<?php

declare(strict_types=1);

namespace Modules\Helpdesk\Http\Controllers;

use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Str;
use JsonException;
use Modules\Helpdesk\Models\GitRepository;
use Modules\Helpdesk\Services\GitWebhookIngestionService;

final class GitWebhookController
{
    /**
     * Ingest a signed Git provider webhook for a registered Helpdesk repository.
     */
    public function __invoke(Request $request, GitRepository $repository, GitWebhookIngestionService $service): JsonResponse
    {
        $provider = strtolower((string) ($repository->provider ?: 'git'));
        $event = $this->eventName($request, $provider);
        $deliveryId = $this->deliveryId($request, $provider);
        $rawPayload = $request->getContent();

        if (! $repository->is_active) {
            $result = ['status' => 'rejected', 'message' => 'Repository is inactive.', 'commit_count' => 0, 'linked_count' => 0, 'ignored_count' => 1];
            $service->logWebhook($repository, $provider, $deliveryId, $event, $result);

            return response()->json($result, 403);
        }

        if (! $this->hasValidSignature($request, $repository, $provider, $rawPayload)) {
            $result = ['status' => 'rejected', 'message' => 'Git webhook signature or token validation failed.', 'commit_count' => 0, 'linked_count' => 0, 'ignored_count' => 1];
            $service->logWebhook($repository, $provider, $deliveryId, $event, $result);

            return response()->json($result, 403);
        }

        try {
            /** @var array<string, mixed> $payload */
            $payload = json_decode($rawPayload, true, 512, JSON_THROW_ON_ERROR);
        } catch (JsonException) {
            $result = ['status' => 'rejected', 'message' => 'Invalid JSON webhook payload.', 'commit_count' => 0, 'linked_count' => 0, 'ignored_count' => 1];
            $service->logWebhook($repository, $provider, $deliveryId, $event, $result);

            return response()->json($result, 400);
        }

        $result = $service->ingest($repository, $payload, $provider, $deliveryId, $event);

        return response()->json($result, 202);
    }

    /**
     * Ingest the local Gitea webhook URL that does not include a repository id.
     */
    public function gitea(Request $request, GitWebhookIngestionService $service): JsonResponse
    {
        $provider = 'gitea';
        $event = $this->eventName($request, $provider);
        $deliveryId = $this->deliveryId($request, $provider);
        $rawPayload = $request->getContent();

        if (! $this->hasValidGiteaAuthorization($request)) {
            return response()->json([
                'status' => 'rejected',
                'message' => 'Gitea webhook authorization failed.',
                'commit_count' => 0,
                'linked_count' => 0,
                'ignored_count' => 1,
            ], 403);
        }

        try {
            /** @var array<string, mixed> $payload */
            $payload = json_decode($rawPayload, true, 512, JSON_THROW_ON_ERROR);
        } catch (JsonException) {
            return response()->json([
                'status' => 'rejected',
                'message' => 'Invalid JSON webhook payload.',
                'commit_count' => 0,
                'linked_count' => 0,
                'ignored_count' => 1,
            ], 400);
        }

        $repository = $this->repositoryForGiteaPayload($payload);

        if (! $repository instanceof GitRepository) {
            return response()->json([
                'status' => 'rejected',
                'message' => 'No active Helpdesk Git repository matched the Gitea webhook payload.',
                'commit_count' => 0,
                'linked_count' => 0,
                'ignored_count' => 1,
            ], 404);
        }

        if (! $this->hasValidSignature($request, $repository, $provider, $rawPayload)) {
            $result = ['status' => 'rejected', 'message' => 'Git webhook signature or token validation failed.', 'commit_count' => 0, 'linked_count' => 0, 'ignored_count' => 1];
            $service->logWebhook($repository, $provider, $deliveryId, $event, $result);

            return response()->json($result, 403);
        }

        $result = $service->ingest($repository, $payload, $provider, $deliveryId, $event);

        return response()->json($result, 202);
    }

    /**
     * Validate provider-specific webhook signatures or tokens.
     */
    private function hasValidSignature(Request $request, GitRepository $repository, string $provider, string $rawPayload): bool
    {
        $secret = $this->secretForProvider($repository, $provider);

        if ($secret === '') {
            return false;
        }

        return match ($provider) {
            'github' => $this->hasValidGitHubSignature($request, $secret, $rawPayload),
            'gitlab' => hash_equals($secret, (string) $request->header('X-Gitlab-Token', '')),
            'gitea' => $this->hasValidGiteaSignature($request, $secret, $rawPayload),
            'bitbucket' => $this->hasValidBitbucketSignature($request, $secret, $rawPayload),
            default => $this->hasValidGenericSignature($request, $secret, $rawPayload),
        };
    }

    /**
     * Resolve the repository webhook secret, with local Gitea env fallback support.
     */
    private function secretForProvider(GitRepository $repository, string $provider): string
    {
        $secret = trim((string) $repository->webhook_secret);

        if ($secret !== '') {
            return $secret;
        }

        return $provider === 'gitea' ? trim((string) config('services.gitea.webhook_secret', '')) : '';
    }

    /**
     * Validate GitHub's current SHA-256 signature and legacy SHA-1 signature.
     */
    private function hasValidGitHubSignature(Request $request, string $secret, string $rawPayload): bool
    {
        $sha256Signature = (string) $request->header('X-Hub-Signature-256', '');
        $sha1Signature = (string) $request->header('X-Hub-Signature', '');

        return hash_equals('sha256=' . hash_hmac('sha256', $rawPayload, $secret), $sha256Signature)
            || hash_equals('sha1=' . hash_hmac('sha1', $rawPayload, $secret), $sha1Signature);
    }

    /**
     * Validate Gitea's raw SHA-256 signature and GitHub-compatible HMAC headers.
     */
    private function hasValidGiteaSignature(Request $request, string $secret, string $rawPayload): bool
    {
        $giteaSignature = (string) $request->header('X-Gitea-Signature', '');

        $sha256 = hash_hmac('sha256', $rawPayload, $secret);
        $sha1 = hash_hmac('sha1', $rawPayload, $secret);

        return hash_equals($sha256, $giteaSignature)
            || hash_equals('sha256=' . $sha256, $giteaSignature)
            || hash_equals('sha1=' . $sha1, $giteaSignature)
            || $this->hasValidGitHubSignature($request, $secret, $rawPayload)
            || $this->hasValidGenericSignature($request, $secret, $rawPayload);
    }

    /**
     * Validate Bitbucket's webhook HMAC signature.
     */
    private function hasValidBitbucketSignature(Request $request, string $secret, string $rawPayload): bool
    {
        $signature = (string) $request->header('X-Hub-Signature', '');

        return hash_equals('sha256=' . hash_hmac('sha256', $rawPayload, $secret), $signature)
            || hash_equals($secret, (string) $request->header('X-Helpdesk-Token', ''));
    }

    /**
     * Validate a generic Git webhook using either a token header or HMAC signature.
     */
    private function hasValidGenericSignature(Request $request, string $secret, string $rawPayload): bool
    {
        $token = (string) ($request->header('X-Helpdesk-Token') ?: $request->header('X-Gitlab-Token') ?: $request->header('X-Gitea-Token'));
        $signature = (string) ($request->header('X-Hub-Signature-256') ?: $request->header('X-Hub-Signature'));

        return hash_equals($secret, $token)
            || hash_equals('sha256=' . hash_hmac('sha256', $rawPayload, $secret), $signature)
            || hash_equals('sha1=' . hash_hmac('sha1', $rawPayload, $secret), $signature);
    }

    /**
     * Validate the optional Authorization header configured for the local Gitea webhook.
     */
    private function hasValidGiteaAuthorization(Request $request): bool
    {
        $expected = trim((string) config('services.gitea.webhook_authorization', ''));

        if ($expected === '') {
            return true;
        }

        $actual = trim((string) $request->header('Authorization', ''));

        return hash_equals($expected, $actual)
            || hash_equals('Basic ' . $expected, $actual)
            || (Str::startsWith($expected, 'Basic ') && hash_equals($expected, $actual));
    }

    /**
     * Match a Gitea webhook payload to the configured Helpdesk repository.
     *
     * @param array<string, mixed> $payload
     */
    private function repositoryForGiteaPayload(array $payload): ?GitRepository
    {
        $repositories = GitRepository::query()
            ->where('is_active', true)
            ->whereRaw('LOWER(provider) IN (?, ?)', ['gitea', 'git'])
            ->get();

        if ($repositories->isEmpty()) {
            Log::warning('Helpdesk Gitea webhook received but no active Gitea/git repository is configured.');

            return null;
        }

        $payloadValues = array_values(array_filter([
            Arr::get($payload, 'repository.full_name'),
            Arr::get($payload, 'repository.name'),
            Arr::get($payload, 'repository.html_url'),
            Arr::get($payload, 'repository.clone_url'),
            Arr::get($payload, 'repository.ssh_url'),
            Arr::get($payload, 'repository.url'),
            Arr::get($payload, 'repository.owner.username') && Arr::get($payload, 'repository.name')
                ? Arr::get($payload, 'repository.owner.username') . '/' . Arr::get($payload, 'repository.name')
                : null,
        ], static fn (mixed $value): bool => is_scalar($value) && trim((string) $value) !== ''));

        $normalisedPayloadValues = array_values(array_filter(array_map(
            fn (mixed $value): ?string => $this->normaliseRepositoryIdentity((string) $value),
            $payloadValues,
        )));

        foreach ($repositories as $repository) {
            $repositoryValues = array_filter([
                $repository->remote_url,
                $repository->name,
                Str::of((string) $repository->remote_url)->afterLast(':')->beforeLast('.git')->value(),
            ], static fn (mixed $value): bool => is_scalar($value) && trim((string) $value) !== '');

            $normalisedRepositoryValues = array_values(array_filter(array_map(
                fn (mixed $value): ?string => $this->normaliseRepositoryIdentity((string) $value),
                $repositoryValues,
            )));

            foreach ($normalisedPayloadValues as $payloadValue) {
                foreach ($normalisedRepositoryValues as $repositoryValue) {
                    if ($payloadValue === $repositoryValue
                        || str_ends_with($repositoryValue, '/' . $payloadValue)
                        || str_ends_with($payloadValue, '/' . $repositoryValue)) {
                        return $repository;
                    }
                }
            }
        }

        if ($repositories->count() === 1) {
            return $repositories->first();
        }

        Log::warning('Helpdesk Gitea webhook did not match any configured repository.', [
            'payload_repository' => Arr::get($payload, 'repository.full_name') ?: Arr::get($payload, 'repository.clone_url') ?: Arr::get($payload, 'repository.html_url'),
            'configured_repository_count' => $repositories->count(),
        ]);

        return null;
    }

    /**
     * Normalise a repository name or URL so Gitea payloads match local settings reliably.
     */
    private function normaliseRepositoryIdentity(string $value): ?string
    {
        $value = trim($value);

        if ($value === '') {
            return null;
        }

        $value = Str::of($value)
            ->replace('\\', '/')
            ->replace('ssh://git@', 'ssh://')
            ->replace('git@', '')
            ->replace('.git', '')
            ->lower()
            ->value();

        $path = parse_url($value, PHP_URL_PATH);

        if (is_string($path) && trim($path, '/') !== '') {
            $value = trim($path, '/');
        } elseif (str_contains($value, ':')) {
            $value = Str::of($value)->afterLast(':')->trim('/')->value();
        }

        $segments = array_values(array_filter(explode('/', trim($value, '/'))));

        if ($segments === []) {
            return null;
        }

        return implode('/', array_slice($segments, -2));
    }

    /**
     * Read the event name from provider-specific headers.
     */
    private function eventName(Request $request, string $provider): ?string
    {
        return match ($provider) {
            'github' => $request->header('X-GitHub-Event'),
            'gitlab' => $request->header('X-Gitlab-Event'),
            'gitea' => $request->header('X-Gitea-Event') ?: $request->header('X-Gitea-Event-Type') ?: $request->header('X-GitHub-Event'),
            'bitbucket' => $request->header('X-Event-Key'),
            default => $request->header('X-Helpdesk-Event') ?: $request->header('X-GitHub-Event') ?: $request->header('X-Gitlab-Event') ?: 'push',
        };
    }

    /**
     * Read the provider delivery/request id used for idempotent audit tracing.
     */
    private function deliveryId(Request $request, string $provider): ?string
    {
        return match ($provider) {
            'github' => $request->header('X-GitHub-Delivery'),
            'gitlab' => $request->header('X-Gitlab-Event-UUID') ?: $request->header('X-Request-Id'),
            'gitea' => $request->header('X-Gitea-Delivery') ?: $request->header('X-GitHub-Delivery') ?: $request->header('X-Request-Id'),
            'bitbucket' => $request->header('X-Request-UUID') ?: $request->header('X-Request-Id'),
            default => $request->header('X-Helpdesk-Delivery') ?: $request->header('X-GitHub-Delivery') ?: $request->header('X-Request-Id'),
        };
    }
}