using System;
using System.Collections.Generic;
using System.Text;
using OpenRa.FileFormats;
using BluntDirectX.Direct3D;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

namespace OpenRa.Game
{
	class TerrainRenderer
	{
		FvfVertexBuffer<Vertex> vertexBuffer;
		IndexBuffer indexBuffer;
		Sheet terrainSheet;
		TileSet tileSet;
		Viewport viewport;

		Renderer renderer;
		Map map;

		public TerrainRenderer(Renderer renderer, Map map, Package tilePackage, Viewport viewport)
		{
			this.renderer = renderer;
			this.viewport = viewport;
			viewport.AddRegion(Region.Create(viewport, DockStyle.Left, viewport.ClientSize.Width - 128, Draw));
			this.map = map;

			tileSet = new TileSet(tilePackage, map.TileSuffix);

			Dictionary<TileReference, Sprite> tileMapping =
				new Dictionary<TileReference, Sprite>();

			Size tileSize = new Size(24, 24);

			List<Vertex> vertices = new List<Vertex>();
			List<ushort> indices = new List<ushort>();

			for (int j = 0; j < map.Height; j++)
				for (int i = 0; i < map.Width; i++)
				{
					TileReference tileRef = map.MapTiles[i + map.XOffset, j + map.YOffset];
					Sprite tile;

					if (!tileMapping.TryGetValue(tileRef, out tile))
						tileMapping.Add(tileRef, tile = SheetBuilder.Add(tileSet.GetBytes(tileRef), tileSize));

					terrainSheet = tile.sheet;

					Util.CreateQuad(vertices, indices, 24 * new float2(i,j), tile, 0);
				}

			vertexBuffer = new FvfVertexBuffer<Vertex>(renderer.Device, vertices.Count, Vertex.Format);
			vertexBuffer.SetData(vertices.ToArray());

			indexBuffer = new IndexBuffer(renderer.Device, indices.Count);
			indexBuffer.SetData(indices.ToArray());
		}

		public void Draw()
		{
			int indicesPerRow = map.Width * 6;
			int verticesPerRow = map.Width * 4;

			int visibleRows = (int)(viewport.Size.Y / 24.0f + 2);

			int firstRow = (int)(viewport.Location.Y / 24.0f);
			int lastRow = firstRow + visibleRows;

			if (lastRow < 0 || firstRow > map.Height)
				return;

			if (firstRow < 0) firstRow = 0;
			if (lastRow > map.Height) lastRow = map.Height;

			renderer.DrawWithShader(ShaderQuality.Low, delegate
			{
				renderer.DrawBatch(vertexBuffer, indexBuffer, 
					new Range<int>(verticesPerRow * firstRow, verticesPerRow * lastRow), 
					new Range<int>(indicesPerRow * firstRow, indicesPerRow * lastRow), 
					terrainSheet.Texture);
			});
		}
	}
}