using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using libTerrain;

namespace OpenSim.Terrain
{
    public class TerrainEngine
    {
        /// <summary>
        /// A [normally] 256x256 heightmap
        /// </summary>
        public Channel heightmap;

        /// <summary>
        /// Whether or not the terrain has been modified since it was last saved and sent to the Physics engine.
        /// Counts the number of modifications since the last save. (0 = Untainted)
        /// </summary>
        public int tainted;

        int w, h;

        /// <summary>
        /// Generate a new TerrainEngine instance and creates a new heightmap
        /// </summary>
        public TerrainEngine()
        {
            w = 256;
            h = 256;
            heightmap = new Channel(w, h);

            tainted++;
        }

        /// <summary>
        /// Converts the heightmap to a 65536 value 1D floating point array
        /// </summary>
        /// <returns>A float[65536] array containing the heightmap</returns>
        public float[] getHeights1D()
        {
            float[] heights = new float[w * h];
            int i;

            for (i = 0; i < w * h; i++)
            {
                heights[i] = (float)heightmap.map[i / w, i % w];
            }

            return heights;
        }

        /// <summary>
        /// Converts the heightmap to a 256x256 value 2D floating point array.
        /// </summary>
        /// <returns>An array of 256,256 values containing the heightmap</returns>
        public float[,] getHeights2D()
        {
            float[,] heights = new float[w, h];
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heights[x, y] = (float)heightmap.map[x, y];
                }
            }
            return heights;
        }

        /// <summary>
        /// Imports a 1D floating point array into the 2D heightmap array
        /// </summary>
        /// <param name="heights">The array to import (must have 65536 members)</param>
        public void setHeights1D(float[] heights)
        {
            int i;
            for (i = 0; i < w * h; i++)
            {
                heightmap.map[i / w, i % w] = heights[i];
            }

            tainted++;
        }

        /// <summary>
        /// Loads a 2D array of values into the heightmap
        /// </summary>
        /// <param name="heights">An array of 256,256 float values</param>
        public void setHeights2D(float[,] heights)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.set(x, y, (double)heights[x, y]);
                }
            }
            tainted++;
        }

        /// <summary>
        /// Processes a terrain-specific command
        /// </summary>
        /// <param name="args">Commandline arguments (space seperated)</param>
        /// <param name="resultText">Reference that returns error or help text if returning false</param>
        /// <returns>If the operation was successful (if not, the error is placed into resultText)</returns>
        public bool RunTerrainCmd(string[] args, ref string resultText)
        {
            string command = args[0];

            try
            {

                switch (command)
                {
                    case "help":
                        resultText += "terrain regenerate - rebuilds the sims terrain using a default algorithm\n";
                        resultText += "terrain seed <seed> - sets the random seed value to <seed>\n";
                        resultText += "terrain load <type> <filename> - loads a terrain from disk, type can be 'F32', 'F64', 'RAW' or 'IMG'\n";
                        resultText += "terrain save <type> <filename> - saves a terrain to disk, type can be 'F32' or 'F64'\n";
                        resultText += "terrain save grdmap <filename> <gradient map> - creates a PNG snapshot of the region using a named gradient map\n";
                        resultText += "terrain rescale <min> <max> - rescales a terrain to be between <min> and <max> meters high\n";
                        resultText += "terrain erode aerobic <windspeed> <pickupmin> <dropmin> <carry> <rounds> <lowest>\n";
                        resultText += "terrain erode thermal <talus> <rounds> <carry>\n";
                        resultText += "terrain multiply <val> - multiplies a terrain by <val>\n";
                        return false;

                    case "seed":
                        setSeed(Convert.ToInt32(args[1]));
                        break;

                    case "erode":
                        switch (args[1].ToLower())
                        {
                            case "aerobic":
                                // WindSpeed, PickupMinimum,DropMinimum,Carry,Rounds,Lowest
                                heightmap.AerobicErosion(Convert.ToDouble(args[2]), Convert.ToDouble(args[3]), Convert.ToDouble(args[4]), Convert.ToDouble(args[5]), Convert.ToInt32(args[6]), Convert.ToBoolean(args[7]));
                                break;
                            case "thermal":
                                heightmap.thermalWeathering(Convert.ToDouble(args[2]), Convert.ToInt32(args[3]), Convert.ToDouble(args[4]));
                                break;
                            default:
                                resultText = "Unknown erosion type";
                                return false;
                        }
                        break;

                    case "regenerate":
                        hills();
                        break;

                    case "rescale":
                        setRange(Convert.ToSingle(args[1]), Convert.ToSingle(args[2]));
                        break;

                    case "multiply":
                        heightmap *= Convert.ToDouble(args[1]);
                        break;

                    case "load":
                        switch (args[1].ToLower())
                        {
                            case "f32":
                                loadFromFileF32(args[2]);
                                break;

                            case "f64":
                                loadFromFileF64(args[2]);
                                break;

                            case "raw":
                                loadFromFileSLRAW(args[2]);
                                break;

                            case "img":
                                resultText = "Error - IMG mode is presently unsupported.";
                                return false;

                            default:
                                resultText = "Unknown image or data format";
                                return false;
                        }
                        break;

                    case "save":
                        switch (args[1].ToLower())
                        {
                            case "f32":
                                writeToFileF32(args[2]);
                                break;

                            case "f64":
                                writeToFileF64(args[2]);
                                break;

                            case "grdmap":
                                exportImage(args[2], args[3]);
                                break;

                            default:
                                resultText = "Unknown image or data format";
                                return false;
                        }
                        break;

                    default:
                        resultText = "Unknown terrain command";
                        return false;
                }
                return true;
            }
            catch (Exception e)
            {
                resultText = "Error running terrain command: " + e.ToString();
                return false;
            }
        }

        /// <summary>
        /// Renormalises the array between min and max
        /// </summary>
        /// <param name="min">Minimum value of the new array</param>
        /// <param name="max">Maximum value of the new array</param>
        public void setRange(float min, float max)
        {
            heightmap.normalise((double)min, (double)max);
            tainted++;
        }

        /// <summary>
        /// Loads a file consisting of 256x256 doubles and imports it as an array into the map.
        /// </summary>
        /// <remarks>TODO: Move this to libTerrain itself</remarks>
        /// <param name="filename">The filename of the double array to import</param>
        public void loadFromFileF64(string filename)
        {
            System.IO.FileInfo file = new System.IO.FileInfo(filename);
            System.IO.FileStream s = file.Open(System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.BinaryReader bs = new System.IO.BinaryReader(s);
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.map[x, y] = bs.ReadDouble();
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Loads a file consisting of 256x256 floats and imports it as an array into the map.
        /// </summary>
        /// <remarks>TODO: Move this to libTerrain itself</remarks>
        /// <param name="filename">The filename of the float array to import</param>
        public void loadFromFileF32(string filename)
        {
            System.IO.FileInfo file = new System.IO.FileInfo(filename);
            System.IO.FileStream s = file.Open(System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.BinaryReader bs = new System.IO.BinaryReader(s);
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.map[x, y] = (double)bs.ReadSingle();
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Loads a file formatted in the SL .RAW Format used on the main grid
        /// </summary>
        /// <remarks>This file format stinks and is best avoided.</remarks>
        /// <param name="filename">A path to the .RAW format</param>
        public void loadFromFileSLRAW(string filename)
        {
            System.IO.FileInfo file = new System.IO.FileInfo(filename);
            System.IO.FileStream s = file.Open(System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.BinaryReader bs = new System.IO.BinaryReader(s);
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.map[x, y] = (double)bs.ReadByte() * ((double)bs.ReadByte() / 127.0);
                    bs.ReadBytes(11); // Advance the stream to next bytes.
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Writes the current terrain heightmap to disk, in the format of a 65536 entry double[] array.
        /// </summary>
        /// <param name="filename">The desired output filename</param>
        public void writeToFileF64(string filename)
        {
            System.IO.FileInfo file = new System.IO.FileInfo(filename);
            System.IO.FileStream s = file.Open(System.IO.FileMode.CreateNew, System.IO.FileAccess.Write);
            System.IO.BinaryWriter bs = new System.IO.BinaryWriter(s);

            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    bs.Write(heightmap.get(x, y));
                }
            }

            bs.Close();
            s.Close();
        }

        /// <summary>
        /// Writes the current terrain heightmap to disk, in the format of a 65536 entry float[] array
        /// </summary>
        /// <param name="filename">The desired output filename</param>
        public void writeToFileF32(string filename)
        {
            System.IO.FileInfo file = new System.IO.FileInfo(filename);
            System.IO.FileStream s = file.Open(System.IO.FileMode.CreateNew, System.IO.FileAccess.Write);
            System.IO.BinaryWriter bs = new System.IO.BinaryWriter(s);

            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    bs.Write((float)heightmap.get(x, y));
                }
            }

            bs.Close();
            s.Close();
        }

        /// <summary>
        /// Sets the random seed to be used by procedural functions which involve random numbers.
        /// </summary>
        /// <param name="val">The desired seed</param>
        public void setSeed(int val)
        {
            heightmap.seed = val;
        }

        /// <summary>
        /// Raises land in a sphere around the specified coordinates
        /// </summary>
        /// <param name="rx">Center of the sphere on the X axis</param>
        /// <param name="ry">Center of the sphere on the Y axis</param>
        /// <param name="size">The radius of the sphere</param>
        /// <param name="amount">Scale the height of the sphere by this amount (recommended 0..2)</param>
        public void raise(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                heightmap.raise(rx, ry, size, amount);
            }

            tainted++;
        }

        /// <summary>
        /// Lowers the land in a sphere around the specified coordinates
        /// </summary>
        /// <param name="rx">The center of the sphere at the X axis</param>
        /// <param name="ry">The center of the sphere at the Y axis</param>
        /// <param name="size">The radius of the sphere in meters</param>
        /// <param name="amount">Scale the height of the sphere by this amount (recommended 0..2)</param>
        public void lower(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                heightmap.lower(rx, ry, size, amount);
            }

            tainted++;
        }

        /// <summary>
        /// Generates a simple set of hills in the shape of an island
        /// </summary>
        public void hills()
        {
            lock (heightmap)
            {
                heightmap.hillsSpheres(200, 20, 40, true, true, false);
                heightmap.normalise();
                heightmap *= 60.0; // Raise to 60m
            }

            tainted++;
        }

        /// <summary>
        /// Multiplies the heightfield by val
        /// </summary>
        /// <param name="meep">The heightfield</param>
        /// <param name="val">The multiplier</param>
        /// <returns></returns>
        public static TerrainEngine operator *(TerrainEngine meep, Double val)
        {
            meep.heightmap *= val;
            meep.tainted++;
            return meep;
        }

        /// <summary>
        /// Returns the height at the coordinates x,y
        /// </summary>
        /// <param name="x">X Coordinate</param>
        /// <param name="y">Y Coordinate</param>
        /// <returns></returns>
        public float this[int x, int y]
        {
            get
            {
                return (float)heightmap.get(x, y);
            }
            set
            {
                tainted++;
                heightmap.set(x, y, (double)value);
            }
        }

        /// <summary>
        /// Exports the current heightmap to a PNG file
        /// </summary>
        /// <param name="filename">The destination filename for the image</param>
        /// <param name="gradientmap">A 1x*height* image which contains the colour gradient to export with. Must be at least 1x2 pixels, 1x256 or more is ideal.</param>
        public void exportImage(string filename, string gradientmap)
        {
            try
            {
                Bitmap gradientmapLd = new Bitmap(gradientmap);

                int pallete = gradientmapLd.Height;

                Bitmap bmp = new Bitmap(heightmap.w, heightmap.h);
                Color[] colours = new Color[pallete];

                for (int i = 0; i < pallete; i++)
                {
                    colours[i] = gradientmapLd.GetPixel(0, i);
                }

                Channel copy = heightmap.copy();
                for (int x = 0; x < copy.w; x++)
                {
                    for (int y = 0; y < copy.h; y++)
                    {
                        // 512 is the largest possible height before colours clamp
                        int colorindex = (int)(Math.Max(Math.Min(1.0, copy.get(x, y) / 512.0), 0.0) * pallete);
                        bmp.SetPixel(y, 255 - x, colours[colorindex]);
                    }
                }

                bmp.Save(filename, System.Drawing.Imaging.ImageFormat.Png);
            }
            catch (Exception e)
            {
                Console.WriteLine("Failed generating terrain map: " + e.ToString());
            }
        }
    }
}