<?php

namespace App\Services\Imports;

use App\Models\Customer;
use App\Models\Service;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Str;

/**
 * Sync customers + services + product mapping from legacy `portal` DB
 * (connection: `legacy`) into the current portal schema.
 *
 * Idempotent via `legacy_id` columns. Conflicting customers (existing email
 * or phone) are skipped — never overwritten.
 */
class LegacyPortalImporter
{
    /** Default new-system product id used when no explicit mapping is given. */
    protected int $defaultVpsProductId = 1;

    /** Map legacy product_id => new product_id. Built from CLI option / config. */
    protected array $productMap = [];

    public function setProductMap(array $map): self
    {
        $this->productMap = $map;
        return $this;
    }

    public function setDefaultVpsProductId(int $id): self
    {
        $this->defaultVpsProductId = $id;
        return $this;
    }

    /**
     * @return array{customers: array, services: array, products: array}
     */
    public function import(bool $preview = false, ?callable $log = null): array
    {
        $log ??= fn ($_msg) => null;

        $summary = [
            'customers' => ['created' => 0, 'skipped_conflict' => 0, 'already_synced' => 0, 'errors' => 0],
            'vmware'    => ['created' => 0, 'updated' => 0, 'vcenter_matched' => 0, 'vcenter_missing' => 0, 'errors' => 0],
            'services'  => ['created' => 0, 'updated' => 0, 'skipped_no_customer' => 0, 'vm_linked' => 0, 'vm_unlinked' => 0, 'errors' => 0],
            'products'  => ['mapped' => 0, 'fallback_default' => 0],
        ];

        $log("→ Connecting to legacy DB and counting rows...");
        $legacyUsers = DB::connection('legacy')->table('users')->count();
        $legacyServices = DB::connection('legacy')->table('services')->count();
        $legacyVmware = DB::connection('legacy')->table('vmware')->count();
        $log("  legacy.users = {$legacyUsers}, legacy.services = {$legacyServices}, legacy.vmware = {$legacyVmware}");

        if ($preview) {
            $log("PREVIEW MODE — no writes will be performed.");
        }

        // ----- Customers -----
        $log("→ Syncing customers...");
        $customerIdMap = []; // legacy user_id => new customer_id

        DB::connection('legacy')->table('users')->orderBy('id')->chunk(200, function ($rows) use (&$summary, &$customerIdMap, $preview, $log) {
            foreach ($rows as $row) {
                try {
                    $existingByLegacy = Customer::where('legacy_id', $row->id)->first();
                    if ($existingByLegacy) {
                        $customerIdMap[$row->id] = $existingByLegacy->id;
                        $summary['customers']['already_synced']++;
                        continue;
                    }

                    $email = trim((string) $row->email) ?: null;
                    $phone = trim((string) ($row->sdt ?? '')) ?: null;

                    $conflict = Customer::query()
                        ->when($email, fn ($q) => $q->where('email', $email))
                        ->when($phone, fn ($q, $p) => $q->orWhere('phone', $p))
                        ->first();

                    if ($conflict) {
                        $customerIdMap[$row->id] = $conflict->id;
                        $summary['customers']['skipped_conflict']++;
                        $log("  · skip user#{$row->id} ({$email}) — conflict with customer#{$conflict->id}");
                        if (! $preview) {
                            // Backfill legacy_id on existing record so future runs are idempotent.
                            $conflict->forceFill(['legacy_id' => $row->id])->saveQuietly();
                        }
                        continue;
                    }

                    $payload = [
                        'legacy_id'              => $row->id,
                        'fullname'               => $row->fullname,
                        'avatar'                 => $row->thumb ?: null,
                        'gender'                 => (int) ($row->gender ?? 0),
                        'address'                => $row->address,
                        'company'                => $row->company,
                        'phone'                  => $phone,
                        'email'                  => $email,
                        'email_verify'           => $row->email_verification,
                        'password'               => $row->password,
                        'credit'                 => (int) ($row->price ?? 0),
                        'total'                  => (int) ($row->total ?? 0),
                        'identity_number'        => $row->cccd,
                        'front_identity_number'  => $row->cccd_mattruoc,
                        'back_identity_number'   => $row->cccd_matsau,
                        'status'                 => (int) ($row->is_active ?? 1),
                        'created_at'             => $row->create_at,
                        'updated_at'             => $row->update_at,
                    ];

                    if ($preview) {
                        // sentinel so services chunk can resolve in dry-run
                        $customerIdMap[$row->id] = -1;
                        $summary['customers']['created']++;
                        continue;
                    }

                    $customer = new Customer();
                    $customer->uuid = (string) Str::uuid();
                    $customer->forceFill($payload)->saveQuietly();

                    $customerIdMap[$row->id] = $customer->id;
                    $summary['customers']['created']++;
                } catch (\Throwable $e) {
                    $summary['customers']['errors']++;
                    Log::warning("LegacyPortalImporter customer#{$row->id} failed", ['error' => $e->getMessage()]);
                    $log("  ! user#{$row->id} ERROR: " . $e->getMessage());
                }
            }
        });

        if (! $preview) {
            Customer::whereNotNull('legacy_id')->pluck('id', 'legacy_id')
                ->each(fn ($newId, $legacyId) => $customerIdMap[$legacyId] = $newId);
        }

        // ----- VMware (module_vmware) -----
        $log("→ Syncing vmware → module_vmware...");
        $vmwareIdMap = []; // legacy_vmware.id => new module_vmware.id

        // Build vCenter inventory lookup: vmware_id string => virtual_machines.id
        $vcenterLookup = DB::table('virtual_machines')->pluck('id', 'vm_id');

        DB::connection('legacy')->table('vmware')->orderBy('id')->chunk(200, function ($rows) use (&$summary, &$vmwareIdMap, $customerIdMap, $vcenterLookup, $preview, $log) {
            foreach ($rows as $row) {
                try {
                    $newCustomerId = $customerIdMap[$row->user_id] ?? null;
                    $vcVmId = $row->vmware_id; // e.g. "vm-4327"
                    $vmInventoryId = $vcVmId ? ($vcenterLookup[$vcVmId] ?? null) : null;

                    if ($vmInventoryId) $summary['vmware']['vcenter_matched']++;
                    else                $summary['vmware']['vcenter_missing']++;

                    $payload = [
                        'legacy_id'          => $row->id,
                        'customer_id'        => $newCustomerId,
                        'name'               => $row->vmware_name,
                        'ip'                 => $row->vmware_ip,
                        'port'               => is_numeric($row->vmware_port) ? (int) $row->vmware_port : null,
                        'user'               => $row->vmware_user,
                        'password'           => $row->vmware_password,
                        'hostname'           => $row->vmware_hostname,
                        'vmware_id'          => $vcVmId,
                        'virtual_machine_id' => $vmInventoryId,
                        'status'             => (int) ($row->vmware_status ?? 1),
                        'created_at'         => $row->create_at,
                        'updated_at'         => $row->update_at,
                    ];

                    if ($preview) {
                        $vmwareIdMap[$row->id] = -1;
                        $summary['vmware']['created']++;
                        continue;
                    }

                    $existing = DB::table('module_vmware')->where('legacy_id', $row->id)->first();
                    if ($existing) {
                        DB::table('module_vmware')->where('id', $existing->id)->update($payload);
                        $vmwareIdMap[$row->id] = $existing->id;
                        $summary['vmware']['updated']++;
                    } else {
                        $newId = DB::table('module_vmware')->insertGetId($payload);
                        $vmwareIdMap[$row->id] = $newId;
                        $summary['vmware']['created']++;
                    }
                } catch (\Throwable $e) {
                    $summary['vmware']['errors']++;
                    Log::warning("LegacyPortalImporter vmware#{$row->id} failed", ['error' => $e->getMessage()]);
                    $log("  ! vmware#{$row->id} ERROR: " . $e->getMessage());
                }
            }
        });

        if (! $preview) {
            DB::table('module_vmware')->whereNotNull('legacy_id')->select('id', 'legacy_id')->get()
                ->each(fn ($r) => $vmwareIdMap[$r->legacy_id] = $r->id);
        }

        // ----- Services -----
        $log("→ Syncing services...");

        DB::connection('legacy')->table('services')->orderBy('id')->chunk(200, function ($rows) use (&$summary, $customerIdMap, $vmwareIdMap, $preview, $log) {
            foreach ($rows as $row) {
                try {
                    $newCustomerId = $customerIdMap[$row->user_id] ?? null;
                    if (! $newCustomerId) {
                        $summary['services']['skipped_no_customer']++;
                        continue;
                    }

                    $productId = $this->resolveProductId((int) $row->product_id, $summary);
                    $newVmId = $row->vmware_id !== null ? ($vmwareIdMap[$row->vmware_id] ?? null) : null;
                    if ($newVmId) $summary['services']['vm_linked']++;
                    else          $summary['services']['vm_unlinked']++;

                    $payload = [
                        'legacy_id'         => $row->id,
                        'customer_id'       => $newCustomerId === -1 ? null : $newCustomerId,
                        'product_id'        => $productId,
                        'legacy_product_id' => (int) $row->product_id,
                        'vm_id'             => $newVmId === -1 ? null : $newVmId,
                        'status'            => $this->mapStatus((int) $row->is_active),
                        'auto_renew'        => (bool) $row->auto_pay,
                        'started_at'        => $row->create_at,
                        'expires_at'        => $row->date_exp,
                        'note'              => 'product_info(legacy): ' . $row->product_info,
                        'created_at'        => $row->create_at,
                        'updated_at'        => $row->create_at,
                    ];

                    if ($preview) {
                        $summary['services']['created']++;
                        continue;
                    }

                    $service = Service::where('legacy_id', $row->id)->first();

                    if ($service) {
                        $service->forceFill($payload)->saveQuietly();
                        $summary['services']['updated']++;
                    } else {
                        $service = new Service();
                        $service->uuid = (string) Str::uuid();
                        $service->forceFill($payload)->saveQuietly();
                        $summary['services']['created']++;
                    }
                } catch (\Throwable $e) {
                    $summary['services']['errors']++;
                    Log::warning("LegacyPortalImporter service#{$row->id} failed", ['error' => $e->getMessage()]);
                    $log("  ! service#{$row->id} ERROR: " . $e->getMessage());
                }
            }
        });

        return $summary;
    }

    protected function resolveProductId(int $legacyProductId, array &$summary): int
    {
        if (isset($this->productMap[$legacyProductId])) {
            $summary['products']['mapped']++;
            return $this->productMap[$legacyProductId];
        }

        $summary['products']['fallback_default']++;
        return $this->defaultVpsProductId;
    }

    /** Convert legacy `is_active` int → new lifecycle string. */
    protected function mapStatus(int $legacy): string
    {
        return match ($legacy) {
            0 => 'expired',
            1 => 'active',
            2 => 'pending',
            3 => 'suspended',
            default => 'pending',
        };
    }
}