using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using GeViSetEditor.Core.Models;

namespace GeViSetEditor.Core.Parsers
{
    /// <summary>
    /// Comprehensive parser that extracts ALL configuration data
    /// Based on binary analysis showing 15K booleans, 9K integers, 6K strings
    /// </summary>
    public class ComprehensiveConfigParser
    {
        private byte[] _data;
        private int _position;
        private int _depth;

        public ComprehensiveConfigFile Parse(byte[] data)
        {
            _data = data;
            _position = 0;
            _depth = 0;

            var config = new ComprehensiveConfigFile
            {
                OriginalData = data,
                FileSize = data.Length
            };

            Console.WriteLine($"\n=== Comprehensive Configuration Parser ===");
            Console.WriteLine($"File size: {data.Length:N0} bytes\n");

            // Parse header
            ParseHeader(config);

            Console.WriteLine($"Starting systematic parse from offset {_position}...\n");

            // Parse all data structures systematically
            int itemsParsed = 0;
            while (_position < _data.Length - 10)
            {
                var node = TryParseNextNode();
                if (node != null)
                {
                    config.RootNodes.Add(node);
                    itemsParsed++;

                    if (itemsParsed % 1000 == 0)
                        Console.WriteLine($"Parsed {itemsParsed} nodes, position: {_position}/{_data.Length}");
                }
                else
                {
                    // Skip unknown byte
                    _position++;
                }
            }

            Console.WriteLine($"\n=== Parse Complete ===");
            Console.WriteLine($"Total nodes parsed: {itemsParsed}");
            Console.WriteLine($"Position: {_position}/{_data.Length}");

            // Calculate statistics
            CalculateStatistics(config);

            return config;
        }

        private void ParseHeader(ComprehensiveConfigFile config)
        {
            // Skip null byte
            if (_position < _data.Length && _data[_position] == 0x00)
            {
                config.HeaderNullPrefix = true;
                _position++;
            }

            // Read header
            if (_position < _data.Length)
            {
                byte headerLen = _data[_position++];
                if (_position + headerLen <= _data.Length)
                {
                    config.Header = Encoding.UTF8.GetString(_data, _position, headerLen);
                    _position += headerLen;
                    Console.WriteLine($"Header: '{config.Header}'");
                    Console.WriteLine($"Header ends at: {_position} (0x{_position:X})\n");
                }
            }
        }

        private ConfigNode TryParseNextNode()
        {
            if (_position >= _data.Length)
                return null;

            int startOffset = _position;
            byte marker = _data[_position];

            ConfigNode node = null;

            switch (marker)
            {
                case 0x01: // Boolean
                    node = ParseBoolean(startOffset);
                    break;

                case 0x04: // Integer
                    node = ParseInteger(startOffset);
                    break;

                case 0x05: // Special marker (Rules, etc.)
                    node = ParseSpecialMarker(startOffset);
                    break;

                case 0x07: // String or Object
                    node = ParseStringOrObject(startOffset);
                    break;

                default:
                    // Unknown marker - might be raw data
                    return null;
            }

            return node;
        }

        private ConfigNode ParseBoolean(int startOffset)
        {
            if (_position + 2 > _data.Length)
                return null;

            _position++; // Skip 0x01
            bool value = _data[_position++] != 0;

            return new ConfigNode
            {
                StartOffset = startOffset,
                EndOffset = _position,
                NodeType = "boolean",
                Value = value
            };
        }

        private ConfigNode ParseInteger(int startOffset)
        {
            if (_position + 5 > _data.Length)
                return null;

            _position++; // Skip 0x04
            int value = BitConverter.ToInt32(_data, _position);
            _position += 4;

            return new ConfigNode
            {
                StartOffset = startOffset,
                EndOffset = _position,
                NodeType = "integer",
                Value = value
            };
        }

        private ConfigNode ParseSpecialMarker(int startOffset)
        {
            if (_position + 2 > _data.Length)
                return null;

            _position++; // Skip 0x05
            byte nameLen = _data[_position++];

            if (nameLen > 100 || _position + nameLen > _data.Length)
            {
                _position = startOffset;
                return null;
            }

            string markerName = Encoding.UTF8.GetString(_data, _position, nameLen);
            _position += nameLen;

            var node = new ConfigNode
            {
                StartOffset = startOffset,
                EndOffset = _position,
                NodeType = "marker",
                Name = markerName
            };

            // If it's "Rules", parse action mappings
            if (markerName == "Rules")
            {
                ParseRulesSection(node);
            }

            return node;
        }

        private ConfigNode ParseStringOrObject(int startOffset)
        {
            if (_position + 2 > _data.Length)
                return null;

            _position++; // Skip 0x07
            byte length = _data[_position++];

            if (length == 0 || length > 200 || _position + length > _data.Length)
            {
                _position = startOffset;
                return null;
            }

            string stringValue = Encoding.UTF8.GetString(_data, _position, length);
            _position += length;

            // Check if this string is followed by typed values (object property)
            if (_position < _data.Length)
            {
                byte nextMarker = _data[_position];

                if (nextMarker == 0x01 || nextMarker == 0x04 || nextMarker == 0x07)
                {
                    // This is a property name followed by value
                    var node = new ConfigNode
                    {
                        StartOffset = startOffset,
                        NodeType = "property",
                        Name = stringValue
                    };

                    // Parse the value
                    var valueNode = TryParseNextNode();
                    if (valueNode != null)
                    {
                        node.Value = valueNode.Value;
                        node.ValueType = valueNode.NodeType;
                        node.EndOffset = _position;
                        return node;
                    }
                }
            }

            // Just a standalone string
            return new ConfigNode
            {
                StartOffset = startOffset,
                EndOffset = _position,
                NodeType = "string",
                Value = stringValue
            };
        }

        private void ParseRulesSection(ConfigNode rulesNode)
        {
            // Skip metadata bytes
            while (_position < _data.Length && _data[_position] <= 0x04)
            {
                _position++;
            }

            // Parse action strings (07 01 40 pattern)
            var actions = new List<string>();
            int attempts = 0;

            while (attempts < 200 && _position + 10 < _data.Length)
            {
                if (_data[_position] == 0x07 &&
                    _data[_position + 1] == 0x01 &&
                    _data[_position + 2] == 0x40)
                {
                    ushort actionLen = BitConverter.ToUInt16(_data, _position + 3);
                    if (actionLen > 0 && actionLen < 500 && _position + 5 + actionLen <= _data.Length)
                    {
                        string action = Encoding.UTF8.GetString(_data, _position + 5, actionLen);
                        actions.Add(action);
                        _position += 5 + actionLen;
                        attempts = 0; // Reset
                    }
                    else
                    {
                        _position++;
                        attempts++;
                    }
                }
                else
                {
                    _position++;
                    attempts++;
                }
            }

            rulesNode.Value = actions;
            rulesNode.EndOffset = _position;
        }

        private void CalculateStatistics(ComprehensiveConfigFile config)
        {
            config.Statistics = new ComprehensiveConfigStatistics
            {
                TotalNodes = config.RootNodes.Count,
                BooleanCount = config.RootNodes.Count(n => n.NodeType == "boolean"),
                IntegerCount = config.RootNodes.Count(n => n.NodeType == "integer"),
                StringCount = config.RootNodes.Count(n => n.NodeType == "string"),
                PropertyCount = config.RootNodes.Count(n => n.NodeType == "property"),
                MarkerCount = config.RootNodes.Count(n => n.NodeType == "marker"),
                RulesCount = config.RootNodes.Count(n => n.NodeType == "marker" && n.Name == "Rules")
            };

            Console.WriteLine($"\n=== Statistics ===");
            Console.WriteLine($"Total nodes: {config.Statistics.TotalNodes:N0}");
            Console.WriteLine($"Properties: {config.Statistics.PropertyCount:N0}");
            Console.WriteLine($"Booleans: {config.Statistics.BooleanCount:N0}");
            Console.WriteLine($"Integers: {config.Statistics.IntegerCount:N0}");
            Console.WriteLine($"Strings: {config.Statistics.StringCount:N0}");
            Console.WriteLine($"Markers: {config.Statistics.MarkerCount:N0}");
            Console.WriteLine($"Rules sections: {config.Statistics.RulesCount:N0}");

            // Count property names
            var propertyNames = config.RootNodes
                .Where(n => n.NodeType == "property")
                .GroupBy(n => n.Name)
                .OrderByDescending(g => g.Count())
                .Take(20);

            if (propertyNames.Any())
            {
                Console.WriteLine($"\n=== Top 20 Property Names ===");
                foreach (var group in propertyNames)
                {
                    Console.WriteLine($"  {group.Key}: {group.Count()} occurrences");
                }
            }
        }
    }
}