@using System.ComponentModel.DataAnnotations
@using RackPeek.Domain.Persistence
@using RackPeek.Domain.Resources.SystemResources
@inject IResourceCollection Repo

@if (IsOpen)
{
    <div class="fixed inset-0 z-50 flex items-center justify-center">
        <!-- Backdrop -->
        <div class="absolute inset-0 bg-black/70" @onclick="Cancel"></div>

        <!-- Modal -->
        <div class="relative bg-zinc-900 border border-zinc-800 rounded w-full max-w-lg p-4">
            <!-- Header -->
            <div class="flex justify-between items-center mb-4">
                <div class="text-zinc-100 text-sm font-medium">
                    @Title
                </div>

                <button
                    class="text-zinc-400 hover:text-zinc-200"
                    @onclick="Cancel">
                    ✕
                </button>
            </div>

            <!-- Form -->
            <EditForm Model="_model" OnValidSubmit="HandleAccept">
                <DataAnnotationsValidator/>

                <div class="space-y-3 text-sm">
                    <!-- Search -->
                    <div>
                        @* ReSharper disable once CSharpWarnings::CS8619 *@
                        <InputText
                            class="w-full bg-zinc-800 border border-zinc-700 rounded px-2 py-1 text-zinc-100"
                            placeholder="Search systems…"
                            Value="@_search"
                            ValueChanged="OnSearchChanged"
                            ValueExpression="() => _search"
                            @oninput="OnSearchInput"/>
                    </div>

                    <!-- Selection -->
                    <div>
                        <InputSelect
                            class="w-full bg-zinc-800 border border-zinc-700 rounded px-2 py-1 text-zinc-100"
                            @bind-Value="_model.Value">
                            <option value="">Select system…</option>

                            @foreach (var group in FilteredSystems)
                            {
                                <optgroup label="@group.Key">
                                    @foreach (var system in group.Value)
                                    {
                                        <option value="@system.Name">
                                            @system.Name
                                        </option>
                                    }
                                </optgroup>
                            }
                        </InputSelect>
                    </div>
                </div>

                <!-- Actions -->
                <div class="flex justify-end items-center mt-5 gap-2">
                    <button
                        type="button"
                        class="px-3 py-1 rounded border border-zinc-700 text-zinc-300 hover:bg-zinc-800"
                        @onclick="Cancel">
                        Cancel
                    </button>

                    <button
                        type="submit"
                        class="px-3 py-1 rounded bg-emerald-600 text-black hover:bg-emerald-500"
                        disabled="@(!CanAccept)">
                        Accept
                    </button>
                </div>
            </EditForm>
        </div>
    </div>
}

@code {
    /* ---------- Parameters ---------- */

    [Parameter] public bool IsOpen { get; set; }
    [Parameter] public EventCallback<bool> IsOpenChanged { get; set; }

    [Parameter] [EditorRequired] public string Title { get; set; } = "Select system";

    /// <summary>
    ///     Default / pre-selected system name (may be null)
    /// </summary>
    [Parameter]
    public string? Value { get; set; }

    /// <summary>
    ///     Called with the selected system name
    /// </summary>
    [Parameter]
    public EventCallback<string?> OnAccept { get; set; }

    /* ---------- State ---------- */

    private SelectionFormModel _model = new();
    private string _search = string.Empty;

    private List<SystemResource> _systems = new();

    private bool CanAccept => !string.IsNullOrWhiteSpace(_model.Value);

    /* ---------- Lifecycle ---------- */

    protected override async Task OnParametersSetAsync()
    {
        if (IsOpen)
        {
            _systems = (await Repo.GetAllOfTypeAsync<SystemResource>())
                .OrderBy(s => s.Type)
                .ThenBy(s => s.Name)
                .ToList();

            _model = new SelectionFormModel
            {
                Value = Value
            };

            _search = string.Empty;
        }
    }

    /* ---------- Computed ---------- */

    private Dictionary<string, List<SystemResource>> FilteredSystems =>
        _systems
            .Where(s =>
                string.IsNullOrWhiteSpace(_search) ||
                s.Name.Contains(_search.Trim(), StringComparison.OrdinalIgnoreCase))
            .GroupBy(s => s.Type ?? "None")
            .ToDictionary(
                g => g.Key,
                g => g.OrderBy(s => s.Name).ToList());

    /* ---------- Actions ---------- */

    private async Task HandleAccept()
    {
        await OnAccept.InvokeAsync(_model.Value);
        await Close();
    }

    private async Task Cancel()
    {
        await Close();
    }

    private async Task Close()
    {
        _model = new SelectionFormModel();
        _search = string.Empty;
        await IsOpenChanged.InvokeAsync(false);
    }

    /* ---------- Model ---------- */

    private sealed class SelectionFormModel
    {
        [Required] public string? Value { get; set; }
    }

    /* ---------- Search ---------- */

    private void OnSearchChanged(string? value)
    {
        _search = value ?? string.Empty;
    }

    private void OnSearchInput(ChangeEventArgs e)
    {
        _search = e.Value?.ToString() ?? string.Empty;

        // Clear selection if it is no longer visible
        if (FilteredSystems
            .SelectMany(g => g.Value)
            .All(s => s.Name != _model.Value))
        {
            _model.Value = null;
        }
    }

}