<?php

namespace App\Services;

use App\Models\Event;
use App\Models\Issue;
use App\Models\Project;
use Illuminate\Support\Carbon;

class EventProcessor
{
    public function __construct(
        private Fingerprinter $fingerprinter,
        private PayloadNormalizer $normalizer,
        private NotificationDispatcher $notificationDispatcher,
    ) {}

    /**
     * Process a raw Sentry event payload for the given project.
     * Returns the created Event model.
     */
    public function process(Project $project, array $rawPayload): Event
    {
        $data = $this->normalizer->normalize($rawPayload);
        $fingerprint = $this->fingerprinter->compute($rawPayload);
        $now = Carbon::now();

        $isNew = false;
        $isRegression = false;
        $issue = $this->findOrCreateIssue($project, $data, $fingerprint, $now, $isNew, $isRegression);

        $event = Event::create([
            'issue_id' => $issue->id,
            'project_id' => $project->id,
            'event_id' => $data['event_id'],
            'level' => $data['level'],
            'message' => $data['message'],
            'platform' => $data['platform'],
            'timestamp' => $data['timestamp'],
            'server_name' => $data['server_name'],
            'release' => $data['release'],
            'environment' => $data['environment'],
            'exception' => $data['exception'],
            'breadcrumbs' => $data['breadcrumbs'],
            'contexts' => $data['contexts'],
            'tags' => $data['tags'],
            'extra' => $data['extra'],
            'user_context' => $data['user_context'],
            'request_context' => $data['request_context'],
            'sdk' => $data['sdk'],
            'raw_payload' => $rawPayload,
        ]);

        $this->dispatchNotifications($project, $issue, $isNew, $isRegression);

        return $event;
    }

    private function findOrCreateIssue(
        Project $project,
        array $data,
        string $fingerprint,
        Carbon $now,
        bool &$isNew,
        bool &$isRegression,
    ): Issue {
        $issue = Issue::where('project_id', $project->id)
            ->where('fingerprint', $fingerprint)
            ->first();

        if ($issue) {
            $isRegression = $this->updateExistingIssue($issue, $data, $now);
            $isNew = false;

            return $issue;
        }

        $isNew = true;
        $isRegression = false;

        return $this->createNewIssue($project, $data, $fingerprint, $now);
    }

    private function createNewIssue(
        Project $project,
        array $data,
        string $fingerprint,
        Carbon $now,
    ): Issue {
        $exception = $this->fingerprinter->extractPrimaryException(
            ['exception' => $data['exception']],
        );

        $title = $this->buildTitle($exception, $data['message']);
        $culprit = $this->buildCulprit($exception);

        return Issue::create([
            'project_id' => $project->id,
            'fingerprint' => $fingerprint,
            'title' => $title,
            'culprit' => $culprit,
            'level' => $data['level'],
            'status' => 'unresolved',
            'first_seen_at' => $now,
            'last_seen_at' => $now,
            'times_seen' => 1,
            'is_regression' => false,
            'first_release' => $data['release'],
            'metadata' => array_filter([
                'platform' => $data['platform'],
                'sdk' => $data['sdk'],
            ]),
        ]);
    }

    private function updateExistingIssue(Issue $issue, array $data, Carbon $now): bool
    {
        $wasResolved = $issue->status === 'resolved';
        $currentRelease = $data['release'];
        $resolvedInRelease = $issue->resolved_in_release;

        $issue->increment('times_seen');
        $issue->update(['last_seen_at' => $now]);

        // Check for regression: issue was resolved, and now appears again
        if ($wasResolved) {
            // If we have release tracking and the issue was resolved in a release,
            // only mark as regression if the current release is different (assumed newer)
            if ($resolvedInRelease && $currentRelease && $currentRelease === $resolvedInRelease) {
                // Same release as resolved - don't mark as regression
                return false;
            }

            $issue->markRegression();

            return true;
        }

        return false;
    }

    private function buildTitle(?array $exception, ?string $message): string
    {
        if ($exception) {
            $type = $exception['type'] ?? 'Error';
            $value = $exception['value'] ?? '';

            return str($value)
                ->whenEmpty(fn () => str($type))
                ->prepend("{$type}: ")
                ->limit(255)
                ->toString();
        }

        return str($message ?? 'Unknown Error')->limit(255)->toString();
    }

    private function buildCulprit(?array $exception): ?string
    {
        if (! $exception) {
            return null;
        }

        $frames = $exception['stacktrace']['frames'] ?? [];
        $last = end($frames);

        if (! $last) {
            return null;
        }

        $file = $last['filename'] ?? $last['abs_path'] ?? '?';
        $function = $last['function'] ?? null;

        return $function ? "{$file} in {$function}" : $file;
    }

    private function dispatchNotifications(
        Project $project,
        Issue $issue,
        bool $isNew,
        bool $isRegression,
    ): void {
        if ($isNew) {
            $this->notificationDispatcher->onNewIssue($project, $issue);
        }

        if ($isRegression) {
            $this->notificationDispatcher->onRegression($project, $issue);
        }

        $this->notificationDispatcher->checkSpike($project, $issue);
    }
}