/**
 * Relatr API Integration
 * 
 * Relatr is a decentralized Web of Trust service that provides global trust scores
 * for Nostr pubkeys. This module provides integration with the Relatr service.
 * 
 * Documentation: https://www.relatr.xyz/
 * GitHub: https://github.com/ContextVM/relatr
 */

export interface RelatrScore {
  source: string;      // Source pubkey (perspective)
  target: string;      // Target pubkey being scored
  score: number;       // Trust score (0-100)
  distance?: number;   // Social graph distance
  hasNip05?: boolean;  // NIP-05 verification status
  hasLud16?: boolean;  // Lightning address status
  timestamp: number;   // When score was calculated
}

export interface RelatrBatchRequest {
  source: string;      // Perspective pubkey
  targets: string[];   // Array of pubkeys to score
}

export interface RelatrBatchResponse {
  scores: Map<string, RelatrScore>;
}

/**
 * Relatr API client
 * 
 * NOTE: This is a placeholder implementation. The actual Relatr API
 * endpoint structure needs to be confirmed from the official documentation.
 * 
 * Relatr provides an MCP (Model Context Protocol) server interface, which
 * may require different integration patterns than a traditional REST API.
 * 
 * Potential API patterns:
 * 1. REST API: https://api.relatr.xyz/v1/scores?source=...&target=...
 * 2. MCP Server: Requires MCP client connection
 * 3. Nostr Events: Trust scores published as Nostr events
 */
export class RelatrClient {
  private apiUrl: string;
  private corsProxy: string;

  constructor(
    apiUrl = 'https://api.relatr.xyz',
    corsProxy = 'https://proxy.shakespeare.diy/?url='
  ) {
    this.apiUrl = apiUrl;
    this.corsProxy = corsProxy;
  }

  /**
   * Fetch trust score for a single target from source's perspective
   * 
   * @param source - Source pubkey (viewer's perspective)
   * @param target - Target pubkey to score
   * @returns Trust score or null if unavailable
   */
  async getScore(source: string, target: string): Promise<RelatrScore | null> {
    try {
      // TODO: Confirm actual Relatr API endpoint structure
      // This is a placeholder based on common REST patterns
      const url = `${this.corsProxy}${encodeURIComponent(
        `${this.apiUrl}/v1/score?source=${source}&target=${target}`
      )}`;

      const response = await fetch(url, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
        },
        signal: AbortSignal.timeout(10000),
      });

      if (!response.ok) {
        console.warn(`[Relatr] API returned ${response.status}`);
        return null;
      }

      const data = await response.json();
      
      return {
        source,
        target,
        score: data.score || 0,
        distance: data.distance,
        hasNip05: data.hasNip05,
        hasLud16: data.hasLud16,
        timestamp: Date.now(),
      };
    } catch (error) {
      console.warn('[Relatr] Failed to fetch score:', error);
      return null;
    }
  }

  /**
   * Fetch trust scores for multiple targets in batch
   * 
   * @param source - Source pubkey (viewer's perspective)
   * @param targets - Array of target pubkeys to score
   * @returns Map of target pubkey to score
   */
  async getBatchScores(
    source: string,
    targets: string[]
  ): Promise<Map<string, RelatrScore>> {
    const scores = new Map<string, RelatrScore>();

    try {
      // TODO: Confirm if Relatr supports batch requests
      // Option 1: Batch endpoint
      const url = `${this.corsProxy}${encodeURIComponent(`${this.apiUrl}/v1/batch`)}`;
      
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ source, targets }),
        signal: AbortSignal.timeout(15000),
      });

      if (!response.ok) {
        console.warn(`[Relatr] Batch API returned ${response.status}`);
        return scores;
      }

      const data = await response.json();
      
      // Parse batch response
      if (Array.isArray(data.scores)) {
        for (const scoreData of data.scores) {
          scores.set(scoreData.target, {
            source,
            target: scoreData.target,
            score: scoreData.score || 0,
            distance: scoreData.distance,
            hasNip05: scoreData.hasNip05,
            hasLud16: scoreData.hasLud16,
            timestamp: Date.now(),
          });
        }
      }

      return scores;
    } catch (error) {
      console.warn('[Relatr] Batch request failed, falling back to individual requests:', error);
      
      // Fallback: Make individual requests (slower but reliable)
      for (const target of targets.slice(0, 10)) { // Limit to 10 to avoid rate limits
        const score = await this.getScore(source, target);
        if (score) {
          scores.set(target, score);
        }
        // Small delay between requests
        await new Promise(resolve => setTimeout(resolve, 100));
      }

      return scores;
    }
  }
}

/**
 * Global Relatr client instance
 * 
 * NOTE: Set RELATR_ENABLED = false until API integration is confirmed
 */
export const RELATR_ENABLED = false; // Toggle when API is ready
export const relatrClient = new RelatrClient();

/**
 * Normalize Relatr score to 0-100 scale
 * Relatr may use different scoring systems, this ensures compatibility
 */
export function normalizeRelatrScore(score: number): number {
  // Assume Relatr uses 0-1 scale, convert to 0-100
  if (score <= 1) {
    return Math.round(score * 100);
  }
  // Already 0-100 scale
  return Math.round(Math.max(0, Math.min(100, score)));
}