import { db } from '../db';
// Environment variables will be mocked in tests
const env = process.env;

type EvolutionGroup = {
  id: string;
  subject: string;
  linkedParent?: string;
  // Other fields from API response
};

export class GroupSyncService {
  private static readonly SYNC_INTERVAL_MS = 24 * 60 * 60 * 1000; // 24 hours
  private static lastSyncAttempt = 0;

  static async syncGroups(): Promise<{ added: number; updated: number }> {
    if (!this.shouldSync()) {
      return { added: 0, updated: 0 };
    }

    try {
      const communityId = env.WHATSAPP_COMMUNITY_ID;
      if (!communityId) {
        throw new Error('WHATSAPP_COMMUNITY_ID is not set');
      }

      const groups = await this.fetchGroupsFromAPI();
      const communityGroups = groups.filter(
        (group) => group.linkedParent === communityId
      );

      return await this.upsertGroups(communityGroups);
    } catch (error) {
      console.error('Group sync failed:', error);
      throw error;
    } finally {
      this.lastSyncAttempt = Date.now();
    }
  }

  private static shouldSync(): boolean {
    const timeSinceLastSync = Date.now() - this.lastSyncAttempt;
    return timeSinceLastSync > this.SYNC_INTERVAL_MS;
  }

  private static async fetchGroupsFromAPI(): Promise<EvolutionGroup[]> {
    const url = `${env.EVOLUTION_API_URL}/group/fetchAllGroups/${env.EVOLUTION_API_INSTANCE}?getParticipants=false`;
    const response = await fetch(url, {
      headers: {
        apikey: env.EVOLUTION_API_KEY,
      },
    });

    if (!response.ok) {
      throw new Error(`API request failed: ${response.statusText}`);
    }

    const data = await response.json();
    if (data.status !== 'success') {
      throw new Error(`API error: ${data.message || 'Unknown error'}`);
    }
    return data.response;
  }

  private static async upsertGroups(groups: EvolutionGroup[]): Promise<{ added: number; updated: number }> {
    let added = 0;
    let updated = 0;

    const transactionResult = db.transaction(() => {
      // First mark all groups as inactive and update verification timestamp
      const inactiveResult = db.prepare(`
        UPDATE groups 
        SET active = FALSE, 
            last_verified = CURRENT_TIMESTAMP
      `).run();
      console.log('Marked groups inactive:', inactiveResult);

      for (const group of groups) {
        const existing = db.prepare('SELECT 1 FROM groups WHERE id = ?').get(group.id);
        console.log('Checking group:', group.id, 'exists:', !!existing);
        
        if (existing) {
          const updateResult = db.prepare(
            'UPDATE groups SET name = ?, active = TRUE, last_verified = CURRENT_TIMESTAMP WHERE id = ?'
          ).run(group.subject, group.id);
          console.log('Updated group:', group.id, 'result:', updateResult);
          updated++;
        } else {
          const insertResult = db.prepare(
            'INSERT INTO groups (id, community_id, name, active) VALUES (?, ?, ?, TRUE)'
          ).run(group.id, env.WHATSAPP_COMMUNITY_ID, group.subject);
          console.log('Added group:', group.id, 'result:', insertResult);
          added++;
        }
      }

      return { added, updated };
    });

    try {
      const result = transactionResult();
      console.log(`Group sync completed: ${result.added} added, ${result.updated} updated`);
      return result;
    } catch (error) {
      console.error('Error in upsertGroups:', error);
      throw error;
    }
  }
}