using System.Reflection;
using RobotNet10.CustomConfiguration.Events;
using RobotNet10.CustomConfiguration.Models;
using RobotNet10.CustomConfiguration.Services;
using RobotNet10.FleetManager.Services.TrafficControl.Models;

namespace RobotNet10.FleetManager.Services.ConfigManager;

/// <summary>
/// Service implementation for managing TrafficControl configurations
/// </summary>
public class TrafficConfig : ITrafficConfig
{
    private readonly IConfigManager _configManager;
    private readonly Logger<TrafficConfig> _logger;

    private readonly Lock _lockObject = new();
    private TrafficControlConfig? _trafficControlConfig;
    private bool _configLoaded = false;

    private const string CONFLICT_DETECTION_CONFIG_TYPE = "TrafficConflictDetectionConfig";
    private const string BASE_HORIZON_CONFIG_TYPE = "TrafficBaseHorizonConfig";
    private const string CONFLICT_RESOLUTION_CONFIG_TYPE = "TrafficConflictResolutionConfig";
    private const string PRIORITY_CONFIG_TYPE = "TrafficPriorityConfig";
    private const string PATH_PLANNING_CONFIG_TYPE = "TrafficPathPlanningConfig";

    public TrafficConfig(IConfigManager configManager, Logger<TrafficConfig> logger)
    {
        _configManager = configManager ?? throw new ArgumentNullException(nameof(configManager));
        _logger = logger;
        
        // Subscribe to config changes
        _configManager.ConfigChanged += OnConfigChanged;
    }

    public TrafficControlConfig GetTrafficControlConfig()
    {
        if (!_configLoaded)
        {
            lock (_lockObject)
            {
                if (!_configLoaded)
                {
                    LoadTrafficControlConfigAsync().GetAwaiter().GetResult();
                }
            }
        }
        return _trafficControlConfig ?? throw new InvalidOperationException("TrafficControl configuration not loaded");
    }

    private async Task LoadTrafficControlConfigAsync()
    {
        try
        {
            // Load all nested configs
            var conflictDetectionConfig = await LoadNestedConfigAsync<ConflictDetectionConfig>(CONFLICT_DETECTION_CONFIG_TYPE);
            var baseHorizonConfig = await LoadNestedConfigAsync<BaseHorizonConfig>(BASE_HORIZON_CONFIG_TYPE);
            var conflictResolutionConfig = await LoadNestedConfigAsync<ConflictResolutionConfig>(CONFLICT_RESOLUTION_CONFIG_TYPE);
            var priorityConfig = await LoadNestedConfigAsync<PriorityConfig>(PRIORITY_CONFIG_TYPE);
            var pathPlanningConfig = await LoadNestedConfigAsync<PathPlanningConfig>(PATH_PLANNING_CONFIG_TYPE);

            // Combine into TrafficControlConfig
            _trafficControlConfig = new TrafficControlConfig
            {
                ConflictDetection = conflictDetectionConfig,
                BaseHorizon = baseHorizonConfig,
                ConflictResolution = conflictResolutionConfig,
                Priority = priorityConfig,
                PathPlanning = pathPlanningConfig
            };

            _configLoaded = true;
            _logger.Info("TrafficControl configuration loaded successfully");
        }
        catch (Exception ex)
        {
            _logger.Error($"Error loading TrafficControl configuration, using defaults: {ex.Message}");
            _trafficControlConfig = new TrafficControlConfig();
            _configLoaded = true;
        }
    }

    private async Task<T> LoadNestedConfigAsync<T>(string configType) where T : new()
    {
        try
        {
            var configFile = await _configManager.GetConfigByTypeAsync(configType);
            
            if (configFile == null)
            {
                _logger.Warning($"{configType} configuration not found, using defaults");
                return new T();
            }

            var config = MapConfigVariablesToObject<T>(configFile.Variables);
            _logger.Info($"{configType} configuration loaded successfully");
            return config;
        }
        catch (Exception ex)
        {
            _logger.Warning($"Error loading {configType} configuration, using defaults: {ex.Message}");
            return new T();
        }
    }

    private void OnConfigChanged(object? sender, ConfigChangedEventArgs e)
    {
        // Reload config if any of our config types changed
        if (e.ConfigType == CONFLICT_DETECTION_CONFIG_TYPE ||
            e.ConfigType == BASE_HORIZON_CONFIG_TYPE ||
            e.ConfigType == CONFLICT_RESOLUTION_CONFIG_TYPE ||
            e.ConfigType == PRIORITY_CONFIG_TYPE ||
            e.ConfigType == PATH_PLANNING_CONFIG_TYPE)
        {
            lock (_lockObject)
            {
                _configLoaded = false;
                _trafficControlConfig = null;
            }
            _logger.Info($"TrafficControl configuration changed ({e.ConfigType}), will reload on next access");
        }
    }

    private T MapConfigVariablesToObject<T>(List<ConfigVariable> variables) where T : new()
    {
        var obj = new T();
        var properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.SetProperty);

        foreach (var property in properties)
        {
            // Find variable by exact name match (case-sensitive)
            var variable = variables.FirstOrDefault(v => v.Name == property.Name);
            
            if (variable != null && variable.Value != null)
            {
                try
                {
                    var convertedValue = ConvertValue(variable.Value, property.PropertyType);
                    property.SetValue(obj, convertedValue);
                }
                catch (Exception ex)
                {
                    _logger.Warning($"Failed to set property {property.Name} from variable {variable.Name}: {ex.Message}");
                }
            }
        }

        return obj;
    }

    private object? ConvertValue(object? value, Type targetType)
    {
        if (value == null)
            return targetType.IsValueType ? Activator.CreateInstance(targetType) : null;

        // If value is already of the correct type, return it
        if (targetType.IsInstanceOfType(value))
            return value;

        try
        {
            // Handle nullable types
            var underlyingType = Nullable.GetUnderlyingType(targetType) ?? targetType;

            // Convert based on target type
            if (underlyingType == typeof(string))
            {
                return value.ToString() ?? string.Empty;
            }
            else if (underlyingType == typeof(int))
            {
                if (value is int i) return i;
                if (int.TryParse(value.ToString(), out var parsed)) return parsed;
                if (value is double d) return (int)d;
                throw new InvalidCastException($"Cannot convert {value.GetType()} to int");
            }
            else if (underlyingType == typeof(double))
            {
                if (value is double d) return d;
                if (double.TryParse(value.ToString(), out var parsed)) return parsed;
                if (value is int i) return i;
                throw new InvalidCastException($"Cannot convert {value.GetType()} to double");
            }
            else if (underlyingType == typeof(bool))
            {
                if (value is bool b) return b;
                if (bool.TryParse(value.ToString(), out var parsed)) return parsed;
                // Handle numeric values: 0/1, "0"/"1", etc.
                if (value.ToString()?.Trim() == "0" || value.ToString()?.Trim().ToLower() == "false") return false;
                if (value.ToString()?.Trim() == "1" || value.ToString()?.Trim().ToLower() == "true") return true;
                throw new InvalidCastException($"Cannot convert {value.GetType()} to bool");
            }
            else if (underlyingType.IsEnum)
            {
                var enumValue = Enum.Parse(underlyingType, value.ToString() ?? "", true);
                return enumValue;
            }
            else if (underlyingType.IsGenericType && underlyingType.GetGenericTypeDefinition() == typeof(Dictionary<,>))
            {
                // Handle Dictionary types - try to parse from JSON string
                return ConvertDictionary(value, underlyingType);
            }
            else
            {
                // Try standard conversion
                return Convert.ChangeType(value, underlyingType);
            }
        }
        catch (Exception ex)
        {
            _logger.Warning($"Error converting value {value} of type {value.GetType()} to {targetType}: {ex.Message}");
            throw;
        }
    }

    /// <summary>
    /// Convert value to Dictionary type (supports Dictionary&lt;NavigationType, PathPlanningMethod&gt;)
    /// </summary>
    private object ConvertDictionary(object value, Type dictionaryType)
    {
        try
        {
            // Get key and value types
            var genericArgs = dictionaryType.GetGenericArguments();
            var keyType = genericArgs[0];
            var valueType = genericArgs[1];

            // If value is already the correct Dictionary type, return it
            if (dictionaryType.IsInstanceOfType(value))
            {
                return value;
            }

            // If value is Dictionary<string, object>, try to convert
            if (value is Dictionary<string, object> stringDict)
            {
                var result = Activator.CreateInstance(dictionaryType);
                var addMethod = dictionaryType.GetMethod("Add");
                
                if (addMethod != null && result != null)
                {
                    foreach (var kvp in stringDict)
                    {
                        var key = ConvertValue(kvp.Key, keyType);
                        var val = ConvertValue(kvp.Value, valueType);
                        addMethod.Invoke(result, [key, val]);
                    }
                    return result;
                }
            }

            // Try parse as JSON string
            var jsonString = value.ToString();
            if (!string.IsNullOrEmpty(jsonString))
            {
                try
                {
                    var doc = System.Text.Json.JsonDocument.Parse(jsonString);
                    if (doc.RootElement.ValueKind == System.Text.Json.JsonValueKind.Object)
                    {
                        var result = Activator.CreateInstance(dictionaryType);
                        var addMethod = dictionaryType.GetMethod("Add");
                        
                        if (addMethod != null && result != null)
                        {
                            foreach (var prop in doc.RootElement.EnumerateObject())
                            {
                                // Convert key (e.g., "Differential" -> NavigationType.Differential)
                                var key = ConvertEnumKey(prop.Name, keyType);
                                
                                // Convert value (e.g., "Basic" -> PathPlanningMethod.Basic)
                                var val = ConvertEnumValue(prop.Value.GetString() ?? prop.Value.GetRawText(), valueType);
                                
                                addMethod.Invoke(result, [key, val]);
                            }
                            return result;
                        }
                    }
                }
                catch (Exception ex)
                {
                    _logger.Warning($"Failed to parse Dictionary from JSON string: {ex.Message}");
                }
            }

            // If all else fails, return default (empty dictionary)
            _logger.Warning($"Cannot convert {value.GetType()} to {dictionaryType}, using default (empty dictionary)");
            return Activator.CreateInstance(dictionaryType) ?? throw new InvalidOperationException($"Cannot create instance of {dictionaryType}");
        }
        catch (Exception ex)
        {
            _logger.Warning($"Error converting Dictionary: {ex.Message}");
            // Return default (empty dictionary)
            return Activator.CreateInstance(dictionaryType) ?? throw new InvalidOperationException($"Cannot create instance of {dictionaryType}");
        }
    }

    /// <summary>
    /// Convert string to enum key (e.g., "Differential" -> NavigationType.Differential)
    /// </summary>
    private static object ConvertEnumKey(string keyString, Type enumType)
    {
        if (enumType.IsEnum)
        {
            if (Enum.TryParse(enumType, keyString, true, out var enumValue))
            {
                return enumValue;
            }
        }
        // If not enum, try standard conversion
        return Convert.ChangeType(keyString, enumType);
    }

    /// <summary>
    /// Convert string to enum value (e.g., "Basic" -> PathPlanningMethod.Basic)
    /// </summary>
    private static object ConvertEnumValue(string valueString, Type enumType)
    {
        if (enumType.IsEnum)
        {
            if (Enum.TryParse(enumType, valueString, true, out var enumValue))
            {
                return enumValue;
            }
        }
        // If not enum, try standard conversion
        return Convert.ChangeType(valueString, enumType);
    }
}