<?php

declare(strict_types=1);

namespace App\Services\TenantConfiguration;

abstract class ExchangePowerShellTargetEvidenceNormalizer
{
    public const string PAYLOAD_SHAPE_VERSION = 'exchange-powershell-normalized-payload-v1';

    public function __construct(
        protected readonly ExchangePowerShellCommandContracts $contracts,
        protected readonly ExchangePowerShellHashInputBuilder $hashes,
    ) {}

    abstract public function resourceType(): string;

    abstract public function normalizerVersion(): string;

    /**
     * @return list<string>
     */
    abstract protected function materialFields(): array;

    /**
     * @return list<list<string>>
     */
    protected function identityAliasGroups(): array
    {
        return [
            ['id', 'sourceId'],
        ];
    }

    public function evaluate(ExchangePowerShellStructuredOutputEnvelope $envelope): ExchangePowerShellNormalizerReadiness
    {
        $definition = $this->definition();

        if ($envelope->resourceType !== $this->resourceType()) {
            return ExchangePowerShellNormalizerReadiness::blocked(
                resourceType: $envelope->resourceType,
                definition: $definition,
                blockers: ['blocked_target_not_ready'],
                itemCount: $envelope->itemCount,
            );
        }

        if (! $envelope->accepted()) {
            return ExchangePowerShellNormalizerReadiness::blocked(
                resourceType: $this->resourceType(),
                definition: $definition,
                blockers: [$envelope->readinessBlocker ?? 'blocked_unknown_output'],
                itemCount: $envelope->itemCount,
            );
        }

        if ($envelope->emptyCollection) {
            return ExchangePowerShellNormalizerReadiness::ready(
                resourceType: $this->resourceType(),
                definition: $definition,
                normalizedPreviews: [],
                hashPreviews: [],
                itemCount: 0,
                emptyCollection: true,
            );
        }

        $previews = [];
        $seenIdentities = [];

        foreach ($envelope->items as $item) {
            $identity = $this->stableIdentity($item);

            if (($identity['allowed'] ?? false) !== true) {
                return ExchangePowerShellNormalizerReadiness::blocked(
                    resourceType: $this->resourceType(),
                    definition: $definition,
                    blockers: [(string) ($identity['blocker'] ?? 'blocked_identity_unproven')],
                    itemCount: $envelope->itemCount,
                );
            }

            $identityKey = (string) $identity['key'];

            if (isset($seenIdentities[$identityKey])) {
                return ExchangePowerShellNormalizerReadiness::blocked(
                    resourceType: $this->resourceType(),
                    definition: $definition,
                    blockers: ['duplicate_stable_identity'],
                    itemCount: $envelope->itemCount,
                );
            }

            $seenIdentities[$identityKey] = true;
            $normalized = $this->normalizePayload($item, $identity);
            $hashInput = $this->hashes->build(
                resourceType: $this->resourceType(),
                sourceSurface: ExchangePowerShellCommandContracts::SOURCE_SURFACE,
                commandContractName: (string) $definition['command_contract_name'],
                commandContractVersion: (string) $definition['command_contract_version'],
                payloadShapeVersion: self::PAYLOAD_SHAPE_VERSION,
                normalizerVersion: $this->normalizerVersion(),
                normalizedPayload: $normalized,
            );

            $hashPreview = $this->hashes->hash($hashInput);
            $previews[] = [
                'identity_key' => $identityKey,
                'identity_sort_key' => (string) $identity['value'],
                'hash_preview' => $hashPreview,
                'normalized_preview' => $normalized,
            ];
        }

        usort($previews, static function (array $left, array $right): int {
            return [$left['identity_sort_key'], $left['identity_key'], $left['hash_preview']]
                <=> [$right['identity_sort_key'], $right['identity_key'], $right['hash_preview']];
        });

        return ExchangePowerShellNormalizerReadiness::ready(
            resourceType: $this->resourceType(),
            definition: $definition,
            normalizedPreviews: array_values(array_map(
                static fn (array $preview): array => $preview['normalized_preview'],
                $previews,
            )),
            hashPreviews: array_values(array_map(
                static fn (array $preview): string => (string) $preview['hash_preview'],
                $previews,
            )),
            itemCount: count($previews),
        );
    }

    /**
     * @return array<string, mixed>
     */
    public function definition(): array
    {
        $contract = $this->contract();
        $shape = is_array($contract['response_shape'] ?? null) ? $contract['response_shape'] : [];

        return [
            'resource_type' => $this->resourceType(),
            'source_surface' => ExchangePowerShellCommandContracts::SOURCE_SURFACE,
            'command_contract_name' => (string) ($contract['command_name'] ?? ''),
            'command_contract_version' => ExchangePowerShellCommandContracts::COMMAND_CONTRACT_VERSION,
            'payload_shape_version' => self::PAYLOAD_SHAPE_VERSION,
            'normalizer_version' => $this->normalizerVersion(),
            'identity_candidate_fields' => $this->stringList($shape['required_identity_candidate_fields'] ?? []),
            'material_fields' => $this->materialFields(),
            'volatile_fields' => $this->stringList($shape['volatile_fields'] ?? []),
            'sensitive_fields' => $this->stringList($shape['sensitive_fields'] ?? []),
            'protected_fields' => $this->stringList($shape['protected_configuration_fields'] ?? []),
            'ordering_rules' => [
                'associative_keys_sorted' => true,
                'unordered_lists_sorted_by_canonical_value' => true,
                'collection_ordering' => 'stable_identity_value_then_hash_preview',
            ],
            'hash_input_rules' => [
                'includes_resource_type' => true,
                'includes_source_surface' => true,
                'includes_command_contract' => true,
                'includes_payload_shape_version' => true,
                'includes_normalizer_version' => true,
                'excludes_raw_stdout' => true,
                'excludes_raw_stderr' => true,
                'excludes_operation_run_context' => true,
                'excludes_runtime_timestamps' => true,
                'excludes_powershell_session_metadata' => true,
                'excludes_credential_metadata' => true,
                'excludes_permission_metadata' => true,
            ],
            'redaction_policy' => [
                'protected_configuration_values' => 'presence_only_redacted',
                'sensitive_values' => 'presence_only_redacted',
                'raw_provider_payload_default_visible' => false,
            ],
            'readiness_blockers' => [
                'blocked_malformed_output',
                'blocked_warning_prefixed_output',
                'blocked_binary_output',
                'blocked_oversized_output',
                'blocked_nonzero_exit',
                'blocked_timeout',
                'identity_conflict',
                'missing_stable_external_id',
                'derived_identity_blocked',
                'display_name_only',
                'duplicate_stable_identity',
                'unsupported_identity',
                'blocked_redaction_unproven',
                'blocked_hash_unready',
                'blocked_target_not_ready',
            ],
        ];
    }

    /**
     * @param  array<string, mixed>  $payload
     * @param  array<string, mixed>  $identity
     * @return array<string, mixed>
     */
    protected function normalizePayload(array $payload, array $identity): array
    {
        $material = [];
        $protected = [];
        $sensitive = [];
        $volatile = $this->volatileFields();

        foreach ($this->materialFields() as $field) {
            if (! array_key_exists($field, $payload) || in_array($field, $volatile, true)) {
                continue;
            }

            if ($this->isProtectedField($field)) {
                $protected[$field] = $this->redactedMarker($payload[$field]);

                continue;
            }

            if ($this->isSensitiveField($field)) {
                $sensitive[$field] = $this->redactedMarker($payload[$field]);

                continue;
            }

            $material[$this->settingKey($field)] = $this->normalizeSettingValue($payload[$field]);
        }

        return $this->sortAssociative([
            'canonical_type' => $this->resourceType(),
            'source_surface' => ExchangePowerShellCommandContracts::SOURCE_SURFACE,
            'payload_shape_version' => self::PAYLOAD_SHAPE_VERSION,
            'normalizer_version' => $this->normalizerVersion(),
            'source_identity' => [
                'field' => $identity['field'],
                'value' => $identity['value'],
            ],
            'material' => $this->sortAssociative($material),
            'protected_configuration' => $this->sortAssociative($protected),
            'sensitive_content' => $this->sortAssociative($sensitive),
            'diagnostics' => [
                'volatile_fields' => $volatile,
                'protected_fields' => array_keys($protected),
                'sensitive_fields' => array_keys($sensitive),
            ],
        ]);
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return array{allowed: bool, key?: string, field?: string, value?: string, blocker?: string}
     */
    protected function stableIdentity(array $payload): array
    {
        foreach ($this->identityAliasGroups() as $group) {
            $values = [];

            foreach ($group as $field) {
                $value = $this->stringValue($payload[$field] ?? null);

                if ($value !== null) {
                    $values[$field] = $value;
                }
            }

            if (count(array_unique(array_values($values))) > 1) {
                return ['allowed' => false, 'blocker' => 'identity_conflict'];
            }
        }

        foreach ($this->identityFields() as $field) {
            $value = $this->stringValue($payload[$field] ?? null);

            if ($value !== null) {
                return [
                    'allowed' => true,
                    'field' => $field,
                    'value' => $value,
                    'key' => $this->resourceType().':'.$field.':'.hash('sha256', $value),
                ];
            }
        }

        if ($this->hasDisplayOnlyIdentity($payload)) {
            return ['allowed' => false, 'blocker' => 'display_name_only'];
        }

        foreach ($this->derivedIdentityFields() as $field) {
            if ($this->stringValue($payload[$field] ?? null) !== null) {
                return ['allowed' => false, 'blocker' => 'derived_identity_blocked'];
            }
        }

        return ['allowed' => false, 'blocker' => 'missing_stable_external_id'];
    }

    /**
     * @param  list<string>  $groupKeys
     * @param  list<string>  $rootKeys
     * @return array<string, mixed>
     */
    protected function settingGroup(array $payload, array $groupKeys, array $rootKeys = []): array
    {
        $settings = [];

        foreach ($groupKeys as $groupKey) {
            $group = $payload[$groupKey] ?? null;

            if (! is_array($group)) {
                continue;
            }

            foreach ($group as $key => $value) {
                $field = (string) $key;
                $settings[$this->settingKey($field)] = $this->redactedOrNormalized($field, $value);
            }
        }

        foreach ($rootKeys as $rootKey) {
            if (! array_key_exists($rootKey, $payload)) {
                continue;
            }

            $settings[$this->settingKey($rootKey)] = $this->redactedOrNormalized($rootKey, $payload[$rootKey]);
        }

        return $this->sortAssociative($settings);
    }

    protected function redactedOrNormalized(string $field, mixed $value): mixed
    {
        if ($this->isProtectedField($field) || $this->isSensitiveField($field)) {
            return $this->redactedMarker($value);
        }

        return $this->normalizeSettingValue($value);
    }

    protected function redactedMarker(mixed $value): array
    {
        return [
            'value' => '[redacted]',
            'present' => $value !== null,
            'count' => is_array($value) ? count($value) : ($value === null ? 0 : 1),
        ];
    }

    protected function normalizeSettingValue(mixed $value): mixed
    {
        if (is_bool($value)) {
            return $value;
        }

        if (is_scalar($value)) {
            $value = trim((string) $value);

            return $value !== '' ? $value : null;
        }

        if (! is_array($value)) {
            return null;
        }

        if (array_is_list($value)) {
            $items = array_values(array_filter(
                array_map(fn (mixed $item): mixed => $this->normalizeSettingValue($item), $value),
                static fn (mixed $item): bool => $item !== null && $item !== '',
            ));

            usort($items, static fn (mixed $left, mixed $right): int => strcmp(
                json_encode($left, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR),
                json_encode($right, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR),
            ));

            return $items;
        }

        $normalized = [];

        foreach ($value as $key => $nestedValue) {
            $normalized[$this->settingKey((string) $key)] = $this->normalizeSettingValue($nestedValue);
        }

        return $this->sortAssociative($normalized);
    }

    /**
     * @param  array<string, mixed>  $payload
     * @return array<string, mixed>
     */
    protected function sortAssociative(array $payload): array
    {
        ksort($payload, SORT_NATURAL | SORT_FLAG_CASE);

        foreach ($payload as $key => $value) {
            if (is_array($value) && ! array_is_list($value)) {
                $payload[$key] = $this->sortAssociative($value);
            }
        }

        return $payload;
    }

    protected function settingKey(string $key): string
    {
        $key = str_replace(
            ['IP', 'TLS', 'OOF', 'TNEF'],
            ['Ip', 'Tls', 'Oof', 'Tnef'],
            $key,
        );

        return str($key)
            ->replaceMatches('/[^A-Za-z0-9]+/', '_')
            ->snake()
            ->trim('_')
            ->toString();
    }

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

        if (is_bool($value)) {
            return $value ? 'true' : 'false';
        }

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

        return $value !== '' ? $value : null;
    }

    /**
     * @return list<string>
     */
    protected function identityFields(): array
    {
        return $this->stringList(data_get($this->contract(), 'response_shape.required_identity_candidate_fields', []));
    }

    /**
     * @return list<string>
     */
    protected function derivedIdentityFields(): array
    {
        return $this->stringList(data_get($this->contract(), 'response_shape.derived_identity_candidate_fields', []));
    }

    /**
     * @return list<string>
     */
    protected function volatileFields(): array
    {
        return $this->stringList(data_get($this->contract(), 'response_shape.volatile_fields', []));
    }

    protected function isSensitiveField(string $field): bool
    {
        return in_array(
            strtolower($field),
            array_map('strtolower', $this->stringList(data_get($this->contract(), 'response_shape.sensitive_fields', []))),
            true,
        );
    }

    protected function isProtectedField(string $field): bool
    {
        return in_array(
            strtolower($field),
            array_map('strtolower', $this->stringList(data_get($this->contract(), 'response_shape.protected_configuration_fields', []))),
            true,
        );
    }

    /**
     * @return array<string, mixed>
     */
    protected function contract(): array
    {
        return $this->contracts->contractForCanonicalType($this->resourceType()) ?? [];
    }

    /**
     * @return list<string>
     */
    protected function stringList(mixed $value): array
    {
        if (! is_array($value)) {
            return [];
        }

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

    private function hasDisplayOnlyIdentity(array $payload): bool
    {
        foreach (['DisplayName', 'displayName', 'Name', 'name'] as $field) {
            if ($this->stringValue($payload[$field] ?? null) !== null) {
                return true;
            }
        }

        return false;
    }
}