<?php

declare(strict_types=1);

namespace Modules\Helpdesk\Services;

use Carbon\CarbonImmutable;
use Illuminate\Support\Facades\Log;
use Modules\Helpdesk\Models\GitCommit;
use Modules\Helpdesk\Models\GitRepository;
use Modules\Helpdesk\Models\GitWebhookLog;
use Modules\Helpdesk\Models\Ticket;
use Throwable;

final class GitWebhookIngestionService
{
    private const TICKET_REFERENCE_PATTERN = '/\bHD-\d{4}-\d{5}\b/i';

    /**
     * Persist supported Git provider commits and link them to matching Helpdesk ticket references.
     *
     * @param  array<string, mixed>  $payload
     * @return array{status: string, message: string, commit_count: int, linked_count: int, ignored_count: int}
     */
    public function ingest(GitRepository $repository, array $payload, string $provider, ?string $deliveryId, ?string $event): array
    {
        if (! $this->isPushEvent($provider, $event)) {
            $result = [
                'status' => 'ignored',
                'message' => sprintf('Ignored unsupported %s event.', $event ?: 'unknown'),
                'commit_count' => 0,
                'linked_count' => 0,
                'ignored_count' => 1,
            ];

            $this->logWebhook($repository, $provider, $deliveryId, $event, $result, $payload);

            return $result;
        }

        $branch = $this->branchFromRef($payload['ref'] ?? null);
        $commits = $this->commitsFromPayload($payload);
        $commitCount = 0;
        $linkedCount = 0;
        $ignoredCount = 0;

        foreach ($commits as $commit) {
            $hash = $this->stringOrNull($commit['id'] ?? $commit['sha'] ?? null);

            if ($hash === null) {
                $ignoredCount++;

                continue;
            }

            $message = $this->stringOrNull($commit['message'] ?? null) ?? '';
            $url = $this->stringOrNull($commit['url'] ?? null);
            $author = is_array($commit['author'] ?? null) ? $commit['author'] : [];
            $committer = is_array($commit['committer'] ?? null) ? $commit['committer'] : [];
            $authorName = $this->stringOrNull($author['name'] ?? $committer['name'] ?? null);
            $authorEmail = $this->stringOrNull($author['email'] ?? $committer['email'] ?? null);
            $committedAt = $this->parseTimestamp($commit['timestamp'] ?? $commit['committed_at'] ?? null);
            $ticket = $this->ticketForCommit($repository, $message, $branch, $url);

            GitCommit::query()->updateOrCreate(
                [
                    'repository_id' => $repository->getKey(),
                    'hash' => $hash,
                ],
                [
                    'ticket_id' => $ticket?->getKey(),
                    'short_hash' => substr($hash, 0, 12),
                    'branch' => $branch,
                    'author_name' => $authorName,
                    'author_email' => $authorEmail,
                    'message' => $message,
                    'url' => $url,
                    'committed_at' => $committedAt,
                ]
            );

            $commitCount++;

            if ($ticket !== null) {
                $linkedCount++;
            }
        }

        $result = [
            'status' => 'accepted',
            'message' => sprintf('Processed %d commit(s), linked %d to tickets.', $commitCount, $linkedCount),
            'commit_count' => $commitCount,
            'linked_count' => $linkedCount,
            'ignored_count' => $ignoredCount,
        ];

        $this->logWebhook($repository, $provider, $deliveryId, $event, $result, $payload);

        return $result;
    }

    /**
     * Record a provider webhook acceptance, rejection or ignore decision for auditability.
     *
     * @param  array{status: string, message: string, commit_count?: int, linked_count?: int, ignored_count?: int}  $result
     * @param  array<string, mixed>|null  $payload
     */
    public function logWebhook(GitRepository $repository, string $provider, ?string $deliveryId, ?string $event, array $result, ?array $payload = null): void
    {
        try {
            GitWebhookLog::query()->create([
                'repository_id' => $repository->getKey(),
                'provider' => $provider,
                'delivery_id' => $deliveryId,
                'event' => $event,
                'status' => $result['status'],
                'message' => $result['message'],
                'commit_count' => (int) ($result['commit_count'] ?? 0),
                'linked_count' => (int) ($result['linked_count'] ?? 0),
                'ignored_count' => (int) ($result['ignored_count'] ?? 0),
                'payload' => $payload,
                'received_at' => now(),
            ]);
        } catch (Throwable $exception) {
            Log::warning('Helpdesk Git webhook audit log could not be written.', [
                'repository_id' => $repository->getKey(),
                'provider' => $provider,
                'event' => $event,
                'status' => $result['status'],
                'error' => $exception->getMessage(),
            ]);
        }
    }

    /**
     * Extract the first Helpdesk ticket reference from arbitrary Git text.
     */
    public function extractTicketReference(string $value): ?string
    {
        if (! preg_match(self::TICKET_REFERENCE_PATTERN, $value, $matches)) {
            return null;
        }

        return strtoupper($matches[0]);
    }

    /**
     * Determine whether the provider event should be processed as a push payload.
     */
    private function isPushEvent(string $provider, ?string $event): bool
    {
        $normalised = strtolower((string) $event);

        return match ($provider) {
            'github' => $normalised === 'push',
            'gitlab' => in_array($normalised, ['push hook', 'push'], true),
            default => $normalised === '' || $normalised === 'push',
        };
    }

    private function branchFromRef(mixed $value): ?string
    {
        $ref = $this->stringOrNull($value);

        if ($ref === null) {
            return null;
        }

        return str_replace('refs/heads/', '', $ref);
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return array<int, array<string, mixed>>
     */
    private function commitsFromPayload(array $payload): array
    {
        $commits = $payload['commits'] ?? [];

        if (! is_array($commits)) {
            return [];
        }

        return array_values(array_filter($commits, static fn (mixed $commit): bool => is_array($commit)));
    }

    private function ticketForCommit(GitRepository $repository, string $message, ?string $branch, ?string $url): ?Ticket
    {
        $reference = $this->extractTicketReference(trim($message.' '.($branch ?? '').' '.($url ?? '')));

        if ($reference === null) {
            return null;
        }

        $query = Ticket::query()->where('reference', $reference);

        if ($repository->company_id !== null) {
            $query->where('company_id', $repository->company_id);
        }

        if ($repository->project_id !== null) {
            $query->where('project_id', $repository->project_id);
        }

        return $query->first();
    }

    private function parseTimestamp(mixed $value): ?CarbonImmutable
    {
        $timestamp = $this->stringOrNull($value);

        if ($timestamp === null) {
            return null;
        }

        try {
            return CarbonImmutable::parse($timestamp);
        } catch (Throwable) {
            return null;
        }
    }

    private function stringOrNull(mixed $value): ?string
    {
        if (! is_scalar($value)) {
            return null;
        }

        $string = trim((string) $value);

        return $string === '' ? null : $string;
    }
}