floor(args.Font.Size), 3);
				
				tex.X1 = CalcPos(HorizontalAnchor, XOffset, tex.Width, game.Width);
				tex.Y1 = CalcY(index, tex.Height);
				Textures[index] = tex;
				lines[index] = text;
			} else {
				int height = PlaceholderHeight[index] ? defaultHeight : 0;
				int y = CalcY(index, height);
				Textures[index] = new Texture(-1, 0, y, 0, height, 0, 0);
				lines[index] = null;
			}
			UpdateDimensions();
		}
		
		Texture DrawSimple(ref DrawTextArgs args) {
			return game.Drawer2D.MakeChatTextTexture(ref args, 0, 0);
		}
		
		unsafe Texture DrawAdvanced(ref DrawTextArgs args, int index, string text) {
			LinkData data = Split(index, text);
			Size total = Size.Empty;
			Size* partSizes = stackalloc Size[data.parts.Length];
			linkData[index] = data;
			
			for (int i = 0; i < data.parts.Length; i++) {
				args.Text = data.parts[i];
				args.Font = (i & 1) == 0 ? font : underlineFont;
				partSizes[i] = game.Drawer2D.MeasureChatSize(ref args);
				total.Height = Math.Max(partSizes[i].Height, total.Height);
				total.Width += partSizes[i].Width;
			}
			
			using (IDrawer2D drawer = game.Drawer2D)
				using (Bitmap bmp = IDrawer2D.CreatePow2Bitmap(total))
			{
				drawer.SetBitmap(bmp);
				int x = 0;
				
				for (int i = 0; i < data.parts.Length; i++) {
					args.Text = data.parts[i];
					args.Font = (i & 1) == 0 ? font : underlineFont;
					Size size = partSizes[i];
					
					drawer.DrawChatText(ref args, x, 0);
					data.bounds[i].X = x;
					data.bounds[i].Width = size.Width;
					x += size.Width;
				}
				return drawer.Make2DTexture(bmp, total, 0, 0);
			}
		}
		
		LinkData Split(int index, string line) {
			int start = 0, lastEnd = 0, count = 0;
			LinkData data = default(LinkData);
			data.parts = new string[GetTokensCount(index, line)];
			data.urls = new string[data.parts.Length];
			data.bounds = new Rectangle[data.parts.Length];
			LinkFlags prevFlags = index > 0 ? linkData[index - 1].flags : 0;
			
			while ((start = NextToken(line, start, ref prevFlags)) >= 0) {
				int nextEnd = line.IndexOf(' ', start);
				if (nextEnd == -1) {
					nextEnd = line.Length;
					data.flags |= LinkFlags.Continue;
				}
				
				data.AddPart(count, GetPart(line, lastEnd, start));     // word bit
				data.AddPart(count + 1, GetPart(line, start, nextEnd)); // url bit
				count += 2;
				
				if ((prevFlags & LinkFlags.Append) != 0) {
					string url = linkData[index - 1].LastUrl + data.urls[count - 1];
					data.urls[count - 1] =  url;
					data.parts[count - 2] = "";
					UpdatePreviousUrls(index - 1, url);
				}
				
				if ((prevFlags & LinkFlags.NewLink) != 0)
					data.flags |= LinkFlags.NewLink;
				start = nextEnd;
				lastEnd = nextEnd;
			}
			
			if (lastEnd < line.Length)
				data.AddPart(count, GetPart(line, lastEnd, line.Length)); // word bit
			return data;
		}
		
		void UpdatePreviousUrls(int i, string url) {
			while (i >= 0 && linkData[i].urls != null && (linkData[i].flags & LinkFlags.Continue) != 0) {
				linkData[i].LastUrl = url;
				if (linkData[i].urls.Length > 2 || (linkData[i].flags & LinkFlags.NewLink) != 0)
					break;
				i--;
			}
		}
		
		string GetPart(string line, int start, int end) {
			string part = line.Substring(start, end - start);
			int colIndex = line.LastIndexOf('&', start, start);
			// We may split up a line into say %e<word><url>
			// url and word both need to have %e at the start.
			
			if (colIndex >= 0 && colIndex < line.Length - 1) {
				if (game.Drawer2D.ValidColour(line[colIndex + 1]))
					part = "&" + line[colIndex + 1] + part;
			}
			return part;
		}
		
		int NextToken(string line, int start, ref LinkFlags prevFlags) {
			bool isWrapped = start == 0 && line.StartsWith("> ");
			if ((prevFlags & LinkFlags.Continue) != 0 && isWrapped) {
				prevFlags = 0;
				if (!Utils.IsUrlPrefix(Utils.StripColours(line), 2))
					prevFlags |= LinkFlags.Append;
				else
					prevFlags |= LinkFlags.NewLink;
				return 2;
			}
			
			prevFlags = LinkFlags.NewLink;
			int nextHttp = line.IndexOf("http://", start);
			int nextHttps = line.IndexOf("https://", start);
			return nextHttp == -1 ? nextHttps : nextHttp;
		}
		
		int GetTokensCount(int index, string line) {
			int start = 0, lastEnd = 0, count = 0;
			LinkFlags prevFlags = index > 0 ? linkData[index - 1].flags : 0;
			
			while ((start = NextToken(line, start, ref prevFlags)) >= 0) {
				int nextEnd = line.IndexOf(' ', start);
				if (nextEnd == -1)
					nextEnd = line.Length;
				
				start = nextEnd;
				lastEnd = nextEnd;
				count += 2;
			}
			
			if (lastEnd < line.Length) count++;
			return count;
		}
		
		struct LinkData {
			public Rectangle[] bounds;
			public string[] parts, urls;
			public LinkFlags flags;
			
			public void AddPart(int index, string part) {
				parts[index] = part;
				urls[index] = part;
			}
			
			public string LastUrl {
				get { return urls[parts.Length - 1]; }
				set { urls[parts.Length - 1] = value; }
			}
		}
		
		[Flags]
		enum LinkFlags : byte {
			Continue = 2, // "part1" "> part2" type urls
			Append = 4, // used for internally combining "part2" and "part2"
			NewLink = 8, // used to signify that part2 is a separate url from part1
		}
	}
}