using OneOf;

namespace InkBlot.ParseHierarchy;

[GenerateOneOf]
public partial class
    MultiDivert : OneOfBase<ThreadDivert, TunnelsAndDivertsList>,
    IStoryNode;

public record Identifier(string[] Elements /* TODO: expressions */)
{
    public virtual bool Equals(Identifier? other)
    {
        return other is not null && Elements.SequenceEqual(other.Elements);
    }

    public override string ToString()
    {
        return "Identifier(" + string.Join('.', Elements) + ")";
    }

    public override int GetHashCode()
    {
        return Elements.GetHashCode();
    }
}

// <- thread_name
public record ThreadDivert(Identifier Identifier) : IStoryNode
{
    public override string ToString()
    {
        return $"ThreadDivert({Identifier})";
    }
}

[GenerateOneOf]
public partial class TunnelListEnding : OneOfBase<TunnelListEndingDivert, TunnelListEndingReturnFromTunnel>;

public record TunnelListEndingDivert(Identifier? Divert);

public record TunnelListEndingReturnFromTunnel(Identifier? Divert);

/// <summary>
///     A sequence of zero or more tunnels, potentially ending in a divert, and potentially providing a tunnel replacement.
///     <code>
/// ->                                                                      // [], divert(null)
/// ->->                                                                    // [], returnFromTunnel(null)
/// -> divertName                                                           // [], divert(divertName)
/// ->-> divertName                                                         // [], returnFromTunnel(divertName)
/// -> tunnelName ->                                                        // [tunnelName], divert(null)
/// -> tunnelName -> divertName                                             // [tunnelName], divert(divertName)
/// -> tunnelName1 -> tunnelName2 ->                                        // [tunnelName1, tunnelName2], divert(null)
/// -> tunnelName1 -> tunnelName2 ->->                                      // [tunnelName1, tunnelName2], returnFromTunnel(null)
/// -> tunnelName1 -> tunnelName2 ->-> divertName                           // [tunnelName1, tunnelName2], returnFromTunnel(divertName)
/// </code>
/// </summary>
public record TunnelsAndDivertsList(Identifier[] TunnelIdentifiers, TunnelListEnding Ending)
    : IStoryNode
{
    private const string Sep = ", ";

    public virtual bool Equals(TunnelsAndDivertsList? other)
    {
        return other is not null && Ending.Equals(other.Ending) &&
               TunnelIdentifiers.SequenceEqual(other.TunnelIdentifiers);
    }

    public override int GetHashCode()
    {
        return HashCode.Combine(TunnelIdentifiers, Ending);
    }

    public override string ToString()
    {
        return $"TunnelsAndDivertsList({string.Join(Sep, TunnelIdentifiers.Select(i => i.ToString()))}, {Ending})";
    }
}