<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;
use RuntimeException;

/** Exact replay of the 28 accepted links into the transported project identities. */
final class ApprovedAnchorTerritories
{
    public const HASH = 'd2893d0a638d630435aca1890f79a8094dc58eb65bbdd65a470bb685fa075190';

    /** @return array{manifest_sha256:string,projects:list<array<string,mixed>>,links:list<array<string,mixed>>} */
    public function plan(): array
    {
        $file = base_path('docs/investmoz/unification/approved-anchor-territories-20261023.json');
        $contents = is_file($file) ? file_get_contents($file) : false;
        if ($contents !== false) {
            $contents = str_replace("\r\n", "\n", $contents);
        }
        if ($contents === false || ! hash_equals(self::HASH, hash('sha256', $contents))) {
            throw new RuntimeException('Reviewed territorial manifest changed.');
        }
        $manifest = json_decode($contents, true, 512, JSON_THROW_ON_ERROR);
        if (count($manifest['items']) !== 28) {
            throw new RuntimeException('Exact 28-link scope required.');
        }
        $projects = [];
        $links = [];
        foreach ($manifest['items'] as $item) {
            $project = DB::table('projects')->where('id', $item['project_id'])->whereNull('deleted_at')->first();
            $dossier = DB::table('investment_dossiers')->where('id', $item['dossier_id'])->whereNull('deleted_at')->first();
            if (! $project || $project->code !== $item['code'] || ! $dossier || $dossier->project_id !== $project->id
                || ! hash_equals($item['content_sha256'], hash('sha256', $dossier->content))
                || ! hash_equals($item['source_sha256'], hash('sha256', $dossier->source))) {
                throw new RuntimeException('Project identity or documentary source changed: '.$item['code']);
            }
            $original = $item['original_relation'];
            $geo = DB::table('geo_locations')->where('id', $original['geo_location_id'])->whereNull('deleted_at')->first();
            foreach (['location_type', 'source_code', 'parent_id', 'data_classification'] as $field) {
                if (! $geo || $item['territory'][$field] !== $geo->$field) {
                    throw new RuntimeException('Territory identity changed: '.$original['geo_location_id']);
                }
            }
            $metadata = $projects[$project->id]['after_metadata'] ?? json_decode($project->metadata, true, 512, JSON_THROW_ON_ERROR);
            $key = $geo->id.':'.$original['role'];
            $evidence = $item['evidence'];
            // Preserve the original dossier id in evidence and explicitly map the destination.
            $evidence['transported_dossier_id'] = $dossier->id;
            if (isset($metadata['documented_location_sources'][$key]) && $metadata['documented_location_sources'][$key] != $evidence) {
                throw new RuntimeException('Existing territorial evidence differs; no overwrite: '.$item['code']);
            }
            $projects[$project->id] ??= ['id' => $project->id, 'code' => $project->code, 'before_version' => (int) $project->version_no, 'before_metadata' => json_decode($project->metadata, true, 512, JSON_THROW_ON_ERROR)];
            $metadata['documented_location_sources'][$key] = $evidence;
            $projects[$project->id]['after_metadata'] = $metadata;
            $existing = DB::table('project_locations')->where('project_id', $project->id)->where('geo_location_id', $geo->id)->where('role', $original['role'])->first();
            if ($existing && ($existing->deleted_at || $existing->data_classification !== 'public')) {
                throw new RuntimeException('Archived or restricted territorial relation must not be revived.');
            }
            $identity = DB::table('project_locations')->where('id', $original['id'])->first();
            if ($identity && (! $existing || $identity->id !== $existing->id)) {
                throw new RuntimeException('Historical relation identity is already occupied.');
            }
            $links[] = ['code' => $item['code'], 'already_present' => (bool) $existing, 'row' => [...$original, 'project_id' => $project->id]];
        }

        return ['manifest_sha256' => self::HASH, 'projects' => array_values($projects), 'links' => $links];
    }

    /** Caller supplies an authenticated, backed-up transaction; no source publication changes.
     * @param  array{manifest_sha256:string,projects:list<array<string,mixed>>,links:list<array<string,mixed>>}  $plan
     * @return array<string,int>
     */
    public function apply(array $plan): array
    {
        if (DB::transactionLevel() < 1 || $this->plan() !== $plan) {
            throw new RuntimeException('Reviewed transaction and unchanged preview required.');
        }
        $inserted = 0;
        $updated = 0;
        foreach ($plan['projects'] as $project) {
            if ($project['before_metadata'] == $project['after_metadata']) {
                continue;
            }
            $count = DB::table('projects')->where('id', $project['id'])->where('version_no', $project['before_version'])->update([
                'metadata' => json_encode($project['after_metadata'], JSON_THROW_ON_ERROR), 'version_no' => $project['before_version'] + 1, 'updated_at' => now(),
            ]);
            if ($count !== 1) {
                throw new RuntimeException('Concurrent project change.');
            }
            DB::table('audit_events')->insert(['source_system' => 'approved-anchor-territories-recovery-v1', 'external_id' => self::HASH.':'.$project['id'], 'entity_type' => 'projects', 'entity_id' => $project['id'], 'action' => 'accepted_territories_restored',
                'data_classification' => 'public', 'before_data' => json_encode(['version_no' => $project['before_version'], 'metadata' => $project['before_metadata']], JSON_THROW_ON_ERROR),
                'after_data' => json_encode(['version_no' => $project['before_version'] + 1, 'manifest_sha256' => self::HASH, 'metadata' => $project['after_metadata'], 'new_approval' => false], JSON_THROW_ON_ERROR)]);
            $updated++;
        }
        foreach ($plan['links'] as $link) {
            if ($link['already_present']) {
                continue;
            }
            DB::table('project_locations')->insert($link['row']);
            $inserted++;
        }

        return ['relations_restored' => $inserted, 'projects_updated' => $updated, 'new_dossiers' => 0, 'publication_changes' => 0];
    }
}