<?php

namespace App\Services;

use App\Models\User;
use Illuminate\Contracts\Encryption\DecryptException;
use Illuminate\Database\Query\Builder;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Crypt;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\Str;

final class TerritorialRegistry
{
    public const PARENTS = ['country' => null, 'province' => 'country', 'district' => 'province', 'admin_post' => 'district', 'locality' => 'admin_post'];

    public function published(): Builder
    {
        // Every ancestor must remain public, in force and backed by an approved source.
        return DB::table('geo_locations as g')->join('geo_territory_profiles as p', 'p.geo_location_id', '=', 'g.id')
            ->whereNull('g.deleted_at')->where('g.data_classification', 'public')->where('p.status', 'published')
            ->whereRaw("NOT EXISTS (WITH RECURSIVE ancestry AS (
                SELECT l.id,l.parent_id,l.deleted_at,l.data_classification,ARRAY[l.id] AS path,false AS cycle FROM geo_locations l WHERE l.id=g.id
                UNION ALL SELECT l.id,l.parent_id,l.deleted_at,l.data_classification,a.path||l.id,l.id=ANY(a.path) FROM geo_locations l JOIN ancestry a ON l.id=a.parent_id WHERE NOT a.cycle
            ) SELECT 1 FROM ancestry a LEFT JOIN geo_territory_profiles ap ON ap.geo_location_id=a.id LEFT JOIN geo_sources s ON s.id=ap.source_id
              WHERE a.cycle OR a.deleted_at IS NOT NULL OR a.data_classification<>'public' OR ap.status IS DISTINCT FROM 'published' OR s.status IS DISTINCT FROM 'approved'
                 OR ap.valid_from>CURRENT_DATE OR ap.valid_to<CURRENT_DATE)");
    }

    /** @param array<string,mixed> $input */
    public function save(User $actor, array $input, ?string $id = null): string
    {
        abort_unless($actor->can('manage-portal') && $actor->two_factor_confirmed_at && $actor->two_factor_secret, 403);
        abort_unless(in_array(strtolower($actor->email), config('territorial.editors', []), true), 403);
        $data = Validator::make($input, [
            'name' => ['required', 'string', 'max:255'], 'code' => ['required', 'string', 'max:100'],
            'location_type' => ['required', 'in:'.implode(',', array_keys(self::PARENTS))],
            'parent_id' => ['nullable', 'uuid', 'exists:geo_locations,id'], 'source_id' => ['required', 'uuid', 'exists:geo_sources,id'],
            'valid_from' => ['required', 'date_format:Y-m-d'], 'valid_to' => ['nullable', 'date_format:Y-m-d', 'after_or_equal:valid_from'],
            'version_no' => [$id ? 'required' : 'prohibited', 'integer', 'min:1'], 'reason' => ['required', 'string', 'min:10', 'max:1000'], 'confirm_baseline_change' => ['sometimes', 'boolean'],
        ])->validate();
        $this->ensureWriteMode($id);
        if ($this->editorialAvailable()) {
            return $this->saveEditorial($actor, $data, $id);
        }

        return DB::transaction(function () use ($actor, $data, $id) {
            // Serialise hierarchy changes to prevent concurrent parent cycles and duplicate paths.
            DB::select('SELECT pg_advisory_xact_lock(280926, 150000)');
            $current = $id ? DB::table('geo_locations')->where('id', $id)->whereNull('deleted_at')->lockForUpdate()->first() : null;
            if ($id) {
                abort_unless($current && DB::table('geo_territory_profiles')->where('geo_location_id', $id)->exists(), 404);
                abort_unless($current->version_no === $data['version_no'], 409);
                abort_unless($current->location_type === $data['location_type'], 422, 'O tipo territorial é imutável.');
            }
            $parentType = self::PARENTS[$data['location_type']];
            $parent = empty($data['parent_id']) ? null : DB::table('geo_locations')->where('id', $data['parent_id'])->whereNull('deleted_at')->first();
            abort_unless($parentType ? $parent && $parent->location_type === $parentType : ! $parent, 422, 'Hierarquia territorial incoerente.');
            $duplicate = DB::table('geo_locations')->where('location_type', $data['location_type'])->whereNull('deleted_at')->when($id, fn ($q) => $q->where('id', '<>', $id))
                ->where(fn ($q) => $q->where('code', $data['code'])->orWhere(fn ($q) => $q->where('parent_id', $data['parent_id'] ?? null)->whereRaw('lower(trim(name))=lower(trim(?))', [$data['name']])))->exists();
            abort_if($duplicate, 422, 'Código ou nome no mesmo pai já existente.');
            $id ??= (string) Str::uuid();
            $version = $current ? $current->version_no + 1 : 1;
            DB::table('geo_locations')->updateOrInsert(['id' => $id], ['name' => $data['name'], 'code' => $data['code'],
                'location_type' => $data['location_type'], 'parent_id' => $data['parent_id'] ?? null,
                'version_no' => $version, 'data_classification' => 'internal', 'updated_at' => now()]);
            DB::table('geo_territory_profiles')->updateOrInsert(['geo_location_id' => $id], ['source_id' => $data['source_id'],
                'valid_from' => $data['valid_from'], 'valid_to' => $data['valid_to'] ?? null, 'status' => 'draft',
                'editor_id' => $actor->id, 'reviewer_id' => null, 'publisher_id' => null, 'updated_at' => now()]);
            $this->snapshot($id, $version, $actor, $data['reason']);

            return $id;
        });
    }

    /** @param array<string,mixed>|null $proposal */
    public function snapshot(string $id, int $version, User $actor, string $reason, ?array $proposal = null): string
    {
        $snapshot = json_encode($proposal ?? ['location' => DB::table('geo_locations')->find($id),
            'profile' => DB::table('geo_territory_profiles')->where('geo_location_id', $id)->first()], JSON_THROW_ON_ERROR);
        $revision = (string) Str::uuid();
        DB::table('geo_territory_revisions')->insert(['id' => $revision, 'geo_location_id' => $id,
            'version_no' => $version, 'actor_id' => $actor->id, 'reason' => Crypt::encryptString($reason),
            'snapshot' => Crypt::encryptString($snapshot), 'checksum' => hash('sha256', $snapshot)]);

        return $revision;
    }

    private const EDITORIAL_SOURCE = 'territorial-editorial-v1';

    public function editorialAvailable(): bool
    {
        return (bool) config('editorial_workflow.territorial_versions') && (bool) config('territorial.enabled') && Schema::hasTable('geo_territory_revisions') && Schema::hasTable('audit_events');
    }

    public function ensureWriteMode(?string $id): void
    {
        if (config('editorial_workflow.territorial_versions')) {
            abort_unless($this->editorialAvailable(), 503, 'Circuito territorial ainda não disponível.');
        } elseif ($id) {
            abort_if(DB::table('audit_events')->where('source_system', self::EDITORIAL_SOURCE)->where('entity_id', $id)->exists(), 503, 'Reactive o circuito para conservar a revisão territorial privada.');
        }
    }

    public function hasEditorialHistory(string $id): bool
    {
        return DB::table('audit_events')->where('source_system', self::EDITORIAL_SOURCE)->where('entity_id', $id)->exists();
    }

    /** @return array<string,mixed> */
    public function preview(string $id): array
    {
        $state = $this->working($id);
        $history = DB::table('geo_territory_revisions')->where('geo_location_id', $id)->orderByDesc('version_no')->limit(100)->get()
            ->map(function ($revision) {
                try {
                    $json = Crypt::decryptString($revision->snapshot);
                    $reason = Crypt::decryptString($revision->reason);
                } catch (DecryptException) {
                    abort(409, 'Histórico territorial indisponível; preserve o original.');
                }
                abort_unless(hash_equals(trim($revision->checksum), hash('sha256', $json)), 409, 'Histórico territorial alterado.');

                return ['id' => $revision->id, 'version_no' => $revision->version_no, 'actor_id' => $revision->actor_id,
                    'reason' => $reason, 'snapshot' => json_decode($json, true, 512, JSON_THROW_ON_ERROR)];
            });

        return ['working' => $state, 'public' => $this->live($id), 'history' => $history];
    }

    /** @return array<string,mixed> */
    private function live(string $id): array
    {
        $location = DB::table('geo_locations')->where('id', $id)->whereNull('deleted_at')->first();
        $profile = DB::table('geo_territory_profiles')->where('geo_location_id', $id)->first();
        abort_unless($location && $profile, 404);

        return ['location' => get_object_vars($location), 'profile' => get_object_vars($profile)];
    }

    /** @param array<string,mixed> $value */
    private function digest(array $value): string
    {
        return hash('sha256', json_encode(Arr::sortRecursive($value), JSON_THROW_ON_ERROR));
    }

    /** @return array<string,mixed> */
    public function working(string $id): array
    {
        $live = $this->live($id);
        $event = DB::table('audit_events')->where('source_system', self::EDITORIAL_SOURCE)->where('entity_id', $id)->orderByRaw("(after_data->>'version_no')::integer DESC")->first();
        if ($event) {
            $details = json_decode($event->after_data, true, 512, JSON_THROW_ON_ERROR);
            $revision = DB::table('geo_territory_revisions')->where('id', $details['revision_id'])->where('geo_location_id', $id)->first();
            abort_unless($revision && hash_equals(trim($revision->checksum), $details['checksum']), 409, 'Referência de revisão territorial alterada.');
            try {
                $json = Crypt::decryptString($revision->snapshot);
            } catch (DecryptException) {
                abort(409, 'Revisão territorial indisponível; conserve o histórico.');
            }
            abort_unless(hash_equals(trim($revision->checksum), hash('sha256', $json)), 409, 'Conteúdo da revisão territorial alterado.');
            $state = json_decode($json, true, 512, JSON_THROW_ON_ERROR);
            abort_unless($state['location']['id'] === $id && $state['location']['version_no'] === (int) $revision->version_no, 409);
            if ($state['_editorial']['private']) {
                $state['public_version_no'] = $live['profile']['status'] === 'published' ? $live['location']['version_no'] : null;
                $state['baseline_changed'] = ! hash_equals($state['_editorial']['baseline_hash'], $this->digest($live));
                $state['fresh'] = ! $state['baseline_changed'] && hash_equals($state['_editorial']['content_hash'], $this->contentHash($state));

                return $state;
            }
            $live['_editorial'] = $state['_editorial'];
        }
        $live['public_version_no'] = $live['profile']['status'] === 'published' ? $live['location']['version_no'] : null;
        $live['location']['version_no'] = max((int) $live['location']['version_no'], (int) DB::table('geo_territory_revisions')->where('geo_location_id', $id)->max('version_no'));
        $live['baseline_changed'] = false;
        $live['fresh'] = true;

        return $live;
    }

    /** @param array<string,mixed> $state
     * @return array<string,mixed>
     */
    private function evidence(array $state): array
    {
        $source = DB::table('geo_sources')->where('id', $state['profile']['source_id'])->first();
        abort_unless($source !== null, 422, 'Fonte indisponível.');
        $parents = [];
        $parent = $state['location']['parent_id'];
        $seen = [$state['location']['id']];
        while ($parent) {
            abort_if(in_array($parent, $seen, true) || count($seen) > 5, 422, 'Hierarquia territorial incoerente.');
            $seen[] = $parent;
            $row = DB::table('geo_locations')->where('id', $parent)->whereNull('deleted_at')->first(['id', 'name', 'code', 'parent_id', 'location_type', 'version_no']);
            abort_unless($row !== null, 422, 'Ascendente indisponível.');
            $parents[] = get_object_vars($row);
            $parent = $row->parent_id;
        }

        return ['source' => Arr::only(get_object_vars($source), ['id', 'name', 'responsible_entity', 'reference', 'license', 'checksum', 'source_version', 'collected_at', 'original_crs']), 'parents' => $parents];
    }

    /** @param array<string,mixed> $state */
    private function contentHash(array $state): string
    {
        return $this->digest(['location' => Arr::only($state['location'], ['id', 'name', 'code', 'location_type', 'parent_id']),
            'profile' => Arr::only($state['profile'], ['source_id', 'valid_from', 'valid_to']),
            'contributors' => $state['_editorial']['contributors'], 'evidence' => $this->evidence($state)]);
    }

    private function editorialActor(User $actor, string $role): void
    {
        abort_unless($actor->can('manage-portal') && $actor->two_factor_confirmed_at && $actor->two_factor_secret && ! app(PortalProfileAccess::class)->has($actor, 'auditor')
            && in_array(strtolower($actor->email), config('territorial.'.$role, []), true) && app(PortalProfileAccess::class)->mfa($actor), 403, 'Função territorial e MFA válido necessários.');
    }

    /** @param array<string,mixed> $data */
    private function shape(array $data, ?string $id): void
    {
        $parentType = self::PARENTS[$data['location_type']];
        $parent = empty($data['parent_id']) ? null : DB::table('geo_locations')->where('id', $data['parent_id'])->whereNull('deleted_at')->first();
        abort_unless($parentType ? $parent && $parent->location_type === $parentType : ! $parent, 422, 'Hierarquia territorial incoerente.');
        $duplicate = DB::table('geo_locations')->where('location_type', $data['location_type'])->whereNull('deleted_at')->when($id, fn ($q) => $q->where('id', '<>', $id))
            ->where(fn ($q) => $q->where('code', $data['code'])->orWhere(fn ($q) => $q->where('parent_id', $data['parent_id'] ?? null)->whereRaw('lower(trim(name))=lower(trim(?))', [$data['name']])))->exists();
        abort_if($duplicate, 422, 'Código ou nome no mesmo pai já existente.');
    }

    /** @param array<string,mixed> $state */
    private function appendEditorial(User $actor, string $id, array $state, string $reason, string $action): void
    {
        unset($state['fresh'], $state['baseline_changed'], $state['public_version_no']);
        $version = (int) $state['location']['version_no'];
        $revision = $this->snapshot($id, $version, $actor, $reason, $state);
        $checksum = DB::table('geo_territory_revisions')->where('id', $revision)->value('checksum');
        $eventId = (string) Str::uuid();
        DB::table('audit_events')->insert(['id' => $eventId, 'source_system' => self::EDITORIAL_SOURCE, 'entity_type' => 'geo_locations', 'entity_id' => $id, 'actor_user_id' => $actor->id,
            'action' => $action, 'data_classification' => 'restricted', 'after_data' => json_encode(['version_no' => $version, 'revision_id' => $revision, 'checksum' => trim($checksum), 'state' => $state['profile']['status']], JSON_THROW_ON_ERROR)]);
        app(PortalEditorialNativeNotices::class)->emit($actor, $eventId, $state['_editorial']['contributors'] ?? []);
    }

    /** @param array<string,mixed> $data */
    private function saveEditorial(User $actor, array $data, ?string $id): string
    {
        $this->editorialActor($actor, 'editors');

        return DB::transaction(function () use ($actor, $data, $id) {
            DB::select('SELECT pg_advisory_xact_lock(280926, 150000)');
            $this->shape($data, $id);
            if (! $id) {
                $id = (string) Str::uuid();
                DB::table('geo_locations')->insert(['id' => $id, 'name' => $data['name'], 'code' => $data['code'], 'location_type' => $data['location_type'], 'parent_id' => $data['parent_id'] ?? null,
                    'version_no' => 1, 'data_classification' => 'internal', 'updated_at' => now()]);
                DB::table('geo_territory_profiles')->insert(['geo_location_id' => $id, 'source_id' => $data['source_id'], 'valid_from' => $data['valid_from'], 'valid_to' => $data['valid_to'] ?? null, 'status' => 'draft', 'editor_id' => $actor->id]);
                $state = $this->live($id);
            } else {
                DB::table('geo_locations')->where('id', $id)->lockForUpdate()->first();
                $state = $this->working($id);
                abort_unless((int) $state['location']['version_no'] === (int) $data['version_no'], 409, 'Versão territorial alterada.');
                abort_unless($state['location']['location_type'] === $data['location_type'], 422, 'O tipo territorial é imutável.');
                abort_if(($state['baseline_changed'] ?? false) && ! ($data['confirm_baseline_change'] ?? false), 409, 'Compare a publicação actual e confirme a reconciliação antes de guardar.');
                if (! $this->hasEditorialHistory($id) && ! DB::table('geo_territory_revisions')->where('geo_location_id', $id)->where('version_no', $state['location']['version_no'])->exists()) {
                    $this->snapshot($id, $state['location']['version_no'], $actor, 'Conservação do estado anterior ao circuito editorial; não constitui nova aprovação.');
                }
                $state['location']['version_no']++;
            }
            $private = $state['_editorial']['private'] ?? false;
            $contributors = array_values(array_unique([...($private ? $state['_editorial']['contributors'] : []), $actor->id]));
            $state['location'] = array_replace($state['location'], Arr::only($data, ['name', 'code', 'location_type', 'parent_id']), ['data_classification' => 'internal']);
            $state['profile'] = array_replace($state['profile'], Arr::only($data, ['source_id', 'valid_from', 'valid_to']), ['status' => 'draft', 'editor_id' => $actor->id, 'reviewer_id' => null, 'publisher_id' => null]);
            $state['_editorial'] = ['private' => true, 'edition_no' => $state['location']['version_no'], 'contributors' => $contributors, 'approval' => null, 'baseline_hash' => $this->digest($this->live($id)), 'evidence' => $this->evidence($state)];
            $state['_editorial']['content_hash'] = $this->contentHash($state);
            $this->appendEditorial($actor, $id, $state, $data['reason'], 'draft_saved');

            return $id;
        });
    }

    /** @param array<string,mixed> $data
     * @return array<string,mixed>
     */
    public function transitionEditorial(User $actor, string $id, array $data): array
    {
        $this->ensureWriteMode($id);
        abort_unless($this->editorialAvailable(), 503);
        $action = $data['action'];
        $role = match ($action) {
            'in_review', 'approved', 'rejected' => 'reviewers',
            'published', 'archived', 'withdrawn' => 'publishers',
            default => 'editors',
        };
        $this->editorialActor($actor, $role);

        return DB::transaction(function () use ($actor, $id, $data, $action) {
            DB::select('SELECT pg_advisory_xact_lock(280926, 150000)');
            DB::table('geo_locations')->where('id', $id)->lockForUpdate()->first();
            DB::table('geo_territory_profiles')->where('geo_location_id', $id)->lockForUpdate()->first();
            $state = $this->working($id);
            abort_unless((int) $state['location']['version_no'] === (int) $data['version_no'], 409, 'Versão territorial alterada.');
            if ($action === 'published') {
                $evidence = $this->evidence($state);
                $parentIds = array_column($evidence['parents'], 'id');
                DB::table('geo_locations')->whereIn('id', $parentIds)->orderBy('id')->lockForUpdate()->get();
                DB::table('geo_territory_profiles')->whereIn('geo_location_id', $parentIds)->orderBy('geo_location_id')->lockForUpdate()->get();
                $sourceIds = DB::table('geo_territory_profiles')->whereIn('geo_location_id', $parentIds)->pluck('source_id')->all();
                $sourceIds[] = $state['profile']['source_id'];
                DB::table('geo_sources')->whereIn('id', $sourceIds)->orderBy('id')->lockForUpdate()->get();
                $state = $this->working($id);
            }
            $private = $state['_editorial']['private'] ?? false;
            $live = $this->live($id);
            if ($action === 'withdrawn' || ($action === 'archived' && ! $private)) {
                abort_unless($live['profile']['status'] === 'published', 409);
                $version = $state['location']['version_no'] + 1;
                DB::table('geo_territory_profiles')->where('geo_location_id', $id)->update(['status' => 'archived', 'updated_at' => now()]);
                DB::table('geo_locations')->where('id', $id)->update(['data_classification' => 'internal', 'version_no' => $version, 'updated_at' => now()]);
                if ($private) {
                    $state['_editorial']['baseline_hash'] = $this->digest($this->live($id));
                } else {
                    $state = $this->live($id);
                    $state['_editorial'] = ['private' => false];
                }
                $state['location']['version_no'] = $version;
                $this->appendEditorial($actor, $id, $state, $data['reason'], 'publication_withdrawn');

                return ['id' => $id, 'status' => $state['profile']['status'], 'version_no' => $version];
            }
            abort_unless($private, 409, 'Guarde uma versão privada antes de iniciar o novo circuito.');
            $from = ['pending_review' => ['draft', 'rejected'], 'in_review' => ['pending_review'], 'approved' => ['in_review'],
                'rejected' => ['pending_review', 'in_review'], 'published' => ['approved'], 'archived' => ['draft', 'pending_review', 'in_review', 'approved', 'rejected']];
            abort_unless(isset($from[$action]) && in_array($state['profile']['status'], $from[$action], true), 409);
            if (in_array($action, ['pending_review', 'approved', 'published'], true)) {
                abort_unless($state['fresh'], 409, 'A publicação, fonte ou hierarquia mudou; reveja a versão.');
            }
            if ($action === 'pending_review') {
                abort_unless($state['profile']['editor_id'] === $actor->id, 403);
            }
            if (in_array($action, ['in_review', 'approved', 'rejected'], true)) {
                abort_if(in_array($actor->id, $state['_editorial']['contributors'], true), 403, 'Revisão independente obrigatória.');
                $state['profile']['reviewer_id'] = $actor->id;
            }
            if ($action === 'approved') {
                $state['_editorial']['approval'] = ['reviewer_id' => $actor->id, 'edition_no' => $state['_editorial']['edition_no'],
                    'content_hash' => $state['_editorial']['content_hash'], 'reason' => $data['reason'], 'at' => now()->toIso8601String()];
            }
            if ($action === 'published') {
                $approval = $state['_editorial']['approval'];
                abort_unless(is_array($approval) && $approval['edition_no'] === $state['_editorial']['edition_no']
                    && hash_equals($approval['content_hash'], $this->contentHash($state)), 409, 'Aprovação não corresponde a esta versão.');
                abort_if(in_array($actor->id, [...$state['_editorial']['contributors'], $approval['reviewer_id']], true), 403, 'Publicação exige terceiro interveniente.');
                $reviewer = User::where('id', $approval['reviewer_id'])->first();
                abort_unless($reviewer && $reviewer->can('manage-portal') && $reviewer->two_factor_confirmed_at && $reviewer->two_factor_secret
                    && ! app(PortalProfileAccess::class)->has($reviewer, 'auditor') && in_array(strtolower($reviewer->email), config('territorial.reviewers', []), true), 409, 'Revisor deixou de ter autoridade.');
                abort_unless(DB::table('geo_sources')->where('id', $state['profile']['source_id'])->where('status', 'approved')->exists(), 422, 'Fonte não aprovada.');
                abort_if($state['profile']['valid_from'] > today()->toDateString() || ($state['profile']['valid_to'] && $state['profile']['valid_to'] < today()->toDateString()), 422, 'Vigência inválida.');
                abort_if($state['location']['parent_id'] && ! $this->published()->where('g.id', $state['location']['parent_id'])->exists(), 422, 'Ascendente não publicado.');
                $this->shape($state['location'], $id);
                $state['profile']['publisher_id'] = $actor->id;
            }
            $state['location']['version_no']++;
            $state['profile']['status'] = $action;
            if ($action === 'published') {
                DB::table('geo_locations')->where('id', $id)->update([...Arr::only($state['location'], ['name', 'code', 'location_type', 'parent_id', 'version_no']), 'data_classification' => 'public', 'updated_at' => now()]);
                DB::table('geo_territory_profiles')->where('geo_location_id', $id)->update([...Arr::only($state['profile'], ['source_id', 'valid_from', 'valid_to', 'status', 'editor_id', 'reviewer_id', 'publisher_id']), 'updated_at' => now()]);
                $state['_editorial']['private'] = false;
            }
            if ($action === 'archived') {
                // Archiving a proposal never withdraws the existing public version.
                $state['_editorial']['private'] = false;
            }
            $this->appendEditorial($actor, $id, $state, $data['reason'], $action);

            return ['id' => $id, 'status' => $action, 'version_no' => $state['location']['version_no']];
        });
    }
}