<?php

namespace App\Filament\Pages;

use App\Filament\Resources\FindingResource;
use App\Jobs\GenerateDriftFindingsJob;
use App\Models\Finding;
use App\Models\OperationRun;
use App\Models\Tenant;
use App\Models\User;
use App\Services\Auth\CapabilityResolver;
use App\Services\Drift\DriftRunSelector;
use App\Services\OperationRunService;
use App\Services\Operations\BulkSelectionIdentity;
use App\Support\Auth\Capabilities;
use App\Support\OperationRunLinks;
use App\Support\OperationRunOutcome;
use App\Support\OperationRunStatus;
use App\Support\OpsUx\OperationUxPresenter;
use App\Support\OpsUx\OpsUxBrowserEvents;
use BackedEnum;
use Filament\Actions\Action;
use Filament\Notifications\Notification;
use Filament\Pages\Page;
use UnitEnum;

class DriftLanding extends Page
{
    protected static string|BackedEnum|null $navigationIcon = 'heroicon-o-arrows-right-left';

    protected static string|UnitEnum|null $navigationGroup = 'Governance';

    protected static ?string $navigationLabel = 'Drift';

    protected string $view = 'filament.pages.drift-landing';

    public ?string $state = null;

    public ?string $message = null;

    public ?string $scopeKey = null;

    public ?int $baselineRunId = null;

    public ?int $currentRunId = null;

    public ?string $baselineFinishedAt = null;

    public ?string $currentFinishedAt = null;

    public ?int $operationRunId = null;

    /** @var array<string, int>|null */
    public ?array $statusCounts = null;

    public static function canAccess(): bool
    {
        return FindingResource::canAccess();
    }

    public function mount(): void
    {
        $tenant = Tenant::current();

        $user = auth()->user();
        if (! $user instanceof User) {
            abort(403, 'Not allowed');
        }

        $latestSuccessful = OperationRun::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('type', 'inventory_sync')
            ->where('status', OperationRunStatus::Completed->value)
            ->whereIn('outcome', [
                OperationRunOutcome::Succeeded->value,
                OperationRunOutcome::PartiallySucceeded->value,
            ])
            ->whereNotNull('completed_at')
            ->orderByDesc('completed_at')
            ->first();

        if (! $latestSuccessful instanceof OperationRun) {
            $this->state = 'blocked';
            $this->message = 'No successful inventory runs found yet.';

            return;
        }

        $latestContext = is_array($latestSuccessful->context) ? $latestSuccessful->context : [];
        $scopeKey = (string) ($latestContext['selection_hash'] ?? '');

        if ($scopeKey === '') {
            $this->state = 'blocked';
            $this->message = 'No inventory scope key was found on the latest successful inventory run.';

            return;
        }

        $this->scopeKey = $scopeKey;

        $selector = app(DriftRunSelector::class);
        $comparison = $selector->selectBaselineAndCurrent($tenant, $scopeKey);

        if ($comparison === null) {
            $this->state = 'blocked';
            $this->message = 'Need at least 2 successful runs for this scope to calculate drift.';

            return;
        }

        $baseline = $comparison['baseline'];
        $current = $comparison['current'];

        $this->baselineRunId = (int) $baseline->getKey();
        $this->currentRunId = (int) $current->getKey();

        $this->baselineFinishedAt = $baseline->completed_at?->toDateTimeString();
        $this->currentFinishedAt = $current->completed_at?->toDateTimeString();

        $existingOperationRun = OperationRun::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('type', 'drift_generate_findings')
            ->where('context->scope_key', $scopeKey)
            ->where('context->baseline_operation_run_id', (int) $baseline->getKey())
            ->where('context->current_operation_run_id', (int) $current->getKey())
            ->latest('id')
            ->first();

        if ($existingOperationRun instanceof OperationRun) {
            $this->operationRunId = (int) $existingOperationRun->getKey();
        }

        $exists = Finding::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('finding_type', Finding::FINDING_TYPE_DRIFT)
            ->where('scope_key', $scopeKey)
            ->where('baseline_operation_run_id', $baseline->getKey())
            ->where('current_operation_run_id', $current->getKey())
            ->exists();

        if ($exists) {
            $this->state = 'ready';
            $newCount = (int) Finding::query()
                ->where('tenant_id', $tenant->getKey())
                ->where('finding_type', Finding::FINDING_TYPE_DRIFT)
                ->where('scope_key', $scopeKey)
                ->where('baseline_operation_run_id', $baseline->getKey())
                ->where('current_operation_run_id', $current->getKey())
                ->where('status', Finding::STATUS_NEW)
                ->count();

            $this->statusCounts = [Finding::STATUS_NEW => $newCount];

            return;
        }

        $existingOperationRun?->refresh();

        if ($existingOperationRun instanceof OperationRun
            && in_array($existingOperationRun->status, ['queued', 'running'], true)
        ) {
            $this->state = 'generating';
            $this->operationRunId = (int) $existingOperationRun->getKey();

            return;
        }

        if ($existingOperationRun instanceof OperationRun
            && $existingOperationRun->status === 'completed'
        ) {
            $counts = is_array($existingOperationRun->summary_counts ?? null) ? $existingOperationRun->summary_counts : [];
            $created = (int) ($counts['created'] ?? 0);

            if ($existingOperationRun->outcome === 'failed') {
                $this->state = 'error';
                $this->message = 'Drift generation failed for this comparison. See the run for details.';
                $this->operationRunId = (int) $existingOperationRun->getKey();

                return;
            }

            if ($created === 0) {
                $this->state = 'ready';
                $this->statusCounts = [Finding::STATUS_NEW => 0];
                $this->message = 'No drift findings for this comparison. If you changed settings after the current run, run Inventory Sync again to capture a newer snapshot.';
                $this->operationRunId = (int) $existingOperationRun->getKey();

                return;
            }
        }

        /** @var CapabilityResolver $resolver */
        $resolver = app(CapabilityResolver::class);

        if (! $resolver->can($user, $tenant, Capabilities::TENANT_SYNC)) {
            $this->state = 'blocked';
            $this->message = 'You can view existing drift findings and run history, but you do not have permission to generate drift.';

            return;
        }

        /** @var BulkSelectionIdentity $selection */
        $selection = app(BulkSelectionIdentity::class);
        $selectionIdentity = $selection->fromQuery([
            'scope_key' => $scopeKey,
            'baseline_operation_run_id' => (int) $baseline->getKey(),
            'current_operation_run_id' => (int) $current->getKey(),
        ]);

        /** @var OperationRunService $opService */
        $opService = app(OperationRunService::class);

        $opRun = $opService->enqueueBulkOperation(
            tenant: $tenant,
            type: 'drift_generate_findings',
            targetScope: [
                'entra_tenant_id' => (string) ($tenant->tenant_id ?? $tenant->external_id),
            ],
            selectionIdentity: $selectionIdentity,
            dispatcher: function ($operationRun) use ($tenant, $user, $baseline, $current, $scopeKey): void {
                GenerateDriftFindingsJob::dispatch(
                    tenantId: (int) $tenant->getKey(),
                    userId: (int) $user->getKey(),
                    baselineRunId: (int) $baseline->getKey(),
                    currentRunId: (int) $current->getKey(),
                    scopeKey: $scopeKey,
                    operationRun: $operationRun,
                );
            },
            initiator: $user,
            extraContext: [
                'scope_key' => $scopeKey,
                'baseline_operation_run_id' => (int) $baseline->getKey(),
                'current_operation_run_id' => (int) $current->getKey(),
            ],
            emitQueuedNotification: false,
        );

        $this->operationRunId = (int) $opRun->getKey();
        $this->state = 'generating';

        if (! $opRun->wasRecentlyCreated) {
            Notification::make()
                ->title('Drift generation already active')
                ->body('This operation is already queued or running.')
                ->warning()
                ->actions([
                    Action::make('view_run')
                        ->label('View run')
                        ->url(OperationRunLinks::view($opRun, $tenant)),
                ])
                ->send();

            return;
        }

        OpsUxBrowserEvents::dispatchRunEnqueued($this);
        OperationUxPresenter::queuedToast((string) $opRun->type)
            ->actions([
                Action::make('view_run')
                    ->label('View run')
                    ->url(OperationRunLinks::view($opRun, $tenant)),
            ])
            ->send();
    }

    public function getFindingsUrl(): string
    {
        return FindingResource::getUrl('index', tenant: Tenant::current());
    }

    public function getBaselineRunUrl(): ?string
    {
        if (! is_int($this->baselineRunId)) {
            return null;
        }

        return route('admin.operations.view', ['run' => $this->baselineRunId]);
    }

    public function getCurrentRunUrl(): ?string
    {
        if (! is_int($this->currentRunId)) {
            return null;
        }

        return route('admin.operations.view', ['run' => $this->currentRunId]);
    }

    public function getOperationRunUrl(): ?string
    {
        if (! is_int($this->operationRunId)) {
            return null;
        }

        return OperationRunLinks::view($this->operationRunId, Tenant::current());
    }
}