<?php

namespace App\Services\Graph;

use App\Models\DirectoryGroup;
use App\Models\DirectoryUser;
use App\Models\Tenant;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Throwable;

/**
 * Réplique utilisateurs et groupes Entra dans la base locale.
 * - Utilisateurs : requête delta (incrémentale), complète si --full ou si le deltaLink a expiré.
 * - Groupes : ceux dont le nom commence par le préfixe configuré, avec appartenance transitive.
 */
class DirectorySync
{
    private const USER_SELECT = 'id,displayName,givenName,surname,jobTitle,department,companyName,officeLocation,businessPhones,mobilePhone,mail,userPrincipalName,streetAddress,postalCode,city,accountEnabled';

    public function run(Tenant $tenant, bool $full = false): array
    {
        $graph = new GraphClient($tenant->entra_tenant_id);
        $stats = ['users' => 0, 'removed' => 0, 'groups' => 0, 'memberships' => 0];

        try {
            [$stats['users'], $stats['removed']] = $this->syncUsers($tenant, $graph, $full);
            [$stats['groups'], $stats['memberships']] = $this->syncGroups($tenant, $graph);
            $tenant->update(['last_sync_at' => now(), 'last_sync_status' => 'ok']);
        } catch (Throwable $e) {
            $tenant->update(['last_sync_at' => now(), 'last_sync_status' => 'erreur : '.mb_substr($e->getMessage(), 0, 200)]);
            Log::error('Synchro annuaire en échec', ['tenant' => $tenant->id, 'error' => $e->getMessage()]);
            throw $e;
        }

        return $stats;
    }

    private function syncUsers(Tenant $tenant, GraphClient $graph, bool $full): array
    {
        $start = (! $full && $tenant->users_delta_link)
            ? $tenant->users_delta_link
            : '/users/delta?$select='.self::USER_SELECT;

        try {
            [$items, $deltaLink] = $graph->all($start);
        } catch (Throwable $e) {
            if ($full || ! $tenant->users_delta_link) {
                throw $e;
            }
            // deltaLink expiré (410) ou invalide : on repart d'une synchro complète.
            [$items, $deltaLink] = $graph->all('/users/delta?$select='.self::USER_SELECT);
            $full = true;
        }

        $now = now();
        $upserted = 0;
        $removed = 0;
        $seen = [];

        foreach ($items as $u) {
            if (isset($u['@removed'])) {
                $removed += DirectoryUser::where('tenant_id', $tenant->id)->where('entra_oid', $u['id'])->delete();
                continue;
            }
            // En delta, seules les propriétés modifiées sont renvoyées : on ne met à jour que celles-là.
            $attrs = array_filter([
                'display_name' => $u['displayName'] ?? null,
                'given_name' => $u['givenName'] ?? null,
                'surname' => $u['surname'] ?? null,
                'job_title' => $u['jobTitle'] ?? null,
                'department' => $u['department'] ?? null,
                'company_name' => $u['companyName'] ?? null,
                'office_location' => $u['officeLocation'] ?? null,
                'business_phone' => array_key_exists('businessPhones', $u) ? ($u['businessPhones'][0] ?? null) : null,
                'mobile_phone' => $u['mobilePhone'] ?? null,
                'mail' => isset($u['mail']) ? strtolower($u['mail']) : null,
                'user_principal_name' => isset($u['userPrincipalName']) ? strtolower($u['userPrincipalName']) : null,
                'street_address' => $u['streetAddress'] ?? null,
                'postal_code' => $u['postalCode'] ?? null,
                'city' => $u['city'] ?? null,
            ], fn ($v, $k) => array_key_exists($this->graphKey($k), $u), ARRAY_FILTER_USE_BOTH);
            if (array_key_exists('accountEnabled', $u)) {
                $attrs['account_enabled'] = (bool) $u['accountEnabled'];
            }
            $attrs['synced_at'] = $now;

            $user = DirectoryUser::withTrashed()->firstOrNew(['tenant_id' => $tenant->id, 'entra_oid' => $u['id']]);
            $user->fill($attrs);
            $user->deleted_at = null;
            $user->save();
            $seen[] = $u['id'];
            $upserted++;
        }

        if ($full) {
            // Synchro complète : tout ce qui n'a pas été vu n'existe plus dans Entra.
            $removed += DirectoryUser::where('tenant_id', $tenant->id)->whereNotIn('entra_oid', $seen)->delete();
        }

        $tenant->users_delta_link = $deltaLink;
        $tenant->save();

        return [$upserted, $removed];
    }

    private function syncGroups(Tenant $tenant, GraphClient $graph): array
    {
        $prefix = str_replace("'", "''", config('signature.graph.group_prefix'));
        [$groups] = $graph->all("/groups?\$filter=startswith(displayName,'{$prefix}')&\$select=id,displayName");

        $memberships = 0;
        $keep = [];
        foreach ($groups as $g) {
            $group = DirectoryGroup::updateOrCreate(
                ['tenant_id' => $tenant->id, 'entra_oid' => $g['id']],
                ['display_name' => $g['displayName'], 'synced_at' => now()],
            );
            $keep[] = $group->id;

            [$members] = $graph->all(
                "/groups/{$g['id']}/transitiveMembers/microsoft.graph.user?\$select=id&\$count=true&\$top=999",
                ['ConsistencyLevel' => 'eventual'],
            );
            $userIds = DirectoryUser::where('tenant_id', $tenant->id)
                ->whereIn('entra_oid', array_column($members, 'id'))
                ->pluck('id')->all();

            DB::transaction(fn () => $group->members()->sync($userIds));
            $memberships += count($userIds);
        }

        DirectoryGroup::where('tenant_id', $tenant->id)->whereNotIn('id', $keep)->delete();

        return [count($groups), $memberships];
    }

    private function graphKey(string $column): string
    {
        return [
            'display_name' => 'displayName', 'given_name' => 'givenName', 'surname' => 'surname',
            'job_title' => 'jobTitle', 'department' => 'department', 'company_name' => 'companyName',
            'office_location' => 'officeLocation', 'business_phone' => 'businessPhones',
            'mobile_phone' => 'mobilePhone', 'mail' => 'mail', 'user_principal_name' => 'userPrincipalName',
            'street_address' => 'streetAddress', 'postal_code' => 'postalCode', 'city' => 'city',
        ][$column];
    }
}