using System.Globalization;

namespace Connected;

public class Converter<TSourceType, TDestinationType>
{
    public event EventHandler<string?>? ErrorOccured;

    /// <summary>
    /// The culture info being used for decimal points, date and time format, etc.
    /// </summary>
    public CultureInfo Culture { get; set; } = Converters.DefaultCulture;

    public TDestinationType? Convert(TSourceType value)
    {
        try
        {
            return ConvertValue(value);
        }
        catch (Exception e)
        {
            TriggerError($"Conversion from {typeof(TSourceType).Name} to {typeof(TDestinationType).Name} failed: {e.Message}", e);
        }

        return default;
    }

    protected virtual TDestinationType? ConvertValue(TSourceType? value)
    {
        return default;
    }

    public TSourceType? ConvertBack(TDestinationType value)
    {
        try
        {
            return ConvertValueBack(value);
        }
        catch (Exception e)
        {
            TriggerError($"Conversion from {typeof(TDestinationType).Name} to {typeof(TSourceType).Name} failed: {e.Message}", e);
        }

        return default;
    }

    protected virtual TSourceType? ConvertValueBack(TDestinationType? value)
    {
        return default;
    }

    protected void TriggerError(string? msg, Exception? e = null)
    {
        ErrorOccured?.Invoke(this, msg);

        OnErrorOccured(msg, e);
    }

    protected virtual void OnErrorOccured(string? msg, Exception? e)
    {

    }
}

/// <summary>
/// Converts values using the supplied lambda functions.
/// </summary>
/// <typeparam name="TSourceType">The source type</typeparam>
/// <typeparam name="TDestinationType">The destination type</typeparam>
public class LambdaConverter<TSourceType, TDestinationType> :Converter<TSourceType, TDestinationType>
{
    private readonly Func<TSourceType, TDestinationType?>? _convertFunction;
    private readonly Func<TDestinationType, TSourceType?>? _convertBackFunction;

    public LambdaConverter(Func<TSourceType, TDestinationType?>? convertFunction = null, Func<TDestinationType, TSourceType?>? convertBackFunction = null) 
    {
        _convertFunction = convertFunction;
        _convertBackFunction = convertBackFunction;
    }

    protected override TDestinationType? ConvertValue(TSourceType? value)
    {
        if (_convertFunction is null)
            return base.ConvertValue(value);

        return _convertFunction.Invoke(value);
    }

    protected override TSourceType? ConvertValueBack(TDestinationType? value)
    {
        if (_convertFunction is null)
            return base.ConvertValueBack(value);

        return _convertBackFunction.Invoke(value);
    }
}

/// <summary>
/// Converter from T to string
///
/// Set converts to string
/// Get converts from string
/// </summary>
public class ToStringConverter<T> : Converter<T, string>
{

    /// <summary>
    /// Custom Format to be applied on bidirectional way.
    /// </summary>
    public string? Format { get; set; } = null;
}