using System;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;

namespace DesertPaintCodex.Models
{
    public class RecipeSearchNode
    {
        private readonly uint[] _reagents;
        private readonly uint _invalidReagent;

        private int _nextReagentPos;
        public int ReagentCount => _nextReagentPos;

        public uint MinConcentration { get; set; } = 10;

        private readonly bool[] _reagentInUse;
        private readonly List<Reagent> _costSortedReagents;
        public PaintRecipe? TestRecipe { get; set; }

        public uint CurrentTargetQuantity { get; set; }
        public uint MaxConcentration { get; set; }
        public uint UsedQuantity { get; private set; }
        public uint CatalystCount { get; set; }
        public uint FullQuantityDepth { get; set; }
        public uint FullQuantity { get; set; }
        public uint MinReagents { get; set; }

        public bool ShouldLog { get; private set; }

        public Action<string>? WriteLog = null;

        private uint _maxReagents;
        public uint MaxReagents
        {
            get => _maxReagents;
            set
            {
                _maxReagents = value;
                CurrentWeights = new uint[_maxReagents];
            }
        }

        public uint[] CurrentWeights { get; private set; }
        
        public uint LastReagent => _reagents[_nextReagentPos - 1];

        public RecipeSearchNode(RecipeSearchNode other)
        {
            _costSortedReagents = new List<Reagent>(other._costSortedReagents);
            _reagents = new uint[_costSortedReagents.Count];
            _invalidReagent = (uint)_costSortedReagents.Count;
            for (int i = 0; i < _costSortedReagents.Count; ++i)
            {
                this._reagents[i] = other._reagents[i];
            }
            _reagentInUse = new bool[_costSortedReagents.Count];
            for (uint i = 0; i < _costSortedReagents.Count; ++i)
            {
                _reagentInUse[i] = other._reagentInUse[i];
            }
            _nextReagentPos = other.ReagentCount;

            CurrentTargetQuantity = other.CurrentTargetQuantity;
            MaxConcentration = other.MaxConcentration;
            UsedQuantity = other.UsedQuantity;
            CatalystCount = other.CatalystCount;
            FullQuantityDepth = other.FullQuantityDepth;
            FullQuantity = other.FullQuantity;
            MinReagents = other.MinReagents;
            MaxReagents = other.MaxReagents;
            CurrentWeights = new uint[MaxReagents];
            for (int i = 0; i < MaxReagents; ++i)
            {
                CurrentWeights[i] = other.CurrentWeights[i];
            }

            RefreshShouldLog();
        }

        public RecipeSearchNode(List<Reagent> costSortedReagents, uint[] reagents)
        {
            _costSortedReagents = new List<Reagent>(costSortedReagents);
            _reagents = new uint[costSortedReagents.Count];
            _invalidReagent = (uint)costSortedReagents.Count;
            _nextReagentPos = reagents.Length;
            for (int i = _reagents.Length - 1; i >= _reagents.Length; --i)
            {
                reagents[i] = _invalidReagent;
            }
            for (int i = reagents.Length - 1; i >= 0; --i)
            {
                _reagents[i] = reagents[i];
                if (reagents[i] == _invalidReagent)
                {
                    _nextReagentPos = i;
                }
            }
            _reagentInUse = new bool[costSortedReagents.Count];
            for (uint reagentIdx = 0; reagentIdx < costSortedReagents.Count; ++reagentIdx)
            {
                _reagentInUse[reagentIdx] = false;
            }
            foreach (uint reagentIdx in this._reagents)
            {
                if (reagentIdx != _invalidReagent)
                {
                    _reagentInUse[reagentIdx] = true;
                }
            }

            MinReagents = (uint) _nextReagentPos;
            MaxReagents = (uint) _nextReagentPos;
            CurrentWeights = new uint[MaxReagents];
            UsedQuantity = 0;

            RefreshShouldLog();
        }

        // top-level search
        public RecipeSearchNode(List<Reagent> costSortedReagents, uint startReagent)
        {
            _costSortedReagents = new List<Reagent>(costSortedReagents);
            _reagents = new uint[costSortedReagents.Count];
            _invalidReagent = (uint)costSortedReagents.Count;
            _nextReagentPos = 0;
            for (int i = 0; i < _reagents.Length; ++i)
            {
                _reagents[i] = _invalidReagent;
            }
            _reagentInUse = new bool[costSortedReagents.Count];
            for (uint reagentIdx = 0; reagentIdx < costSortedReagents.Count; ++reagentIdx)
            {
                _reagentInUse[reagentIdx] = false;
            }
            _reagents[_nextReagentPos++] = NextFreeReagent(startReagent);
            //Console.WriteLine("Added reagent {0} at pos {1}", this.reagents[nextReagentPos-1], nextReagentPos-1);
            MinReagents = 1; // don't iterate up beyond the start reagent
            MaxReagents = 1;
            CurrentWeights = new uint[MaxReagents];
            UsedQuantity = 0;

            RefreshShouldLog();
        }

        public RecipeSearchNode(List<Reagent> costSortedReagents)
        {
            _costSortedReagents = costSortedReagents;
            _reagents = new uint[costSortedReagents.Count];
            _invalidReagent = (uint)costSortedReagents.Count;
            _nextReagentPos = 0;
            for (int i = 0; i < _reagents.Length; ++i)
            {
                _reagents[i] = _invalidReagent;
            }
            _reagentInUse = new bool[costSortedReagents.Count];
            for (uint reagentIdx = 0; reagentIdx < costSortedReagents.Count; ++reagentIdx)
            {
                _reagentInUse[reagentIdx] = false;
            }
            _reagents[_nextReagentPos++] = NextFreeReagent(0);
            MinReagents = 0;
            MaxReagents = 1;
            CurrentWeights = new uint[MaxReagents];
            UsedQuantity = 0;

            RefreshShouldLog();
        }

        private void RefreshShouldLog()
        {
            ShouldLog = false;
            // (ReagentCount == 5) && (GetReagent(0).Name == "Iron") && (GetReagent(1).Name == "Red Sand") && (GetReagent(2).Name == "Sulfur") && (GetReagent(3).Name == "Carrot") && (GetReagent(4).Name == "Copper");
        }

        public Reagent GetReagent(int idx)
        {
            return _costSortedReagents[(int)_reagents[idx]];
        }

        public void RemoveLastReagent()
        {
            uint reagentIdx = _reagents[_nextReagentPos - 1];
            ReleaseReagent(reagentIdx);
            if (_costSortedReagents[(int)reagentIdx].IsCatalyst)
            {
                --CatalystCount;
            }
            _reagents[_nextReagentPos - 1] = _invalidReagent;
            --_nextReagentPos;
            RefreshShouldLog();
        }

        public void ReplaceLastReagent(uint reagentIdx)
        {
            uint oldReagentIdx = _reagents[_nextReagentPos - 1];
            ReleaseReagent(oldReagentIdx);
            _reagents[_nextReagentPos - 1] = reagentIdx;
            if (_costSortedReagents[(int)oldReagentIdx].IsCatalyst)
            {
                --CatalystCount;
            }
            if (_costSortedReagents[(int)reagentIdx].IsCatalyst)
            {
                ++CatalystCount;
            }
            RefreshShouldLog();
        }

        public uint NextFreeReagent(uint startIdx)
        {
            uint idx = startIdx;
            for (; idx < _costSortedReagents.Count; ++idx)
            {
                bool inUse = _reagentInUse[idx];
                if ((inUse == false) && (_costSortedReagents[(int)idx].Enabled))
                {
                    //Console.WriteLine("Found free reagent idx {0}", idx);
                    _reagentInUse[idx] = true;
                    return idx;
                }
            }
            //Console.WriteLine("Failed to find free reagent.");
            return (uint)_costSortedReagents.Count;
        }

        private void ReleaseReagent(uint reagentIdx)
        {
            _reagentInUse[reagentIdx] = false;
        }

        public bool AddNextReagent()
        {
            if (ReagentCount >= MaxReagents) return false;

            uint nextReagent = NextFreeReagent(0);
            _reagents[_nextReagentPos++] = nextReagent;
            if (_costSortedReagents[(int)nextReagent].IsCatalyst)
            {
                ++CatalystCount;
            }
            InitForQuantity(CurrentTargetQuantity);

            return true;
        }

        public void InitForQuantity(uint quantity)
        {
            //System.Console.WriteLine("Init for quantity: {0}, reagent count: {1} ({2} catalysts)", quantity, ReagentCount, CatalystCount);
            CurrentTargetQuantity = quantity;
            if (CurrentTargetQuantity < (MinConcentration + CatalystCount))
            {
                // invalid quantity
                return;
            }
            UsedQuantity = 0;
            if (ShouldLog)
            {
                WriteLog?.Invoke($" == initializing {this} @ quantity {CurrentTargetQuantity} with {CatalystCount} catalysts ==");
            }
            uint remainingReagents = ((uint)_nextReagentPos); // Remaining reagents, including catalysts
            uint remainingWeight = CurrentTargetQuantity - CatalystCount;
            for (int i = 0; i < _nextReagentPos; ++i)
            {
                Reagent reagent = GetReagent(i);

                if (reagent.IsCatalyst)
                {
                    //Console.WriteLine("Init catalyst {0} weight 1", reagent.Name);
                    CurrentWeights[i] = 1;
                    ++UsedQuantity;
                    // This takes quantity but not weight (concentration)
                    if (ShouldLog)
                    {
                        WriteLog?.Invoke($"    + 1 {reagent.Name} (catalyst)");
                    }
                }
                else
                {
                    uint reagentMaxWeight = reagent.RecipeMax;
                    if (ReagentCount <= FullQuantityDepth)
                    {
                        reagentMaxWeight = Math.Max(FullQuantity, reagentMaxWeight);
                    }
                    uint weight = Math.Min(remainingWeight - (remainingReagents-1), reagentMaxWeight);
                    //Console.WriteLine("Init reagent {0} weight {1}", reagent.Name, weight);
                    if (ShouldLog)
                    {
                        WriteLog?.Invoke($"    + {weight} {reagent.Name} (remain: weight={remainingWeight} reagents={remainingReagents})");
                    }
                    remainingWeight -= weight;
                    CurrentWeights[i] = weight;
                    UsedQuantity += weight;
                }
                --remainingReagents;
            }
            RefreshShouldLog();
        }

        public void SetWeight(int idx, uint quantity)
        {
            UsedQuantity -= CurrentWeights[idx];
            CurrentWeights[idx] = quantity;
            UsedQuantity += quantity;
        }

        public void SaveState(StreamWriter writer)
        {
            writer.WriteLine("---SearchNode---");
            writer.WriteLine("MinReagents: {0}", MinReagents);
            writer.WriteLine("MaxReagents: {0}", MaxReagents);
            writer.WriteLine("Reagents: {0}", _nextReagentPos);
            for (int i = 0; i < _nextReagentPos; ++i)
            {
                uint idx = _reagents[i];
                uint weight = CurrentWeights[i];
                writer.WriteLine("Reagent: {0},{1},{2}", idx, _reagentInUse[idx] ? 1 : 0, weight);
            }
            // pulled from parent: List<Reagent> costSortedReagents;
            // new on construct: PaintRecipe testRecipe = null;
            writer.WriteLine("CurrentTargetQuantity: {0}", CurrentTargetQuantity);
            writer.WriteLine("MinConcentration: {0}", MinConcentration);
            writer.WriteLine("MaxConcentration: {0}", MaxConcentration);
            writer.WriteLine("UsedQuantity: {0}", UsedQuantity);
            writer.WriteLine("CatalystCount: {0}", CatalystCount);
            writer.WriteLine("FullQuantity: {0}", FullQuantity);
            writer.WriteLine("FullQuantityDepth: {0}", FullQuantityDepth);
            writer.WriteLine("---EndNode---");
            
        }

        static readonly Regex keyValueRegex = new Regex(@"(\w+)\:\s*(.*)\s*$");
        static readonly Regex reagentPartsRegex = new Regex(@"(?<id>\d+),(?<inUse>\d+),(?<weight>\d+)");
        public bool LoadState(StreamReader reader)
        {
            string? line = reader.ReadLine();
            
            if ((line == null) || !line.Equals("---SearchNode---"))
            {
                return false;
            }

            bool success = true;
            while ((line = reader.ReadLine()) != null)
            {
                if (line.Equals("---EndNode---"))
                {
                    break;
                }
                Match match = keyValueRegex.Match(line);
                if (match.Success)
                {
                    switch (match.Groups[1].Value)
                    {
                        case "Reagents":
                            {
                                //int reagentCount = int.Parse(match.Groups[2].Value);
                                for (int i = 0; i < _reagents.Length; ++i)
                                {
                                    _reagents[i] = _invalidReagent;
                                    _reagentInUse[i] = false;
                                }
                                _nextReagentPos = 0;
                            }
                            break;
                        case "Reagent":
                            {
                                Match reagentInfo = reagentPartsRegex.Match(match.Groups[2].Value);
                                if (reagentInfo.Success)
                                {
                                    uint reagentId = uint.Parse(reagentInfo.Groups["id"].Value);
                                    int isInUse = int.Parse(reagentInfo.Groups["inUse"].Value);
                                    uint weight = uint.Parse(reagentInfo.Groups["weight"].Value);
                                    _reagents[_nextReagentPos] = reagentId;
                                    CurrentWeights[_nextReagentPos] = weight;
                                    if (isInUse != 0)
                                    {
                                        if (reagentId != _invalidReagent)
                                        {
                                            _reagentInUse[reagentId] = true;
                                        }
                                    }
                                    ++_nextReagentPos;
                                }
                                else
                                {
                                    success = false;
                                }
                            }
                            break;
                        case "CurrentTargetQuantity":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                CurrentTargetQuantity = value;
                            }
                            break;
                        case "MaxQuantity":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MaxConcentration = value;
                            }
                            break;
                        case "MinConcentration":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MinConcentration = value;
                            }
                            break;
                        case "MaxConcentration":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MaxConcentration = value;
                            }
                            break;
                        case "MinReagents":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MinReagents = value;
                            }
                            break;
                        case "MaxReagents":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MaxReagents = value;
                            }
                            break;
                        case "UsedQuantity":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                UsedQuantity = value;
                            }
                            break;
                        case "CatalystCount":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                CatalystCount = value;
                            }
                            break;
                        case "InitialCount":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                MinReagents = value;
                            }
                            break;
                        case "FullQuantity":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                FullQuantity = value;
                            }
                            break;
                        case "FullQuantityDepth":
                            {
                                uint value = uint.Parse(match.Groups[2].Value);
                                FullQuantityDepth = value;
                            }
                            break;
                        default:
                            success = false;
                            break;
                    }
                }
                else
                {
                    success = false;
                    break;
                }
            }
            RefreshShouldLog();
            return success;
        }

        public override string ToString()
        {
            if (_nextReagentPos == 0)
            {
                return "No ingredients";
            }
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            sb.Append(_costSortedReagents[(int)_reagents[0]].Name);
            for (int idx = 1; idx < _nextReagentPos; ++idx)
            {
                Reagent reagent = _costSortedReagents[(int)_reagents[idx]];
                sb.Append($", {reagent.Name}");
            }
            return sb.ToString();
        }
    }
}