/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;

using LSL_Float = OpenSim.Region.ScriptEngine.Shared.LSL_Types.LSLFloat;
using LSL_Integer = OpenSim.Region.ScriptEngine.Shared.LSL_Types.LSLInteger;
using LSL_Key = OpenSim.Region.ScriptEngine.Shared.LSL_Types.LSLString;
using LSL_List = OpenSim.Region.ScriptEngine.Shared.LSL_Types.list;
using LSL_Rotation = OpenSim.Region.ScriptEngine.Shared.LSL_Types.Quaternion;
using LSL_String = OpenSim.Region.ScriptEngine.Shared.LSL_Types.LSLString;
using LSL_Vector = OpenSim.Region.ScriptEngine.Shared.LSL_Types.Vector3;

namespace OpenSim.Region.ScriptEngine.XMREngine {

    public class ScriptConst {

        public static Dictionary<string, ScriptConst> scriptConstants = Init ();

        /**
         * @brief look up the value of a given built-in constant.
         * @param name = name of constant
         * @returns null: no constant by that name defined
         *          else: pointer to ScriptConst struct
         */
        public static ScriptConst Lookup (string name)
        {
            ScriptConst sc;
            if (!scriptConstants.TryGetValue (name, out sc)) sc = null;
            return sc;
        }

        private static Dictionary<string, ScriptConst> Init ()
        {
            Dictionary<string, ScriptConst> sc = new Dictionary<string, ScriptConst> ();

            /*
             * For every event code, define XMREVENTCODE_<eventname> and XMREVENTMASKn_<eventname> symbols.
             */
            for (int i = 0; i < 64; i ++) {
                try {
                    string s = ((ScriptEventCode)i).ToString ();
                    if ((s.Length > 0) && (s[0] >= 'a') && (s[0] <= 'z')) {
                        new ScriptConst (sc, 
                                         "XMREVENTCODE_" + s, 
                                         new CompValuInteger (new TokenTypeInt (null), i));
                        int n = i / 32 + 1;
                        int m = 1 << (i % 32);
                        new ScriptConst (sc, 
                                         "XMREVENTMASK" + n + "_" + s, 
                                         new CompValuInteger (new TokenTypeInt (null), m));
                    }
                } catch { }
            }

            /*
             * Also get all the constants from XMRInstAbstract and ScriptBaseClass etc as well.
             */
            for (Type t = typeof (XMRInstAbstract); t != typeof (object); t = t.BaseType) {
                AddInterfaceConstants (sc, t.GetFields ());
            }

            return sc;
        }

        /**
         * @brief Add all constants defined by the given interface.
         */
        // this one accepts only upper-case named fields
        public static void AddInterfaceConstants (Dictionary<string, ScriptConst> sc, FieldInfo[] allFields)
        {
            List<FieldInfo> ucfs = new List<FieldInfo> (allFields.Length);
            foreach (FieldInfo f in allFields) {
                string fieldName = f.Name;
                int i;
                for (i = fieldName.Length; -- i >= 0;) {
                    if ("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_".IndexOf (fieldName[i]) < 0) break;
                }
                if (i < 0) ucfs.Add (f);
            }
            AddInterfaceConstants (sc, ucfs.GetEnumerator ());
        }

        // this one accepts all fields given to it
        public static void AddInterfaceConstants (Dictionary<string, ScriptConst> sc, IEnumerator<FieldInfo> fields)
        {
            if (sc == null) sc = scriptConstants;

            for (fields.Reset (); fields.MoveNext ();) {
                FieldInfo constField = fields.Current;
                Type fieldType = constField.FieldType;
                CompValu cv;

                /*
                 * The location of a simple number is the number itself.
                 * Access to the value gets compiled as an ldc instruction.
                 */
                if (fieldType == typeof (double)) {
                    cv = new CompValuFloat (new TokenTypeFloat (null),
                                            (double)(double)constField.GetValue (null));
                } else if (fieldType == typeof (int)) {
                    cv = new CompValuInteger (new TokenTypeInt (null),
                                              (int)constField.GetValue (null));
                } else if (fieldType == typeof (LSL_Integer)) {
                    cv = new CompValuInteger (new TokenTypeInt (null),
                                              ((LSL_Integer)constField.GetValue (null)).value);
                }

                /*
                 * The location of a string is the string itself.
                 * Access to the value gets compiled as an ldstr instruction.
                 */
                else if (fieldType == typeof (string)) {
                    cv = new CompValuString (new TokenTypeStr (null), 
                                             (string)constField.GetValue (null));
                } else if (fieldType == typeof (LSL_String)) {
                    cv = new CompValuString (new TokenTypeStr (null), 
                                             (string)(LSL_String)constField.GetValue (null));
                }

                /*
                 * The location of everything else (objects) is the static field in the interface definition.
                 * Access to the value gets compiled as an ldsfld instruction.
                 */
                else {
                    cv = new CompValuSField (TokenType.FromSysType (null, fieldType), constField);
                }

                /*
                 * Add to dictionary.
                 */
                new ScriptConst (sc, constField.Name, cv);
            }
        }

        /**
         * @brief Add arbitrary constant available to script compilation.
         * CAUTION: These values get compiled-in to a script and must not
         *          change over time as previously compiled scripts will
         *          still have the old values.
         */
        public static ScriptConst AddConstant (string name, object value)
        {
            CompValu cv = null;

            if (value is char) {
                cv = new CompValuChar (new TokenTypeChar (null), (char)value);
            }
            if (value is double) {
                cv = new CompValuFloat (new TokenTypeFloat (null), (double)(double)value);
            }
            if (value is float) {
                cv = new CompValuFloat (new TokenTypeFloat (null), (double)(float)value);
            }
            if (value is int) {
                cv = new CompValuInteger (new TokenTypeInt (null), (int)value);
            }
            if (value is string) {
                cv = new CompValuString (new TokenTypeStr (null), (string)value);
            }

            if (value is LSL_Float) {
                cv = new CompValuFloat (new TokenTypeFloat (null), (double)((LSL_Float)value).value);
            }
            if (value is LSL_Integer) {
                cv = new CompValuInteger (new TokenTypeInt (null), ((LSL_Integer)value).value);
            }
            if (value is LSL_Rotation) {
                LSL_Rotation r = (LSL_Rotation)value;
                CompValu x = new CompValuFloat (new TokenTypeFloat (null), r.x);
                CompValu y = new CompValuFloat (new TokenTypeFloat (null), r.y);
                CompValu z = new CompValuFloat (new TokenTypeFloat (null), r.z);
                CompValu s = new CompValuFloat (new TokenTypeFloat (null), r.s);
                cv = new CompValuRot (new TokenTypeRot (null), x, y, z, s);
            }
            if (value is LSL_String) {
                cv = new CompValuString (new TokenTypeStr (null), (string)(LSL_String)value);
            }
            if (value is LSL_Vector) {
                LSL_Vector v = (LSL_Vector)value;
                CompValu x = new CompValuFloat (new TokenTypeFloat (null), v.x);
                CompValu y = new CompValuFloat (new TokenTypeFloat (null), v.y);
                CompValu z = new CompValuFloat (new TokenTypeFloat (null), v.z);
                cv = new CompValuVec (new TokenTypeVec (null), x, y, z);
            }

            if (value is OpenMetaverse.Quaternion) {
                OpenMetaverse.Quaternion r = (OpenMetaverse.Quaternion)value;
                CompValu x = new CompValuFloat (new TokenTypeFloat (null), r.X);
                CompValu y = new CompValuFloat (new TokenTypeFloat (null), r.Y);
                CompValu z = new CompValuFloat (new TokenTypeFloat (null), r.Z);
                CompValu s = new CompValuFloat (new TokenTypeFloat (null), r.W);
                cv = new CompValuRot (new TokenTypeRot (null), x, y, z, s);
            }
            if (value is OpenMetaverse.UUID) {
                cv = new CompValuString (new TokenTypeKey (null), value.ToString ());
            }
            if (value is OpenMetaverse.Vector3) {
                OpenMetaverse.Vector3 v = (OpenMetaverse.Vector3)value;
                CompValu x = new CompValuFloat (new TokenTypeFloat (null), v.X);
                CompValu y = new CompValuFloat (new TokenTypeFloat (null), v.Y);
                CompValu z = new CompValuFloat (new TokenTypeFloat (null), v.Z);
                cv = new CompValuVec (new TokenTypeVec (null), x, y, z);
            }

            if (cv == null) throw new Exception ("bad type " + value.GetType ().Name);
            return new ScriptConst (scriptConstants, name, cv);
        }

        /*
         * Instance variables
         */
        public string name;
        public CompValu rVal;

        private ScriptConst (Dictionary<string, ScriptConst> lc, string name, CompValu rVal)
        {
            lc.Add (name, this);
            this.name = name;
            this.rVal = rVal;
        }
    }
}