<?php

namespace App\Modules\Analytics\Application;

use App\Modules\Learner\Domain\LearningEvent;
use Illuminate\Support\Facades\DB;

final class AnalyticsProjectionService
{
    private const PROCESSOR = 'daily-metrics';

    private const VERSION = 1;

    public function process(LearningEvent $event): bool
    {
        return DB::transaction(function () use ($event): bool {
            $claimed = DB::table('analytics_event_projections')->insertOrIgnore([
                'id' => (string) str()->ulid(),
                'organization_id' => $event->organization_id,
                'learning_event_id' => $event->getKey(),
                'processor' => self::PROCESSOR,
                'processor_version' => self::VERSION,
                'processed_at' => now(),
                'created_at' => now(),
                'updated_at' => now(),
            ]);
            if ($claimed === 0) {
                return false;
            }

            $this->refreshDate($event->organization_id, $event->occurred_at->toDateString());

            return true;
        });
    }

    public function rebuild(string $organizationId): int
    {
        DB::table('analytics_event_projections')->where('organization_id', $organizationId)->delete();
        DB::table('analytics_daily_metrics')->where('organization_id', $organizationId)->delete();
        $count = 0;
        LearningEvent::query()->where('organization_id', $organizationId)->orderBy('occurred_at')->orderBy('id')->each(function (LearningEvent $event) use (&$count): void {
            if ($this->process($event)) {
                $count++;
            }
        });

        return $count;
    }

    private function refreshDate(string $organizationId, string $date): void
    {
        $events = LearningEvent::query()->where('organization_id', $organizationId)->whereDate('occurred_at', $date)->get();
        $durations = $events->sum(fn (LearningEvent $event) => max(0, min(21600, (int) ($event->payload['durationSeconds'] ?? 0))));
        $assessmentScores = $events->where('event_type', 'assessment.completed')->map(fn (LearningEvent $event) => $event->payload['score'] ?? null)->filter(fn ($score) => is_numeric($score));
        $metrics = [
            'events' => $events->count(),
            'activeLearners' => $events->pluck('learner_id')->unique()->count(),
            'sessions' => $events->pluck('session_id')->filter()->unique()->count(),
            'learningMinutes' => round($durations / 60, 1),
            'coursesOpened' => $events->where('event_type', 'course.opened')->count(),
            'coursesCompleted' => $events->where('event_type', 'course.completed')->count(),
            'lessonsStarted' => $events->where('event_type', 'lesson.started')->count(),
            'lessonsCompleted' => $events->where('event_type', 'lesson.completed')->count(),
            'blocksViewed' => $events->where('event_type', 'block.viewed')->count(),
            'blocksInteracted' => $events->whereIn('event_type', ['block.interacted', 'block.completed'])->count(),
            'videoStarted' => $events->where('event_type', 'video.started')->count(),
            'videoCompleted' => $events->where('event_type', 'video.completed')->count(),
            'assessmentsCompleted' => $assessmentScores->count(),
            'assessmentAverage' => $assessmentScores->isEmpty() ? null : round((float) $assessmentScores->average(), 1),
        ];

        DB::table('analytics_daily_metrics')->updateOrInsert(
            ['organization_id' => $organizationId, 'metric_date' => $date, 'scope_type' => 'organization', 'scope_id' => $organizationId],
            ['id' => (string) str()->ulid(), 'metrics' => json_encode($metrics, JSON_THROW_ON_ERROR), 'calculated_at' => now(), 'created_at' => now(), 'updated_at' => now()],
        );
    }
}