<?php

namespace Modules\Maintenance\Services;

use App\Business;
use Modules\Maintenance\Models\Equipment;
use Modules\Maintenance\Models\FailureReport;
use Modules\Maintenance\Models\Overhaul;
use Modules\Maintenance\Models\PreventiveSchedule;
use Modules\Maintenance\Models\RebuildProject;
use Modules\Maintenance\Models\SparePart;
use Modules\Maintenance\Models\WorkOrder;
use Carbon\Carbon;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Modules\Maintenance\Utils\MaintenanceUtil;

class MaintenanceDashboardService
{
    public function __construct(
        protected MaintenanceUtil $maintenanceUtil
    ) {}
    public function getStats(Business $business): array
    {
        $bid = $business->id;
        $today = Carbon::today();
        $monthStart = Carbon::now()->startOfMonth();

        $totalEquipment = Equipment::where('business_id', $bid)->count();
        $activeEquipment = Equipment::where('business_id', $bid)->where('status', 'active')->count();
        $underOverhaul = Equipment::where('business_id', $bid)->where('status', 'under_overhaul')->count();

        $upcomingOverhauls = Overhaul::where('business_id', $bid)
            ->whereIn('status', ['planned', 'approved', 'waiting'])
            ->where('start_date', '>=', $today)
            ->where('start_date', '<=', $today->copy()->addDays(30))
            ->count();

        $delayedOverhauls = Overhaul::where('business_id', $bid)
            ->whereIn('status', ['planned', 'approved', 'waiting', 'in_progress'])
            ->where('end_date', '<', $today)
            ->count();

        $todayTasks = WorkOrder::where('business_id', $bid)
            ->whereIn('status', ['open', 'in_progress'])
            ->whereDate('scheduled_at', $today)
            ->count();

        $monthlyCosts = (int) WorkOrder::where('business_id', $bid)
            ->where('status', 'completed')
            ->where('completed_at', '>=', $monthStart)
            ->sum('cost')
            + (int) Overhaul::where('business_id', $bid)
                ->where('status', 'completed')
                ->where('updated_at', '>=', $monthStart)
                ->sum('actual_cost');

        $avgHealth = (float) Equipment::where('business_id', $bid)->avg('health_percentage');

        $mttr = $this->calculateMttr($bid);
        $mtbf = $this->calculateMtbf($bid);

        $maintenanceStats = [
            'preventive_due' => PreventiveSchedule::where('business_id', $bid)
                ->where('is_active', true)
                ->where('next_due_at', '<=', now()->addDays(7))
                ->count(),
            'open_work_orders' => WorkOrder::where('business_id', $bid)
                ->whereIn('status', ['open', 'in_progress'])
                ->count(),
            'completed_this_month' => WorkOrder::where('business_id', $bid)
                ->where('status', 'completed')
                ->where('completed_at', '>=', $monthStart)
                ->count(),
            'low_stock_parts' => SparePart::where('business_id', $bid)
                ->whereColumn('quantity', '<=', 'min_stock')
                ->count(),
        ];

        return [
            'equipment' => [
                'total' => $totalEquipment,
                'active' => $activeEquipment,
                'under_overhaul' => $underOverhaul,
                'health_percentage' => round($avgHealth, 1),
            ],
            'overhauls' => [
                'upcoming' => $upcomingOverhauls,
                'delayed' => $delayedOverhauls,
            ],
            'tasks' => [
                'today' => $todayTasks,
            ],
            'costs' => [
                'monthly' => $monthlyCosts,
            ],
            'kpi' => [
                'mttr_hours' => $mttr,
                'mtbf_hours' => $mtbf,
            ],
            'maintenance' => $maintenanceStats,
        ];
    }

    public function getRecentActivities(Business $business, int $limit = 10): array
    {
        if (! Schema::hasTable('maintenance_activity_logs')) {
            return [];
        }

        return DB::table('maintenance_activity_logs')
            ->where('business_id', $business->id)
            ->orderByDesc('created_at')
            ->limit($limit)
            ->get()
            ->toArray();
    }

    public function getCalendarEvents(Business $business, string $start, string $end): array
    {
        $bid = $business->id;
        $events = [];

        $overhauls = Overhaul::where('business_id', $bid)
            ->whereBetween('start_date', [$start, $end])
            ->with('equipment:id,name,code')
            ->get();

        foreach ($overhauls as $o) {
            $events[] = [
                'id' => 'overhaul-'.$o->id,
                'type' => 'overhaul',
                'title' => $o->title,
                'start' => $o->start_date?->toDateString(),
                'end' => $o->end_date?->toDateString(),
                'start_jalali' => $this->maintenanceUtil->formatDate($o->start_date),
                'end_jalali' => $this->maintenanceUtil->formatDate($o->end_date),
                'status' => $o->status,
                'equipment' => $o->equipment?->name,
            ];
        }

        $schedules = PreventiveSchedule::where('business_id', $bid)
            ->where('is_active', true)
            ->whereBetween('next_due_at', [$start, $end])
            ->with('equipment:id,name,code')
            ->get();

        foreach ($schedules as $s) {
            $events[] = [
                'id' => 'pm-'.$s->id,
                'type' => 'preventive',
                'title' => $s->title,
                'start' => $s->next_due_at?->toDateString(),
                'start_jalali' => $this->maintenanceUtil->formatDateTime($s->next_due_at),
                'equipment' => $s->equipment?->name,
            ];
        }

        $workOrders = WorkOrder::where('business_id', $bid)
            ->whereBetween('scheduled_at', [$start, $end])
            ->with('equipment:id,name,code')
            ->get();

        foreach ($workOrders as $w) {
            $events[] = [
                'id' => 'wo-'.$w->id,
                'type' => 'work_order',
                'title' => $w->work_order_number,
                'start' => $w->scheduled_at?->toDateString(),
                'start_jalali' => $this->maintenanceUtil->formatDateTime($w->scheduled_at),
                'status' => $w->status,
                'equipment' => $w->equipment?->name,
            ];
        }

        $rebuilds = RebuildProject::where('business_id', $bid)
            ->whereNotIn('status', ['draft', 'cancelled'])
            ->where(function ($q) use ($start, $end) {
                $q->whereBetween('planned_start_date', [$start, $end])
                    ->orWhereBetween('planned_end_date', [$start, $end]);
            })
            ->get();

        foreach ($rebuilds as $r) {
            $events[] = [
                'id' => 'rebuild-'.$r->id,
                'type' => 'rebuild',
                'title' => $r->title,
                'start' => $r->planned_start_date?->toDateString(),
                'end' => $r->planned_end_date?->toDateString(),
                'start_jalali' => $this->maintenanceUtil->formatDate($r->planned_start_date),
                'end_jalali' => $this->maintenanceUtil->formatDate($r->planned_end_date),
                'status' => $r->status,
            ];
        }

        return $events;
    }

    public function getChartData(Business $business): array
    {
        $bid = $business->id;
        $months = collect(range(5, 0))->map(fn ($i) => Carbon::now()->subMonths($i));

        $costByMonth = $months->map(function ($month) use ($bid) {
            $start = $month->copy()->startOfMonth();
            $end = $month->copy()->endOfMonth();

            return [
                'label' => $this->maintenanceUtil->formatMonthLabel($month),
                'cost' => (int) WorkOrder::where('business_id', $bid)
                    ->where('status', 'completed')
                    ->whereBetween('completed_at', [$start, $end])
                    ->sum('cost'),
            ];
        });

        $statusDistribution = Equipment::where('business_id', $bid)
            ->select('status', DB::raw('count(*) as count'))
            ->groupBy('status')
            ->pluck('count', 'status')
            ->toArray();

        return [
            'monthly_costs' => $costByMonth->values()->toArray(),
            'equipment_by_status' => $statusDistribution,
        ];
    }

    protected function calculateMttr(int $businessId): float
    {
        if (! Schema::hasTable('maintenance_failure_reports')) {
            return 0;
        }

        $avg = FailureReport::where('business_id', $businessId)
            ->where('repair_hours', '>', 0)
            ->avg('repair_hours');

        return round((float) $avg, 2);
    }

    protected function calculateMtbf(int $businessId): float
    {
        if (! Schema::hasTable('maintenance_failure_reports')) {
            return 0;
        }

        $equipmentIds = Equipment::where('business_id', $businessId)->pluck('id');
        if ($equipmentIds->isEmpty()) {
            return 0;
        }

        $failureCount = FailureReport::where('business_id', $businessId)->count();
        if ($failureCount === 0) {
            return 0;
        }

        $totalHours = Equipment::where('business_id', $businessId)->sum('working_hours');

        return round($totalHours / $failureCount, 2);
    }
}