namespace Entity.Common;

/// <summary>
///     分页组件实体类
/// </summary>
/// <typeparam name="T">泛型实体</typeparam>
[Serializable]
public class PageList<T> : List<T>, IPageList<T>
{
    /// <summary>
    ///     构造函数
    /// </summary>
    /// <param name="source">数据源</param>
    /// <param name="pageIndex">分页索引</param>
    /// <param name="pageSize">分页大小</param>
    public PageList(IQueryable<T> source, int pageIndex, int pageSize)
    {
        var total = source.Count();
        TotalCount = total;
        TotalPages = total / pageSize;

        if (total % pageSize > 0)
            TotalPages++;

        PageSize = pageSize;
        PageIndex = pageIndex;

        AddRange(source.Skip(pageIndex * pageSize).Take(pageSize).ToList());
    }

    /// <summary>
    ///     构造函数
    /// </summary>
    /// <param name="source">数据源</param>
    /// <param name="pageIndex">分页索引</param>
    /// <param name="pageSize">分页大小</param>
    public PageList(IList<T> source, int pageIndex, int pageSize)
    {
        TotalCount = source.Count();
        TotalPages = TotalCount / pageSize;

        if (TotalCount % pageSize > 0)
            TotalPages++;

        PageSize = pageSize;
        PageIndex = pageIndex;
        AddRange(source.Skip(pageIndex * pageSize).Take(pageSize).ToList());
    }

    /// <summary>
    ///     构造函数
    /// </summary>
    /// <param name="source">数据源</param>
    /// <param name="pageIndex">分页索引</param>
    /// <param name="pageSize">分页大小</param>
    /// <param name="totalCount">总记录数</param>
    public PageList(IEnumerable<T> source, int pageIndex, int pageSize, int totalCount)
    {
        TotalCount = totalCount;
        TotalPages = TotalCount / pageSize;

        if (TotalCount % pageSize > 0)
            TotalPages++;

        PageSize = pageSize;
        PageIndex = pageIndex;
        AddRange(source);
    }

    /// <summary>
    ///     分页索引
    /// </summary>
    public int PageIndex { get; }

    /// <summary>
    ///     分页大小
    /// </summary>
    public int PageSize { get; private set; }

    /// <summary>
    ///     总记录数
    /// </summary>
    public int TotalCount { get; }

    /// <summary>
    ///     总页数
    /// </summary>
    public int TotalPages { get; }

    /// <summary>
    ///     是否有上一页
    /// </summary>
    public bool HasPreviousPage => PageIndex > 0;

    /// <summary>
    ///     是否有下一页
    /// </summary>
    public bool HasNextPage => PageIndex + 1 < TotalPages;
}