<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Stancl\Tenancy\Middleware\InitializeTenancyByDomain;

class IdentifyTenantIfNeeded
{
    /**
     * Handle an incoming request.
     */
    public function handle(Request $request, Closure $next)
    {
        $host = $request->getHost();
        $centralDomains = config('tenancy.central_domains', ['127.0.0.1', 'localhost', 'hrm.test']);

        if (in_array($host, $centralDomains, true) || filter_var($host, FILTER_VALIDATE_IP)) {
            $headerTenantId = $request->header('X-Tenant') ?? $request->header('X-Subdomain') ?? $request->header('X-Tenant-Id') ?? $request->subdomain ?? $request->tenant;
            if ($headerTenantId && class_exists('\App\Models\Tenant')) {
                $targetTenant = \App\Models\Tenant::find($headerTenantId);
                if (!$targetTenant) {
                    $domainMatch = \Stancl\Tenancy\Database\Models\Domain::where('domain', $headerTenantId)->first();
                    $targetTenant = $domainMatch ? $domainMatch->tenant : null;
                }
                if ($targetTenant) {
                    if (function_exists('tenancy') && tenancy()->initialized) {
                        tenancy()->end();
                    }
                    tenancy()->initialize($targetTenant);
                }
            }

            // Fallback: Auto-discover tenant from Sanctum Bearer token if X-Tenant header is not present
            if (!function_exists('tenant') || !tenant()) {
                $bearer = $request->bearerToken();
                if ($bearer && str_contains($bearer, ':') && str_contains($bearer, '|')) {
                    [$tokenTenantId, $cleanToken] = explode(':', $bearer, 2);
                    $targetTenant = \App\Models\Tenant::find($tokenTenantId);
                    if ($targetTenant) {
                        if (function_exists('tenancy') && tenancy()->initialized) {
                            tenancy()->end();
                        }
                        tenancy()->initialize($targetTenant);
                        // Strip tenant prefix from Authorization header for Sanctum authentication
                        $request->headers->set('Authorization', 'Bearer ' . $cleanToken);
                        $request->server->set('HTTP_AUTHORIZATION', 'Bearer ' . $cleanToken);
                        $_SERVER['HTTP_AUTHORIZATION'] = 'Bearer ' . $cleanToken;
                    }
                }

                if ((!function_exists('tenant') || !tenant()) && $bearer && str_contains($bearer, '|')) {
                    [$tokenId, $plainText] = explode('|', $bearer, 2);
                    $tokenHash = hash('sha256', $plainText);
                    
                    // 1. O(1) Direct Lookup via Central Token Index Table
                    try {
                        $centralIndex = \Illuminate\Support\Facades\DB::connection('sqlite')
                            ->table('central_token_indexes')
                            ->where('token_id', $tokenId)
                            ->first();

                        if ($centralIndex && class_exists('\App\Models\Tenant')) {
                            $targetTenant = \App\Models\Tenant::find($centralIndex->tenant_id);
                            if ($targetTenant) {
                                if (function_exists('tenancy') && tenancy()->initialized) {
                                    tenancy()->end();
                                }
                                tenancy()->initialize($targetTenant);
                            }
                        }
                    } catch (\Throwable $e) {}

                    // 2. Legacy Fallback auto-discovery if not present in central index
                    if ((!function_exists('tenant') || !tenant()) && class_exists('\App\Models\Tenant')) {
                        $tenants = \App\Models\Tenant::on('sqlite')->get();
                        foreach ($tenants as $t) {
                            $db1 = database_path('tenant_' . $t->id . '.sqlite');
                            $db2 = database_path('tenant_' . $t->id);
                            if (!file_exists($db1) && !file_exists($db2)) continue;
                            try {
                                $tokenFound = $t->run(function () use ($tokenId, $tokenHash) {
                                    return \Laravel\Sanctum\PersonalAccessToken::where('id', $tokenId)
                                        ->where('token', $tokenHash)
                                        ->first();
                                });
                                if ($tokenFound) {
                                    if (function_exists('tenancy') && tenancy()->initialized) {
                                        tenancy()->end();
                                    }
                                    tenancy()->initialize($t);
                                    // Backport index into central table for O(1) subsequent calls
                                    try {
                                        \Illuminate\Support\Facades\DB::connection('sqlite')->table('central_token_indexes')->updateOrInsert(
                                            ['token_id' => $tokenId],
                                            ['tenant_id' => $t->id, 'created_at' => now(), 'updated_at' => now()]
                                        );
                                    } catch (\Throwable $e2) {}
                                    break;
                                }
                            } catch (\Throwable $e) {}
                        }
                    }
                }
            }

            if (class_exists(\Spatie\Permission\PermissionRegistrar::class)) {
                app(\Spatie\Permission\PermissionRegistrar::class)->forgetCachedPermissions();
            }
            return $next($request);
        }

        try {
            $response = app(InitializeTenancyByDomain::class)->handle($request, $next);
            if (function_exists('tenant') && tenant()) {
                try {
                    $enabledModules = \App\Models\TenantModule::where('enabled', 1)->pluck('module_key')->toArray();
                    $inquiryKeys = [];
                    foreach (\App\Constants\ModuleContract::MODULE_MAP as $inqKey => $cfg) {
                        if (in_array($cfg['module_key'], $enabledModules)) {
                            $inquiryKeys[] = $inqKey;
                        }
                    }
                    $allowedPermissions = \App\Constants\ModuleContract::getPermissionsForInquiryKeys($inquiryKeys);
                    foreach ($allowedPermissions as $perm) {
                        $moduleName = 'General';
                        foreach (\App\Constants\ModuleContract::MODULE_MAP as $inqKey => $cfg) {
                            if (in_array($perm, $cfg['permissions'], true)) {
                                $moduleName = $cfg['label'] ?? $cfg['module_key'];
                                break;
                            }
                        }
                        $pRecord = \Spatie\Permission\Models\Permission::findOrCreate($perm, 'web');
                        if (empty($pRecord->module) || $pRecord->module !== $moduleName) {
                            $pRecord->module = $moduleName;
                            $pRecord->save();
                        }
                    }
                } catch (\Exception $e) {}
            }
            return $response;
        } catch (\Stancl\Tenancy\Exceptions\TenantDatabaseDoesNotExistException $e) {
            $tenant = tenant();
            if ($tenant) {
                $tenantId = $tenant->id;
                $dbFile = database_path('tenant_' . $tenantId);
                $dbFileSqlite = database_path('tenant_' . $tenantId . '.sqlite');
                if (!file_exists($dbFile)) { touch($dbFile); }
                if (!file_exists($dbFileSqlite)) { touch($dbFileSqlite); }

                \Illuminate\Support\Facades\Artisan::call('migrate', [
                    '--database' => 'tenant',
                    '--path' => [
                        'database/migrations/tenant',
                        'database/migrations',
                    ],
                    '--force' => true,
                ]);

                return app(InitializeTenancyByDomain::class)->handle($request, $next);
            }
            abort(503, 'Tenant database setup is incomplete.');
        }
    }
}