<?php

namespace App\Services;

use App\Models\Contact;
use App\Models\ContactPhone;
use App\Models\ImportBatch;
use App\Models\Lead;
use App\Models\LeadAssignment;
use App\Models\LeadStatus;
use App\Models\PipelineStage;
use App\Models\Setting;
use Illuminate\Support\Facades\DB;
use Maatwebsite\Excel\Facades\Excel;

class ImportService
{
    public function preview(string $filePath): array
    {
        $rows = Excel::toArray([], $filePath)[0] ?? [];
        if (empty($rows)) {
            throw new \Exception('فایل اکسل خالی است');
        }

        $headers = $rows[0];
        $dataRows = array_slice($rows, 1);

        return [
            'headers' => $headers,
            'total_rows' => count($dataRows),
            'preview' => array_slice($dataRows, 0, 5),
        ];
    }

    public function confirm(int $batchId, array $columnMapping, ?int $campaignId = null, ?array $agentIds = null, ?int $assignedById = null): ImportBatch
    {
        $batch = ImportBatch::with('rows')->findOrFail($batchId);
        $defaultStatus = LeadStatus::where('is_default', true)->first();
        $defaultStage = PipelineStage::where('is_default', true)->first();
        $assignedStage = PipelineStage::where('slug', 'waiting_call')->first();
        $duplicatePolicy = Setting::where('key', 'duplicate_phone_policy')->value('value') ?? 'warn';

        DB::transaction(function () use ($batch, $columnMapping, $campaignId, $agentIds, $assignedById, $defaultStatus, $defaultStage, $assignedStage, $duplicatePolicy) {
            $agentIndex = 0;
            $agentCount = count($agentIds ?? []);

            foreach ($batch->rows as $row) {
                if ($row->status !== 'pending') {
                    continue;
                }

                $data = $row->original_data;
                $leadData = $this->mapColumns($data, $columnMapping);

                if (! $leadData['company']) {
                    $row->update(['status' => 'failed', 'error' => 'نام کسب‌وکار الزامی است']);
                    $batch->increment('failed_rows');

                    continue;
                }

                if (! $leadData['phone']) {
                    $row->update(['status' => 'failed', 'error' => 'شماره تلفن الزامی است']);
                    $batch->increment('failed_rows');

                    continue;
                }

                $existing = Lead::where('phone', $leadData['phone'])->first();
                if ($existing) {
                    if ($duplicatePolicy === 'allow') {
                        // Continue and create a new lead below.
                    } elseif ($duplicatePolicy === 'block') {
                        $row->update(['status' => 'failed', 'lead_id' => $existing->id, 'error' => 'شماره تلفن تکراری است']);
                        $batch->increment('failed_rows');

                        continue;
                    } else {
                        $row->update(['status' => 'skipped', 'lead_id' => $existing->id, 'error' => 'شماره تلفن تکراری است؛ نیازمند بررسی یا ادغام']);
                        $batch->increment('skipped_rows');

                        continue;
                    }
                }

                $leadData['first_name'] = $leadData['first_name'] ?: $leadData['company'];
                $leadData['last_name'] = $leadData['last_name'] ?: 'رابط';
                $leadData['lead_status_id'] = $defaultStatus?->id;
                $leadData['pipeline_stage_id'] = $defaultStage?->id;
                $leadData['campaign_id'] = $campaignId;
                $leadData['priority'] = isset($leadData['priority']) && $leadData['priority'] !== '' ? (int) $leadData['priority'] : 0;
                $leadData['lead_score'] = isset($leadData['lead_score']) && $leadData['lead_score'] !== '' ? (int) $leadData['lead_score'] : 0;
                $leadData['interest_level'] = $leadData['interest_level'] ?: 'cold';

                if ($agentCount > 0) {
                    $leadData['assigned_to'] = $agentIds[$agentIndex % $agentCount];
                    $leadData['assigned_by'] = $assignedById;
                    $leadData['is_unassigned'] = false;
                    $leadData['pipeline_stage_id'] = $assignedStage?->id ?? $leadData['pipeline_stage_id'];
                    $agentIndex++;
                }

                $lead = Lead::create($leadData);
                $this->createPrimaryContact($lead, $assignedById);

                if ($leadData['assigned_to'] ?? null) {
                    LeadAssignment::create([
                        'lead_id' => $lead->id,
                        'user_id' => $leadData['assigned_to'],
                        'assigned_by' => $assignedById,
                        'method' => 'import',
                    ]);
                    NotificationService::notifyAssignment((int) $leadData['assigned_to'], $lead->full_name ?: ($lead->company ?? "لید {$lead->id}"));
                }

                $row->update(['status' => 'imported', 'lead_id' => $lead->id]);
                $batch->increment('imported_rows');
            }

            $batch->update([
                'campaign_id' => $campaignId,
                'column_mapping' => $columnMapping,
                'status' => 'completed',
            ]);
        });

        ActivityLogger::log('import_completed', "Import batch {$batchId} completed", $batch);

        return $batch->fresh();
    }

    public function rollback(int $batchId): void
    {
        $batch = ImportBatch::with('rows')->findOrFail($batchId);

        DB::transaction(function () use ($batch) {
            foreach ($batch->rows as $row) {
                if ($row->status === 'imported' && $row->lead_id) {
                    $row->lead?->delete();
                    $row->update(['status' => 'rolled_back']);
                }
            }
            $batch->update(['status' => 'rolled_back', 'can_rollback' => false]);
        });

        ActivityLogger::log('import_rolled_back', "Import batch {$batchId} rolled back", $batch);
    }

    private function mapColumns(array $data, array $mapping): array
    {
        $leadData = [
            'company' => null,
            'first_name' => null,
            'last_name' => null,
            'phone' => null,
            'phone_secondary' => null,
            'email' => null,
            'city' => null,
            'province' => null,
            'source' => null,
            'product_interest' => null,
            'priority' => null,
            'lead_score' => null,
            'interest_level' => null,
            'notes' => null,
            'tags' => null,
        ];
        foreach ($mapping as $field => $columnIndex) {
            if (isset($data[$columnIndex])) {
                $leadData[$field] = is_string($data[$columnIndex]) ? trim($data[$columnIndex]) : $data[$columnIndex];
            }
        }

        return $leadData;
    }

    private function createPrimaryContact(Lead $lead, ?int $createdById): void
    {
        $contact = Contact::create([
            'lead_id' => $lead->id,
            'name' => trim(($lead->first_name ?? '').' '.($lead->last_name ?? '')) ?: ($lead->company ?? 'مخاطب اولیه'),
            'role' => 'رابط',
            'description' => 'مخاطب اولیه import',
            'status' => 'active',
            'is_primary' => true,
            'primary_reason' => 'مخاطب اولیه import',
            'created_by' => $createdById,
        ]);

        foreach (array_filter([$lead->phone, $lead->phone_secondary]) as $phone) {
            ContactPhone::create([
                'contact_id' => $contact->id,
                'phone' => $phone,
                'type' => 'mobile',
                'status' => 'active',
            ]);
        }
    }
}