import * as plugins from '../../plugins.js';
import type {
  IFundamentalsProvider,
  IStockFundamentals,
  IFundamentalsRequest,
  IFundamentalsCurrentRequest,
  IFundamentalsBatchRequest
} from '../interfaces/fundamentals.js';

/**
 * Configuration for SEC EDGAR provider
 */
export interface ISecEdgarConfig {
  userAgent: string; // Required: Format "Company Name Email" (e.g., "fin.cx info@fin.cx")
  cikCacheTTL?: number; // Default: 30 days (CIK codes rarely change)
  fundamentalsCacheTTL?: number; // Default: 90 days (quarterly filings)
  timeout?: number; // Request timeout in ms
}

/**
 * Rate limiter for SEC EDGAR API
 * SEC requires: 10 requests per second maximum
 */
class RateLimiter {
  private requestTimes: number[] = [];
  private readonly maxRequestsPerSecond = 10;

  public async waitForSlot(): Promise<void> {
    const now = Date.now();
    const oneSecondAgo = now - 1000;

    // Remove requests older than 1 second
    this.requestTimes = this.requestTimes.filter(time => time > oneSecondAgo);

    // If we've hit the limit, wait
    if (this.requestTimes.length >= this.maxRequestsPerSecond) {
      const oldestRequest = this.requestTimes[0];
      const waitTime = 1000 - (now - oldestRequest) + 10; // +10ms buffer
      await plugins.smartdelay.delayFor(waitTime);
      return this.waitForSlot(); // Recursively check again
    }

    // Record this request
    this.requestTimes.push(now);
  }
}

/**
 * SEC EDGAR Fundamental Data Provider
 *
 * Features:
 * - Free public access (no API key required)
 * - All US public companies
 * - Financial data from 10-K/10-Q filings
 * - US GAAP standardized metrics
 * - Historical data back to ~2009
 * - < 1 minute filing delay
 *
 * Documentation: https://www.sec.gov/edgar/sec-api-documentation
 *
 * Rate Limits:
 * - 10 requests per second (enforced by SEC)
 * - Requires User-Agent header in format: "Company Name Email"
 *
 * Data Sources:
 * - Company Facts API: /api/xbrl/companyfacts/CIK##########.json
 * - Ticker Lookup: /files/company_tickers.json
 */
export class SecEdgarProvider implements IFundamentalsProvider {
  public name = 'SEC EDGAR';
  public priority = 100; // High priority - free, authoritative, comprehensive
  public readonly requiresAuth = false; // No API key needed!
  public readonly rateLimit = {
    requestsPerMinute: 600, // 10 requests/second = 600/minute
    requestsPerDay: undefined // No daily limit
  };

  private logger = console;
  private baseUrl = 'https://data.sec.gov/api/xbrl';
  private tickersUrl = 'https://www.sec.gov/files/company_tickers.json';
  private userAgent: string;
  private config: Required<ISecEdgarConfig>;

  // Caching
  private cikCache = new Map<string, { cik: string; timestamp: Date }>();
  private tickerListCache: { data: any; timestamp: Date } | null = null;

  // Rate limiting
  private rateLimiter = new RateLimiter();

  constructor(config: ISecEdgarConfig) {
    // Validate User-Agent
    if (!config.userAgent) {
      throw new Error('User-Agent is required for SEC EDGAR provider (format: "Company Name Email")');
    }

    // Validate User-Agent format (must contain space and @ symbol)
    if (!config.userAgent.includes(' ') || !config.userAgent.includes('@')) {
      throw new Error(
        'Invalid User-Agent format. Required: "Company Name Email" (e.g., "fin.cx info@fin.cx")'
      );
    }

    this.userAgent = config.userAgent;
    this.config = {
      userAgent: config.userAgent,
      cikCacheTTL: config.cikCacheTTL || 30 * 24 * 60 * 60 * 1000, // 30 days
      fundamentalsCacheTTL: config.fundamentalsCacheTTL || 90 * 24 * 60 * 60 * 1000, // 90 days
      timeout: config.timeout || 30000
    };
  }

  /**
   * Unified data fetching method
   */
  public async fetchData(
    request: IFundamentalsRequest
  ): Promise<IStockFundamentals | IStockFundamentals[]> {
    switch (request.type) {
      case 'fundamentals-current':
        return this.fetchFundamentals(request);
      case 'fundamentals-batch':
        return this.fetchBatchFundamentals(request);
      default:
        throw new Error(`Unsupported request type: ${(request as any).type}`);
    }
  }

  /**
   * Fetch fundamental data for a single ticker
   */
  private async fetchFundamentals(request: IFundamentalsCurrentRequest): Promise<IStockFundamentals> {
    try {
      // 1. Get CIK for ticker (with caching)
      const cik = await this.getCIK(request.ticker);

      // 2. Fetch company facts from SEC (with rate limiting)
      const companyFacts = await this.fetchCompanyFacts(cik);

      // 3. Parse facts into structured fundamental data
      return this.parseCompanyFacts(request.ticker, cik, companyFacts);
    } catch (error) {
      this.logger.error(`Failed to fetch fundamentals for ${request.ticker}:`, error);
      throw new Error(`SEC EDGAR: Failed to fetch fundamentals for ${request.ticker}: ${plugins.getErrorMessage(error)}`);
    }
  }

  /**
   * Fetch fundamental data for multiple tickers
   */
  private async fetchBatchFundamentals(
    request: IFundamentalsBatchRequest
  ): Promise<IStockFundamentals[]> {
    const results: IStockFundamentals[] = [];
    const errors: string[] = [];

    for (const ticker of request.tickers) {
      try {
        const fundamentals = await this.fetchFundamentals({
          type: 'fundamentals-current',
          ticker
        });
        results.push(fundamentals);
      } catch (error) {
        this.logger.warn(`Failed to fetch fundamentals for ${ticker}:`, error);
        errors.push(`${ticker}: ${plugins.getErrorMessage(error)}`);
        // Continue with other tickers
      }
    }

    if (results.length === 0) {
      throw new Error(`Failed to fetch fundamentals for all tickers. Errors: ${errors.join(', ')}`);
    }

    return results;
  }

  /**
   * Get CIK (Central Index Key) for a ticker symbol
   * Uses SEC's public ticker-to-CIK mapping file
   */
  private async getCIK(ticker: string): Promise<string> {
    const tickerUpper = ticker.toUpperCase();

    // Check cache first
    const cached = this.cikCache.get(tickerUpper);
    if (cached) {
      const age = Date.now() - cached.timestamp.getTime();
      if (age < this.config.cikCacheTTL) {
        return cached.cik;
      }
      // Cache expired, remove it
      this.cikCache.delete(tickerUpper);
    }

    // Fetch ticker list (with caching at list level)
    const tickers = await this.fetchTickerList();

    // Find ticker in list (case-insensitive)
    const entry = Object.values(tickers).find((t: any) => t.ticker === tickerUpper);

    if (!entry) {
      throw new Error(`CIK not found for ticker ${ticker}`);
    }

    const cik = String((entry as any).cik_str);

    // Cache the result
    this.cikCache.set(tickerUpper, {
      cik,
      timestamp: new Date()
    });

    return cik;
  }

  /**
   * Fetch the SEC ticker-to-CIK mapping list
   * Cached for 24 hours (list updates daily)
   * Uses native fetch for automatic gzip decompression
   */
  private async fetchTickerList(): Promise<any> {
    // Check cache
    if (this.tickerListCache) {
      const age = Date.now() - this.tickerListCache.timestamp.getTime();
      if (age < 24 * 60 * 60 * 1000) { // 24 hours
        return this.tickerListCache.data;
      }
    }

    // Wait for rate limit slot
    await this.rateLimiter.waitForSlot();

    // Fetch from SEC using native fetch (handles gzip automatically)
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), this.config.timeout);

    try {
      const response = await fetch(this.tickersUrl, {
        headers: {
          'User-Agent': this.userAgent,
          'Accept': 'application/json'
          // Note: Accept-Encoding is set automatically by fetch
        },
        signal: controller.signal
      });

      clearTimeout(timeoutId);

      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }

      const data = await response.json();

      // Cache the list
      this.tickerListCache = {
        data,
        timestamp: new Date()
      };

      return data;
    } catch (error) {
      clearTimeout(timeoutId);
      throw error;
    }
  }

  /**
   * Fetch company facts from SEC EDGAR
   * Uses native fetch for automatic gzip decompression
   */
  private async fetchCompanyFacts(cik: string): Promise<any> {
    // Pad CIK to 10 digits
    const paddedCIK = cik.padStart(10, '0');
    const url = `${this.baseUrl}/companyfacts/CIK${paddedCIK}.json`;

    // Wait for rate limit slot
    await this.rateLimiter.waitForSlot();

    // Fetch from SEC using native fetch (handles gzip automatically)
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), this.config.timeout);

    try {
      const response = await fetch(url, {
        headers: {
          'User-Agent': this.userAgent,
          'Accept': 'application/json',
          'Host': 'data.sec.gov'
          // Note: Accept-Encoding is set automatically by fetch and gzip is handled transparently
        },
        signal: controller.signal
      });

      clearTimeout(timeoutId);

      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }

      const data = await response.json();

      // Validate response
      if (!data || !data.facts) {
        throw new Error('Invalid response from SEC EDGAR API');
      }

      return data;
    } catch (error) {
      clearTimeout(timeoutId);
      throw error;
    }
  }

  /**
   * Parse SEC company facts into structured fundamental data
   */
  private parseCompanyFacts(ticker: string, cik: string, data: any): IStockFundamentals {
    const usGaap = data.facts?.['us-gaap'];

    if (!usGaap) {
      throw new Error('No US GAAP data available');
    }

    // Extract latest values for key metrics
    const fundamentals: IStockFundamentals = {
      ticker: ticker.toUpperCase(),
      cik: cik,
      companyName: data.entityName,
      provider: this.name,
      timestamp: new Date(),
      fetchedAt: new Date(),

      // Per-share metrics
      earningsPerShareBasic: this.getLatestValue(usGaap, 'EarningsPerShareBasic'),
      earningsPerShareDiluted: this.getLatestValue(usGaap, 'EarningsPerShareDiluted'),
      sharesOutstanding: this.getLatestValue(usGaap, 'CommonStockSharesOutstanding'),
      weightedAverageSharesOutstanding: this.getLatestValue(
        usGaap,
        'WeightedAverageNumberOfSharesOutstandingBasic'
      ),

      // Income statement
      revenue: this.getLatestValue(usGaap, 'Revenues') ||
               this.getLatestValue(usGaap, 'RevenueFromContractWithCustomerExcludingAssessedTax'),
      netIncome: this.getLatestValue(usGaap, 'NetIncomeLoss'),
      operatingIncome: this.getLatestValue(usGaap, 'OperatingIncomeLoss'),
      grossProfit: this.getLatestValue(usGaap, 'GrossProfit'),
      costOfRevenue: this.getLatestValue(usGaap, 'CostOfRevenue'),

      // Balance sheet
      assets: this.getLatestValue(usGaap, 'Assets'),
      liabilities: this.getLatestValue(usGaap, 'Liabilities'),
      stockholdersEquity: this.getLatestValue(usGaap, 'StockholdersEquity'),
      cash: this.getLatestValue(usGaap, 'CashAndCashEquivalentsAtCarryingValue'),
      propertyPlantEquipment: this.getLatestValue(usGaap, 'PropertyPlantAndEquipmentNet'),

      // Metadata (from latest available data point)
      fiscalYear: this.getLatestMetadata(usGaap, 'EarningsPerShareDiluted')?.fy,
      fiscalQuarter: this.getLatestMetadata(usGaap, 'EarningsPerShareDiluted')?.fp,
      filingDate: this.getLatestMetadata(usGaap, 'EarningsPerShareDiluted')?.filed
        ? new Date(this.getLatestMetadata(usGaap, 'EarningsPerShareDiluted')!.filed)
        : undefined,
      form: this.getLatestMetadata(usGaap, 'EarningsPerShareDiluted')?.form
    };

    return fundamentals;
  }

  /**
   * Get the latest value for a US GAAP metric
   */
  private getLatestValue(usGaap: any, metricName: string): number | undefined {
    const metric = usGaap[metricName];
    if (!metric?.units) {
      return undefined;
    }

    // Get the first unit type (USD, shares, etc.)
    const unitType = Object.keys(metric.units)[0];
    const values = metric.units[unitType];

    if (!values || !Array.isArray(values) || values.length === 0) {
      return undefined;
    }

    // Get the latest value (last in array)
    const latest = values[values.length - 1];
    return latest?.val;
  }

  /**
   * Get metadata from the latest data point
   */
  private getLatestMetadata(usGaap: any, metricName: string): any | undefined {
    const metric = usGaap[metricName];
    if (!metric?.units) {
      return undefined;
    }

    const unitType = Object.keys(metric.units)[0];
    const values = metric.units[unitType];

    if (!values || !Array.isArray(values) || values.length === 0) {
      return undefined;
    }

    return values[values.length - 1];
  }

  /**
   * Check if SEC EDGAR API is available
   * Uses native fetch for automatic gzip decompression
   */
  public async isAvailable(): Promise<boolean> {
    try {
      // Test with Apple's well-known CIK
      const url = `${this.baseUrl}/companyfacts/CIK0000320193.json`;

      const controller = new AbortController();
      const timeoutId = setTimeout(() => controller.abort(), 5000);

      const response = await fetch(url, {
        headers: {
          'User-Agent': this.userAgent,
          'Accept': 'application/json'
        },
        signal: controller.signal
      });

      clearTimeout(timeoutId);

      if (!response.ok) {
        return false;
      }

      const data = await response.json();
      return data && data.facts !== undefined;
    } catch (error) {
      this.logger.warn('SEC EDGAR provider is not available:', error);
      return false;
    }
  }

  /**
   * Get cache statistics
   */
  public getCacheStats(): {
    cikCacheSize: number;
    hasTickerList: boolean;
  } {
    return {
      cikCacheSize: this.cikCache.size,
      hasTickerList: this.tickerListCache !== null
    };
  }

  /**
   * Clear all caches
   */
  public clearCache(): void {
    this.cikCache.clear();
    this.tickerListCache = null;
    this.logger.log('SEC EDGAR cache cleared');
  }
}