// Copyright (C) 2018 Kazuhiro Fujieda <fujieda@users.osdn.me>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;

namespace KancolleSniffer.Model
{
    public class AlarmCounter
    {
        private readonly Func<int> _getCount;
        private int _now;

        public AlarmCounter(Func<int> getCount)
        {
            _getCount = getCount;
        }

        public int Max { get; set; }
        public int Margin { private get; set; }
        public bool Alarm { get; set; }
        public bool TooMany => Max != 0 && Now >= Max - Margin;
        public int Rest => Max == 0 ? 0 : Max - Now;

        public int Now
        {
            get
            {
                var prev = _now;
                _now = _getCount();
                if (Max == 0)
                    return _now;
                var limit = Max - Margin;
                Alarm = Alarm || prev < limit && _now >= limit;
                return _now;
            }
        }
    }
}