namespace WxAgent.Core;

public sealed class UiTraversalGuard(int maxNodes = 10_000, int maxDepth = 40)
{
    private readonly HashSet<string> _visited = new(StringComparer.Ordinal);
    public int NodeCount { get; private set; }
    public bool Truncated { get; private set; }
    public bool CycleDetected { get; private set; }

    public bool TryVisit(string runtimeId, int depth)
    {
        if (NodeCount >= maxNodes || depth > maxDepth)
        {
            Truncated = true;
            return false;
        }
        if (runtimeId.Length > 0 && !_visited.Add(runtimeId))
        {
            CycleDetected = true;
            return false;
        }
        NodeCount++;
        return true;
    }
}

public sealed record UiSnapshotComparison(IReadOnlyList<string> AddedAutomationIds,
    IReadOnlyList<string> RemovedAutomationIds, IReadOnlyList<string> MissingRequiredControls)
{
    public static UiSnapshotComparison Compare(UiNodeSnapshot baseline, UiNodeSnapshot current)
    {
        static IEnumerable<string> ReadIds(UiNodeSnapshot root) =>
            new[] { root.AutomationId }.Concat(root.Children.SelectMany(ReadIds));
        static HashSet<string> Ids(UiNodeSnapshot root) => ReadIds(root)
            .Where(id => id.Length > 0 && !id.StartsWith("[id:", StringComparison.Ordinal))
            .ToHashSet(StringComparer.Ordinal);
        var before = Ids(baseline);
        var after = Ids(current);
        return new UiSnapshotComparison(
            after.Except(before).Order(StringComparer.Ordinal).ToArray(),
            before.Except(after).Order(StringComparer.Ordinal).ToArray(),
            WechatLocators.RequiredAutomationIds.Where(id => !after.Contains(id)).ToArray());
    }
}