@*
 *                                dbMango
 *
 * Copyright 2025 Deutsche Bank AG
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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.
 *@
<CascadingValue Value="this">

    <div class="@TabControlClass">
        @if (ShowHeaders)
        {
            <div class="tab-content fit-content">
                <ul class="@TabPanelClass" role="tablist">
                    @foreach (var tabPage in _pages)
                    {
                        if (tabPage.IsSelectable)
                        {
                            <li class="nav-item">
                                <a
                                class="nav-link @GetButtonClass(tabPage)"
                                style="cursor: pointer"
                                data-toggle="tab"
                                role="tab"
                                aria-controls="nav-home"
                                aria-selected="@IsSelected(tabPage)" @onclick=@(() => ActivatePage(tabPage))>
                                    @tabPage.Text
                                </a>
                            </li>
                        }
                        else
                        {
                            <li class="nav-item">
                                <div class="@TabGroupClass">
                                    @tabPage.Text
                                </div>
                            </li>
                        }
                    }
                </ul>
            </div>
        }
        
        @ChildContent
    </div>
</CascadingValue>

@code {
    // Next line is needed so we are able to add <TabPage> components inside
    [Parameter] public RenderFragment? ChildContent   { get; set; }
    [Parameter] public string          Class          { get; set; } = "";
    [Parameter] public string          TabGroupClass  { get; set; } = "";
    [Parameter] public bool            ShowHeaders    { get; set; } = true;
    [Parameter] public bool            Vertical       { get; set; }
    [Parameter] public bool            PersistAllTabs { get; set; }

    [Parameter] public string ActivePage
    {
        get => _activePage?.Text ?? "";
        set
        {
            if (value == null)
                return;

            if (_activePage?.Text == value)
                return;

            var page = _pages.FirstOrDefault(x => x.Text == value);
            if ( page?.IsSelectable != true)
                return;

            _activePage = page;
            ActivePageChanged.InvokeAsync(_activePage?.Text);
        }
    }

    [Parameter] public EventCallback<string> ActivePageChanged { get; set; }

    private List<TabPage> _pages = [];
    private TabPage?      _activePage;

    private string TabControlClass => $"{Class}";
    private string TabPanelClass   => Vertical
        ? "nav nav-tabs flex-column"
        : "nav nav-tabs";
    protected override void OnInitialized()
    {
        base.OnInitialized();
        _pages = [];
    }

    private int IndexOf(TabPage tabPage)
    {
        for( var i = 0; i < _pages.Count; i+=1 )
        {
            if (_pages[i].Text == tabPage.Text)
                return i;
        }
        return -1;
    }

    internal void AddPage(TabPage tabPage)
    {
        if (string.IsNullOrWhiteSpace(tabPage?.Text))
            throw new ApplicationException("TabPage must have Text field filled in");

        var oldPage = IndexOf(tabPage);
        if ( oldPage < 0 )
        {
            _pages.Add(tabPage);
            StateHasChanged();
        }
        else if (_pages[oldPage] != tabPage)
        {
            _pages[oldPage] = tabPage;
            StateHasChanged();
        }

        if (_pages.Count == 1)
            ActivePage = tabPage.Text;
    }

    bool IsSelected(TabPage page) => ActivePage == page.Text;

    string GetButtonClass(TabPage page) => page.Text == ActivePage ? "active show" : "";

    void ActivatePage(TabPage page)
    {
        ActivePage = page.Text;
    }
}