using Cryville.Common.Pdt;
using System;
using System.Collections.Generic;
using UnityEngine;

namespace Cryville.Crtr {
	public class PdtEvaluator : PdtEvaluatorBase {
		static readonly Dictionary<OperatorSignature, PdtOperator> _shortops = new Dictionary<OperatorSignature, PdtOperator>();
		static readonly Dictionary<string, PdtOperator> _longops = new Dictionary<string, PdtOperator>();
		readonly Dictionary<string, PdtOperator> _ctxops = new Dictionary<string, PdtOperator>();
		struct OperatorSignature : IEquatable<OperatorSignature> {
			public string Name { get; private set; }
			public int ParamCount { get; private set; }
			readonly int _hash;
			public OperatorSignature(string name, int paramCount) {
				Name = name;
				ParamCount = paramCount;
				_hash = name.GetHashCode() ^ paramCount;
			}
			public override bool Equals(object obj) {
				if (!(obj is OperatorSignature)) return false;
				return Equals((OperatorSignature)obj);
			}
			public bool Equals(OperatorSignature other) {
				return Name == other.Name && ParamCount == other.ParamCount;
			}
			public override int GetHashCode() {
				return _hash;
			}
		}

		readonly byte[] _numbuf = new byte[4];
		protected override void GetVariable(string name, out int type, out byte[] value) {
			switch (name) {
				case "w": LoadNum(ChartPlayer.hitRect.width); type = PdtInternalType.Number; value = _numbuf; return;
				case "h": LoadNum(ChartPlayer.hitRect.height); type = PdtInternalType.Number; value = _numbuf; return;
				case "true": LoadNum(1); type = PdtInternalType.Number; value = _numbuf; return;
				case "false": LoadNum(0); type = PdtInternalType.Number; value = _numbuf; return;
				default:
					PropSrc prop;
					string str;
					if (ContextEvent != null && ContextEvent.PropSrcs.TryGetValue(name, out prop)) {
						prop.Get(out type, out value);
					}
					else if (ContextJudge != null && ContextJudge.GetFormattedScoreStrings().TryGetValue(name, out str)) {
						type = PdtInternalType.String;
						value = GetBytes(str);
						RevokePotentialConstant();
					}
					else {
						PropSrc.Arbitrary result;
						foreach (var cas in ContextCascade) {
							if (cas.TryGetValue(name, out result)) {
								result.Get(out type, out value);
								return;
							}
						}
						type = PdtInternalType.Undefined;
						value = GetBytes(name);
					}
					return;
			}
		}
		unsafe void LoadNum(float value) {
			fixed (byte* ptr = _numbuf) *(float*)ptr = value;
		}
		unsafe byte[] GetBytes(string value) {
			int strlen = value.Length;
			byte[] result = new byte[strlen * sizeof(char) + sizeof(int)];
			fixed (byte* _ptr = result) {
				char* ptr = (char*)(_ptr + sizeof(int));
				*(int*)_ptr = strlen;
				int i = 0;
				foreach (var c in value) ptr[i++] = c;
			}
			return result;
		}
		protected override PdtOperator GetOperator(string name, int pc) {
			PdtOperator result;
			if (name.Length == 1 && _shortops.TryGetValue(new OperatorSignature(name, pc), out result)) {
				return result;
			}
			else if (name == ",") {
				result = new op_arr(pc);
				_shortops.Add(new OperatorSignature(",", pc), result);
				return result;
			}
			else if (_longops.TryGetValue(name, out result)) {
				return result;
			}
			else if (_ctxops.TryGetValue(name, out result)) {
				return result;
			}
			else throw new KeyNotFoundException(string.Format("Undefined operator {0}({1})", name, pc));
		}

		protected override bool Collapse(string name, PdtVariableMemory param) {
			switch (name) {
				case "&": return param.AsNumber() == 0;
				case "|": return param.AsNumber() != 0;
				default: throw new KeyNotFoundException(string.Format("Undefined collapse operator {0}", name));
			}
		}

		public ChartEvent ContextEvent { private get; set; }
		public Transform ContextTransform { private get; set; }
		public Judge ContextJudge { private get; set; }
		public PropSrc ContextSelfValue { private get; set; }

		readonly List<Dictionary<string, PropSrc.Arbitrary>> ContextCascade = new List<Dictionary<string, PropSrc.Arbitrary>>();
		public void ContextCascadeInsert() {
			ContextCascade.Add(new Dictionary<string, PropSrc.Arbitrary>());
		}
		public void ContextCascadeUpdate(string key, PropSrc.Arbitrary value) {
			ContextCascade[ContextCascade.Count - 1][key] = value;
		}
		public void ContextCascadeDiscard() {
			ContextCascade.RemoveAt(ContextCascade.Count - 1);
		}

		public PdtEvaluator() {
			_ctxops.Add("screen_edge", new func_screen_edge(() => ContextTransform));
			_ctxops.Add("int", new func_int(() => ContextSelfValue));
			_ctxops.Add("clamp", new func_clamp(() => ContextSelfValue));
			_ctxops.Add("min", new func_min(() => ContextSelfValue));
			_ctxops.Add("max", new func_max(() => ContextSelfValue));
		}
		static PdtEvaluator() {
			_shortops.Add(new OperatorSignature("*", 2), new op_mul_2());
			_shortops.Add(new OperatorSignature("/", 2), new op_div_2());
			_shortops.Add(new OperatorSignature("%", 2), new op_mod_2());

			_shortops.Add(new OperatorSignature("+", 1), new op_add_1());
			_shortops.Add(new OperatorSignature("+", 2), new op_add_2());
			_shortops.Add(new OperatorSignature("-", 1), new op_sub_1());
			_shortops.Add(new OperatorSignature("-", 2), new op_sub_2());

			_shortops.Add(new OperatorSignature("=", 2), new op_eq_2());
			_shortops.Add(new OperatorSignature("<", 2), new op_lt_2());
			_shortops.Add(new OperatorSignature(">", 2), new op_gt_2());

			_shortops.Add(new OperatorSignature("!", 1), new op_not_1());

			_longops.Add("frame_seq", new func_frame_seq());
		}
		#region Operators
#pragma warning disable IDE1006
		class op_add_1 : PdtOperator {
			public op_add_1() : base(1) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_add_2 : PdtOperator {
			public op_add_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() + GetOperand(1).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_sub_1 : PdtOperator {
			public op_sub_1() : base(1) { }
			protected override void Execute() {
				float result = -GetOperand(0).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_sub_2 : PdtOperator {
			public op_sub_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() - GetOperand(1).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_mul_2 : PdtOperator {
			public op_mul_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() * GetOperand(1).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_div_2 : PdtOperator {
			public op_div_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() / GetOperand(1).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_mod_2 : PdtOperator {
			public op_mod_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() % GetOperand(1).AsNumber();
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_eq_2 : PdtOperator {
			public op_eq_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() == GetOperand(1).AsNumber() ? 1 : 0;
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_lt_2 : PdtOperator {
			public op_lt_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() < GetOperand(1).AsNumber() ? 1 : 0;
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_gt_2 : PdtOperator {
			public op_gt_2() : base(2) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() > GetOperand(1).AsNumber() ? 1 : 0;
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_not_1 : PdtOperator {
			public op_not_1() : base(1) { }
			protected override void Execute() {
				float result = GetOperand(0).AsNumber() == 0 ? 1 : 0;
				GetReturnFrame(PdtInternalType.Number, sizeof(float)).SetNumber(result);
			}
		}
		class op_arr : PdtOperator {
			public op_arr(int pc) : base(pc) { }
			protected override void Execute() {
				var o0 = GetOperand(0);
				int type = o0.Type;
				int len = o0.Length;
				bool blit = !IsBlittable(type);
				for (var i = 1; i < ParamCount; i++) {
					var o = GetOperand(i);
					if (o.Type != type) throw new InvalidOperationException("Cannot create variant type array");
					else if (!IsBlittable(o.Type)) blit = true;
					len += o.Length;
				}
				if (blit) GetReturnFrame(PdtInternalType.Array, len + 2 * sizeof(int)).SetArraySuffix(type, ParamCount);
				else GetReturnFrame(PdtInternalType.Vector, len + sizeof(int)).SetArraySuffix(type);
			}
			bool IsBlittable(int type) {
				return type == PdtInternalType.Number;
			}
		}
		class func_frame_seq : PdtOperator {
			public func_frame_seq() : base(3) { }
			protected override unsafe void Execute() {
				string pf = GetOperand(0).AsString();
				int f = (int)GetOperand(1).AsNumber();
				int t = (int)GetOperand(2).AsNumber();
				int pfl = pf.Length;
				int fc = t - f + 1;
				if (fc <= 0) throw new ArgumentException("Start index is greater than end index");
				int l = (f == 0 ? 1 : 0) + pfl * fc;
				for (int p = 1, i = 1; p < 4; p++, i *= 10) {
					int j = i * 10 - 1;
					if (f <= j && t >= i) {
						int m = Math.Max(f, i);
						int n = Math.Min(t, j);
						l += (n - m + 1) * i;
					}
				}
				l *= sizeof(char);
				l += sizeof(int) * (fc + 2);
				var ret = GetReturnFrame(PdtInternalType.Array, l);
				ret.SetArraySuffix(PdtInternalType.String, fc);
				int o = 0;
				for (int i = f; i <= t; i++) {
					var s = pf + i.ToString();
					ret.SetString(s, o);
					o += sizeof(int) + s.Length * sizeof(char);
				}
			}
		}
		class func_screen_edge : PdtOperator {
			readonly Func<Transform> _ctxcb;
			public func_screen_edge(Func<Transform> ctxcb) : base(1) {
				_ctxcb = ctxcb;
			}
			protected override unsafe void Execute() {
				var ctx = _ctxcb();
				float dist;
				var ray = new Ray(ctx.position, ctx.rotation * Vector3.forward);
				ChartPlayer.frustumPlanes[(int)GetOperand(0).AsNumber()].Raycast(ray, out dist);
				var ret = GetReturnFrame(PdtInternalType.Vector, sizeof(Vector3) + sizeof(int));
				var ptr = (Vector3*)ret.TrustedAsOfLength(sizeof(Vector3) + sizeof(int));
				*ptr++ = ray.GetPoint(dist);
				*(int*)ptr = PdtInternalType.Number;
			}
		}
		class func_int : PdtOperator {
			readonly Func<PropSrc> _ctxcb;
			public func_int(Func<PropSrc> ctxcb) : base(1) {
				_ctxcb = ctxcb;
			}
			protected override unsafe void Execute() {
				var ret = GetReturnFrame(PdtInternalType.Number, sizeof(float));
				float v;
				switch (LoadedOperandCount) {
					case 0: v = oputil.AsNumber(_ctxcb()); break;
					case 1: v = GetOperand(0).AsNumber(); break;
					default: throw new ArgumentException("Argument count not 0 or 1");
				}
				ret.SetNumber(Mathf.Floor(v));
			}
		}
		class func_clamp : PdtOperator {
			readonly Func<PropSrc> _ctxcb;
			public func_clamp(Func<PropSrc> ctxcb) : base(3) {
				_ctxcb = ctxcb;
			}
			protected override unsafe void Execute() {
				var ret = GetReturnFrame(PdtInternalType.Number, sizeof(float));
				float min = GetOperand(0).AsNumber();
				float value, max;
				switch (LoadedOperandCount) {
					case 2:
						value = oputil.AsNumber(_ctxcb());
						max = GetOperand(1).AsNumber();
						break;
					case 3:
						value = GetOperand(1).AsNumber();
						max = GetOperand(2).AsNumber();
						break;
					default: throw new ArgumentException("Argument count not 2 or 3");
				}
				ret.SetNumber(Mathf.Clamp(value, min, max));
			}
		}
		class func_min : PdtOperator {
			readonly Func<PropSrc> _ctxcb;
			public func_min(Func<PropSrc> ctxcb) : base(2) {
				_ctxcb = ctxcb;
			}
			protected override unsafe void Execute() {
				var ret = GetReturnFrame(PdtInternalType.Number, sizeof(float));
				float a = GetOperand(0).AsNumber();
				float b;
				switch (LoadedOperandCount) {
					case 1: b = oputil.AsNumber(_ctxcb()); break;
					case 2: b = GetOperand(1).AsNumber(); break;
					default: throw new ArgumentException("Argument count not 2 or 3");
				}
				ret.SetNumber(Mathf.Min(a, b));
			}
		}
		class func_max : PdtOperator {
			readonly Func<PropSrc> _ctxcb;
			public func_max(Func<PropSrc> ctxcb) : base(2) {
				_ctxcb = ctxcb;
			}
			protected override unsafe void Execute() {
				var ret = GetReturnFrame(PdtInternalType.Number, sizeof(float));
				var a = GetOperand(0).AsNumber();
				float b;
				switch (LoadedOperandCount) {
					case 1: b = oputil.AsNumber(_ctxcb()); break;
					case 2: b = GetOperand(1).AsNumber(); break;
					default: throw new ArgumentException("Argument count not 2 or 3");
				}
				ret.SetNumber(Mathf.Max(a, b));
			}
		}
		unsafe static class oputil {
			public static float AsNumber(PropSrc src) {
				int type; byte[] value;
				src.Get(out type, out value);
				if (type != PdtInternalType.Number)
					throw new ArgumentException("Not a number");
				fixed (byte* ptr = value) {
					return *(float*)ptr;
				}
			}
		}
#pragma warning restore IDE1006
		#endregion
	}
}