<?php

declare(strict_types=1);

namespace App\Services\TenantConfiguration;

use App\Models\ManagedEnvironment;
use App\Models\ProviderConnection;
use App\Models\TenantConfigurationResource;
use App\Models\TenantConfigurationResourceEvidence;
use App\Models\TenantConfigurationResourceType;
use App\Models\TenantConfigurationSupportedScope;
use App\Support\TenantConfiguration\CaptureOutcome;
use App\Support\TenantConfiguration\ClaimState;
use App\Support\TenantConfiguration\CoverageLevel;
use App\Support\TenantConfiguration\EvidenceState;
use App\Support\TenantConfiguration\IdentityState;
use Carbon\CarbonInterface;
use InvalidArgumentException;
use Throwable;

final class EntraCertifiedComparePackEvaluator
{
    public const SCOPE_KEY = 'entra_core_compare_certified';

    public const CLAIM_LABEL = 'Certified Entra Core Compare Pack: Conditional Access and Security Defaults';

    /**
     * @var list<string>
     */
    public const DENOMINATOR = [
        'conditionalAccessPolicy',
        'securityDefaults',
    ];

    /**
     * @var array<string, string>
     */
    private const EXPECTED_CONTRACT_KEYS = [
        'conditionalAccessPolicy' => 'conditionalAccessPolicy',
        'securityDefaults' => 'securityDefaults',
    ];

    /**
     * @var list<string>
     */
    private const BLOCKER_PRIORITY = [
        EntraCertifiedComparePackResult::BLOCKED_MISSING_EVIDENCE,
        EntraCertifiedComparePackResult::BLOCKED_IDENTITY,
        EntraCertifiedComparePackResult::BLOCKED_COMPARE,
        EntraCertifiedComparePackResult::BLOCKED_RENDER,
        EntraCertifiedComparePackResult::BLOCKED_REDACTION,
        EntraCertifiedComparePackResult::BLOCKED_CLAIM_GUARD,
    ];

    /**
     * @var list<string>
     */
    private const SENSITIVE_KEY_PARTS = [
        'access_token',
        'authorization',
        'bearer',
        'certificate',
        'client_secret',
        'cookie',
        'credential',
        'id_token',
        'password',
        'private_key',
        'refresh_token',
        'secret',
        'set-cookie',
        'token',
    ];

    public function __construct(
        private readonly SupportedScopeResolver $supportedScopes,
        private readonly EntraCoverageComparator $comparator,
        private readonly EntraRenderableSummaryBuilder $summaryBuilder,
        private readonly CoveragePayloadRedactor $redactor,
        private readonly ClaimGuard $claimGuard,
    ) {}

    public function evaluate(
        ManagedEnvironment $environment,
        ProviderConnection $providerConnection,
    ): EntraCertifiedComparePackResult {
        $this->assertSameScope($environment, $providerConnection);

        $scope = $this->supportedScopes->findActive(self::SCOPE_KEY);

        if (! $scope instanceof TenantConfigurationSupportedScope) {
            return new EntraCertifiedComparePackResult(
                scopeKey: self::SCOPE_KEY,
                denominator: self::DENOMINATOR,
                state: EntraCertifiedComparePackResult::NOT_EVALUATED,
                blockers: ['supported_scope_missing'],
            );
        }

        $scopeBlockers = $this->scopeBlockers($scope);

        if ($scopeBlockers !== []) {
            return new EntraCertifiedComparePackResult(
                scopeKey: self::SCOPE_KEY,
                denominator: self::DENOMINATOR,
                state: EntraCertifiedComparePackResult::BLOCKED_MISSING_EVIDENCE,
                blockers: $scopeBlockers,
            );
        }

        $resourceResults = [];
        $blockers = [];

        foreach (self::DENOMINATOR as $canonicalType) {
            $typeResult = $this->evaluateCanonicalType($canonicalType, $environment, $providerConnection);
            $resourceResults[] = $typeResult;
            $blockers = [...$blockers, ...$typeResult['blockers']];
        }

        $blockers = $this->uniqueStrings($blockers);
        $claimState = null;

        if ($blockers === []) {
            $claimState = $this->claimGuard->evaluateCertifiedComparePackStatement(
                claim: self::CLAIM_LABEL,
                packPassed: true,
                internalOperatorOnly: true,
            );

            if ($claimState !== ClaimState::InternalOnly) {
                $blockers[] = EntraCertifiedComparePackResult::BLOCKED_CLAIM_GUARD;
            }
        }

        return new EntraCertifiedComparePackResult(
            scopeKey: self::SCOPE_KEY,
            denominator: self::DENOMINATOR,
            state: $this->overallState($blockers),
            resourceResults: $resourceResults,
            blockers: $this->uniqueStrings($blockers),
            claimState: $claimState,
        );
    }

    /**
     * @return array<string, mixed>
     */
    private function evaluateCanonicalType(
        string $canonicalType,
        ManagedEnvironment $environment,
        ProviderConnection $providerConnection,
    ): array {
        $resourceType = TenantConfigurationResourceType::query()
            ->active()
            ->where('canonical_type', $canonicalType)
            ->orderBy('source_class')
            ->first();

        if (! $resourceType instanceof TenantConfigurationResourceType) {
            return $this->blockedTypeResult($canonicalType, ['resource_type_missing']);
        }

        $resources = TenantConfigurationResource::query()
            ->where('workspace_id', (int) $environment->workspace_id)
            ->where('managed_environment_id', (int) $environment->getKey())
            ->where('provider_connection_id', (int) $providerConnection->getKey())
            ->where('resource_type_id', (int) $resourceType->getKey())
            ->where('canonical_type', $canonicalType)
            ->with([
                'latestEvidence.operationRun:id,workspace_id,managed_environment_id',
            ])
            ->orderBy('canonical_resource_key')
            ->get();

        if ($resources->isEmpty()) {
            return $this->blockedTypeResult($canonicalType, ['current_same_scope_resource_missing']);
        }

        $resourceResults = $resources
            ->map(fn (TenantConfigurationResource $resource): array => $this->evaluateResource($resource, $canonicalType))
            ->values();

        $blockers = $this->uniqueStrings($resourceResults
            ->flatMap(fn (array $result): array => $result['blockers'])
            ->all());

        return [
            'canonical_type' => $canonicalType,
            'resource_count' => $resources->count(),
            'criteria' => [
                'evidence' => $resourceResults->every(fn (array $result): bool => (bool) $result['criteria']['evidence']),
                'identity' => $resourceResults->every(fn (array $result): bool => (bool) $result['criteria']['identity']),
                'compare' => $resourceResults->every(fn (array $result): bool => (bool) $result['criteria']['compare']),
                'render' => $resourceResults->every(fn (array $result): bool => (bool) $result['criteria']['render']),
                'redaction' => $resourceResults->every(fn (array $result): bool => (bool) $result['criteria']['redaction']),
            ],
            'certified' => $blockers === [],
            'blockers' => $blockers,
            'resources' => $resourceResults->all(),
        ];
    }

    /**
     * @return array<string, mixed>
     */
    private function evaluateResource(TenantConfigurationResource $resource, string $canonicalType): array
    {
        $evidence = $resource->latestEvidence;
        $blockers = [];
        $criteria = [
            'evidence' => false,
            'identity' => false,
            'compare' => false,
            'render' => false,
            'redaction' => false,
        ];
        $reasons = [];

        [$criteria['evidence'], $evidenceReasons] = $this->evidencePasses($resource, $evidence, $canonicalType);
        $reasons = [...$reasons, ...$evidenceReasons];

        if (! $criteria['evidence']) {
            $blockers[] = EntraCertifiedComparePackResult::BLOCKED_MISSING_EVIDENCE;
        }

        [$criteria['identity'], $identityReasons] = $this->identityPasses($resource);
        $reasons = [...$reasons, ...$identityReasons];

        if (! $criteria['identity']) {
            $blockers[] = EntraCertifiedComparePackResult::BLOCKED_IDENTITY;
        }

        $renderSummary = null;

        if ($evidence instanceof TenantConfigurationResourceEvidence && is_array($evidence->normalized_payload)) {
            [$criteria['compare'], $compareReasons] = $this->comparePasses($canonicalType, $evidence);
            [$criteria['render'], $renderSummary, $renderReasons] = $this->renderPasses($resource, $canonicalType, $evidence);
            [$criteria['redaction'], $redactionReasons] = $this->redactionPasses($evidence, $renderSummary);
            $reasons = [...$reasons, ...$compareReasons, ...$renderReasons, ...$redactionReasons];
        }

        if (! $criteria['compare']) {
            $blockers[] = EntraCertifiedComparePackResult::BLOCKED_COMPARE;
        }

        if (! $criteria['render']) {
            $blockers[] = EntraCertifiedComparePackResult::BLOCKED_RENDER;
        }

        if (! $criteria['redaction']) {
            $blockers[] = EntraCertifiedComparePackResult::BLOCKED_REDACTION;
        }

        return [
            'resource_id' => (int) $resource->getKey(),
            'canonical_resource_key' => (string) $resource->canonical_resource_key,
            'criteria' => $criteria,
            'certified' => $blockers === [],
            'blockers' => $this->uniqueStrings($blockers),
            'reasons' => $this->uniqueStrings($reasons),
        ];
    }

    /**
     * @return array{0: bool, 1: list<string>}
     */
    private function evidencePasses(
        TenantConfigurationResource $resource,
        mixed $evidence,
        string $canonicalType,
    ): array {
        $reasons = [];

        if (! $evidence instanceof TenantConfigurationResourceEvidence) {
            return [false, ['latest_evidence_missing']];
        }

        if ((int) $resource->latest_evidence_id !== (int) $evidence->getKey()) {
            $reasons[] = 'latest_evidence_pointer_mismatch';
        }

        foreach ([
            'resource_id' => (int) $resource->getKey(),
            'workspace_id' => (int) $resource->workspace_id,
            'managed_environment_id' => (int) $resource->managed_environment_id,
            'provider_connection_id' => (int) $resource->provider_connection_id,
            'resource_type_id' => (int) $resource->resource_type_id,
        ] as $column => $expected) {
            if ((int) $evidence->{$column} !== $expected) {
                $reasons[] = $column.'_scope_mismatch';
            }
        }

        if ($evidence->evidence_state !== EvidenceState::ContentBacked) {
            $reasons[] = 'evidence_not_content_backed';
        }

        if ($evidence->capture_outcome !== CaptureOutcome::Captured) {
            $reasons[] = 'evidence_not_captured';
        }

        if (! is_array($evidence->raw_payload) || $evidence->raw_payload === []) {
            $reasons[] = 'raw_payload_missing';
        }

        if (! is_array($evidence->normalized_payload) || $evidence->normalized_payload === []) {
            $reasons[] = 'normalized_payload_missing';
        }

        if (! is_string($evidence->payload_hash) || ! preg_match('/^[a-f0-9]{64}$/', $evidence->payload_hash)) {
            $reasons[] = 'payload_hash_invalid';
        }

        if ((string) $resource->latest_payload_hash !== (string) $evidence->payload_hash) {
            $reasons[] = 'latest_payload_hash_mismatch';
        }

        if ((string) $evidence->source_contract_key !== self::EXPECTED_CONTRACT_KEYS[$canonicalType]) {
            $reasons[] = 'source_contract_mismatch';
        }

        foreach (['source_endpoint', 'source_version'] as $field) {
            if (! is_string($evidence->{$field}) || trim($evidence->{$field}) === '') {
                $reasons[] = $field.'_missing';
            }
        }

        if (! $evidence->captured_at instanceof CarbonInterface) {
            $reasons[] = 'captured_at_missing';
        }

        if ((int) $evidence->operation_run_id <= 0 || ! $evidence->operationRun) {
            $reasons[] = 'operation_run_link_missing';
        } elseif ((int) $evidence->operationRun->workspace_id !== (int) $resource->workspace_id
            || (int) $evidence->operationRun->managed_environment_id !== (int) $resource->managed_environment_id
        ) {
            $reasons[] = 'operation_run_scope_mismatch';
        }

        if ($this->hasNewerEvidence($resource, $evidence)) {
            $reasons[] = 'latest_evidence_not_current';
        }

        return [$reasons === [], $reasons];
    }

    /**
     * @return array{0: bool, 1: list<string>}
     */
    private function identityPasses(TenantConfigurationResource $resource): array
    {
        return $resource->latest_identity_state === IdentityState::Stable
            ? [true, []]
            : [false, ['identity_state_'.$this->stateValue($resource->latest_identity_state)]];
    }

    /**
     * @return array{0: bool, 1: list<string>}
     */
    private function comparePasses(string $canonicalType, TenantConfigurationResourceEvidence $evidence): array
    {
        $normalizedPayload = is_array($evidence->normalized_payload) ? $evidence->normalized_payload : [];
        $result = $this->comparator->compare($canonicalType, $normalizedPayload, $normalizedPayload);
        $changes = collect(is_array($result['changes'] ?? null) ? $result['changes'] : []);
        $unsupportedFields = data_get($normalizedPayload, 'diagnostics.unsupported_fields', []);
        $reasons = [];

        if (($result['supported'] ?? false) !== true) {
            $reasons[] = 'compare_not_supported';
        }

        if (($result['classification'] ?? null) !== 'unchanged' || ($result['changed'] ?? true) !== false) {
            $reasons[] = 'compare_not_deterministic';
        }

        if ($changes->contains(fn (mixed $change): bool => is_array($change) && ($change['classification'] ?? null) === 'unsupported_field')
            || (is_array($unsupportedFields) && $unsupportedFields !== [])
        ) {
            $reasons[] = 'unsupported_fields_present';
        }

        return [$reasons === [], $reasons];
    }

    /**
     * @return array{0: bool, 1: array<string, mixed>|null, 2: list<string>}
     */
    private function renderPasses(
        TenantConfigurationResource $resource,
        string $canonicalType,
        TenantConfigurationResourceEvidence $evidence,
    ): array {
        $reasons = [];
        $coverageLevel = $this->coverageLevel($evidence->coverage_level);

        if (! $coverageLevel?->meets(CoverageLevel::Renderable)) {
            $reasons[] = 'coverage_not_renderable';
        }

        $summary = $this->summaryBuilder->build($canonicalType, $evidence->normalized_payload, [
            'claim_state' => $resource->latest_claim_state,
            'identity_state' => $resource->latest_identity_state,
            'evidence_state' => $resource->latest_evidence_state,
            'coverage_level' => $evidence->coverage_level,
            'last_captured' => $resource->latest_captured_at?->toDayDateTimeString(),
            'source_version' => $evidence->source_version,
            'source_schema_hash' => $evidence->source_schema_hash,
        ]);

        if (! is_array($summary) || $summary === []) {
            $reasons[] = 'render_summary_missing';
        }

        return [$reasons === [], $summary, $reasons];
    }

    /**
     * @param  array<string, mixed>|null  $summary
     * @return array{0: bool, 1: list<string>}
     */
    private function redactionPasses(TenantConfigurationResourceEvidence $evidence, ?array $summary): array
    {
        $reasons = [];
        $redactedRaw = $this->redactor->redact($evidence->raw_payload);
        $sensitiveValues = $this->sensitiveValues($evidence->raw_payload, $redactedRaw);
        $safeOutput = [
            'normalized_payload' => $evidence->normalized_payload,
            'render_summary' => $summary,
            'claim_label' => self::CLAIM_LABEL,
        ];
        $encoded = json_encode($safeOutput, JSON_UNESCAPED_SLASHES | JSON_THROW_ON_ERROR);
        $lowerEncoded = strtolower($encoded);

        foreach (['raw_payload', 'raw graph response', 'raw_graph_response', 'permission_context'] as $forbiddenToken) {
            if (str_contains($lowerEncoded, $forbiddenToken)) {
                $reasons[] = 'forbidden_output_token_'.$forbiddenToken;
            }
        }

        foreach ($sensitiveValues as $value) {
            if ($value !== '' && str_contains($encoded, $value)) {
                $reasons[] = 'sensitive_value_leaked';

                break;
            }
        }

        return [$reasons === [], $reasons];
    }

    /**
     * @return list<string>
     */
    private function scopeBlockers(TenantConfigurationSupportedScope $scope): array
    {
        $metadata = is_array($scope->metadata) ? $scope->metadata : [];
        $reasons = [];

        try {
            $resolved = $this->supportedScopes->resolveDefinition(
                $scope,
                TenantConfigurationResourceType::query()
                    ->active()
                    ->get(['canonical_type', 'source_class']),
            );
        } catch (Throwable) {
            return ['supported_scope_unresolvable'];
        }

        if ($resolved['included_resource_types'] !== self::DENOMINATOR) {
            $reasons[] = 'supported_scope_denominator_mismatch';
        }

        if ($resolved['minimum_coverage_level'] !== CoverageLevel::Certified) {
            $reasons[] = 'supported_scope_minimum_not_certified';
        }

        if ($resolved['allow_beta'] !== false) {
            $reasons[] = 'supported_scope_beta_allowed';
        }

        if ($resolved['customer_claims_allowed'] !== false) {
            $reasons[] = 'supported_scope_customer_claims_allowed';
        }

        if (($metadata['graph_fallback_allowlist'] ?? null) !== ['securityDefaults']) {
            $reasons[] = 'supported_scope_graph_fallback_allowlist_mismatch';
        }

        if (($metadata['resource_type_denominator'] ?? null) !== self::DENOMINATOR) {
            $reasons[] = 'supported_scope_metadata_denominator_mismatch';
        }

        return $reasons;
    }

    /**
     * @param  list<string>  $reasons
     * @return array<string, mixed>
     */
    private function blockedTypeResult(string $canonicalType, array $reasons): array
    {
        return [
            'canonical_type' => $canonicalType,
            'resource_count' => 0,
            'criteria' => [
                'evidence' => false,
                'identity' => false,
                'compare' => false,
                'render' => false,
                'redaction' => false,
            ],
            'certified' => false,
            'blockers' => [EntraCertifiedComparePackResult::BLOCKED_MISSING_EVIDENCE],
            'resources' => [],
            'reasons' => $reasons,
        ];
    }

    private function assertSameScope(ManagedEnvironment $environment, ProviderConnection $providerConnection): void
    {
        if ((int) $providerConnection->workspace_id !== (int) $environment->workspace_id
            || (int) $providerConnection->managed_environment_id !== (int) $environment->getKey()
        ) {
            throw new InvalidArgumentException('Provider connection scope mismatch while evaluating Entra certified compare pack.');
        }
    }

    private function hasNewerEvidence(
        TenantConfigurationResource $resource,
        TenantConfigurationResourceEvidence $evidence,
    ): bool {
        if (! $evidence->captured_at instanceof CarbonInterface) {
            return true;
        }

        return TenantConfigurationResourceEvidence::query()
            ->where('resource_id', (int) $resource->getKey())
            ->where('workspace_id', (int) $resource->workspace_id)
            ->where('managed_environment_id', (int) $resource->managed_environment_id)
            ->where('provider_connection_id', (int) $resource->provider_connection_id)
            ->where('resource_type_id', (int) $resource->resource_type_id)
            ->where('id', '<>', (int) $evidence->getKey())
            ->where('evidence_state', EvidenceState::ContentBacked->value)
            ->where('capture_outcome', CaptureOutcome::Captured->value)
            ->where(function ($query) use ($evidence): void {
                $query->where('captured_at', '>', $evidence->captured_at)
                    ->orWhere(function ($query) use ($evidence): void {
                        $query->where('captured_at', '=', $evidence->captured_at)
                            ->where('id', '>', (int) $evidence->getKey());
                    });
            })
            ->exists();
    }

    private function overallState(array $blockers): string
    {
        $blockers = $this->uniqueStrings($blockers);

        if ($blockers === []) {
            return EntraCertifiedComparePackResult::PASSED;
        }

        foreach (self::BLOCKER_PRIORITY as $blocker) {
            if (in_array($blocker, $blockers, true)) {
                return $blocker;
            }
        }

        return EntraCertifiedComparePackResult::NOT_EVALUATED;
    }

    private function coverageLevel(mixed $value): ?CoverageLevel
    {
        if ($value instanceof CoverageLevel) {
            return $value;
        }

        return is_string($value) ? CoverageLevel::tryFrom($value) : null;
    }

    /**
     * @return list<string>
     */
    private function uniqueStrings(array $values): array
    {
        return array_values(array_unique(array_filter(
            array_map(static fn (mixed $value): string => is_scalar($value) ? trim((string) $value) : '', $values),
            static fn (string $value): bool => $value !== '',
        )));
    }

    private function stateValue(mixed $state): string
    {
        return $state instanceof \BackedEnum ? (string) $state->value : (string) $state;
    }

    /**
     * @return list<string>
     */
    private function sensitiveValues(mixed $raw, mixed $redacted): array
    {
        $values = [];

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

        foreach ($raw as $key => $value) {
            $key = (string) $key;
            $redactedValue = is_array($redacted) ? ($redacted[$key] ?? null) : null;

            if ($redactedValue === '[redacted]' && is_scalar($value)) {
                $values[] = (string) $value;

                continue;
            }

            if ($this->isSensitiveKey($key) && is_scalar($value)) {
                $values[] = (string) $value;
            }

            if (is_array($value)) {
                $values = [...$values, ...$this->sensitiveValues($value, $redactedValue)];
            }
        }

        return $this->uniqueStrings($values);
    }

    private function isSensitiveKey(string $key): bool
    {
        $normalized = strtolower($key);
        $compact = str_replace(['_', '-', ' '], '', $normalized);

        foreach (self::SENSITIVE_KEY_PARTS as $part) {
            $compactPart = str_replace(['_', '-', ' '], '', $part);

            if (str_contains($normalized, $part) || str_contains($compact, $compactPart)) {
                return true;
            }
        }

        return false;
    }
}