using System.Linq;
using NUnit.Framework.Constraints;
using OrderDomain;

namespace OrderTests;

/// <summary>
/// Custom NUnit matcher that bundles multiple order assertions into one.
/// Participants: you do not need to understand how this works —
/// just recognize the pattern and use it as an example for the agent.
/// </summary>
public static class Has
{
    public static IResolveConstraint OrderState(decimal expectedTotal, decimal[] expectedLineValues)
    {
        return new OrderStateConstraint(expectedTotal, expectedLineValues);
    }
}

public class OrderStateConstraint : Constraint
{
    private readonly decimal _expectedTotal;
    private readonly decimal[] _expectedLineValues;

    public OrderStateConstraint(decimal expectedTotal, decimal[] expectedLineValues)
        : base($"order with total {expectedTotal} and line values [{string.Join(", ", expectedLineValues)}]")
    {
        _expectedTotal = expectedTotal;
        _expectedLineValues = expectedLineValues;
    }

    public override ConstraintResult ApplyTo<TActual>(TActual actual)
    {
        var order = (Order)(object)actual!;
        var actualTotal = order.Total;
        var actualLineValues = order.Lines.Select(l => l.Value).ToArray();

        var totalMatch = actualTotal == _expectedTotal;
        var linesMatch = actualLineValues.SequenceEqual(_expectedLineValues);

        var messages = new List<string>();
        if (!totalMatch)
            messages.Add($"Total: expected {_expectedTotal}, got {actualTotal}");
        if (!linesMatch)
            messages.Add($"Line values: expected [{string.Join(", ", _expectedLineValues)}], got [{string.Join(", ", actualLineValues)}]");

        return new ConstraintResult(this, actual, totalMatch && linesMatch);
    }
}