<?php

namespace App\Services;

use App\Models\Deal;
use App\Models\FollowUp;
use App\Models\Lead;
use App\Models\Notification;
use App\Models\NotificationPreference;
use App\Models\SlaBreach;
use App\Models\SlaRule;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Carbon;

class SlaMonitorService
{
    public function __construct(private AutomationDispatcher $automations) {}

    public function run(): int
    {
        $created = 0;
        foreach (SlaRule::where('is_active', true)->where('event', '!=', 'stale_deal')->get() as $rule) {
            foreach ($this->candidates($rule) as [$subject, $baseAt, $assignedTo]) {
                $dueAt = $baseAt->copy()->addMinutes($rule->breach_minutes);
                $status = $dueAt->isPast() ? 'breached' : 'warning';
                $eventKey = "sla:{$rule->id}:".strtolower(class_basename($subject)).":{$subject->getKey()}";
                $breach = SlaBreach::firstOrCreate(['event_key' => $eventKey], [
                    'sla_rule_id' => $rule->id, 'breachable_type' => $subject::class, 'breachable_id' => $subject->getKey(),
                    'assigned_to' => $assignedTo, 'status' => $status, 'due_at' => $dueAt,
                    'warned_at' => now(), 'breached_at' => $status === 'breached' ? now() : null,
                    'details' => ['event' => $rule->event],
                ]);
                if (! $breach->wasRecentlyCreated) {
                    continue;
                }
                $created++;
                $this->notify($breach, $rule->name);
                $this->automations->dispatch('sla_breached', $subject, "sla:{$breach->id}", ['sla_breach_id' => $breach->id, 'status' => $status, 'rule_id' => $rule->id]);
            }
        }

        return $created;
    }

    /** @return iterable<array{Model, Carbon, int|null}> */
    private function candidates(SlaRule $rule): iterable
    {
        if ($rule->event === 'first_contact') {
            foreach (Lead::whereDoesntHave('calls')->where('created_at', '<=', now()->subMinutes($rule->warning_minutes))->limit(500)->get() as $lead) {
                yield [$lead, $lead->created_at, $lead->assigned_to];
            }
        } elseif ($rule->event === 'follow_up') {
            foreach (FollowUp::where('status', 'pending')->where('scheduled_at', '<=', now()->subMinutes($rule->warning_minutes))->limit(500)->get() as $followUp) {
                yield [$followUp, $followUp->scheduled_at, $followUp->user_id];
            }
        } elseif ($rule->event === 'stale_deal') {
            foreach (Deal::whereNotIn('status', ['won', 'lost'])->where(fn ($q) => $q->where('last_activity_at', '<=', now()->subMinutes($rule->warning_minutes))->orWhere(fn ($empty) => $empty->whereNull('last_activity_at')->where('created_at', '<=', now()->subMinutes($rule->warning_minutes))))->limit(500)->get() as $deal) {
                yield [$deal, $deal->last_activity_at ?? $deal->created_at, $deal->owner_id];
            }
        }
    }

    private function notify(SlaBreach $breach, string $ruleName): void
    {
        if (! $breach->assigned_to) {
            return;
        }
        $preference = NotificationPreference::where('user_id', $breach->assigned_to)->where('notification_type', 'sla')->first();
        if ($preference && (! $preference->in_app_enabled || $preference->is_muted)) {
            return;
        }
        Notification::firstOrCreate(['idempotency_key' => "sla-breach:{$breach->id}"], [
            'user_id' => $breach->assigned_to, 'title' => $breach->status === 'breached' ? 'نقض SLA' : 'هشدار SLA',
            'message' => "مهلت قانون «{$ruleName}» نیازمند اقدام است.", 'type' => 'sla',
            'data' => ['url' => '/operations', 'sla_breach_id' => $breach->id],
        ]);
    }
}