import { GoogleGenAI } from "@google/genai";

/**
 * Generates a VTuber avatar image based on user description.
 * Uses gemini-3-pro-image-preview for high quality.
 */
export const generateAvatarImage = async (description: string): Promise<string> => {
  try {
    // Initialize client inside the function to ensure we use the most up-to-date API key
    // after the user has completed the selection flow.
    const ai = new GoogleGenAI({ apiKey: process.env.API_KEY });

    // We construct a prompt that encourages a good format for a 2D avatar (front facing, clean background)
    const prompt = `
      Create a high-quality, flat 2D anime or stylized character illustration suitable for a VTuber avatar.
      The character should be facing forward (front view).
      The background should be a solid, single color (white or bright green) to allow for easy removal or masking.
      
      Character Description: ${description}
      
      Style: Vibrant, clean lines, detailed eyes.
      Focus: Head and shoulders only.
    `;

    const response = await ai.models.generateContent({
      model: 'gemini-3-pro-image-preview',
      contents: {
        parts: [
          { text: prompt }
        ]
      },
      config: {
        imageConfig: {
          aspectRatio: "1:1",
          imageSize: "1K"
        }
      }
    });

    // Parse response for image data
    for (const part of response.candidates[0].content.parts) {
      if (part.inlineData) {
        const base64EncodeString = part.inlineData.data;
        return `data:image/png;base64,${base64EncodeString}`;
      }
    }

    throw new Error("No image data found in response");
  } catch (error) {
    console.error("Error generating avatar:", error);
    throw error;
  }
};