using System.Collections.Generic;

namespace System.Application.Models
{
    /// <summary>
    /// 分页模型
    /// </summary>
    public interface IPagedModel : IExplicitHasValue
    {
        /// <summary>
        /// 当前页码，页码从1开始，不能取负数，如果&lt;=0，则必定是空集合
        /// </summary>
        int Current { get; set; }

        /// <summary>
        /// 页大小，即每页条数，不能取负数，如果&lt;=0，则必定是空集合
        /// </summary>
        int PageSize { get; set; }

        /// <summary>
        /// 默认的当前页码
        /// </summary>
        public const int DefaultCurrent = 1;

        /// <summary>
        /// 默认的页大小
        /// </summary>
        public const int DefaultPageSize = 10;

        /// <summary>
        /// 总数据数
        /// </summary>
        int Total { get; set; }

        /// <summary>
        /// 总页数
        /// </summary>
        public int PageCount
        {
            get
            {
                float total = Total;
                float pageSize = PageSize;
                var pageCount = (int)MathF.Ceiling(total / pageSize);
                return pageCount < 0 ? 0 : pageCount;
            }
        }
    }

    /// <inheritdoc cref="IPagedModel"/>
    public interface IPagedModel<T> : IPagedModel
    {
        /// <inheritdoc cref="IPagedModel.DataSource"/>
        IList<T> DataSource { get; set; }
    }

    /// <inheritdoc cref="IPagedModel"/>
    public interface IReadOnlyPagedModel<out T> : IPagedModel
    {
        /// <inheritdoc cref="IPagedModel.DataSource"/>
        IReadOnlyList<T> DataSource { get; }
    }
}