<?php

declare(strict_types=1);

namespace App\Services\TenantConfiguration;

final class SecurityComplianceReadinessEvaluator
{
    /**
     * @param  array<string, mixed>|null  $normalizedPayload
     * @param  array<string, mixed>  $context
     * @param  array<string, mixed>|null  $compareResult
     * @return array<string, mixed>
     */
    public function evaluate(
        string $canonicalType,
        ?array $normalizedPayload,
        array $context = [],
        ?array $compareResult = null,
    ): array {
        if ($normalizedPayload === null) {
            return $this->result(
                state: 'readiness_not_assessed',
                label: 'Not assessed',
                reason: 'No structured Security and Compliance evidence is available for operator review.',
                blockers: ['not_assessed'],
            );
        }

        if (($normalizedPayload['supported'] ?? false) !== true) {
            return $this->result(
                state: 'readiness_blocked_unsupported',
                label: 'Blocked',
                reason: 'This Security and Compliance resource type is not supported by this readiness pack.',
                blockers: ['unsupported_type'],
            );
        }

        if ($this->evidenceBlocked($context)) {
            return $this->result(
                state: $this->permissionBlocked($context) ? 'readiness_blocked_permission' : 'readiness_blocked_evidence',
                label: 'Blocked',
                reason: $this->permissionBlocked($context)
                    ? 'Provider permission or source availability blocks reliable operator review.'
                    : 'Content-backed captured evidence is required before readiness can be assessed.',
                blockers: [$this->permissionBlocked($context) ? 'permission_blocked' : 'evidence_blocked'],
            );
        }

        if ($this->identityBlocked($context)) {
            return $this->result(
                state: 'readiness_blocked_identity',
                label: 'Blocked',
                reason: 'Identity is unsafe for Security and Compliance readiness assessment.',
                blockers: ['identity_blocked'],
            );
        }

        $unsupportedFields = $this->actionableUnsupportedFields($normalizedPayload);
        $manualReviewFields = $this->diagnosticFields($normalizedPayload, 'manual_review_fields');

        if ($manualReviewFields !== []) {
            return $this->result(
                state: 'readiness_requires_manual_review',
                label: 'Manual review required',
                reason: 'Unsupported Security and Compliance fields require internal operator review.',
                manualReviewRequired: true,
                blockers: array_values(array_unique([
                    ...array_map(static fn (string $field): string => 'manual_review:'.$field, $manualReviewFields),
                ])),
            );
        }

        if ($unsupportedFields !== []) {
            return $this->result(
                state: 'readiness_blocked_unsupported',
                label: 'Blocked',
                reason: 'Unsupported fields require review before this evidence can be trusted.',
                blockers: array_values(array_unique([
                    ...array_map(static fn (string $field): string => 'unsupported:'.$field, $unsupportedFields),
                ])),
            );
        }

        if ($this->requiresManualReview($compareResult)) {
            return $this->result(
                state: 'readiness_requires_manual_review',
                label: 'Manual review required',
                reason: 'Critical Security and Compliance changes require internal operator review.',
                manualReviewRequired: true,
                blockers: ['critical_material_change'],
            );
        }

        return $this->result(
            state: 'readiness_ready_for_operator_review',
            label: 'Ready for operator review',
            reason: 'Structured evidence is available for internal operator review.',
        );
    }

    /**
     * @return array<string, mixed>
     */
    private function result(
        string $state,
        string $label,
        string $reason,
        bool $manualReviewRequired = false,
        array $blockers = [],
    ): array {
        return [
            'state' => $state,
            'label' => $label,
            'reason' => $reason,
            'manual_review_required' => $manualReviewRequired,
            'blockers' => array_values($blockers),
        ];
    }

    /**
     * @param  array<string, mixed>  $context
     */
    private function evidenceBlocked(array $context): bool
    {
        return $this->permissionBlocked($context)
            || ($context['evidence_state'] ?? null) !== 'content_backed'
            || ($context['capture_outcome'] ?? null) !== 'captured'
            || ! in_array($context['coverage_level'] ?? null, ['renderable', 'comparable'], true);
    }

    /**
     * @param  array<string, mixed>  $context
     */
    private function permissionBlocked(array $context): bool
    {
        return (bool) ($context['permission_blocked'] ?? false);
    }

    /**
     * @param  array<string, mixed>  $context
     */
    private function identityBlocked(array $context): bool
    {
        return in_array($context['identity_state'] ?? null, [
            'identity_conflict',
            'missing_external_id',
            'unsupported_identity',
        ], true);
    }

    /**
     * @param  array<string, mixed>|null  $compareResult
     */
    private function requiresManualReview(?array $compareResult): bool
    {
        if ($compareResult === null) {
            return false;
        }

        if (($compareResult['classification'] ?? null) === 'manual_review_required') {
            return true;
        }

        $changes = $compareResult['changes'] ?? [];

        if (! is_array($changes)) {
            return false;
        }

        foreach ($changes as $change) {
            if (! is_array($change)) {
                continue;
            }

            if (($change['classification'] ?? null) === 'manual_review_required'
                || ($change['importance'] ?? null) === 'critical'
                || ($change['importance'] ?? null) === 'manual_review_required'
            ) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return list<string>
     */
    private function diagnosticFields(array $payload, string $key): array
    {
        $fields = data_get($payload, 'diagnostics.'.$key, []);

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

        return array_values(array_filter(
            array_map(static fn (mixed $field): string => is_string($field) ? trim($field) : '', $fields),
            static fn (string $field): bool => $field !== '',
        ));
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return list<string>
     */
    private function actionableUnsupportedFields(array $payload): array
    {
        $unsupportedFields = $this->diagnosticFields($payload, 'unsupported_fields');
        $redactedFields = $this->diagnosticFields($payload, 'redacted_fields');

        return array_values(array_filter(
            $unsupportedFields,
            static fn (string $field): bool => ! in_array($field, $redactedFields, true),
        ));
    }
}