@page "/tire-checkout"
@using Lagerbestand.Components.Shared
@implements IAsyncDisposable
@inject ICustomerService CustomerService
@inject ITireStackService TireStackService
@inject IStorageLocationService StorageLocationService
@inject UserSessionService UserSession

<PageTitle>Reifenstapel Abholen - Reifen Späth Lagerverwaltung</PageTitle>

<SeoMetaTags 
    Title="Reifenstapel Abholen - Reifen Späth Lagerverwaltung"
    Description="Reifen abholen in der Reifen Späth Lagerverwaltung. Schnelle Abwicklung von Kundenabholungen."
    Robots="noindex, nofollow" />

@if (!UserSession.IsWorkerOrAdmin)
{
    <section class="access-denied" role="alert" aria-labelledby="access-denied-title">
        <div class="access-denied-icon" aria-hidden="true">🔒</div>
        <h1 id="access-denied-title">Zugriff verweigert</h1>
        <p>Diese Seite ist nur für Mitarbeiter und Administratoren zugänglich.</p>
        <a href="/" class="btn btn-primary">Zur Startseite</a>
    </section>
}
else
{
<main class="checkout-page" role="main">
    <header class="page-header">
        <h1>Reifenstapel Abholen</h1>
        <p>Suchen Sie nach Ticket-Nummer, Kundenname, Fahrzeug oder Lagerplatz-Code</p>
    </header>

    @* Search Section *@
    <section class="checkout-card" aria-labelledby="search-heading">
        <h2 id="search-heading" class="visually-hidden">Suche</h2>
        <div class="search-section">
            <label for="search-input" class="visually-hidden">Suche nach Ticket-Nr., Kunde, Fahrzeug oder Lagerplatz</label>
            <input type="search" 
                   id="search-input"
                   class="form-control search-input" 
                   placeholder="Ticket-Nr., Kunde, Fahrzeug oder Lagerplatz (z.B. 2135)..."
                   @bind="searchTerm"
                   @bind:event="oninput"
                   @onkeyup="SearchTireStacks" />
        </div>

        @if (!string.IsNullOrEmpty(errorMessage))
        {
            <div class="alert alert-danger" role="alert" aria-live="assertive">@errorMessage</div>
        }

        @if (!string.IsNullOrEmpty(successMessage))
        {
            <div class="alert alert-success" role="status" aria-live="polite">@successMessage</div>
        }
    </section>

    @* Scanned Items List *@
    @if (scannedTireStacks.Count > 0)
    {
        <div class="scanned-section" aria-labelledby="scanned-items-heading">
            <div class="scanned-header">
                <h2 id="scanned-items-heading">
                    <span class="scan-count">@scannedTireStacks.Count</span>
                    Reifenstapel zum Abholen
                </h2>
                <button class="btn btn-sm btn-outline-danger" @onclick="ClearAllScanned">
                    Alle entfernen
                </button>
            </div>

            <div class="scanned-summary" role="complementary">
                <div class="summary-item">
                    <span class="summary-value">@scannedTireStacks.Count</span>
                    <span class="summary-label">Stapel</span>
                </div>
                <div class="summary-item">
                    <span class="summary-value">@(scannedTireStacks.Count * TireStack.TiresPerStack)</span>
                    <span class="summary-label">Reifen gesamt</span>
                </div>
                <div class="summary-item">
                    <span class="summary-value">@scannedTireStacks.Select(ts => ts.StorageLocation?.Code).Distinct().Count()</span>
                    <span class="summary-label">Lagerplätze</span>
                </div>
            </div>

            <div class="scanned-list" role="list">
                @foreach (var ts in scannedTireStacks)
                {
                    <div class="scanned-item @(ts == lastAddedTireStack ? "highlight" : "")" role="listitem">
                        <div class="scanned-item-header">
                            <div class="scanned-item-main">
                                <span class="ticket-number">@ts.TicketNumber</span>
                                @if (ts.StorageLocation != null)
                                {
                                    <LocationDisplay Code="@ts.StorageLocation.Code" 
                                                     DisplayMode="LocationDisplayMode.Compact" 
                                                     Size="LocationDisplaySize.Small" />
                                }
                                else
                                {
                                    <span class="location-badge">📍 -</span>
                                }
                            </div>
                            <button class="btn-remove" @onclick="() => RemoveScannedItem(ts)" title="Entfernen" aria-label="Entfernen von @ts.TicketNumber">✕</button>
                        </div>
                        
                        <div class="scanned-item-body">
                            <div class="scanned-customer">
                                @if (ts.Customer != null)
                                {
                                    <span class="customer-name">@ts.Customer.FullName</span>
                                    @if (ts.Vehicle != null)
                                    {
                                        <span class="vehicle-info">@ts.Vehicle.ShortName</span>
                                    }
                                }
                                else if (ts.CatalogItem != null)
                                {
                                    <span class="customer-name inventory">📦 @ts.CatalogItem.Name</span>
                                }
                                else
                                {
                                    <span class="customer-name inventory">📦 Lagerbestand</span>
                                }
                            </div>
                            
                            <div class="scanned-details">
                                <span class="tire-count">1 Stapel (@TireStack.TiresPerStack Reifen)</span>
                                <span class="tire-season">
                                    @(ts.Season == TireSeason.Sommer ? "☀️" : ts.Season == TireSeason.Winter ? "❄️" : "🔄")
                                </span>
                                @if (!string.IsNullOrEmpty(ts.TireSize))
                                {
                                    <span class="tire-size">@ts.TireSize</span>
                                }
                                @if (ts.WithRims)
                                {
                                    <span class="with-rims">mit Felgen</span>
                                }
                            </div>

                            @if (!string.IsNullOrEmpty(ts.TireBrand))
                            {
                                <div class="scanned-brand">
                                    @ts.TireBrand @ts.TireModel
                                </div>
                            }

                            <div class="scanned-meta">
                                <span class="stored-date">Eingelagert: @ts.StoredAt.ToLocalTime().ToString("dd.MM.yyyy")</span>
                                <span class="days-stored">(@ts.DaysStored Tage)</span>
                            </div>
                        </div>
                    </div>
                }
            </div>

            <div class="scanned-actions">
                <button class="btn btn-primary btn-lg w-100" 
                        @onclick="ProcessBatchPickup" 
                        disabled="@(isProcessing || scannedTireStacks.Count == 0)">
                    @if (isProcessing)
                    {
                        <span class="spinner"></span>
                    }
                    <span>@scannedTireStacks.Count Stapel abholen (@(scannedTireStacks.Count * TireStack.TiresPerStack) Reifen)</span>
                </button>
            </div>
        </div>
    }

    @* Tire Swap Panel *@
    @if (swapOutgoing != null)
    {
        <section class="swap-panel" aria-labelledby="swap-heading">
            <header class="swap-header">
                <h2 id="swap-heading"><span aria-hidden="true">🔄</span> Reifenwechsel</h2>
                <button type="button" class="btn btn-sm btn-outline" @onclick="CancelSwap" disabled="@isProcessing">Abbrechen</button>
            </header>

            <div class="swap-columns">
                @* Outgoing *@
                <div class="swap-box outgoing">
                    <h3 class="swap-box-title"><span aria-hidden="true">⬆️</span> Herausgabe (wird montiert)</h3>
                    <dl class="swap-rows">
                        <div class="swap-row"><dt>Ticket</dt><dd class="mono">@swapOutgoing.TicketNumber</dd></div>
                        <div class="swap-row"><dt>Kunde</dt><dd>@swapOutgoing.Customer?.FullName</dd></div>
                        @if (swapOutgoing.Vehicle != null)
                        {
                            <div class="swap-row"><dt>Fahrzeug</dt><dd>@swapOutgoing.Vehicle.Make @swapOutgoing.Vehicle.Model</dd></div>
                        }
                        <div class="swap-row"><dt>Saison</dt><dd>@SeasonLabel(swapOutgoing.Season)</dd></div>
                        <div class="swap-row"><dt>Größe</dt><dd class="mono">@(swapOutgoing.TireSize ?? "-")</dd></div>
                        <div class="swap-row"><dt>Marke / Modell</dt><dd>@(string.IsNullOrWhiteSpace(swapOutgoing.TireBrand) && string.IsNullOrWhiteSpace(swapOutgoing.TireModel) ? "-" : $"{swapOutgoing.TireBrand} {swapOutgoing.TireModel}".Trim())</dd></div>
                        <div class="swap-row"><dt>Lagerplatz</dt><dd>
                            @if (swapOutgoing.StorageLocation != null)
                            {
                                <LocationDisplay Code="@swapOutgoing.StorageLocation.Code" DisplayMode="LocationDisplayMode.Compact" Size="LocationDisplaySize.Small" />
                            }
                            else
                            {
                                <span>-</span>
                            }
                        </dd></div>
                    </dl>
                </div>

                @* Incoming *@
                <div class="swap-box incoming">
                    <h3 class="swap-box-title"><span aria-hidden="true">⬇️</span> Einlagerung (kommt vom Fahrzeug)</h3>

                    <div class="swap-tabs" role="tablist">
                        <button type="button" class="swap-tab @(swapUseHistory ? "active" : "")" role="tab" aria-selected="@swapUseHistory"
                                @onclick="() => swapUseHistory = true" disabled="@(swapHistory.Count == 0)">
                            Aus Historie (@swapHistory.Count)
                        </button>
                        <button type="button" class="swap-tab @(!swapUseHistory ? "active" : "")" role="tab" aria-selected="@(!swapUseHistory)"
                                @onclick="() => swapUseHistory = false">
                            Neu erfassen
                        </button>
                    </div>

                    @if (swapUseHistory)
                    {
                        <div class="history-list" role="list">
                            @foreach (var h in swapHistory)
                            {
                                var isSameSeason = h.Season == swapOutgoing.Season;
                                <button type="button" class="history-item @(swapSelectedHistory?.Id == h.Id ? "selected" : "") @(isSameSeason ? "same-season" : "")"
                                        role="listitem" @onclick="() => swapSelectedHistory = h">
                                    <span class="history-season">@SeasonIcon(h.Season)</span>
                                    <span class="history-main">
                                        <span class="mono">@h.TicketNumber</span>
                                        <span class="history-detail">@(h.TireSize ?? "-") @(string.IsNullOrWhiteSpace(h.TireBrand) ? "" : $"| {h.TireBrand} {h.TireModel}".Trim()) @(h.WithRims ? "| mit Felgen" : "")</span>
                                        <span class="history-meta">@h.StatusText @(h.PickedUpAt.HasValue ? $"seit {h.PickedUpAt.Value.ToLocalTime():dd.MM.yyyy}" : "")</span>
                                    </span>
                                    @if (isSameSeason)
                                    {
                                        <span class="history-warn" title="Gleiche Saison wie Herausgabe">⚠️</span>
                                    }
                                </button>
                            }
                        </div>
                    }
                    else
                    {
                        <div class="form-grid">
                            <div class="form-group">
                                <label for="swap-season">Saison</label>
                                <select id="swap-season" class="form-control" @bind="swapNew.Season">
                                    <option value="@TireSeason.Sommer">☀️ Sommer</option>
                                    <option value="@TireSeason.Winter">❄️ Winter</option>
                                    <option value="@TireSeason.Allrad">🔄 Allrad</option>
                                </select>
                            </div>
                            <div class="form-group">
                                <label for="swap-size">Reifengröße</label>
                                <input id="swap-size" class="form-control" @bind="swapNew.TireSize" placeholder="z.B. 225/45R17" />
                            </div>
                            <div class="form-group">
                                <label for="swap-brand">Marke</label>
                                <input id="swap-brand" class="form-control" @bind="swapNew.TireBrand" placeholder="z.B. Michelin" />
                            </div>
                            <div class="form-group">
                                <label for="swap-model">Modell</label>
                                <input id="swap-model" class="form-control" @bind="swapNew.TireModel" placeholder="z.B. Pilot Sport 4" />
                            </div>
                            <div class="form-group">
                                <label for="swap-rims">Felgen</label>
                                <select id="swap-rims" class="form-control" @bind="swapNew.WithRims">
                                    <option value="true">Mit Felgen</option>
                                    <option value="false">Ohne Felgen</option>
                                </select>
                            </div>
                            <div class="form-group">
                                <label for="swap-condition">Zustand</label>
                                <select id="swap-condition" class="form-control" @bind="swapNew.Condition">
                                    <option value="@TireCondition.Excellent">Sehr gut</option>
                                    <option value="@TireCondition.Good">Gut</option>
                                    <option value="@TireCondition.Fair">Ausreichend</option>
                                    <option value="@TireCondition.Poor">Mangelhaft</option>
                                    <option value="@TireCondition.Critical">Kritisch</option>
                                </select>
                            </div>
                            <div class="form-group form-group-wide">
                                <label for="swap-notes">Notizen</label>
                                <textarea id="swap-notes" class="form-control" rows="2" @bind="swapNew.Notes"></textarea>
                            </div>
                        </div>
                    }
                </div>
            </div>

            @* Target location *@
            <div class="swap-location">
                <span class="swap-location-label">Lagerplatz für Einlagerung:</span>
                @if (swapTargetLocation != null)
                {
                    <LocationDisplay Code="@swapTargetLocation.Code" DisplayMode="LocationDisplayMode.Compact" Size="LocationDisplaySize.Small" />
                    @if (swapTargetLocation.Id == swapOutgoing.StorageLocationId)
                    {
                        <span class="swap-location-hint">(frei werdender Platz)</span>
                    }
                    else
                    {
                        <button type="button" class="btn btn-sm btn-outline" @onclick="ResetTargetLocation">Zurück zum alten Platz</button>
                    }
                }
                else
                {
                    <span class="swap-location-hint">Kein Lagerplatz gewählt</span>
                }
                <button type="button" class="btn btn-sm btn-outline" @onclick="() => showLocationPicker = true">
                    <span aria-hidden="true">▦</span> Anderen Platz wählen
                </button>
            </div>

            <div class="swap-actions">
                <button type="button" class="btn btn-primary btn-lg w-100" @onclick="ProcessSwap" disabled="@(isProcessing || !CanSwap)">
                    @if (isProcessing)
                    {
                        <span class="spinner"></span>
                    }
                    <span>Reifenwechsel durchführen</span>
                </button>
            </div>
        </section>
    }

    @* Search Results *@
    @if (searchResults.Count > 0)
    {
        <div class="results-section" aria-labelledby="search-results-heading">
            <h2 id="search-results-heading" class="results-count">
                @searchResults.Count Ergebnis(se)
            </h2>
            
            <div class="tireset-list" role="list">
                @foreach (var ts in searchResults)
                {
                    var isAlreadyScanned = scannedTireStacks.Any(s => s.Id == ts.Id);
                    <div class="tireset-card @(isAlreadyScanned ? "already-scanned" : "")" 
                         @onclick="() => OnResultClicked(ts)" role="listitem">
                        <div class="tireset-header">
                            <span class="ticket-number">@ts.TicketNumber</span>
                            <span class="status-badge @ts.Status.ToString().ToLower()">
                                @if (isAlreadyScanned)
                                {
                                    <span>✓ Ausgewählt</span>
                                }
                                else
                                {
                                    @ts.StatusText
                                }
                            </span>
                        </div>
                        <div class="tireset-body">
                            <div class="customer-info">
                                @if (ts.Customer != null)
                                {
                                    <span class="customer-name">@ts.Customer.FullName</span>
                                    @if (ts.Vehicle != null)
                                    {
                                        <span class="vehicle-info">@ts.Vehicle.ShortName</span>
                                    }
                                }
                                else
                                {
                                    <span class="customer-name">📦 @(ts.CatalogItem?.Name ?? "Lagerbestand")</span>
                                }
                            </div>
                            <div class="tire-info">
                                <span class="tire-count">1 Stapel (@TireStack.TiresPerStack Reifen)</span>
                                <span class="tire-details">@ts.Season @(ts.TireSize != null ? $"| {ts.TireSize}" : "")</span>
                            </div>
                            <div class="location-info">
                                @if (ts.StorageLocation != null)
                                {
                                    <LocationDisplay Code="@ts.StorageLocation.Code" 
                                                     DisplayMode="LocationDisplayMode.Full" 
                                                     Size="LocationDisplaySize.Small" />
                                }
                                else
                                {
                                    <span class="location">📍 Kein Lagerplatz</span>
                                }
                                <span class="stored-date">Seit @ts.StoredAt.ToLocalTime().ToString("dd.MM.yyyy")</span>
                            </div>
                        </div>
                    </div>
                }
            </div>
        </div>
    }

    @* Storage location picker (rack view) for swap *@
    @if (swapOutgoing != null)
    {
        <StorageLocationPickerModal @bind-IsOpen="showLocationPicker"
                                    SelectedLocationId="@swapTargetLocation?.Id"
                                    HighlightLocationId="@swapOutgoing.StorageLocationId"
                                    Subtitle="@($"Einlagerung für {swapOutgoing.Customer?.FullName} – {SeasonLabel(swapUseHistory ? (swapSelectedHistory?.Season ?? swapNew.Season) : swapNew.Season)}")"
                                    OnSelected="OnTargetLocationSelected" />
    }

    @* Action Chooser Modal *@
    @if (actionCandidate != null)
    {
        <div class="success-overlay" @onclick="CloseActionChooser">
            <div class="success-modal action-modal" @onclick:stopPropagation="true" role="dialog" aria-modal="true" aria-labelledby="action-title">
                <h2 id="action-title">Aktion wählen</h2>
                <p class="action-subject">
                    <strong>@actionCandidate.Customer?.FullName</strong>
                    @if (actionCandidate.Vehicle != null)
                    {
                        <span class="vehicle-info">@actionCandidate.Vehicle.Make @actionCandidate.Vehicle.Model</span>
                    }
                    <br />
                    <span class="mono">@actionCandidate.TicketNumber</span> · @SeasonLabel(actionCandidate.Season) @(actionCandidate.TireSize != null ? $"· {actionCandidate.TireSize}" : "")
                </p>
                <div class="action-buttons">
                    <button type="button" class="action-btn" @onclick="ChoosePickup">
                        <span class="action-icon" aria-hidden="true">📤</span>
                        <span class="action-label">Abholen</span>
                        <span class="action-desc">Kunde nimmt die Reifen mit</span>
                    </button>
                    <button type="button" class="action-btn swap" @onclick="ChooseSwap">
                        <span class="action-icon" aria-hidden="true">🔄</span>
                        <span class="action-label">Reifenwechsel</span>
                        <span class="action-desc">Satz montieren, anderen Satz einlagern</span>
                    </button>
                </div>
                <button type="button" class="btn btn-outline" @onclick="CloseActionChooser">Abbrechen</button>
            </div>
        </div>
    }

    @* Swap Success Modal *@
    @if (swapResult != null)
    {
        <div class="success-overlay" @onclick="CloseSwapSuccess">
            <div class="success-modal" @onclick:stopPropagation="true">
                <div class="success-icon">✓</div>
                <h2>Reifenwechsel erfolgreich!</h2>
                <div class="pickup-list" role="list">
                    <div class="pickup-item" role="listitem">
                        <span class="ticket">⬆️ @swapResult.Outgoing.TicketNumber</span>
                        <span class="info">@SeasonLabel(swapResult.Outgoing.Season) montiert</span>
                    </div>
                    <div class="pickup-item" role="listitem">
                        <span class="ticket">⬇️ @swapResult.Incoming.TicketNumber</span>
                        <span class="info">@SeasonLabel(swapResult.Incoming.Season) eingelagert auf <strong>@swapResult.NewLocationCode</strong></span>
                    </div>
                </div>
                @if (swapResult.FreedLocationCode != null && swapResult.FreedLocationCode != swapResult.NewLocationCode)
                {
                    <p class="success-detail">Lagerplatz <strong>@swapResult.FreedLocationCode</strong> ist wieder frei.</p>
                }
                <button class="btn btn-primary" @onclick="CloseSwapSuccess">OK</button>
            </div>
        </div>
    }

    @* Success Modal *@
    @if (showSuccess)
    {
        <div class="success-overlay" @onclick="CloseSuccess">
            <div class="success-modal" @onclick:stopPropagation="true">
                <div class="success-icon">✓</div>
                <h2>Abholung erfolgreich!</h2>
                
                @if (pickedUpTireStacks.Count == 1)
                {
                    <p><strong>@pickedUpTireStacks[0].TicketNumber</strong> wurde abgeholt.</p>
                    <p class="pickup-detail">1 Stapel (@TireStack.TiresPerStack Reifen) abgeholt</p>
                }
                else
                {
                    <p><strong>@pickedUpTireStacks.Count Reifenstapel</strong> wurden abgeholt.</p>
                    <p class="pickup-detail">@(pickedUpTireStacks.Count * TireStack.TiresPerStack) Reifen insgesamt</p>
                    
                    <div class="pickup-list" role="list">
                        @foreach (var ts in pickedUpTireStacks)
                        {
                            <div class="pickup-item" role="listitem">
                                <span class="ticket">@ts.TicketNumber</span>
                                <span class="info">1 Stapel | @(ts.Customer?.FullName ?? ts.CatalogItem?.Name ?? "Lagerbestand")</span>
                            </div>
                        }
                    </div>
                }
                
                <p class="success-detail">
                    @if (freedLocations.Count == 1)
                    {
                        <span>Lagerplatz <strong>@freedLocations[0]</strong> ist wieder frei.</span>
                    }
                    else if (freedLocations.Count > 1)
                    {
                        <span><strong>@freedLocations.Count Lagerplätze</strong> sind wieder frei.</span>
                    }
                </p>
                
                <button class="btn btn-primary" @onclick="CloseSuccess">OK</button>
            </div>
        </div>
    }
</main>
}

@code {
    private bool isProcessing;
    private bool showSuccess;
    private string searchTerm = "";
    private string? errorMessage;
    private string? successMessage;

    private List<TireStack> searchResults = new();
    private List<TireStack> scannedTireStacks = new();
    private List<TireStack> pickedUpTireStacks = new();
    private List<string> freedLocations = new();
    private TireStack? lastAddedTireStack;
    private CancellationTokenSource? _searchDebounceCts;
    private readonly SemaphoreSlim _searchLock = new(1, 1);

    // Action chooser / swap flow
    private TireStack? actionCandidate;
    private TireStack? swapOutgoing;
    private List<TireStack> swapHistory = new();
    private TireStack? swapSelectedHistory;
    private bool swapUseHistory;
    private TireStack swapNew = new();
    private bool showLocationPicker;
    private StorageLocation? swapTargetLocation;
    private Guid? swapTargetLocationId => swapTargetLocation?.Id;
    private SwapResult? swapResult;

    private bool CanSwap => swapOutgoing != null && (swapUseHistory ? swapSelectedHistory != null : !string.IsNullOrWhiteSpace(swapNew.TireSize));

    [SupplyParameterFromQuery(Name = "stackId")]
    public Guid? PreselectedStackId { get; set; }

    protected override async Task OnInitializedAsync()
    {
        if (!PreselectedStackId.HasValue || !UserSession.IsWorkerOrAdmin) return;

        try
        {
            var stack = await TireStackService.GetByIdAsync(PreselectedStackId.Value);
            if (stack == null)
            {
                errorMessage = "Der gewählte Reifenstapel wurde nicht gefunden.";
                return;
            }

            searchResults = new List<TireStack> { stack };
            OnResultClicked(stack);
        }
        catch (Exception ex)
        {
            errorMessage = $"Reifenstapel konnte nicht geladen werden: {ex.Message}";
        }
    }

    private static string SeasonIcon(TireSeason s) => s == TireSeason.Sommer ? "☀️" : s == TireSeason.Winter ? "❄️" : "🔄";
    private static string SeasonLabel(TireSeason s) => s == TireSeason.Sommer ? "☀️ Sommer" : s == TireSeason.Winter ? "❄️ Winter" : "🔄 Allrad";

    private void OnResultClicked(TireStack ts)
    {
        if (ts.Status != TireStackStatus.Stored)
        {
            errorMessage = $"'{ts.TicketNumber}' ist nicht eingelagert";
            return;
        }

        // Inventory stacks and already selected stacks toggle directly
        if (ts.IsInventory || scannedTireStacks.Any(s => s.Id == ts.Id))
        {
            AddToScannedList(ts);
            return;
        }

        actionCandidate = ts;
        errorMessage = null;
    }

    private void CloseActionChooser() => actionCandidate = null;

    private void ChoosePickup()
    {
        if (actionCandidate == null) return;
        AddToScannedList(actionCandidate);
        actionCandidate = null;
    }

    private async Task ChooseSwap()
    {
        if (actionCandidate == null) return;
        var ts = actionCandidate;
        actionCandidate = null;
        await StartSwap(ts);
    }

    private async Task StartSwap(TireStack outgoing)
    {
        swapOutgoing = outgoing;
        swapResult = null;
        showLocationPicker = false;
        swapTargetLocation = outgoing.StorageLocation;
        swapSelectedHistory = null;
        errorMessage = null;
        successMessage = null;

        var oppositeSeason = outgoing.Season == TireSeason.Sommer ? TireSeason.Winter
            : outgoing.Season == TireSeason.Winter ? TireSeason.Sommer
            : TireSeason.Allrad;

        swapNew = new TireStack
        {
            Season = oppositeSeason,
            TireSize = outgoing.Vehicle?.TireSize ?? outgoing.TireSize,
            WithRims = outgoing.WithRims,
            Condition = TireCondition.Good,
            CustomerId = outgoing.CustomerId,
            VehicleId = outgoing.VehicleId
        };

        await _searchLock.WaitAsync();
        try
        {
            var history = outgoing.CustomerId.HasValue
                ? await TireStackService.GetByCustomerAsync(outgoing.CustomerId.Value)
                : new List<TireStack>();

            swapHistory = history
                .Where(h => h.Id != outgoing.Id && (h.Status == TireStackStatus.OnVehicle || h.Status == TireStackStatus.PickedUp))
                .OrderBy(h => h.Season == outgoing.Season)
                .ThenByDescending(h => h.PickedUpAt)
                .ToList();
        }
        catch (Exception ex)
        {
            swapHistory = new();
            errorMessage = $"Historie konnte nicht geladen werden: {ex.Message}";
        }
        finally
        {
            _searchLock.Release();
        }

        swapUseHistory = swapHistory.Count > 0;
        swapSelectedHistory = swapHistory.FirstOrDefault(h => h.Season != outgoing.Season) ?? swapHistory.FirstOrDefault();
    }

    private void OnTargetLocationSelected(StorageLocation loc)
    {
        swapTargetLocation = loc;
    }

    private void ResetTargetLocation()
    {
        swapTargetLocation = swapOutgoing?.StorageLocation;
    }

    private void CancelSwap()
    {
        swapOutgoing = null;
        swapHistory.Clear();
        swapSelectedHistory = null;
        showLocationPicker = false;
        swapTargetLocation = null;
    }

    private async Task ProcessSwap()
    {
        if (swapOutgoing == null || !CanSwap) return;

        isProcessing = true;
        errorMessage = null;
        StateHasChanged();

        await _searchLock.WaitAsync();
        try
        {
            var incoming = swapUseHistory
                ? new TireStack
                {
                    Id = swapSelectedHistory!.Id,
                    Condition = swapSelectedHistory.Condition,
                    Notes = swapSelectedHistory.Notes,
                    VehicleId = swapOutgoing.VehicleId
                }
                : swapNew;

            var targetLocation = swapTargetLocationId == swapOutgoing.StorageLocationId ? null : swapTargetLocationId;

            swapResult = await TireStackService.SwapAsync(
                swapOutgoing.Id,
                incoming,
                targetLocation,
                UserSession.CurrentUser?.Id);

            CancelSwap();
            searchResults.Clear();
            searchTerm = "";
        }
        catch (Exception ex)
        {
            errorMessage = $"Fehler beim Reifenwechsel: {ex.Message}";
        }
        finally
        {
            _searchLock.Release();
            isProcessing = false;
        }
    }

    private void CloseSwapSuccess() => swapResult = null;

    private async Task SearchTireStacks()
    {
        if (string.IsNullOrWhiteSpace(searchTerm) || searchTerm.Length < 2)
        {
            searchResults.Clear();
            return;
        }

        // Debounce: cancel previous pending search, wait briefly for typing to settle
        _searchDebounceCts?.Cancel();
        _searchDebounceCts?.Dispose();
        var cts = new CancellationTokenSource();
        _searchDebounceCts = cts;

        try
        {
            await Task.Delay(300, cts.Token);
        }
        catch (TaskCanceledException)
        {
            return;
        }

        // Serialize DB access: scoped DbContext must not be used concurrently
        await _searchLock.WaitAsync();
        try
        {
            if (cts.IsCancellationRequested) return;

            searchResults = await TireStackService.SearchAsync(searchTerm);
            errorMessage = null;
        }
        catch (Exception ex)
        {
            errorMessage = $"Suchfehler: {ex.Message}";
        }
        finally
        {
            _searchLock.Release();
        }
    }

    private void AddToScannedList(TireStack tireStack)
    {
        if (tireStack.Status != TireStackStatus.Stored)
        {
            errorMessage = $"'{tireStack.TicketNumber}' ist nicht eingelagert";
            return;
        }

        if (scannedTireStacks.Any(ts => ts.Id == tireStack.Id))
        {
            // Remove if already in list (toggle behavior)
            scannedTireStacks.RemoveAll(ts => ts.Id == tireStack.Id);
            if (lastAddedTireStack?.Id == tireStack.Id)
            {
                lastAddedTireStack = null;
            }
        }
        else
        {
            scannedTireStacks.Add(tireStack);
            lastAddedTireStack = tireStack;
        }
        
        errorMessage = null;
    }

    private void RemoveScannedItem(TireStack tireStack)
    {
        scannedTireStacks.Remove(tireStack);
        if (lastAddedTireStack?.Id == tireStack.Id)
        {
            lastAddedTireStack = null;
        }
    }

    private void ClearAllScanned()
    {
        scannedTireStacks.Clear();
        lastAddedTireStack = null;
        errorMessage = null;
        successMessage = null;
    }

    private async Task ProcessBatchPickup()
    {
        if (scannedTireStacks.Count == 0) return;

        isProcessing = true;
        errorMessage = null;
        StateHasChanged();

        try
        {
            pickedUpTireStacks.Clear();
            freedLocations.Clear();

            foreach (var tireStack in scannedTireStacks)
            {
                var locationCode = tireStack.StorageLocation?.Code;
                if (!string.IsNullOrEmpty(locationCode) && !freedLocations.Contains(locationCode))
                {
                    freedLocations.Add(locationCode);
                }
            }

            var pickedUp = await TireStackService.PickupBatchAsync(
                scannedTireStacks.Select(ts => ts.Id),
                UserSession.CurrentUser?.Id);

            pickedUpTireStacks.AddRange(pickedUp);

            showSuccess = true;
            scannedTireStacks.Clear();
            searchResults.Clear();
            searchTerm = "";
            lastAddedTireStack = null;
        }
        catch (Exception ex)
        {
            errorMessage = $"Fehler bei Abholung: {ex.Message}";
            pickedUpTireStacks.Clear();
            freedLocations.Clear();
        }
        finally
        {
            isProcessing = false;
        }
    }

    private void CloseSuccess()
    {
        showSuccess = false;
        pickedUpTireStacks.Clear();
        freedLocations.Clear();
    }

    public ValueTask DisposeAsync()
    {
        _searchDebounceCts?.Cancel();
        _searchDebounceCts?.Dispose();
        _searchLock.Dispose();
        return ValueTask.CompletedTask;
    }
}