import { getApiKey } from './storage.js';

const BASE = 'https://openrouter.ai/api/v1/chat/completions';
const MASTER_PROMPT = 'minimal black and white line doodle, single stroke, white background, kawaii style';

/**
 * Generates a single image frame via OpenRouter.
 * @param {Object} opts
 * @param {string} opts.model
 * @param {Array} opts.messages - chat history messages
 * @param {string} opts.imageSize - "1K" or "0.5K"
 * @param {string} opts.aspectRatio - e.g. "1:1"
 * @returns {Promise<{base64: string, assistantMsg: Object}>}
 */
export async function generateFrame({ model, messages, imageSize, aspectRatio }) {
  const isGemini = model.startsWith('google/');

  const body = {
    model,
    messages,
    modalities: ['image'],
    image_config: {
      aspect_ratio: aspectRatio,
      image_size: imageSize,
    },
  };

  if (!isGemini && imageSize === '0.5K') {
    body.image_config.image_size = '1K';
  }

  const res = await fetch(BASE, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${getApiKey()}`,
      'Content-Type': 'application/json',
      'HTTP-Referer': 'https://vibegif.lol',
      'X-Title': 'vibegif.lol',
    },
    body: JSON.stringify(body),
  });

  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err?.error?.message || `API error ${res.status}`);
  }

  const data = await res.json();
  const choice = data.choices?.[0];
  if (!choice) throw new Error('No response from model');

  const images = choice.message?.images;
  if (!images?.length) throw new Error('No image in response. The model may have refused or returned text only.');

  const url = images[0].image_url?.url || images[0].url;
  if (!url) throw new Error('Could not parse image from response');

  const base64 = url.startsWith('data:') ? url : `data:image/png;base64,${url}`;

  const assistantMsg = {
    role: 'assistant',
    content: [
      { type: 'image_url', image_url: { url: base64 } }
    ]
  };

  return { base64, assistantMsg };
}

/**
 * Build the first user message (frame 1).
 */
export function buildFirstMessage(userPrompt) {
  return {
    role: 'user',
    content: `${MASTER_PROMPT}, ${userPrompt}`
  };
}

/**
 * Build follow-up user message for subsequent frames.
 */
export function buildNextMessage(frameIndex, frameCount) {
  return {
    role: 'user',
    content: `imagine we are trying to create a ${frameCount} frame gif. generate the next meaningful frame (frame ${frameIndex} of ${frameCount})`
  };
}