import { Injectable } from '@nestjs/common';
import { HttpService } from '@nestjs/axios';
import { ConfigService } from '@nestjs/config';
import { lastValueFrom } from 'rxjs';
import { PrometheusMetric } from './prometheus-metric.interface';
import { MenuItem } from './menu/menu.interface';

@Injectable()
export class PrometheusService {
  private readonly prometheusUrl: string;

  constructor(
    private readonly httpService: HttpService,
    private readonly configService: ConfigService
  ) {
    this.prometheusUrl = this.configService.get<string>('PROMETHEUS_API', 'http://localhost:9090');
    console.log('Prometheus API URL:', this.prometheusUrl);
  }

  async fetchMetricType(metric: string): Promise<string | null> {
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/metadata`, {
          params: { metric },
        })
      );
      const metadata = response.data.data[metric];
      return metadata?.length ? metadata[0].type : null;
    } catch (error) {
      console.error(`Ошибка при получении типа метрики ${metric}:`, error);
      return null;
    }
  }

  async fetchMetricDescription(metric: string): Promise<string | undefined> {
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/metadata`, {
          params: { metric },
        })
      );
      const metadata = response.data.data[metric];
      return metadata?.length ? metadata[0].help : undefined;
    } catch (error) {
      console.error(`Ошибка при получении описания метрики ${metric}:`, error);
      return undefined;
    }
  }

  async fetchMetrics(metric: string): Promise<PrometheusMetric[]> {
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/query`, {
          params: { query: metric },
        })
      );

      const metricType = await this.fetchMetricType(metric);
      const metricDescription = await this.fetchMetricDescription(metric);

      return response.data.data.result.map((entry): PrometheusMetric => ({
        __name__: entry.metric.__name__ || metric,
        device: entry.metric.device,
        instance: entry.metric.instance,
        job: entry.metric.job,
        source_id: entry.metric.source_id,
        status: entry.metric.status || '0',
        timestamp: entry.value[0] * 1000,
        value: parseFloat(entry.value[1]),
        type: metricType || 'gauge',
        description: metricDescription,
        ...entry.metric
      }));
    } catch (error) {
      console.error(`Error fetching metrics for ${metric}:`, error);
      throw error;
    }
  }

  async fetchMetricsWithFilters(metric: string, filters: Record<string, string>): Promise<PrometheusMetric[]> {
    try {
      const query = this.buildFilteredQuery(metric, filters);
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/query`, {
          params: { query }
        })
      );

      const metricType = await this.fetchMetricType(metric);
      const metricDescription = await this.fetchMetricDescription(metric);

      return response.data.data.result.map((entry): PrometheusMetric => ({
        __name__: entry.metric.__name__ || metric,
        device: entry.metric.device,
        instance: entry.metric.instance,
        job: entry.metric.job,
        source_id: entry.metric.source_id,
        status: entry.metric.status || '0',
        timestamp: entry.value[0] * 1000,
        value: parseFloat(entry.value[1]),
        type: metricType || 'gauge',
        description: metricDescription,
        ...entry.metric
      }));
    } catch (error) {
      console.error(`Error fetching metrics with filters for ${metric}:`, error);
      throw error;
    }
  }

  private buildFilteredQuery(metric: string, filters: Record<string, string>): string {
    const filterParts = Object.entries(filters)
      .filter(([_, value]) => value !== undefined && value !== null && value !== "")
      .map(([key, value]) => {
        if (key === 'source_id' && !value.startsWith('module$')) {
          return `${key}="module$${value}"`;
        }
        return `${key}="${value}"`;
      });

    return filterParts.length > 0
      ? `${metric}{${filterParts.join(',')}}`
      : metric;
  }

  async fetchMetricsRange(metric: string, start: number, end: number, step: number, filters: Record<string, string> = {}): Promise<PrometheusMetric[]> {
    const query = this.buildFilteredQuery(metric, filters);
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/query_range`, {
          params: {
            query,
            start,
            end,
            step: step.toString()
          },
        })
      );

      const metricType = await this.fetchMetricType(metric);
      const metricDescription = await this.fetchMetricDescription(metric);

      return response.data.data.result.flatMap((entry) =>
        entry.values.map((value): PrometheusMetric => ({
          __name__: entry.metric.__name__ || metric,
          device: entry.metric.device,
          instance: entry.metric.instance,
          job: entry.metric.job,
          source_id: entry.metric.source_id,
          status: entry.metric.status || '0',
          timestamp: value[0] * 1000,
          value: parseFloat(value[1]),
          type: metricType || 'gauge',
          description: metricDescription,
          ...entry.metric
        }))
      );
    } catch (error) {
      console.error('Error in fetchMetricsRange:', {
        error: error.response?.data || error.message,
        query,
        filters
      });
      throw error;
    }
  }

  async getMetricsForMenuItem(menuItem: MenuItem): Promise<PrometheusMetric[]> {
    if (!menuItem.metric || !menuItem.filters) {
      throw new Error('MenuItem is not a metric item');
    }

    return this.fetchMetricsWithFilters(menuItem.metric, menuItem.filters);
  }

  // ✅ Новый метод: получает базовое описание метрики (help, type)
  async fetchMetricMetadata(metric: string): Promise<{
    name: string;
    help?: string;
    type?: string;
  }> {
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/metadata`, {
          params: { metric }
        })
      );

      const data = response.data?.data?.[metric]?.[0];

      return {
        name: metric,
        help: data?.help,
        type: data?.type
      };
    } catch (error) {
      console.error(`Error fetching metadata for ${metric}:`, error);
      return {
        name: metric
      };
    }
  }

  // ✅ Новый метод: получает ВСЕ серии метрики (все комбинации label-ов)
  async fetchMetricSeries(metric: string): Promise<Record<string, string>[]> {
    try {
      const response = await lastValueFrom(
        this.httpService.get(`${this.prometheusUrl}/series`, {
          params: { 'match[]': metric }
        })
      );

      return response.data.data || [];
    } catch (error) {
      console.error(`Error fetching series for ${metric}:`, error);
      return [];
    }
  }

  async fetchAllMetrics(): Promise<string[]> {
    const response = await lastValueFrom(
      this.httpService.get(`${this.prometheusUrl}/label/__name__/values`)
    );
    return response.data.data;
  }

  async fetchAllMetricsWithValues(): Promise<any[]> {
    const metricNames = await this.fetchAllMetrics();
    const promises = metricNames.map(async (metric) => {
      const data = await this.fetchMetrics(metric);
      return { metric, data };
    });
    return Promise.all(promises);
  }
}