import { Injectable } from '@nestjs/common';
import { DbService } from '../db/db.service';

type EdgeRow = {
  id: string;
  name: string;
  tag_count: number;
  current_tag_count: number;
  live_tag_count: number;
  last_data_at: Date | null;
  created_at: Date;
  updated_at: Date;
};

type EdgeItem = {
  id: string;
  name: string;
  tagCount: number;
  currentTagCount: number;
  liveTagCount: number;
  lastDataAt: Date | null;
  createdAt: Date;
  updatedAt: Date;
};

type EdgeResponse = {
  items: EdgeItem[];
};

@Injectable()
export class EdgeService {
  constructor(private readonly db: DbService) {}

  // Возвращает каталог буровых с легкой сводкой по свежести данных для dashboard UI.
  async findAll(): Promise<EdgeResponse> {
    const result = await this.db.query<EdgeRow>(`
      SELECT
        e.id,
        e.name,
        count(DISTINCT et.tag_id)::integer AS tag_count,
        count(DISTINCT cv.tag_id)::integer AS current_tag_count,
        count(DISTINCT cv.tag_id) FILTER (
          WHERE cv.time >= now() - INTERVAL '30 seconds'
        )::integer AS live_tag_count,
        max(cv.time) AS last_data_at,
        e.created_at,
        e.updated_at
      FROM edge AS e
      LEFT JOIN edge_tag AS et
        ON et.edge_id = e.id
      LEFT JOIN current_values AS cv
        ON cv.edge_id = e.id
        AND cv.tag_id = et.tag_id
      GROUP BY e.id, e.name, e.created_at, e.updated_at
      ORDER BY e.name ASC, e.id ASC
    `);

    return {
      items: result.rows.map((row) => ({
        id: row.id,
        name: row.name,
        tagCount: row.tag_count,
        currentTagCount: row.current_tag_count,
        liveTagCount: row.live_tag_count,
        lastDataAt: row.last_data_at,
        createdAt: row.created_at,
        updatedAt: row.updated_at,
      })),
    };
  }
}