const fs = require('fs');
const path = require('path');
const axios = require('axios');
const config = require('../config');
const aiUsage = require('./aiUsage');

const UPLOADS_DIR = process.env.UPLOADS_DIR || '/var/www/zeropost-uploads';

let sharp = null;
try { sharp = require('sharp'); } catch {}

if (!fs.existsSync(UPLOADS_DIR)) fs.mkdirSync(UPLOADS_DIR, { recursive: true });

/**
 * Стили картинок к постам — словарь для перевода в промпт.
 */
const IMAGE_STYLES = {
  'realistic-photo': {
    label: 'Реалистичное фото',
    prompt: 'photorealistic, high-quality photography, natural lighting, professional camera shot, sharp focus, realistic textures',
  },
  'flat-illustration': {
    label: 'Плоская иллюстрация',
    prompt: 'flat vector illustration, clean geometric shapes, modern editorial style, smooth gradients, minimal',
  },
  '3d-render': {
    label: '3D рендер',
    prompt: '3D render, soft studio lighting, isometric perspective, smooth surfaces, modern materials, Pixar-like quality',
  },
  'cartoon': {
    label: 'Мультяшный',
    prompt: 'cartoon illustration, bold outlines, vibrant colors, expressive characters, comic book style',
  },
  'minimal': {
    label: 'Минимализм',
    prompt: 'extremely minimalist composition, single focal element, lots of negative space, monochrome or duotone',
  },
  'abstract': {
    label: 'Абстракция',
    prompt: 'abstract artwork, layered shapes, conceptual composition, no literal objects, mood and texture focused',
  },
  'sketch': {
    label: 'Эскиз / скетч',
    prompt: 'hand-drawn sketch style, pencil and ink, loose lines, notebook page aesthetic',
  },
  'cyberpunk': {
    label: 'Киберпанк',
    prompt: 'cyberpunk aesthetic, neon lights, futuristic city, dark atmospheric mood, blade runner vibe',
  },
};

const IMAGE_PALETTES = {
  'auto':     '',
  'dark':     'dark color palette, deep blues, blacks, subtle highlights',
  'light':    'light color palette, soft whites, pastels, airy mood',
  'warm':     'warm color palette, oranges, reds, golden tones',
  'cool':     'cool color palette, blues, teals, purples',
  'mono':     'monochromatic palette, single hue with shades',
  'vibrant':  'vibrant saturated colors, high energy palette',
};

/**
 * Генерирует картинку к посту через GPT-5 /v1/responses + image_generation.
 */
async function generatePostImage({ post, channel, style = {} }) {
  // Если задано несколько стилей через запятую — случайно выбираем один
  const styleList = (style.image_style || 'flat-illustration')
    .split(',').map(s => s.trim()).filter(s => s && s !== 'auto');
  const pickedStyle = styleList[Math.floor(Math.random() * styleList.length)] || 'flat-illustration';
  const imageStyle = IMAGE_STYLES[pickedStyle] || IMAGE_STYLES['flat-illustration'];
  const palette = style.image_custom_colors
    ? `custom brand palette: ${style.image_custom_colors}`
    : IMAGE_PALETTES[style.image_palette] || '';

  // Извлекаем суть поста для промпта (первые 250 символов)
  const postExcerpt = post.replace(/[#*_`>]/g, '').slice(0, 250);

  const prompt = `Editorial illustration for a social media post. Topic essence: "${postExcerpt}"

Style: ${imageStyle.prompt}.
${palette ? `Color palette: ${palette}.` : ''}
Channel context: ${channel.niche || channel.name}.
${style.image_prompt_instructions ? `\nChannel visual guidelines: ${style.image_prompt_instructions}` : ''}

Composition: 16:9 wide format, balanced, suitable for social media.
Strictly: no text, no letters, no logos, no faces of real people.`;

  // Используем Nyxos /images/generations (первичный провайдер)
  // с fallback на aiguoguo — тот же путь что для обложек статей
  const model = config.ai.imageModel || 'gpt-image-2';

  async function tryProvider(baseUrl, apiKey) {
    const started = Date.now();
    try {
      const res = await axios.post(
        `${baseUrl}/images/generations`,
        { model, prompt: prompt.slice(0, 4000), n: 1, size: '1024x1024', response_format: 'url' },
        { headers: { Authorization: `Bearer ${apiKey}` }, timeout: 120_000 }
      );
      const item = res.data?.data?.[0];
      if (!item) throw new Error('No image data');
      aiUsage.log({ provider: aiUsage.providerFromBaseUrl(baseUrl), requestType: 'image', model, imageCount: 1, meta: { channel_id: channel.id }, succeeded: true }).catch(() => {});
      if (item.url) {
        const r = await axios.get(item.url, { responseType: 'arraybuffer', timeout: 60_000 });
        return Buffer.from(r.data);
      }
      if (item.b64_json) return Buffer.from(item.b64_json, 'base64');
      throw new Error('No url or b64_json');
    } catch (err) {
      aiUsage.log({ provider: aiUsage.providerFromBaseUrl(baseUrl), requestType: 'image', model, imageCount: 1, meta: { channel_id: channel.id }, succeeded: false, errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500) }).catch(() => {});
      throw err;
    }
  }

  let bytes;
  try {
    bytes = await tryProvider(config.ai.imageBaseUrl, config.ai.imageApiKey);
  } catch (err) {
    const status = err.response?.status;
    if (!status || status >= 500) {
      console.warn('[postImages] primary failed, trying fallback...');
      bytes = await tryProvider(config.ai.imageFallbackBaseUrl, config.ai.imageFallbackApiKey);
    } else { throw err; }
  }

  const tsKey = `post-${channel.id}-${Date.now()}`;
  const ext = 'png';

  // Оптимизация через sharp если есть
  let publicUrl;
  if (sharp) {
    const webpName = `${tsKey}.webp`;
    await sharp(bytes)
      .resize(1600, null, { withoutEnlargement: true })
      .webp({ quality: 84 })
      .toFile(path.join(UPLOADS_DIR, webpName));
    publicUrl = `/uploads/${webpName}`;
  } else {
    const name = `${tsKey}.${ext}`;
    fs.writeFileSync(path.join(UPLOADS_DIR, name), bytes);
    publicUrl = `/uploads/${name}`;
  }

  return { url: publicUrl, style: style.image_style, palette: style.image_palette };
}

module.exports = { generatePostImage, IMAGE_STYLES, IMAGE_PALETTES };