const pdfParse = require('pdf-parse');
const fs = require('fs');

// Known suppliers with their aliases and associated charge categories
const SUPPLIERS = [
  { name: 'EDF', patterns: [/\bedf\b/i, /\bélectricité de france\b/i], category: 'electricite' },
  { name: 'Engie', patterns: [/\bengie\b/i, /\bgdf\s*suez\b/i], category: 'gaz' },
  { name: 'TotalEnergies', patterns: [/\btotal\s*energies?\b/i, /\btotal\s*direct\s*energie\b/i], category: 'electricite' },
  { name: 'Eni', patterns: [/\beni\s/i, /\beni\.com\b/i], category: 'gaz' },
  { name: 'Veolia', patterns: [/\bveolia\b/i], category: 'eau' },
  { name: 'Suez', patterns: [/\bsuez\b/i, /\blyonnaise des eaux\b/i], category: 'eau' },
  { name: 'Saur', patterns: [/\bsaur\b/i], category: 'eau' },
  { name: 'Eau de Paris', patterns: [/\beau de paris\b/i], category: 'eau' },
  { name: 'GRDF', patterns: [/\bgrdf\b/i], category: 'gaz' },
  { name: 'Enedis', patterns: [/\benedis\b/i, /\berdf\b/i], category: 'electricite' },
  { name: 'Orange', patterns: [/\borange\b/i, /\bfrance\s*t[eé]l[eé]com\b/i], category: 'autre' },
  { name: 'SFR', patterns: [/\bsfr\b/i], category: 'autre' },
  { name: 'Free', patterns: [/\bfree\s*mobile\b/i, /\bfree\.fr\b/i, /\biliad\b/i], category: 'autre' },
  { name: 'Bouygues Telecom', patterns: [/\bbouygues\s*tel/i], category: 'autre' },
  { name: 'Axa', patterns: [/\baxa\b/i], category: 'assurance' },
  { name: 'Maif', patterns: [/\bmaif\b/i], category: 'assurance' },
  { name: 'MACIF', patterns: [/\bmacif\b/i], category: 'assurance' },
  { name: 'Groupama', patterns: [/\bgroupama\b/i], category: 'assurance' },
  { name: 'Allianz', patterns: [/\ballianz\b/i], category: 'assurance' },
  { name: 'MMA', patterns: [/\bmma\b/i], category: 'assurance' },
  { name: 'MAAF', patterns: [/\bmaaf\b/i], category: 'assurance' },
  { name: 'Generali', patterns: [/\bgenerali\b/i], category: 'assurance' },
  { name: 'Matmut', patterns: [/\bmatmut\b/i], category: 'assurance' },
  { name: 'Otis', patterns: [/\botis\b/i], category: 'ascenseur' },
  { name: 'Schindler', patterns: [/\bschindler\b/i], category: 'ascenseur' },
  { name: 'Kone', patterns: [/\bkone\b/i], category: 'ascenseur' },
  { name: 'ThyssenKrupp', patterns: [/\bthyssen\s*krupp\b/i], category: 'ascenseur' },
];

// Category keywords for fallback detection
const CATEGORY_KEYWORDS = {
  eau: [/\beau\b/i, /\bassainissement\b/i, /\bconsommation\s*d'eau\b/i],
  gaz: [/\bgaz\b/i, /\bgaz\s*naturel\b/i],
  electricite: [/\b[eé]lectricit[eé]\b/i, /\bconsommation\s*[eé]lectrique\b/i, /\bkwh\b/i],
  entretien: [/\bentretien\b/i, /\bmaintenance\b/i, /\bnettoyage\b/i, /\bravalement\b/i, /\br[eé]paration\b/i],
  ascenseur: [/\bascenseur\b/i, /\b[eé]l[eé]vateur\b/i],
  ordures: [/\bordures\b/i, /\bd[eé]chets\b/i, /\bom\b/i, /\bteom\b/i, /\btaxe.*enl[eè]vement\b/i],
  assurance: [/\bassurance\b/i, /\bprime\b/i, /\bcotisation\b/i, /\bsinistre\b/i, /\bgarantie\b/i],
};

// Amount patterns (French format: 1 234,56 € or 1234.56)
const AMOUNT_PATTERNS = [
  /(?:total\s*(?:ttc|à\s*payer|net|facture|dû|du))\s*[:\s]*(\d[\d\s]*[.,]\d{2})\s*(?:€|eur)/i,
  /(?:montant\s*(?:ttc|total|à\s*payer|net|dû|du))\s*[:\s]*(\d[\d\s]*[.,]\d{2})\s*(?:€|eur)/i,
  /(?:net\s*à\s*payer)\s*[:\s]*(\d[\d\s]*[.,]\d{2})\s*(?:€|eur)/i,
  /(?:total\s*(?:ttc|à\s*payer|net|facture|dû|du))\s*[:\s]*(\d[\d\s]*[.,]\d{2})/i,
  /(?:montant\s*(?:ttc|total|à\s*payer|net|dû|du))\s*[:\s]*(\d[\d\s]*[.,]\d{2})/i,
  /(?:net\s*à\s*payer)\s*[:\s]*(\d[\d\s]*[.,]\d{2})/i,
  /(\d[\d\s]*[.,]\d{2})\s*(?:€|eur)\s*(?:ttc)/i,
  /(\d[\d\s]*[.,]\d{2})\s*(?:€|eur)/i,
];

function parseAmount(raw) {
  if (!raw) return null;
  const cleaned = raw.replace(/\s/g, '').replace(',', '.');
  const val = parseFloat(cleaned);
  return isNaN(val) ? null : Math.round(val * 100) / 100;
}

function detectSupplier(text) {
  for (const supplier of SUPPLIERS) {
    for (const pattern of supplier.patterns) {
      if (pattern.test(text)) {
        return { name: supplier.name, category: supplier.category };
      }
    }
  }
  return null;
}

function detectCategory(text) {
  for (const [category, patterns] of Object.entries(CATEGORY_KEYWORDS)) {
    for (const pattern of patterns) {
      if (pattern.test(text)) return category;
    }
  }
  return 'autre';
}

function detectAmount(text) {
  for (const pattern of AMOUNT_PATTERNS) {
    const match = text.match(pattern);
    if (match) {
      const amount = parseAmount(match[1]);
      if (amount && amount > 0 && amount < 100000) return amount;
    }
  }
  return null;
}

async function analyzeFile(filePath) {
  const ext = filePath.toLowerCase().split('.').pop();

  if (ext === 'pdf') {
    return analyzePdf(filePath);
  }

  // For images (jpg, png, webp) - extract info from filename only
  return analyzeFromFilename(filePath);
}

async function analyzePdf(filePath) {
  const buffer = fs.readFileSync(filePath);
  let text = '';
  try {
    const data = await pdfParse(buffer);
    text = data.text || '';
  } catch (err) {
    console.warn(`Could not parse PDF ${filePath}:`, err.message);
    return analyzeFromFilename(filePath);
  }

  const supplierInfo = detectSupplier(text);
  const detectedAmount = detectAmount(text);
  const detectedCategory = supplierInfo?.category || detectCategory(text);
  const detectedSupplier = supplierInfo?.name || null;

  // Try to build a label
  let label = '';
  if (detectedSupplier) label = `Facture ${detectedSupplier}`;
  else if (detectedCategory !== 'autre') {
    const catLabels = { eau: 'Eau', gaz: 'Gaz', electricite: 'Électricité', entretien: 'Entretien', ascenseur: 'Ascenseur', ordures: 'Ordures ménagères', assurance: 'Assurance' };
    label = `Facture ${catLabels[detectedCategory] || detectedCategory}`;
  } else {
    label = 'Facture à identifier';
  }

  return {
    detected_supplier: detectedSupplier,
    detected_category: detectedCategory,
    detected_amount: detectedAmount,
    detected_label: label,
  };
}

function analyzeFromFilename(filePath) {
  const basename = filePath.split('/').pop().replace(/\.[^.]+$/, '').replace(/[_-]/g, ' ');

  const supplierInfo = detectSupplier(basename);
  const detectedCategory = supplierInfo?.category || detectCategory(basename) || 'autre';
  const detectedSupplier = supplierInfo?.name || null;

  // Try to find amount in filename (e.g., "EDF_150.50_2024.pdf")
  const amountMatch = basename.match(/(\d+[.,]\d{2})/);
  const detectedAmount = amountMatch ? parseAmount(amountMatch[1]) : null;

  let label = detectedSupplier ? `Facture ${detectedSupplier}` : 'Facture à identifier';

  return {
    detected_supplier: detectedSupplier,
    detected_category: detectedCategory,
    detected_amount: detectedAmount,
    detected_label: label,
  };
}

module.exports = { analyzeFile, detectSupplier, detectCategory, detectAmount, SUPPLIERS };