// Copyright (c) Pixel Crushers. All rights reserved.

using System;
using System.Collections.Generic;

// [PixelCrushers] Adds extra methods to make LuaInterpreter work with Unity.
namespace Language.Lua
{

    public class LuaFunctionCallException : Exception 
    {
        public LuaFunctionCallException(string message) : base(message) { }
    }

    public static class LuaInterpreterExtensions
    {

        /// <summary>
        /// This method replaces List.ConvertAll(), which isn't supported in WinRT.
        /// </summary>
        /// <returns>The list of evaluated expressions.</returns>
        /// <param name="exprList">A list of expressions to evaluate.</param>
        /// <param name="environment">Lua environment.</param>
        public static List<LuaValue> EvaluateAll(List<Expr> exprList, LuaTable environment)
        {
            List<LuaValue> values = new List<LuaValue>();
            int i = 0;
            foreach (var expr in exprList)
            {
                try
                {
                    values.Add(expr.Evaluate(environment));
                    i++;
                }
                catch (LuaFunctionCallException e)
                {
                    var primaryExpr = exprList[i] as PrimaryExpr;
                    if (primaryExpr != null)
                    {
                        if (primaryExpr.Base is VarName)
                        { 
                            throw new Exception($"Tried to call {(primaryExpr.Base as VarName).Name}() as a function but failed. Is it a registered Lua function?"); 
                        }
                    }
                    throw e;                    
                }
            }
            return values;
        }

        /// <summary>
        /// Returns a LuaValue containing the object's value.
        /// </summary>
        /// <returns>A LuaValue.</returns>
        /// <param name="o">An object of any standard type.</param>
        public static LuaValue ObjectToLuaValue(object o)
        {
            if (o == null) return LuaNil.Nil;
            System.Type objectType = o.GetType();
            if (objectType == typeof(bool)) return ((bool)o) ? LuaBoolean.True : LuaBoolean.False;
            if (objectType == typeof(string)) return new LuaString((string)o);
            if (objectType == typeof(int)) return new LuaNumber((double)((int)o));
            if (objectType == typeof(float)) return new LuaNumber((double)((float)o));
            if (objectType == typeof(double)) return new LuaNumber((double)o);
            if (objectType == typeof(byte)) return new LuaNumber((double)((byte)o));
            if (objectType == typeof(sbyte)) return new LuaNumber((double)((sbyte)o));
            if (objectType == typeof(short)) return new LuaNumber((double)((short)o));
            if (objectType == typeof(ushort)) return new LuaNumber((double)((ushort)o));
            if (objectType == typeof(uint)) return new LuaNumber((double)((uint)o));
            if (objectType == typeof(long)) return new LuaNumber((double)((long)o));
            if (objectType == typeof(ulong)) return new LuaNumber((double)((ulong)o));
            if (o is LuaValue) return (o as LuaValue);
            return new LuaString(o.ToString());
        }

        public static object LuaValueToObject(LuaValue luaValue)
        {
            if (luaValue == null) return null;
            if (luaValue is LuaNumber) return (float)((luaValue as LuaNumber).Number);
            return luaValue.Value;
        }

    }

}