<?php

namespace App\Console\Commands;

use App\Mail\AlertTriggered;
use App\Models\Alert;
use App\Services\AnalyticsQueryService;
use Illuminate\Console\Command;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\Mail;

class CheckAlerts extends Command
{
    protected $signature = 'analytics:check-alerts';

    protected $description = 'Evaluate active alerts and trigger notifications';

    public function handle(): int
    {
        $alerts = Alert::with('website.user')
            ->where('is_active', true)
            ->get();

        $triggered = 0;

        foreach ($alerts as $alert) {
            // Skip if triggered recently (within the period to avoid spam)
            if ($this->wasRecentlyTriggered($alert)) {
                continue;
            }

            $currentValue = $this->getCurrentValue($alert);
            $shouldTrigger = $this->evaluate($alert, $currentValue);

            if ($shouldTrigger) {
                $this->trigger($alert, $currentValue);
                $triggered++;
            }
        }

        $this->info("Checked {$alerts->count()} alerts, triggered {$triggered}.");

        return self::SUCCESS;
    }

    private function getCurrentValue(Alert $alert): float
    {
        $to = Carbon::now();
        $from = $alert->period === 'hourly'
            ? Carbon::now()->subHour()
            : Carbon::today()->startOfDay();

        $service = AnalyticsQueryService::for($alert->website, $from, $to);
        $summary = $service->summary();

        return match ($alert->metric) {
            'page_views' => $summary['page_views'],
            'visitors' => $summary['visitors'],
            'sessions' => $summary['sessions'],
            'bounce_rate' => $summary['bounce_rate'],
            default => 0,
        };
    }

    private function evaluate(Alert $alert, float $currentValue): bool
    {
        return match ($alert->condition) {
            'above' => $currentValue > $alert->threshold,
            'below' => $currentValue < $alert->threshold,
            'change_up' => $this->percentageChange($alert) > $alert->threshold,
            'change_down' => $this->percentageChange($alert) < -$alert->threshold,
            default => false,
        };
    }

    private function percentageChange(Alert $alert): float
    {
        if ($alert->period === 'hourly') {
            // Compare current hour with previous hour
            $currentTo = Carbon::now();
            $currentFrom = Carbon::now()->subHour();
            $prevTo = Carbon::now()->subHour();
            $prevFrom = Carbon::now()->subHours(2);

            $current = $this->getValueForPeriod($alert, $currentFrom, $currentTo);
            $previous = $this->getValueForPeriod($alert, $prevFrom, $prevTo);
        } else {
            // Compare today so far with yesterday same time
            $currentTo = Carbon::now();
            $currentFrom = Carbon::today()->startOfDay();
            $prevTo = Carbon::yesterday()->setTime($currentTo->hour, $currentTo->minute, $currentTo->second);
            $prevFrom = Carbon::yesterday()->startOfDay();

            $current = $this->getValueForPeriod($alert, $currentFrom, $currentTo);
            $previous = $this->getValueForPeriod($alert, $prevFrom, $prevTo);
        }

        if ($previous == 0) {
            return $current > 0 ? 100 : 0;
        }

        return (($current - $previous) / $previous) * 100;
    }

    private function getValueForPeriod(Alert $alert, Carbon $from, Carbon $to): float
    {
        $service = AnalyticsQueryService::for($alert->website, $from, $to);
        $summary = $service->summary();

        return $summary[$alert->metric] ?? 0;
    }

    private function wasRecentlyTriggered(Alert $alert): bool
    {
        if (!$alert->last_triggered_at) {
            return false;
        }

        $cooldown = $alert->period === 'hourly' ? 1 : 24; // hours
        $threshold = Carbon::now()->subHours($cooldown);

        return $alert->last_triggered_at->isAfter($threshold);
    }

    private function trigger(Alert $alert, float $currentValue): void
    {
        $conditionLabel = Alert::$conditions[$alert->condition] ?? $alert->condition;
        $metricLabel = Alert::$metrics[$alert->metric] ?? $alert->metric;

        $message = "{$metricLabel} {$conditionLabel} {$alert->threshold} (current: {$currentValue}) for {$alert->website->name}";

        $notification = $alert->notifications()->create([
            'value' => $currentValue,
            'message' => $message,
        ]);

        $alert->update(['last_triggered_at' => now()]);

        if (in_array($alert->channel, ['email', 'both'])) {
            Mail::to($alert->website->user)->send(new AlertTriggered($alert, $notification));
        }

        $this->line("  → Triggered: {$alert->name} — {$message}");
    }
}