src/utils/hfClient.ts

import axios from "axios";
import FormData from "form-data";
import dotenv from "dotenv";
dotenv.config();

const FASHION_CLIP_URL = process.env.FASHION_CLIP_URL || "https://nexusbert-fashionclip.hf.space";

export interface ClassificationResult {
  label: string;
  score: number;
}

export interface IdentifyResult {
  label: string;
  score: number;
  type: "brand" | "item" | "color" | "accessory" | "combined";
}

export interface IdentifyResponse {
  precise_identification: IdentifyResult[];
  detected_components: {
    top_colors: Array<{ color: string; score: number }>;
    top_items: Array<{ item: string; score: number }>;
    top_accessories: Array<{ accessory: string; score: number }>;
    top_brands: Array<{ brand: string; score: number }>;
  };
}

/**
 * Classify a fashion image using the FashionCLIP /classify endpoint
 * @param fileBuffer - The image file buffer
 * @param filename - The original filename
 * @param mimetype - The file MIME type
 * @returns Array of classification results sorted by score (highest first)
 */
export async function classifyFashionImage(
  fileBuffer: Buffer,
  filename: string,
  mimetype: string
): Promise<ClassificationResult[]> {
  const endpoint = `${FASHION_CLIP_URL}/classify`;

  // Create form data with file
  const formData = new FormData();
  formData.append("file", fileBuffer, {
    filename: filename,
    contentType: mimetype,
  });

  let lastError: any = null;
  const maxAttempts = 2;
  
  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
    try {
      const response = await axios.post<ClassificationResult[]>(endpoint, formData, {
        headers: {
          ...formData.getHeaders(),
        },
        timeout: 60000, // 60 second timeout for model inference
        validateStatus: (status) => status >= 200 && status < 300,
      });
      
      // Response is already an array of {label, score} objects
      return response.data;
    } catch (error: any) {
      lastError = error;
      const status = error?.response?.status;
      
      // Retry once for transient errors
      if (attempt < maxAttempts && (status === 429 || status === 503 || status === 502)) {
        console.log(`FashionCLIP classify API returned ${status}. Retrying...`);
        await new Promise((r) => setTimeout(r, 2000));
        continue;
      }
      
      // Provide clearer error messages
      if (error?.response?.data?.detail) {
        throw new Error(`FashionCLIP classify API error: ${error.response.data.detail}`);
      }
      
      if (error?.code === "ECONNREFUSED" || error?.code === "ETIMEDOUT") {
        throw new Error("Unable to connect to FashionCLIP service. Please try again later.");
      }
      
      throw error;
    }
  }
  
  throw lastError;
}

export async function identifyFashionItem(
  fileBuffer: Buffer,
  filename: string,
  mimetype: string,
  topK: number = 5
): Promise<IdentifyResponse> {
  const clampedTopK = Math.max(1, Math.min(20, topK));
  const endpoint = `${FASHION_CLIP_URL}/identify?top_k=${clampedTopK}`;

  const formData = new FormData();
  formData.append("file", fileBuffer, {
    filename: filename,
    contentType: mimetype,
  });

  let lastError: any = null;
  const maxAttempts = 2;
  
  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
    try {
      const response = await axios.post<IdentifyResponse>(endpoint, formData, {
        headers: {
          ...formData.getHeaders(),
        },
        timeout: 60000,
        validateStatus: (status) => status >= 200 && status < 300,
      });
      
      return response.data;
    } catch (error: any) {
      lastError = error;
      const status = error?.response?.status;
      
      if (attempt < maxAttempts && (status === 429 || status === 503 || status === 502)) {
        console.log(`FashionCLIP identify API returned ${status}. Retrying...`);
        await new Promise((r) => setTimeout(r, 2000));
        continue;
      }
      
      if (error?.response?.data?.detail) {
        throw new Error(`FashionCLIP identify API error: ${error.response.data.detail}`);
      }
      
      if (error?.code === "ECONNREFUSED" || error?.code === "ETIMEDOUT") {
        throw new Error("Unable to connect to FashionCLIP service. Please try again later.");
      }
      
      throw error;
    }
  }
  
  throw lastError;
}