using System.Collections.Generic;

namespace Trash.Sonarr.ReleaseProfile
{
    public class ScopedState<T>
    {
        private readonly T _defaultValue;
        private readonly Stack<Node> _scopeStack = new();

        public ScopedState(T defaultValue = default!)
        {
            _defaultValue = defaultValue;
        }

        public T Value => _scopeStack.Count > 0 ? _scopeStack.Peek().Value : _defaultValue;

        public int? ActiveScope => _scopeStack.Count > 0 ? _scopeStack.Peek().Scope : null;

        public int StackSize => _scopeStack.Count;

        public void PushValue(T value, int scope)
        {
            if (_scopeStack.Count == 0 || _scopeStack.Peek().Scope < scope)
            {
                _scopeStack.Push(new Node(value, scope));
            }
            else if (_scopeStack.Peek().Scope == scope)
            {
                _scopeStack.Peek().Value = value;
            }
        }

        public bool Reset(int scope)
        {
            if (_scopeStack.Count == 0)
            {
                return false;
            }

            var prevCount = StackSize;
            while (_scopeStack.Count > 0 && _scopeStack.Peek().Scope >= scope)
            {
                _scopeStack.Pop();
            }

            return prevCount != StackSize;
        }

        private class Node
        {
            public Node(T value, int scope)
            {
                Value = value;
                Scope = scope;
            }

            public T Value { get; set; }
            public int Scope { get; }
        }
    }
}