/**
 * Minimal ConversionIQ SDK - Core functionality only
 * Target: <15KB gzipped
 */

import { ConversionIQConfig, EventData, TrackingOptions } from './types/index';

interface MinimalConfig {
  apiKey?: string;
  websiteId?: string;
  endpoint?: string;
  debug?: boolean;
}

export class MinimalConversionIQ {
  private config: MinimalConfig;
  private sessionId: string;
  private userId?: string;

  constructor(config: MinimalConfig = {}) {
    this.config = {
      endpoint: 'https://conversioniq-api-dev.azurewebsites.net',
      debug: false,
      ...config
    };
    this.sessionId = this.generateSessionId();
  }

  /**
   * Set user identification
   */
  public identify(userId: string): void {
    this.userId = userId;
    this.track('identify', { user_id: userId });
  }

  /**
   * Track a custom event
   */
  public async track(eventType: string, data?: Record<string, any>): Promise<void> {
    // Validate required configuration
    if (!this.config.websiteId) {
      const error = 'ConversionIQ: websiteId is required but not configured';
      if (this.config.debug) {
        console.error(error);
      }
      throw new Error(error);
    }

    const payload = {
      website_id: this.config.websiteId,
      event_type: eventType,
      user_id: this.userId,
      session_id: this.sessionId,
      timestamp: new Date().toISOString(),
      user_agent: navigator.userAgent,
      page_url: window.location.href,
      metadata: {
        ...data,
        viewport_width: window.innerWidth,
        viewport_height: window.innerHeight,
        sdk_version: '2.0.12-minimal'
      }
    };

    try {
      await this.sendEvent(payload);
      if (this.config.debug) {
        console.log('ConversionIQ: Event tracked', payload);
      }
    } catch (error) {
      if (this.config.debug) {
        console.error('ConversionIQ: Failed to track event', error);
      }
      throw error;
    }
  }

  /**
   * Track a conversion
   */
  public async trackConversion(value: number, currency = 'USD', metadata?: Record<string, any>): Promise<void> {
    await this.track('conversion', {
      value,
      currency,
      ...metadata
    });
  }

  /**
   * Track a page view
   */
  public async trackPageView(): Promise<void> {
    await this.track('page_view', {
      url: window.location.href,
      title: document.title,
      referrer: document.referrer
    });
  }

  /**
   * Track element click
   */
  public async trackClick(selector: string, metadata?: Record<string, any>): Promise<void> {
    await this.track('click', {
      element: selector,
      page_url: window.location.href,
      ...metadata
    });
  }

  private async sendEvent(payload: any): Promise<void> {
    const response = await fetch(`${this.config.endpoint}/api/v1/events`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${this.config.apiKey}`
      },
      body: JSON.stringify(payload)
    });

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

  private generateSessionId(): string {
    return 'ciq_' + Date.now().toString(36) + Math.random().toString(36).substring(2);
  }
}

// Auto-initialization for script tag usage only
// Only run when loaded via <script> tag, not when imported as a module
// Skip auto-initialization in test environment
if (typeof window !== 'undefined' && process.env.NODE_ENV !== 'test') {
  const scriptTag = document.currentScript as HTMLScriptElement;
  const hasGlobalConfig = !!(window as any).__conversioniq_config;

  // Only auto-initialize if loaded via script tag OR has global config
  if (scriptTag || hasGlobalConfig) {
    const config = (window as any).__conversioniq_config || {};

    if (scriptTag?.dataset.apiKey) {
      config.apiKey = scriptTag.dataset.apiKey;
      config.websiteId = scriptTag.dataset.websiteId || scriptTag.dataset.apiKey;
    }

    const sdk = new MinimalConversionIQ(config);
    (window as any).ConversionIQ = sdk;

    // Log initialization info
    if (config.debug || !config.websiteId) {
      console.log('ConversionIQ Minimal SDK initialized', {
        websiteId: config.websiteId || 'NOT SET - Events will fail!',
        apiKey: config.apiKey ? '***' : 'NOT SET',
        endpoint: config.endpoint,
        debug: config.debug
      });
    }

    // Auto-track page view with error handling
    const trackInitialPageView = async () => {
      try {
        await sdk.trackPageView();
      } catch (error) {
        console.error('ConversionIQ: Failed to track initial page view', error);
        // Don't throw - allow the SDK to continue working
      }
    };

    if (document.readyState === 'loading') {
      document.addEventListener('DOMContentLoaded', trackInitialPageView);
    } else {
      trackInitialPageView();
    }
  }
}

export default MinimalConversionIQ;