import { getModelsForTask } from './aiConfig';

const API_ENDPOINT = 'https://generativelanguage.googleapis.com/v1beta/models/';

export interface SavScanResult {
  scores: Record<string, number>;
  varga: string;
}

/**
 * Vision Service for extracting structured data from JHora screenshots.
 */
export class VisionScanner {
  private static apiKey = import.meta.env.VITE_GEMINI_API_KEY;

  /**
   * Scans a Sarvastakavarga (SAV) image and returns the 4x4 grid of scores.
   */
  static async scanSAV(base64Image: string, varga: string = 'D1'): Promise<SavScanResult> {
    if (!this.apiKey) {
      throw new Error('Gemini API key is missing. Please add VITE_GEMINI_API_KEY to your .env file.');
    }

    // Strip data:image/png;base64, prefix if present
    const cleanBase64 = base64Image.replace(/^data:image\/(png|jpg|jpeg);base64,/, '');
    
    const taskConfig = getModelsForTask('SAV_OCR');
    
    try {
      // Try primary model (3.1-flash-lite)
      return await this.callGemini(cleanBase64, varga, taskConfig.primary);
    } catch (error: any) {
      console.warn(`Primary model (${taskConfig.primary}) failed:`, error.message);
      
      // Fallback to secondary (2.5-flash-lite)
      console.info(`Attempting fallback to ${taskConfig.secondary}...`);
      return await this.callGemini(cleanBase64, varga, taskConfig.secondary);
    }
  }

  private static async callGemini(base64: string, varga: string, model: string): Promise<SavScanResult> {
    const url = `${API_ENDPOINT}${model}:generateContent?key=${this.apiKey}`;
    
    const prompt = `
      EXTRACT SARVASTAKAVARGA (SAV) GRID:
      1. Look for a 12-box chart (often drawn as a 4x4 grid with an empty center) of numbers in the provided JHora screenshot.
      2. This is the SAV (Sarvastakavarga) chart for the divisional chart: ${varga}, formatted as a South Indian astrology chart.
      3. In the South Indian chart format, the Zodiac signs are ALWAYS in these fixed positions (read the integer from each box):
         - Top row (left to right): PISCES (top-left corner), ARIES, TAURUS, GEMINI (top-right corner).
         - Right column (continuing down): CANCER, LEO.
         - Bottom row (right to left): VIRGO (bottom-right corner), LIBRA, SCORPIO, SAGITTARIUS (bottom-left corner).
         - Left column (continuing up): CAPRICORN, AQUARIUS.
      4. RETURN ONLY VALID JSON in this exact format, mapping the extracted number from each position to its respective sign:
      {
        "ARIES": number,
        "TAURUS": number,
        "GEMINI": number,
        "CANCER": number,
        "LEO": number,
        "VIRGO": number,
        "LIBRA": number,
        "SCORPIO": number,
        "SAGITTARIUS": number,
        "CAPRICORN": number,
        "AQUARIUS": number,
        "PISCES": number
      }
    `;

    const response = await fetch(url, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        contents: [{
          parts: [
            { text: prompt },
            { inline_data: { mime_type: "image/png", data: base64 } }
          ]
        }],
        generationConfig: {
          response_mime_type: "application/json"
        }
      })
    });

    if (!response.ok) {
      const err = await response.json();
      throw new Error(err.error?.message || 'Gemini API call failed');
    }

    const json = await response.json();
    const resultText = json.candidates?.[0]?.content?.parts?.[0]?.text;
    
    if (!resultText) {
      throw new Error('AI returned an empty response.');
    }

    try {
      const scores = JSON.parse(resultText);
      return { scores, varga };
    } catch (e) {
      console.error('Failed to parse AI JSON:', resultText);
      throw new Error('AI returned malformed JSON data.');
    }
  }
}