import { Injectable, Logger } from '@nestjs/common';

export interface WhatsappConfig {
  enabled: boolean;
  provider: 'meta' | 'twilio' | 'wati';
  apiKey: string;
  phoneNumberId: string;
  businessAccountId: string;
  webhookVerifyToken: string;
  notifications: {
    orderConfirmation: boolean;
    shippingUpdate: boolean;
    deliveryConfirmation: boolean;
    returnUpdate: boolean;
    lowStock: boolean;
    priceChange: boolean;
  };
}

export interface MessageTemplate {
  id: string;
  name: string;
  content: string;
  variables: string[];
  category: string;
}

@Injectable()
export class WhatsappService {
  private readonly logger = new Logger(WhatsappService.name);

  // In-memory config store (in production, use database)
  private configs: Map<string, WhatsappConfig> = new Map();
  private messageLogs: Map<string, any[]> = new Map();

  async getConfig(tenantId: string): Promise<WhatsappConfig> {
    return (
      this.configs.get(tenantId) || {
        enabled: false,
        provider: 'meta',
        apiKey: '',
        phoneNumberId: '',
        businessAccountId: '',
        webhookVerifyToken: '',
        notifications: {
          orderConfirmation: true,
          shippingUpdate: true,
          deliveryConfirmation: true,
          returnUpdate: true,
          lowStock: false,
          priceChange: false,
        },
      }
    );
  }

  async updateConfig(
    tenantId: string,
    data: Partial<WhatsappConfig>,
  ): Promise<WhatsappConfig> {
    const current = await this.getConfig(tenantId);
    const updated = { ...current, ...data };
    this.configs.set(tenantId, updated);
    this.logger.log(`WhatsApp config updated for tenant ${tenantId}`);
    return updated;
  }

  async sendTestMessage(tenantId: string, phone: string, message: string) {
    const config = await this.getConfig(tenantId);
    if (!config.enabled) {
      return { success: false, error: 'WhatsApp entegrasyonu aktif değil' };
    }

    // In production, this would call WhatsApp Business API
    this.logger.log(`Test message sent to ${phone}: ${message}`);
    this.addLog(tenantId, {
      type: 'test',
      phone,
      message,
      status: 'sent',
      sentAt: new Date().toISOString(),
    });

    return { success: true, messageId: `msg_${Date.now()}` };
  }

  async sendMessage(
    tenantId: string,
    phone: string,
    template: string,
    variables: Record<string, string>,
  ) {
    const config = await this.getConfig(tenantId);
    if (!config.enabled) {
      return { success: false, error: 'WhatsApp entegrasyonu aktif değil' };
    }

    const tmpl = (await this.getTemplates(tenantId)).find(
      (t) => t.id === template,
    );
    if (!tmpl) {
      return { success: false, error: 'Şablon bulunamadı' };
    }

    let messageBody = tmpl.content;
    Object.entries(variables).forEach(([key, value]) => {
      messageBody = messageBody.replace(`{{${key}}}`, value);
    });

    this.logger.log(
      `WhatsApp message sent via template "${template}" to ${phone}`,
    );
    this.addLog(tenantId, {
      type: template,
      phone,
      message: messageBody,
      status: 'sent',
      sentAt: new Date().toISOString(),
    });

    return { success: true, messageId: `msg_${Date.now()}` };
  }

  async getTemplates(_tenantId: string): Promise<MessageTemplate[]> {
    return [
      {
        id: 'order_confirmation',
        name: 'Sipariş Onayı',
        content:
          'Merhaba {{customerName}}, {{orderId}} numaralı siparişiniz onaylandı! Toplam: ₺{{totalAmount}}. Teşekkür ederiz! 🛒',
        variables: ['customerName', 'orderId', 'totalAmount'],
        category: 'Sipariş',
      },
      {
        id: 'shipping_update',
        name: 'Kargo Bilgisi',
        content:
          'Merhaba {{customerName}}, siparişiniz kargoya verildi! 📦 Takip No: {{trackingNumber}} Kargo: {{shippingProvider}}',
        variables: ['customerName', 'trackingNumber', 'shippingProvider'],
        category: 'Kargo',
      },
      {
        id: 'delivery_confirmation',
        name: 'Teslimat Onayı',
        content:
          'Merhaba {{customerName}}, siparişiniz teslim edildi! ✅ Memnun kaldıysanız değerlendirme bırakabilirsiniz: {{reviewLink}}',
        variables: ['customerName', 'reviewLink'],
        category: 'Teslimat',
      },
      {
        id: 'return_approved',
        name: 'İade Onayı',
        content:
          'Merhaba {{customerName}}, {{returnId}} numaralı iade talebiniz onaylandı. Ürünü kargoya verebilirsiniz. İade kargo kodu: {{returnCode}}',
        variables: ['customerName', 'returnId', 'returnCode'],
        category: 'İade',
      },
      {
        id: 'low_stock_alert',
        name: 'Düşük Stok Uyarısı',
        content:
          '⚠️ Dikkat: {{productName}} (SKU: {{sku}}) stoku {{currentStock}} adede düştü. Yeniden sipariş vermeniz önerilir.',
        variables: ['productName', 'sku', 'currentStock'],
        category: 'Stok',
      },
      {
        id: 'campaign_notification',
        name: 'Kampanya Bilgisi',
        content:
          '🎉 {{campaignName}} kampanyası başladı! {{discount}} indirim fırsatını kaçırmayın. Son tarih: {{endDate}}',
        variables: ['campaignName', 'discount', 'endDate'],
        category: 'Pazarlama',
      },
    ];
  }

  async getLogs(tenantId: string, page: number, limit: number) {
    const allLogs = this.messageLogs.get(tenantId) || this.getDefaultLogs();
    const start = (page - 1) * limit;
    return {
      data: allLogs.slice(start, start + limit),
      total: allLogs.length,
      page,
    };
  }

  private addLog(tenantId: string, log: any) {
    const logs = this.messageLogs.get(tenantId) || [];
    logs.unshift({ id: `log_${Date.now()}`, ...log });
    this.messageLogs.set(tenantId, logs);
  }

  private getDefaultLogs() {
    return [
      {
        id: 'log_1',
        type: 'order_confirmation',
        phone: '+905551234567',
        message: 'Sipariş onayı gönderildi',
        status: 'delivered',
        sentAt: '2026-02-14T10:30:00Z',
      },
      {
        id: 'log_2',
        type: 'shipping_update',
        phone: '+905559876543',
        message: 'Kargo bilgisi gönderildi',
        status: 'delivered',
        sentAt: '2026-02-14T09:15:00Z',
      },
      {
        id: 'log_3',
        type: 'delivery_confirmation',
        phone: '+905553456789',
        message: 'Teslimat onayı gönderildi',
        status: 'read',
        sentAt: '2026-02-13T16:45:00Z',
      },
      {
        id: 'log_4',
        type: 'low_stock_alert',
        phone: '+905551112233',
        message: 'Düşük stok uyarısı gönderildi',
        status: 'sent',
        sentAt: '2026-02-13T08:00:00Z',
      },
      {
        id: 'log_5',
        type: 'return_approved',
        phone: '+905554445566',
        message: 'İade onayı gönderildi',
        status: 'failed',
        sentAt: '2026-02-12T14:20:00Z',
      },
    ];
  }
}