/**
 * AI Design Advisor — GPT-4o powered design tips, material recommendations, and DALL-E 3 renders
 * Helps customers feel confident about their wardrobe design choices.
 */
import OpenAI from 'openai';
import crypto from 'crypto';

let openaiClient = null;

function getOpenAIClient() {
  if (!openaiClient) {
    if (!process.env.OPENAI_API_KEY) {
      throw new Error('OPENAI_API_KEY is not configured. Add it to server/.env');
    }
    openaiClient = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
  }
  return openaiClient;
}

/* -------------------------------------------------------------------------- */
/*  1. Design Tips (GPT-4o text)                                              */
/* -------------------------------------------------------------------------- */

const DESIGN_TIP_PROMPT = `Tu es un designer d'intérieur suisse spécialisé dans les armoires sur mesure haut de gamme.
À partir de la configuration ci-dessous, donne UN SEUL conseil ou commentaire positif en 1-2 phrases maximum.
Le ton doit être chaleureux, professionnel et encourageant — le client doit se sentir confiant dans son choix.

Varie tes réponses : parfois un compliment sur la combinaison, parfois un conseil pratique, parfois une info sur les tendances.

Réponds UNIQUEMENT en JSON :
{ "tip": "…votre conseil en français…", "category": "compliment" | "conseil" | "tendance" }`;

/**
 * Generate a design tip for the current configuration
 * @param {object} config - { width, height, depth, columns (array of {type, shelves, drawers, hasRod}), material, installationType }
 * @returns {{ tip: string, category: string }}
 */
export async function getDesignTip(config) {
  const client = getOpenAIClient();

  const configSummary = buildConfigSummary(config);

  const response = await client.chat.completions.create({
    model: 'gpt-4o',
    temperature: 0.9,
    max_tokens: 200,
    messages: [
      { role: 'system', content: DESIGN_TIP_PROMPT },
      { role: 'user', content: configSummary }
    ],
    response_format: { type: 'json_object' }
  });

  const raw = response.choices[0]?.message?.content;
  try {
    return JSON.parse(raw);
  } catch {
    return { tip: raw, category: 'conseil' };
  }
}

/* -------------------------------------------------------------------------- */
/*  2. Material Recommendations (GPT-4o)                                      */
/* -------------------------------------------------------------------------- */

const MATERIAL_REC_PROMPT = `Tu es un conseiller en matériaux et couleurs pour armoires sur mesure suisses haut de gamme.
À partir de la configuration actuelle et de la liste de matériaux disponibles, recommande 3 à 5 matériaux qui iraient parfaitement ensemble.

Critères de recommandation :
- Harmonie des couleurs avec les matériaux déjà sélectionnés
- Cohérence avec le style d'armoire (dimensions, configuration)
- Tendances actuelles en design d'intérieur suisse
- Si un contexte de pièce est fourni, s'accorder avec le style de la pièce

Réponds UNIQUEMENT en JSON :
{
  "recommendations": [
    { "finishId": <number>, "reason": "…raison courte en français…" }
  ]
}`;

/**
 * Recommend materials that complement the current configuration
 * @param {object} config - Current wardrobe configuration
 * @param {Array} availableFinishes - [{ id, name, collection, code }]
 * @param {object} [roomAnalysis] - Optional room photo analysis
 * @returns {{ recommendations: Array<{ finishId: number, reason: string }> }}
 */
export async function recommendMaterials(config, availableFinishes, roomAnalysis) {
  const client = getOpenAIClient();

  const configSummary = buildConfigSummary(config);

  // Compact finish list (only names + ids to save tokens)
  const finishList = availableFinishes
    .slice(0, 80) // limit to avoid token overflow
    .map(f => `${f.id}: ${f.name || f.label} (${f.collection || '?'})`)
    .join('\n');

  let userMessage = `CONFIGURATION ACTUELLE:\n${configSummary}\n\nMATÉRIAUX DISPONIBLES:\n${finishList}`;

  if (roomAnalysis) {
    userMessage += `\n\nCONTEXTE PIÈCE:\n${JSON.stringify(roomAnalysis, null, 1)}`;
  }

  const response = await client.chat.completions.create({
    model: 'gpt-4o',
    temperature: 0.7,
    max_tokens: 400,
    messages: [
      { role: 'system', content: MATERIAL_REC_PROMPT },
      { role: 'user', content: userMessage }
    ],
    response_format: { type: 'json_object' }
  });

  const raw = response.choices[0]?.message?.content;
  try {
    const parsed = JSON.parse(raw);
    return { recommendations: (parsed.recommendations || []).slice(0, 5) };
  } catch {
    return { recommendations: [] };
  }
}

/* -------------------------------------------------------------------------- */
/*  3. Photorealistic Render (DALL-E 3)                                       */
/* -------------------------------------------------------------------------- */

// Simple in-memory render cache (config hash → image URL)
const renderCache = new Map();

/**
 * Generate a photorealistic render of the configured wardrobe using DALL-E 3
 * @param {object} config - Current wardrobe configuration
 * @param {object} [roomContext] - Optional room analysis for context
 * @returns {{ imageUrl: string, cached: boolean }}
 */
export async function generateRender(config, roomContext) {
  const client = getOpenAIClient();

  // Cache by config hash
  const hash = crypto.createHash('md5').update(JSON.stringify(config)).digest('hex');
  if (renderCache.has(hash)) {
    return { imageUrl: renderCache.get(hash), cached: true };
  }

  const prompt = buildRenderPrompt(config, roomContext);

  const response = await client.images.generate({
    model: 'dall-e-3',
    prompt,
    n: 1,
    size: '1792x1024',
    quality: 'hd',
    style: 'natural'
  });

  const imageUrl = response.data[0]?.url;

  if (imageUrl) {
    renderCache.set(hash, imageUrl);
    // Auto-evict after 30 minutes (DALL-E URLs expire after ~1h)
    setTimeout(() => renderCache.delete(hash), 30 * 60 * 1000);
  }

  return { imageUrl, cached: false };
}

/* -------------------------------------------------------------------------- */
/*  Helpers                                                                    */
/* -------------------------------------------------------------------------- */

function buildConfigSummary(config) {
  const columns = (config.columns || config.modules || [])
    .map((c, i) => `  Colonne ${i + 1}: ${c.type || c.moduleCode || '?'} — ${c.width || '?'}mm, ${c.shelves || 0} étagères, ${c.drawers || 0} tiroirs${c.hasRod ? ', tringle' : ''}`)
    .join('\n');

  return `Armoire sur mesure SIGNATURE
Dimensions: ${config.width || '?'}mm × ${config.height || '?'}mm × ${config.depth || '?'}mm
Installation: ${config.installationType || 'libre'}
Colonnes:\n${columns}
Matériau principal: ${config.materialName || config.finishLabel || 'non défini'}
Portes: ${config.doorType || 'battantes'}`;
}

function buildRenderPrompt(config, roomContext) {
  const cols = (config.columns || config.modules || []);
  const colDesc = cols.map((c, i) => {
    const type = c.type || c.moduleCode || 'standard';
    const parts = [];
    if (c.hasRod) parts.push('a hanging rod');
    if (c.shelves > 0) parts.push(`${c.shelves} shelves`);
    if (c.drawers > 0) parts.push(`${c.drawers} drawers`);
    return `column ${i + 1}: ${type} with ${parts.join(', ') || 'empty space'}`;
  }).join('; ');

  const widthM = ((config.width || 2400) / 1000).toFixed(1);
  const heightM = ((config.height || 2400) / 1000).toFixed(1);

  let roomDesc = 'a modern, well-lit bedroom with neutral walls';
  if (roomContext) {
    const walls = roomContext.walls || [];
    const wallColors = walls.filter(w => w.color).map(w => w.color).join(', ');
    roomDesc = `a ${roomContext.roomType || 'bedroom'} with ${wallColors || 'neutral'} walls`;
  }

  return `Professional interior design photograph of a premium Swiss-made custom wardrobe in ${roomDesc}. 
The wardrobe is ${widthM}m wide and ${heightM}m tall, built-in style, with ${cols.length} columns: ${colDesc}. 
Material: ${config.materialName || 'light oak wood finish'}. Doors are ${config.doorType === 'coulissantes' ? 'sliding' : 'hinged'}, partially open to reveal the interior.
Style: clean Scandinavian-Swiss aesthetic, warm natural lighting, photorealistic quality. Shot with a wide-angle lens at eye level.
The wardrobe should look premium, well-crafted, and perfectly integrated into the room.`;
}