const fs = require('fs');
const path = require('path');
const { extractTextFromImage, uploadImageToHosting } = require('./imageProcessor');

// Map angka kata -> digit
const NUMBER_WORDS = {
  'nol': '0', 'satu': '1', 'dua': '2', 'tiga': '3', 'empat': '4', 'lima': '5',
  'enam': '6', 'tujuh': '7', 'delapan': '8', 'sembilan': '9', 'sepuluh': '10',
  'sebelas': '11', 'belas': '', 'puluh': '', 'ratus': '', 'ribu': ''
};

// Simple leet replacements
const LEET_MAP = {
  '4': 'a', '@': 'a', '8': 'b', '3': 'e', '6': 'g', '1': 'i', '!': 'i', '0': 'o',
  '5': 's', '$': 's', '7': 't', '+': 't', '2': 'z'
};

function safeString(s) {
  return (s || '').toString();
}

async function extractTextFromBuffer(imageBuffer) {
  try {
    if (!imageBuffer) throw new Error('No image buffer provided');
    if (!Buffer.isBuffer(imageBuffer)) throw new Error('extractTextFromBuffer expects a Buffer');

    console.log('🖼️ DEBUG extractTextFromBuffer: Received buffer, size:', imageBuffer.length, 'bytes');

    const result = await extractTextFromImage(imageBuffer);
    console.log('✅ DEBUG extractTextFromBuffer: Hasil ekstraksi:', result);
    return result;
  } catch (error) {
    console.error('❌ DEBUG extractTextFromBuffer Error:', error.message);
    return { status: false, response: 'Gagal memproses gambar' };
  }
}

function removeAccents(str) {
  return safeString(str).normalize('NFD').replace(/[\u0300-\u036f]/g, '');
}

function applyLeetMap(str) {
  let out = '';
  for (const ch of str) {
    out += (LEET_MAP[ch] !== undefined) ? LEET_MAP[ch] : ch;
  }
  return out;
}

function wordsToNumbers(str) {
  // Very simple conversion for single-word numbers in Indonesian (e.g., "tujuh" -> "7")
  const tokens = str.split(/\s+/);
  return tokens.map(t => {
    const low = t.toLowerCase();
    return NUMBER_WORDS[low] !== undefined ? NUMBER_WORDS[low] : t;
  }).join(' ');
}

function normalizeText(text) {
  const original = safeString(text);
  let normalized = removeAccents(original);
  normalized = normalized.toLowerCase();
  normalized = applyLeetMap(normalized);
  // keep letters, numbers and spaces only
  normalized = normalized.replace(/[^a-z0-9\s]/g, ' ').replace(/\s+/g, ' ').trim();
  // map simple number words
  normalized = wordsToNumbers(normalized);
  console.log(`🔤 DEBUG normalizeText: "${original}" -> "${normalized}"`);
  return normalized;
}

// Levenshtein distance for fuzzy matching
function levenshtein(a = '', b = '') {
  const alen = a.length, blen = b.length;
  if (alen === 0) return blen;
  if (blen === 0) return alen;
  const matrix = Array.from({ length: alen + 1 }, () => new Array(blen + 1));
  for (let i = 0; i <= alen; i++) matrix[i][0] = i;
  for (let j = 0; j <= blen; j++) matrix[0][j] = j;
  for (let i = 1; i <= alen; i++) {
    for (let j = 1; j <= blen; j++) {
      const cost = a[i - 1] === b[j - 1] ? 0 : 1;
      matrix[i][j] = Math.min(
        matrix[i - 1][j] + 1,
        matrix[i][j - 1] + 1,
        matrix[i - 1][j - 1] + cost
      );
    }
  }
  return matrix[alen][blen];
}

function similarity(a, b) {
  a = safeString(a);
  b = safeString(b);
  if (a === b) return 1;
  const dist = levenshtein(a, b);
  const maxLen = Math.max(a.length, b.length);
  return maxLen === 0 ? 1 : 1 - (dist / maxLen);
}

function tryEvaluateMathExpression(s) {
  // allow simple expressions like "3+4", " 7 - 2 ", "2 * (3+1)"
  try {
    const cleaned = s.replace(/[^0-9+\-*/().\s]/g, '');
    if (!/[0-9]/.test(cleaned)) return null;
    // eslint-disable-next-line no-new-func
    const val = Function(`"use strict"; return (${cleaned});`)();
    if (typeof val === 'number' && isFinite(val)) return String(val);
    return null;
  } catch {
    return null;
  }
}

// compare OCR value with expected soal (question) with multiple heuristics
function isValueMatch(value, soal, options = {}) {
  const { fuzzyThreshold = 0.75 } = options;
  console.log('🔍 DEBUG isValueMatch: Value="%s", Soal="%s"', value, soal);
  if (!value && !soal) return false;

  const vNorm = normalizeText(safeString(value));
  const sNorm = normalizeText(safeString(soal));

  // exact match
  if (vNorm === sNorm) {
    console.log('✅ DEBUG exact match');
    return true;
  }

  // try math evaluation for both sides
  const vMath = tryEvaluateMathExpression(vNorm);
  const sMath = tryEvaluateMathExpression(sNorm);
  if (vMath !== null && sMath !== null && vMath === sMath) {
    console.log('✅ DEBUG math match:', vMath);
    return true;
  }
  if (vMath !== null && sMath === null && vMath === sNorm) {
    console.log('✅ DEBUG math->soal match:', vMath);
    return true;
  }
  if (sMath !== null && vMath === null && sMath === vNorm) {
    console.log('✅ DEBUG soal->math match:', sMath);
    return true;
  }

  // numeric comparison if either is numeric
  const vNum = parseFloat(vNorm);
  const sNum = parseFloat(sNorm);
  if (!isNaN(vNum) && !isNaN(sNum) && Math.abs(vNum - sNum) < 1e-9) {
    console.log('✅ DEBUG numeric equal');
    return true;
  }

  // fuzzy text similarity
  const sim = similarity(vNorm, sNorm);
  console.log('📊 DEBUG Similarity:', sim);
  if (sim >= fuzzyThreshold) {
    console.log('✅ DEBUG fuzzy match (threshold=', fuzzyThreshold, ')');
    return true;
  }

  // partial match: one contains the other with decent length
  if (vNorm && sNorm) {
    if (vNorm.includes(sNorm) || sNorm.includes(vNorm)) {
      const longer = Math.max(vNorm.length, sNorm.length);
      if (longer >= 3) {
        console.log('✅ DEBUG partial contains match');
        return true;
      }
    }
  }

  console.log('❌ DEBUG: No match found');
  return false;
}

function mapAnswer(soalArray, jawaban, botIndex) {
  console.log(`🤖 DEBUG mapAnswer: Bot ${botIndex}, Jawaban: "${jawaban}"`);
  // jawaban can be object or string; normalize to string for now
  if (jawaban && typeof jawaban === 'object' && jawaban.response) {
    return jawaban.response;
  }
  return jawaban;
}

// --- Integrated helper from userscript: countPairs ---
function countPairs(s1 = '', s2 = '') {
  s1 = safeString(s1).toLowerCase().replace(/[^a-z]/g, '');
  s2 = safeString(s2).toLowerCase().replace(/[^a-z]/g, '');
  const n1 = s1.length, n2 = s2.length;
  const freq1 = Array(26).fill(0);
  const freq2 = Array(26).fill(0);
  for (let i = 0; i < n1; i++) freq1[s1.charCodeAt(i) - 97] = (freq1[s1.charCodeAt(i) - 97] || 0) + 1;
  for (let i = 0; i < n2; i++) freq2[s2.charCodeAt(i) - 97] = (freq2[s2.charCodeAt(i) - 97] || 0) + 1;
  let count = 0;
  for (let i = 0; i < 26; i++) count += Math.min(freq1[i], freq2[i]);
  return count;
}

// Export utilities
module.exports = {
  extractTextFromBuffer,
  mapAnswer,
  normalizeText,
  isValueMatch,
  levenshtein,
  similarity,
  NUMBER_WORDS,
  LEET_MAP,
  countPairs
};