using Connected.Components;

namespace Connected;

public class RangeConverter<T> : ToStringConverter<Range<T>>
{
	readonly DefaultConverter<T> _converter;

	public RangeConverter()
	{
		_converter = new DefaultConverter<T>();
	}

	protected override string? ConvertValue(Range<T>? value)
	{
		return OnSet(value);
	}

	protected override Range<T>? ConvertValueBack(string? value)
	{
		return OnGet(value);
	}

	private Range<T> OnGet(string value)
	{
		if (!Split(value, out var valueStart, out var valueEnd))
			return null;

		return new Range<T>(_converter.ConvertBack(valueStart), _converter.ConvertBack(valueEnd));
	}

	private string OnSet(Range<T> arg)
	{
		if (arg == null)
			return string.Empty;

		return Join(_converter.Convert(arg.Start), _converter.Convert(arg.End));
	}

	public static string Join(string valueStart, string valueEnd)
	{
		if (string.IsNullOrEmpty(valueStart) && string.IsNullOrEmpty(valueEnd))
			return string.Empty;

		return $"[{valueStart};{valueEnd}]";
	}

	public static bool Split(string value, out string valueStart, out string valueEnd)
	{
		valueStart = valueEnd = string.Empty;

		if (string.IsNullOrEmpty(value) || value[0] != '[' || value[^1] != ']')
		{
			return false;
		}

		var idx = value.IndexOf(';');

		if (idx < 1)
		{
			return false;
		}

		valueStart = value[1..idx];
		valueEnd = value[(idx + 1)..^1];

		return true;
	}
}