@namespace AntDesign
@using AntDesign.Internal
@inherits AntDomComponentBase

@{

    // When hideOnSinglePage is true and there is only 1 page, hide the pager
    if (HideOnSinglePage == true && Total <= PageSize)
    {
        return;
    }

    var allPages = CalculatePage(null, _pageSize, Total);
    var pagerList = new LinkedList<RenderFragment>();
    RenderFragment jumpPrev = null;
    RenderFragment jumpNext = null;
    RenderFragment firstPager = null;
    RenderFragment lastPager = null;
    RenderFragment gotoButton = null;

    var goButton = ShowQuickJumper ? GoButton : null;
    var pageBufferSize = ShowLessItems ? 1 : 2;

    var prevPage = _current - 1 > 0 ? _current - 1 : 0;
    var nextPage = _current + 1 < allPages ? _current + 1 : allPages;
    var dataOrAriaAttributeProps = UnmatchedAttributes?
        .Where(pair => pair.Key.StartsWith("data-") || pair.Key.StartsWith("aria-") || pair.Key == "role")
        .ToDictionary(e => e.Key, e => e.Value);
    if (Simple)
    {
        RenderFragment? goButtonRender;
        if (ShowQuickJumper)
        {
            if (goButton == null)
            {
                goButtonRender =
                    @<button type="button" @onclick="HandleGoTO" @onkeyup="HandleGoTO">
                        @Locale.JumpToConfirm
                    </button>;
            }
            else
            {
                goButtonRender =
                    @<span @onclick="HandleGoTO" @onkeyup="HandleGoTO">
                        @goButton
                    </span>;
            }
            gotoButton =
                @<li
                     title="@(ShowTitle ? $"{Locale.JumpTo}{_current}/{allPages}" : null)"
                     class="@($"{PrefixCls}-simple-pager")">
                    @goButtonRender
                </li>;
        }
        <ul
            class="@ClassMapper.Class"
            style="@Style"
            @ref="Ref"
            @attributes="@dataOrAriaAttributeProps">
            <li
                title="@(ShowTitle ? Locale.PrevPage : null)"
                @onclick="Prev"
                tabIndex="@(HasPrev() ? 0 : null)"
                @onkeypress="RunIfEnterPrev"
                class="@_prevClass.Class"
                aria-disabled="@(!HasPrev())">
                @RenderPrev(prevPage)
            </li>
            <li
                title="@(ShowTitle ? $"{_current}/{allPages}" : null)"
                class="@($"{PrefixCls}-simple-pager")">
                <input
                    type="text"
                    value="@_currentInputValue"
                    disabled="@Disabled"
                    @onkeyup="HandleKeyUp"
                    @onchange="HandleKeyUp"
                    size="3"/>
                <span class="@($"{PrefixCls}-slash")">/</span>
                @allPages
            </li>
            <li
                title="@(ShowTitle ? Locale.NextPage : null)"
                @onclick="Next"
                tabIndex="@(HasPrev() ? 0 : null)"
                @onkeypress="RunIfEnterNext"
                class="@_nextClass.Class"
                aria-disabled="@(!HasNext())">
                @RenderNext(nextPage)
            </li>
            @gotoButton
        </ul>
    }
    else
    {
        if (allPages <= 3 + pageBufferSize * 2)
        {
            if (allPages == 0)
            {
                pagerList.AddLast(
                    @<PaginationPager
                         RootPrefixCls="@PrefixCls"
                         OnClick="HandleChange"
                         OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                         ShowTitle="ShowTitle"
                         @key="@("noPager")"
                         Page="@allPages"
                         Class="@($"{PrefixCls}-disabled")"
                         ItemRender="@ItemRender"/>
                    );
            }
            for (var i = 1; i <= allPages; i += 1)
            {
                var key = i;
                pagerList.AddLast(
                    @<PaginationPager
                         RootPrefixCls="@PrefixCls"
                         OnClick="HandleChange"
                         OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                         ShowTitle="ShowTitle"
                         @key="@key"
                         Page="@key"
                         Active="@(_current == key)"
                         ItemRender="@ItemRender"/>
                    );
            }
        }
        else
        {
            var prevItemTitle = ShowLessItems ? Locale.Prev3 : Locale.Prev5;
            var nextItemTitle = ShowLessItems ? Locale.Next3 : Locale.Next5;
            if (ShowPrevNextJumpers)
            {
                jumpPrev =
                    @<li
                         title="@(ShowTitle ? prevItemTitle : null)"
                         @key="@("prev")"
                         @onclick="JumpPrev"
                         tabIndex="0"
                         @onkeypress="RunIfEnterJumpPrev"
                         class="@_jumpPrevClass.Class">
                        @ItemRender(new(
                            GetJumpPrevPage(),
                            PaginationItemType.JumpPrev,
                            GetItemIcon(JumpPrevIcon, "prev page")
                            ))
                    </li>;

                jumpNext =
                    @<li
                         title="@(ShowTitle ? nextItemTitle : null)"
                         @key="@("next")"
                         tabIndex="0"
                         @onclick="JumpNext"
                         @onkeypress="RunIfEnterJumpNext"
                         class="@_jumpNextClass.Class">
                        @ItemRender(new(
                            GetJumpNextPage(),
                            PaginationItemType.JumpNext,
                            GetItemIcon(JumpNextIcon, "next page")
                            ))
                    </li>;
            }
            lastPager =
                @<PaginationPager
                     Last
                     RootPrefixCls="@PrefixCls"
                     OnClick="HandleChange"
                     OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                     @key="@("allPages")"
                     Page="allPages"
                     Active="@false"
                     ShowTitle="ShowTitle"
                     ItemRender="@ItemRender"/>;
            firstPager =
                @<PaginationPager
                     RootPrefixCls="@PrefixCls"
                     OnClick="HandleChange"
                     OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                     @key="1"
                     Page="1"
                     Active="@false"
                     ShowTitle="ShowTitle"
                     ItemRender="@ItemRender"/>;

            var left = Math.Max(1, _current - pageBufferSize);
            var right = Math.Min(_current + pageBufferSize, allPages);

            if (_current - 1 <= pageBufferSize)
            {
                right = 1 + pageBufferSize * 2;
            }

            if (allPages - _current <= pageBufferSize)
            {
                left = allPages - pageBufferSize * 2;
            }
            var itemAfterJumpPrev = _current - 1 >= pageBufferSize * 2 && _current != 1 + 2;
            var itemBeforeJumpNext = allPages - _current >= pageBufferSize * 2 && _current != allPages - 2;
            for (var i = left; i <= right; i += 1)
            {
                var key = i;
                pagerList.AddLast(
                    @<PaginationPager
                         RootPrefixCls="@PrefixCls"
                         OnClick="HandleChange"
                         OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                         @key="@key"
                         Page="@key"
                         Active="@(_current == key)"
                         ShowTitle="ShowTitle"
                         ItemRender="@ItemRender"/>
                    );
            }

            if (itemAfterJumpPrev)
            {
                pagerList.First.Value =
                    @<PaginationPager
                         RootPrefixCls="@PrefixCls"
                         OnClick="HandleChange"
                         OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                         @key="@left"
                         Page="@left"
                         Active="@(_current == left)"
                         ShowTitle="ShowTitle"
                         Class="@($"{PrefixCls}-item-after-jump-prev")"
                         ItemRender="@ItemRender"/>;
                pagerList.AddFirst(jumpPrev);
            }
            if (itemBeforeJumpNext)
            {
                pagerList.Last.Value =
                    @<PaginationPager
                         RootPrefixCls="@PrefixCls"
                         OnClick="HandleChange"
                         OnKeyPress="args => RunIfEnter(args.e, args.callback)"
                         @key="@right"
                         Page="@right"
                         Active="@(_current == right)"
                         ShowTitle="ShowTitle"
                         Class="@($"{PrefixCls}-item-after-jump-prev")"
                         ItemRender="@ItemRender"/>;
                pagerList.AddLast(jumpNext);
            }

            if (left != 1)
            {
                pagerList.AddFirst(firstPager);
            }
            if (right != allPages)
            {
                pagerList.AddLast(lastPager);
            }
        }

        RenderFragment totalText = null;

        if (ShowTotal.HasValue)
        {
            totalText =
                @<li class="@PrefixCls-total-text">
                    @if (ShowTotal.Value.IsT0)
                    {
                        @ShowTotal.Value.AsT0(new(Total, (
                            Total == 0 ? 0 : (_current - 1) * _pageSize + 1,
                                _current * _pageSize > Total ? Total : _current * _pageSize
                            )))
                    }
                    else if (ShowTotal.Value.IsT1)
                    {
                        @ShowTotal.Value.AsT1(new(Total, (
                            Total == 0 ? 0 : (_current - 1) * _pageSize + 1,
                                _current * _pageSize > Total ? Total : _current * _pageSize
                            )))
                    }
                </li>;
        }
        var prevDisabled = !HasPrev() || allPages != 0;
        var nextDisabled = !HasNext() || allPages != 0;

        <ul
            class="@ClassMapper.Class"
            style="@Style"
            unselectable="unselectable"
            @ref="Ref"
            @attributes="@dataOrAriaAttributeProps">
            @totalText
            <li
                title="@(ShowTitle ? Locale.PrevPage : null)"
                @onclick="Prev"
                tabIndex="@(prevDisabled ? null : 0)"
                @onkeypress="RunIfEnterPrev"
                class="@_prevClass.Class"
                aria-disabled="prevDisabled">
                @RenderPrev(prevPage)
            </li>
            @foreach (var pager in pagerList)
            {
                @pager
            }
            <li
                title="@(ShowTitle ? Locale.NextPage : null)"
                @onclick="Next"
                tabIndex="@(nextDisabled ? null : 0)"
                @onkeypress="RunIfEnterNext"
                class="@_nextClass.Class"
                aria-disabled="nextDisabled">
                @RenderNext(nextPage)
            </li>

            <PaginationOptions
                IsSmall="@IsSmall"
                Disabled="@Disabled"
                RootPrefixCls="@PrefixCls"
                ChangeSize="@(GetShowSizeChanger() ? ChangePageSize : null)"
                Current="@Current"
                PageSize="@PageSize"
                PageSizeOptions="@PageSizeOptions"
                QuickGo="@(ShouldDisplayQuickJumper() ? HandleChange : null)"
                GoButton="@goButton"/>
        </ul>
    }
}

@code {

    private void SetIcon()
    {
        RenderFragment ellipsis = @<span class="@($"{PrefixCls}-item-ellipsis")">•••</span>;
        RenderFragment<PaginationItemRenderContext> prevIcon = context =>
            @<button class="@($"{PrefixCls}-item-link")" type="button" tabIndex="-1" disabled="@context.Disabled">
                <Icon Type="left" Theme="outline"/>
            </button>;
        RenderFragment<PaginationItemRenderContext> nextIcon = context =>
            @<button class="@($"{PrefixCls}-item-link")" type="button" tabIndex="-1" disabled="@context.Disabled">
                <Icon Type="right" Theme="outline"/>
            </button>;
        RenderFragment<PaginationItemRenderContext> jumpPrevIcon = _ =>
            @<a class="@($"{PrefixCls}-item-link")">
                @* You can use transition effects in the container :) *@
                <div class="@($"{PrefixCls}-item-container")">
                    <Icon Type="double-left" Class="@($"{PrefixCls}-item-link-icon")"></Icon>
                    @ellipsis
                </div>
            </a>;
        RenderFragment<PaginationItemRenderContext> jumpNextIcon = _ =>
            @<a class="@($"{PrefixCls}-item-link")">
                @* You can use transition effects in the container :) *@
                <div class="@($"{PrefixCls}-item-container")">
                    <Icon Type="double-right" Class="@($"{PrefixCls}-item-link-icon")"></Icon>
                    @ellipsis
                </div>
            </a>;

        // change arrows direction in right-to-left direction
        if (Direction == "rtl")
        {
            PrevIcon ??= prevIcon;
            NextIcon ??= nextIcon;
            JumpPrevIcon ??= jumpPrevIcon;
            JumpNextIcon ??= jumpNextIcon;
        }
        else
        {
            PrevIcon ??= prevIcon;
            NextIcon ??= nextIcon;
            JumpPrevIcon ??= jumpPrevIcon;
            JumpNextIcon ??= jumpNextIcon;
        }
    }

    /// <summary>
    /// computed icon node that need to be rendered.
    /// </summary>
    /// <param name="icon"></param>
    /// <param name="label"></param>
    /// <returns></returns>
    private RenderFragment<PaginationItemRenderContext> GetItemIcon(RenderFragment<PaginationItemRenderContext>? icon, string label)
    {
        RenderFragment<PaginationItemRenderContext> defaultIconRender = ctx =>
            @<button type="button" aria-label="@label" class="@PrefixCls-item-link" disabled="@ctx.Disabled"/>;

        var iconNode = icon ?? defaultIconRender;
        return iconNode;
    }

}