<?php

namespace App\Filament\Pages;

use App\Filament\Resources\BulkOperationRunResource;
use App\Filament\Resources\FindingResource;
use App\Filament\Resources\InventorySyncRunResource;
use App\Jobs\GenerateDriftFindingsJob;
use App\Models\BulkOperationRun;
use App\Models\Finding;
use App\Models\InventorySyncRun;
use App\Models\Tenant;
use App\Models\User;
use App\Services\BulkOperationService;
use App\Services\Drift\DriftRunSelector;
use App\Support\RunIdempotency;
use BackedEnum;
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 = 'Drift';

    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 $bulkOperationRunId = 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 = InventorySyncRun::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('status', InventorySyncRun::STATUS_SUCCESS)
            ->whereNotNull('finished_at')
            ->orderByDesc('finished_at')
            ->first();

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

            return;
        }

        $scopeKey = (string) $latestSuccessful->selection_hash;
        $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->finished_at?->toDateTimeString();
        $this->currentFinishedAt = $current->finished_at?->toDateTimeString();

        $idempotencyKey = RunIdempotency::buildKey(
            tenantId: (int) $tenant->getKey(),
            operationType: 'drift.generate',
            targetId: $scopeKey,
            context: [
                'scope_key' => $scopeKey,
                'baseline_run_id' => (int) $baseline->getKey(),
                'current_run_id' => (int) $current->getKey(),
            ],
        );

        $exists = Finding::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('finding_type', Finding::FINDING_TYPE_DRIFT)
            ->where('scope_key', $scopeKey)
            ->where('baseline_run_id', $baseline->getKey())
            ->where('current_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_run_id', $baseline->getKey())
                ->where('current_run_id', $current->getKey())
                ->where('status', Finding::STATUS_NEW)
                ->count();

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

            return;
        }

        $latestRun = BulkOperationRun::query()
            ->where('tenant_id', $tenant->getKey())
            ->where('idempotency_key', $idempotencyKey)
            ->latest('id')
            ->first();

        $activeRun = RunIdempotency::findActiveBulkOperationRun((int) $tenant->getKey(), $idempotencyKey);
        if ($activeRun instanceof BulkOperationRun) {
            $this->state = 'generating';
            $this->bulkOperationRunId = (int) $activeRun->getKey();

            return;
        }

        if ($latestRun instanceof BulkOperationRun && $latestRun->status === 'completed') {
            $this->state = 'ready';
            $this->bulkOperationRunId = (int) $latestRun->getKey();

            $newCount = (int) Finding::query()
                ->where('tenant_id', $tenant->getKey())
                ->where('finding_type', Finding::FINDING_TYPE_DRIFT)
                ->where('scope_key', $scopeKey)
                ->where('baseline_run_id', $baseline->getKey())
                ->where('current_run_id', $current->getKey())
                ->where('status', Finding::STATUS_NEW)
                ->count();

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

            if ($newCount === 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.';
            }

            return;
        }

        if ($latestRun instanceof BulkOperationRun && in_array($latestRun->status, ['failed', 'aborted'], true)) {
            $this->state = 'error';
            $this->message = 'Drift generation failed for this comparison. See the run for details.';
            $this->bulkOperationRunId = (int) $latestRun->getKey();

            return;
        }

        $bulkOperationService = app(BulkOperationService::class);
        $run = $bulkOperationService->createRun(
            tenant: $tenant,
            user: $user,
            resource: 'drift',
            action: 'generate',
            itemIds: [$scopeKey],
            totalItems: 1,
        );

        $run->update(['idempotency_key' => $idempotencyKey]);

        $this->state = 'generating';
        $this->bulkOperationRunId = (int) $run->getKey();

        GenerateDriftFindingsJob::dispatch(
            tenantId: (int) $tenant->getKey(),
            userId: (int) $user->getKey(),
            baselineRunId: (int) $baseline->getKey(),
            currentRunId: (int) $current->getKey(),
            scopeKey: $scopeKey,
            bulkOperationRunId: (int) $run->getKey(),
        );
    }

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

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

        return InventorySyncRunResource::getUrl('view', ['record' => $this->baselineRunId], tenant: Tenant::current());
    }

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

        return InventorySyncRunResource::getUrl('view', ['record' => $this->currentRunId], tenant: Tenant::current());
    }

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

        return BulkOperationRunResource::getUrl('view', ['record' => $this->bulkOperationRunId], tenant: Tenant::current());
    }
}