import axios from "axios";

export interface DataPoint {
  date: string;
  value: number;
}

export class DataCommonsClient {
  private baseUrl = "https://api.datacommons.org";

  /**
   * Fetches statistical series for a specific variable and place.
   * @param placeId DCID of the place (e.g., 'country/DEU' for Germany)
   * @param variable DCID of the statistical variable (e.g., 'Count_Person')
   */
  async getStatSeries(placeId: string, variable: string): Promise<DataPoint[]> {
    try {
      // https://docs.datacommons.org/api/rest/v2/stat_series
      const response = await axios.get(`${this.baseUrl}/v2/stat/series`, {
        params: {
          place: placeId,
          stat_var: variable,
        },
      });

      // Response format: { "series": { "country/DEU": { "Count_Person": { "val": { "2020": 83166711, ... } } } } }
      const seriesData = response.data?.series?.[placeId]?.[variable]?.val;

      if (!seriesData) {
        return [];
      }

      return Object.entries(seriesData)
        .map(([date, value]) => ({ date, value: Number(value) }))
        .sort((a, b) => a.date.localeCompare(b.date));
    } catch (error) {
      console.error(`DataCommons Error (${placeId}, ${variable}):`, error);
      return [];
    }
  }

  /**
   * Search for entities (places, etc.)
   */
  async resolveEntity(name: string): Promise<string | null> {
    // Search API or simple mapping for now.
    // DC doesn't have a simple "search" endpoint in v2 public API easily accessible without key sometimes?
    // Let's rely on LLM to provide DCIDs for now, or implement a naive search if needed.
    // For now, return null to force LLM to guess/know DCIDs.
    return null;
  }
}