<?php

namespace App\Services;

use App\Models\EconomicCluster;
use Illuminate\Database\Query\Builder;
use Illuminate\Support\Facades\Crypt;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\ValidationException;

final class ClusterCompetitiveness
{
    public const FORCES = ['rivalry', 'entrants', 'substitutes', 'suppliers', 'buyers'];

    public const FIELDS = ['evidence', 'source', 'period', 'rationale', 'limitations', 'opportunity'];

    private const SOURCE = 'cluster-competitiveness';

    private function events(string $cluster): Builder
    {
        return DB::table('audit_events')->where('source_system', self::SOURCE)
            ->where('entity_type', 'economic_clusters')->where('entity_id', $cluster);
    }

    /**
     * @return array<array-key, mixed>
     */
    private function decode(?\stdClass $event): array
    {
        return $event ? json_decode(Crypt::decryptString(json_decode($event->after_data, true, 512, JSON_THROW_ON_ERROR)['snapshot']), true, 512, JSON_THROW_ON_ERROR)
            : ['version' => 0, 'draft' => null, 'approved' => null];
    }

    /**
     * @return array<array-key, mixed>
     */
    public function current(string $cluster): array
    {
        return $this->decode($this->events($cluster)->orderByRaw("(after_data->>'version')::integer DESC")->first());
    }

    /**
     * @return array<array-key, mixed>
     */
    public function management(string $cluster): array
    {
        $state = $this->current($cluster);
        $state['history'] = $this->events($cluster)->orderByRaw("(after_data->>'version')::integer DESC")->limit(50)->get()
            ->map(fn ($event) => ['version' => json_decode($event->after_data, true)['version'],
                'action' => $event->action, 'at' => $event->occurred_at, 'actor' => $event->actor_user_id])->all();

        return $state;
    }

    /**
     * @param  array<array-key, mixed>  $draft
     * @return array<array-key, mixed>
     */
    public function validateDraft(array $draft, string $cluster): array
    {
        $rules = ['version' => 'required|integer|in:1', 'clusterId' => 'required|string|in:'.$cluster,
            'sector' => 'present|nullable|string|max:200', 'region' => 'present|nullable|string|max:1000',
            'forces' => 'required|array:'.implode(',', self::FORCES)];
        foreach (self::FORCES as $force) {
            $rules["forces.$force"] = 'required|array:pressure,'.implode(',', self::FIELDS);
            $rules["forces.$force.pressure"] = 'present|nullable|in:low,medium,high';
            foreach (self::FIELDS as $field) {
                $rules["forces.$force.$field"] = 'present|nullable|string|max:5000';
            }
        }
        $clean = Validator::make($draft, $rules)->validate();
        $clean['version'] = 1;
        $clean['sector'] = trim($clean['sector'] ?? '');
        $clean['region'] = trim($clean['region'] ?? '');
        foreach (self::FORCES as $force) {
            foreach (['pressure', ...self::FIELDS] as $field) {
                $clean['forces'][$force][$field] = trim($clean['forces'][$force][$field] ?? '');
            }
        }

        return $clean;
    }

    /**
     * @param  array<array-key, mixed>|null  $draft
     */
    private function assertComplete(?array $draft): void
    {
        $missing = ! $draft || ! $draft['sector'] || ! $draft['region'];
        foreach (self::FORCES as $force) {
            $row = $draft['forces'][$force] ?? [];
            $missing = $missing || ! in_array($row['pressure'] ?? '', ['low', 'medium', 'high'], true);
            foreach (self::FIELDS as $field) {
                $missing = $missing || trim($row[$field] ?? '') === '';
            }
        }
        if ($missing) {
            throw ValidationException::withMessages(['approval' => 'Complete o âmbito e as evidências, fontes, períodos, justificação, limitações e oportunidades das cinco forças antes de aprovar.']);
        }
    }

    /** Reuse the portal's encrypted, append-only audit snapshots; no new schema or mutable publication fields.
     * @param  array<array-key, mixed>  $input
     * @return array<array-key, mixed>
     */
    public function change(EconomicCluster $cluster, int $actor, int $expected, string $action, array $input = []): array
    {
        return DB::transaction(function () use ($cluster, $actor, $expected, $action, $input) {
            EconomicCluster::whereKey($cluster->id)->lockForUpdate()->firstOrFail();
            $before = $this->current($cluster->id);
            abort_if($before['version'] !== $expected, 409, 'A análise foi alterada. Conserve os campos actuais e compare a versão do servidor antes de voltar a guardar.');
            $state = $before;
            if ($action === 'saved') {
                $state['draft'] = $this->validateDraft($input['draft'], $cluster->id);
            } elseif ($action === 'restored') {
                $event = $this->events($cluster->id)->where('after_data->version', $input['revision'])->first();
                abort_unless($event !== null, 404);
                $state['draft'] = $this->decode($event)['draft'];
            } elseif ($action === 'approved') {
                $this->assertComplete($state['draft']);
                $state['approved'] = ['draft' => $state['draft'], 'at' => now()->toISOString(), 'actor' => $actor,
                    'version' => $expected + 1, 'evidence' => $input['reason']];
            } elseif ($action === 'withdrawn') {
                $state['approved'] = null;
            } else {
                throw new \LogicException('Unsupported competitiveness action');
            }
            $state['version']++;
            DB::table('audit_events')->insert(['source_system' => self::SOURCE, 'entity_type' => 'economic_clusters',
                'entity_id' => $cluster->id, 'external_id' => $cluster->id.':'.$state['version'], 'actor_user_id' => $actor,
                'action' => $action, 'data_classification' => 'restricted',
                'before_data' => json_encode(['version' => $before['version']], JSON_THROW_ON_ERROR),
                'after_data' => json_encode(['version' => $state['version'], 'restored_from' => $input['revision'] ?? null,
                    'reason' => Crypt::encryptString($input['reason'] ?? ''),
                    'snapshot' => Crypt::encryptString(json_encode($state, JSON_THROW_ON_ERROR))], JSON_THROW_ON_ERROR)]);

            return $this->management($cluster->id);
        });
    }

    /**
     * @return array<array-key, mixed>|null
     */
    public function publicData(string $cluster): ?array
    {
        $approved = $this->current($cluster)['approved'];

        // Explicit projection: never return editor identity, approval evidence, history or the unapproved draft.
        return $approved ? ['draft' => $approved['draft'], 'version' => $approved['version'], 'at' => $approved['at']] : null;
    }
}