import { supabase } from "@/integrations/supabase/client";

export interface NotificationPayload {
  workflowId: string;
  subscriberId: string;
  payload: Record<string, any>;
  overrides?: Record<string, any>;
}

export interface SubscriberData {
  subscriberId: string;
  email?: string;
  firstName?: string;
  lastName?: string;
  phone?: string;
  avatar?: string;
  data?: Record<string, any>;
}

export interface NotificationPreferences {
  channelPreferences: {
    in_app: boolean;
    email: boolean;
    push: boolean;
    sms: boolean;
  };
  workflowPreferences: Record<string, boolean>;
  frequencySettings: {
    digest: 'realtime' | 'hourly' | 'daily' | 'weekly';
    max_per_hour: number;
  };
}

class NotificationService {
  private readonly isNovuEnabled: boolean;

  constructor() {
    this.isNovuEnabled = !!import.meta.env.VITE_NOVU_APPLICATION_IDENTIFIER;
  }

  private extractErrorMessage(error: unknown): string {
    if (error instanceof Error) {
      return error.message;
    }
    if (error && typeof error === 'object' && 'message' in error && typeof error.message === 'string') {
      return error.message;
    }
    return 'An unexpected error occurred';
  }

  /**
   * Create or update a Novu subscriber
   */
  async createSubscriber(subscriberData: SubscriberData): Promise<{ success: boolean; error?: string }> {
    if (!this.isNovuEnabled) {
      console.warn('Novu is not configured. Skipping subscriber creation.');
      return { success: false, error: 'Novu not configured' };
    }

    try {
      const { data, error } = await supabase.functions.invoke('create-novu-subscriber', {
        body: subscriberData,
      });

      if (error) {
        console.error('Edge function error creating Novu subscriber:', error);
        throw error;
      }

      if (!data || !data.subscriberId) {
        const errorMsg = 'Invalid response from create-novu-subscriber function';
        console.error(errorMsg, { data });
        return { success: false, error: errorMsg };
      }

      const { error: dbError } = await supabase
        .from('user_notification_preferences')
        .upsert({
          user_id: subscriberData.subscriberId,
          novu_subscriber_id: data.subscriberId,
        });

      if (dbError) {
        console.error('Database error storing subscriber preferences:', dbError);
        throw dbError;
      }

      console.log('Novu subscriber created successfully:', data.subscriberId);
      return { success: true };
    } catch (error: unknown) {
      console.error('Error creating Novu subscriber:', error);
      return { success: false, error: this.extractErrorMessage(error) };
    }
  }

  /**
   * Update an existing Novu subscriber's profile information
   */
  async updateSubscriber(subscriberData: SubscriberData): Promise<{ success: boolean; error?: string }> {
    if (!this.isNovuEnabled) {
      console.warn('Novu is not configured. Skipping subscriber update.');
      return { success: false, error: 'Novu not configured' };
    }

    try {
      const { data, error } = await supabase.functions.invoke('update-novu-subscriber', {
        body: subscriberData,
      });

      if (error) {
        console.error('Edge function error updating Novu subscriber:', error);
        throw error;
      }

      console.log('Novu subscriber updated successfully:', subscriberData.subscriberId);
      return { success: true };
    } catch (error: unknown) {
      console.error('Error updating Novu subscriber:', error);
      return { success: false, error: this.extractErrorMessage(error) };
    }
  }

  /**
   * Update subscriber preferences in Novu
   */
  async updatePreferences(
    userId: string,
    preferences: NotificationPreferences
  ): Promise<{ success: boolean; error?: string }> {
    if (!this.isNovuEnabled) {
      try {
        const { error } = await supabase
          .from('user_notification_preferences')
          .upsert({
            user_id: userId,
            channel_preferences: preferences.channelPreferences,
            workflow_preferences: preferences.workflowPreferences,
            frequency_settings: preferences.frequencySettings,
          });

        if (error) {
          console.error('Database error saving preferences (Novu disabled):', error);
          throw error;
        }

        console.log('Preferences saved to local database:', userId);
        return { success: true };
      } catch (error: unknown) {
        console.error('Error saving preferences to local database:', error);
        return { success: false, error: this.extractErrorMessage(error) };
      }
    }

    try {
      const { error } = await supabase.functions.invoke('update-novu-preferences', {
        body: {
          userId,
          preferences,
        },
      });

      if (error) {
        console.error('Edge function error updating Novu preferences:', error);
        throw error;
      }

      const { error: dbError } = await supabase
        .from('user_notification_preferences')
        .upsert({
          user_id: userId,
          channel_preferences: preferences.channelPreferences,
          workflow_preferences: preferences.workflowPreferences,
          frequency_settings: preferences.frequencySettings,
        });

      if (dbError) {
        console.error('Database error saving preferences locally:', dbError);
        throw dbError;
      }

      console.log('Preferences updated successfully:', userId);
      return { success: true };
    } catch (error: unknown) {
      console.error('Error updating preferences:', error);
      return { success: false, error: this.extractErrorMessage(error) };
    }
  }

  /**
   * Trigger a notification workflow
   */
  async trigger(payload: NotificationPayload): Promise<{ success: boolean; transactionId?: string; error?: string }> {
    if (!this.isNovuEnabled) {
      console.warn('Novu is not configured. Notification not sent.');
      return { success: false, error: 'Novu not configured' };
    }

    try {
      const { data, error } = await supabase.functions.invoke('trigger-notification', {
        body: payload,
      });

      if (error) {
        console.error('Edge function error triggering notification:', error);
        throw error;
      }

      if (!data || !data.transactionId) {
        const errorMsg = 'Invalid response from trigger-notification function';
        console.error(errorMsg, { data });
        return { success: false, error: errorMsg };
      }

      await this.logNotification({
        userId: payload.subscriberId,
        workflowId: payload.workflowId,
        transactionId: data.transactionId,
        payload: payload.payload,
      });

      console.log('Notification triggered successfully:', data.transactionId);
      return { success: true, transactionId: data.transactionId };
    } catch (error: unknown) {
      console.error('Error triggering notification:', error);
      return { success: false, error: this.extractErrorMessage(error) };
    }
  }

  /**
   * Get user's notification preferences
   */
  async getPreferences(userId: string): Promise<NotificationPreferences | null> {
    try {
      const { data, error } = await supabase
        .from('user_notification_preferences')
        .select('channel_preferences, workflow_preferences, frequency_settings')
        .eq('user_id', userId)
        .single();

      if (error && error.code !== 'PGRST116') {
        console.error('Database error fetching preferences:', error);
        throw error;
      }

      if (!data) {
        console.log('No preferences found for user, returning defaults:', userId);
        return {
          channelPreferences: {
            in_app: true,
            email: true,
            push: false,
            sms: false,
          },
          workflowPreferences: {},
          frequencySettings: {
            digest: 'daily',
            max_per_hour: 10,
          },
        };
      }

      return {
        channelPreferences: data.channel_preferences as any,
        workflowPreferences: data.workflow_preferences as any,
        frequencySettings: data.frequency_settings as any,
      };
    } catch (error: unknown) {
      console.error('Error fetching notification preferences for user:', userId, error);
      return null;
    }
  }

  /**
   * Get notification templates
   */
  async getTemplates(): Promise<any[]> {
    try {
      const { data, error } = await supabase
        .from('notification_templates')
        .select('*')
        .eq('is_active', true)
        .order('category', { ascending: true });

      if (error) {
        console.error('Database error fetching notification templates:', error);
        throw error;
      }

      return data || [];
    } catch (error: unknown) {
      console.error('Error fetching notification templates:', error);
      return [];
    }
  }

  /**
   * Log notification in database
   */
  private async logNotification(log: {
    userId: string;
    workflowId: string;
    transactionId: string;
    payload: Record<string, any>;
  }): Promise<void> {
    try {
      // Get template ID from workflow ID
      const { data: template } = await supabase
        .from('notification_templates')
        .select('id')
        .eq('workflow_id', log.workflowId)
        .single();

      const { error: logError } = await supabase.from('notification_logs').insert({
        user_id: log.userId,
        template_id: template?.id,
        novu_transaction_id: log.transactionId,
        channel: 'multi',
        status: 'sent',
        payload: log.payload,
      });
      
      if (logError) {
        console.error('Error inserting notification log:', logError);
      }
    } catch (error) {
      console.error('Error logging notification:', error);
    }
  }

  /**
   * Notify all moderators about a new submission
   */
  async notifyModerators(payload: {
    submission_id: string;
    submission_type: string;
    submitter_name: string;
    action: string;
  }): Promise<{ success: boolean; count: number; error?: string }> {
    try {
      const { data, error } = await supabase.functions.invoke('notify-moderators-submission', {
        body: payload,
      });

      if (error) {
        console.error('Edge function error notifying moderators:', error);
        throw error;
      }

      console.log('Moderators notified successfully:', data);
      return { 
        success: true, 
        count: data?.count || 0 
      };
    } catch (error: unknown) {
      console.error('Error notifying moderators:', error);
      return { 
        success: false, 
        count: 0,
        error: this.extractErrorMessage(error) 
      };
    }
  }

  /**
   * Check if Novu is enabled
   */
  isEnabled(): boolean {
    return this.isNovuEnabled;
  }
}

export const notificationService = new NotificationService();