<?php

namespace App\Services\Intune;

use App\Models\Policy;
use App\Models\PolicyVersion;
use App\Models\Tenant;
use App\Services\Graph\AssignmentFetcher;
use App\Services\Graph\GroupResolver;
use App\Services\Graph\ScopeTagResolver;
use Carbon\CarbonImmutable;

class VersionService
{
    public function __construct(
        private readonly AuditLogger $auditLogger,
        private readonly PolicySnapshotService $snapshotService,
        private readonly AssignmentFetcher $assignmentFetcher,
        private readonly GroupResolver $groupResolver,
        private readonly ScopeTagResolver $scopeTagResolver,
    ) {}

    public function captureVersion(
        Policy $policy,
        array $payload,
        ?string $createdBy = null,
        array $metadata = [],
        ?array $assignments = null,
        ?array $scopeTags = null,
    ): PolicyVersion {
        $versionNumber = $this->nextVersionNumber($policy);

        $version = PolicyVersion::create([
            'tenant_id' => $policy->tenant_id,
            'policy_id' => $policy->id,
            'version_number' => $versionNumber,
            'policy_type' => $policy->policy_type,
            'platform' => $policy->platform,
            'created_by' => $createdBy,
            'captured_at' => CarbonImmutable::now(),
            'snapshot' => $payload,
            'metadata' => $metadata,
            'assignments' => $assignments,
            'scope_tags' => $scopeTags,
            'assignments_hash' => $assignments ? hash('sha256', json_encode($assignments)) : null,
            'scope_tags_hash' => $scopeTags ? hash('sha256', json_encode($scopeTags)) : null,
        ]);

        $this->auditLogger->log(
            tenant: $policy->tenant,
            action: 'policy.versioned',
            context: [
                'metadata' => [
                    'policy_id' => $policy->id,
                    'version_number' => $versionNumber,
                ],
            ],
            actorEmail: $createdBy,
            resourceType: 'policy',
            resourceId: (string) $policy->id
        );

        return $version;
    }

    public function captureFromGraph(
        Tenant $tenant,
        Policy $policy,
        ?string $createdBy = null,
        array $metadata = [],
        bool $includeAssignments = true,
        bool $includeScopeTags = true,
    ): PolicyVersion {
        $graphOptions = $tenant->graphOptions();
        $tenantIdentifier = $graphOptions['tenant'] ?? $tenant->graphTenantId() ?? (string) $tenant->getKey();

        $snapshot = $this->snapshotService->fetch($tenant, $policy, $createdBy);

        if (isset($snapshot['failure'])) {
            $reason = $snapshot['failure']['reason'] ?? 'Unable to fetch policy snapshot';

            throw new \RuntimeException($reason);
        }

        $payload = $snapshot['payload'];
        $assignments = null;
        $scopeTags = null;
        $assignmentMetadata = [];

        if ($includeAssignments) {
            try {
                $rawAssignments = $this->assignmentFetcher->fetch($tenantIdentifier, $policy->external_id, $graphOptions);

                if (! empty($rawAssignments)) {
                    $assignments = $rawAssignments;

                    // Resolve groups
                    $groupIds = collect($rawAssignments)
                        ->pluck('target.groupId')
                        ->filter()
                        ->unique()
                        ->values()
                        ->toArray();

                    $resolvedGroups = $this->groupResolver->resolveGroupIds($groupIds, $tenantIdentifier, $graphOptions);

                    $assignmentMetadata['has_orphaned_assignments'] = collect($resolvedGroups)
                        ->contains(fn (array $group) => $group['orphaned'] ?? false);
                    $assignmentMetadata['assignments_count'] = count($rawAssignments);
                }
            } catch (\Throwable $e) {
                $assignmentMetadata['assignments_fetch_failed'] = true;
                $assignmentMetadata['assignments_fetch_error'] = $e->getMessage();
            }
        }

        if ($includeScopeTags) {
            $scopeTagIds = $payload['roleScopeTagIds'] ?? ['0'];
            $scopeTags = $this->resolveScopeTags($tenant, $scopeTagIds);
        }

        $metadata = array_merge(
            ['source' => 'version_capture'],
            $metadata,
            $assignmentMetadata
        );

        return $this->captureVersion(
            policy: $policy,
            payload: $payload,
            createdBy: $createdBy,
            metadata: $metadata,
            assignments: $assignments,
            scopeTags: $scopeTags,
        );
    }

    /**
     * @param  array<int, string>  $scopeTagIds
     * @return array{ids:array<int, string>,names:array<int, string>}
     */
    private function resolveScopeTags(Tenant $tenant, array $scopeTagIds): array
    {
        $scopeTags = $this->scopeTagResolver->resolve($scopeTagIds, $tenant);

        $names = [];
        foreach ($scopeTagIds as $id) {
            $scopeTag = collect($scopeTags)->firstWhere('id', $id);
            $names[] = $scopeTag['displayName'] ?? ($id === '0' ? 'Default' : "Unknown (ID: {$id})");
        }

        return [
            'ids' => $scopeTagIds,
            'names' => $names,
        ];
    }

    private function nextVersionNumber(Policy $policy): int
    {
        $current = PolicyVersion::query()
            ->where('policy_id', $policy->id)
            ->max('version_number');

        return (int) ($current ?? 0) + 1;
    }
}