const Tesseract = require("tesseract.js");
const sharp = require("sharp");

function levenshtein(s, t) {
    if (s === t) {
        return 0;
    }
    var n = s.length, m = t.length;
    if (n === 0) return m;
    if (m === 0) return n;
    var d = [];
    for (var i = 0; i <= n; i++) d[i] = [];
    for (var i = 0; i <= n; i++) d[i][0] = i;
    for (var j = 0; j <= m; j++) d[0][j] = j;
    for (var i = 1; i <= n; i++) {
        for (var j = 1; j <= m; j++) {
            var cost = (s.charAt(i - 1) === t.charAt(j - 1)) ? 0 : 1;
            d[i][j] = Math.min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + cost);
        }
    }
    return d[n][m];
}

const DICTIONARIES = {
    wordnumber: { ONE: '1', TWO: '2', THREE: '3', FOUR: '4', FIVE: '5', SIX: '6', SEVEN: '7', EIGHT: '8', NINE: '9', TEN: '10' },
    numberword: { '1': 'ONE', '2': 'TWO', '3': 'THREE', '4': 'FOUR', '5': 'FIVE', '6': 'SIX', '7': 'SEVEN', '8': 'EIGHT', '9': 'NINE', '10': 'TEN' },
    numberroman: { '1': 'I', '2': 'II', '3': 'III', '4': 'IV', '5': 'V', '6': 'VI', '7': 'VII', '8': 'VIII', '9': 'IX', '10': 'X' },
    romannumber: { I: '1', II: '2', III: '3', IV: '4', V: '5', VI: '6', VII: '7', VIII: '8', IX: '9', X: '10', VILL: '7' },
    mathans: { '2-1': '1', '1+1': '2', '141': '2', '1+2': '3', '2+2': '4', '242': '4', '3+2': '5', '342': '5', '2+4': '6', '244': '6', '3+4': '7', '344': '7', '4+4': '8', '444': '8', '1+8': '9', '148': '9', '5+6': '11' },
    ansmath: { '1': '3-2', '2': '8-6', '3': '1+2', '4': '3+1', '5': '9-4', '6': '3+3', '7': '6+1', '8': '2*4', '9': '3+6', '10': '2+8' },
    oox: { '--X': 'OOX', '-X-': 'OXO', 'X--': 'XOO', 'XX-': 'XXO', '-XX': 'OXX', 'X-X': 'XOX', '---': 'OOO', 'XXX': 'XXX', 'X-X-': 'XOXO', '-X-X': 'OXOX' },
    xxx: { '--X': '--+', '-X-': '-+-', 'X--': '+--', 'XX-': '++-', '-XX': '-++', 'X-X': '+-+', '---': '---', 'XXX': '+++', 'X-X-': '+-+-', '-X-X': '-+-+' },
    xox: { '--X': 'OO+', '-X-': 'O+O', 'X--': '+OO', 'XX-': '++O', '-XX': 'O++', 'X-X': '+O+', '---': 'OOO', 'XXX': '+++', 'X-X-': '+O+O', '-X-X': 'O+O+' },
    oxo: { OOX: '--+', OXO: '-+-', XOO: '+--', XXO: '++-', OXX: '-++', XOX: '+-+', OOO: '---', XXX: '+++', XOXO: '+-+-', OXOX: '-+-+' },
    zoo: { ZOO: '200', OZO: '020', OOZ: '002', SOO: '500', '0SO': '050', OOS: '005', LOL: '101', SOS: '505', ZOZ: '202', LLL: '111' },
    ooz: { '200': 'ZOO', '020': 'OZO', '002': 'OOZ', '500': 'SOO', '050': 'OSO', '005': 'OOS', '101': 'LOL', '505': 'SOS', '202': 'ZOZ', '111': 'LLL' },
    animals: { CAT: 'C@T', DOG: 'D0G', LION: '1!0N', TIGER: 'T!G3R', MONKEY: 'M0NK3Y', ELEPHANT: '31EPH@NT', COW: 'C0W', FOX: 'F0X', MOUSE: 'M0US3', ANT: '@NT' }
};

function applyVariations(word, type) {
    let w = word.toUpperCase();
    
    if (['numberword', 'mathans', 'ansmath'].includes(type)) {
        w = w.replace(/[LIF\|\}]/g, '1').replace(/¢/g, '6').replace(/T/g, '+').replace(/Z/g, '2')
             .replace(/Q/g, '7').replace(/\(/g, '6').replace(/#/g, '1+')
             .replace(/FEN/g, 'TEN').replace(/4NREE/g, 'THREE')
             .replace(/142|W2/g, '1+2').replace(/343/g, '3+3').replace(/SVEN/g, 'SEVEN')
             .replace(/GIVE/g, 'FIVE').replace(/341/g, '3+1').replace(/1\+7/g, '1+1');
    }
    
    if (['romannumber', 'numberroman'].includes(type)) {
        w = w.replace(/U/g, 'V').replace(/R/g, 'X').replace(/1/g, 'I')
             .replace(/\\\\/g, 'VI').replace(/[\\\|]/g, 'I').replace(/™/g, 'III').replace(/XX/g, 'X');
    }
    
    if (['oxo', 'xox', 'xxx', 'oox'].includes(type)) {
        w = w.replace(/[0D]/g, 'O').replace(/[TF]/g, '+');
    }
    
    if (type === 'zoo') {
        w = w.replace(/0/g, 'O').replace(/[I\|]/g, 'L').replace(/8/g, 'S')
             .replace(/\$/g, '5').replace(/S°S/g, 'SOS');
    }
    
    if (type === 'ooz') {
        w = w.replace(/O/g, '0');
    }
    
    if (type === 'animals') {
        w = w.replace(/ENT|@RT|ONT/g, 'ANT').replace(/TLG3R/g, 'TIGER').replace(/MOUSS/g, 'MOUSE')
             .replace(/CET/g, 'CAT').replace(/10/g, 'LION')
             .replace(/0/g, 'O').replace(/3/g, 'E').replace(/!/g, 'I').replace(/1/g, 'L').replace(/@/g, 'A');
    }

    return w;
}

function normalize(text) {
    return text.replace(/[^a-zA-Z0-9+\-*@!]/g, "").toUpperCase();
}

function findBestMatch(scannedText) {
    const cleanScanned = normalize(scannedText);
    let bestMatch = { type: 'unknown', value: cleanScanned, score: 0 };

    for (const [type, dict] of Object.entries(DICTIONARIES)) {
        const variedText = applyVariations(cleanScanned, type);

        if (dict[variedText]) return { type, value: dict[variedText], original: variedText };

        for (const [key, val] of Object.entries(dict)) {
            if (val === variedText) return { type, value: key, original: variedText };

            const distKey = levenshtein(variedText, key);
            const distVal = levenshtein(variedText, val);

            if (distKey <= 1) return { type, value: val, original: key }; 
            if (distVal <= 1) return { type, value: key, original: val }; 
        }
    }
    
    return bestMatch;
}

const buf = b => Buffer.from(b.replace(/^data:image\/\w+;base64,/, ""), "base64");

async function preprocessImage(imageBuffer, type = 'main') {
    let pipeline = sharp(imageBuffer)
        .grayscale()
        .normalize();

    if (type === 'main') {
        pipeline = pipeline
            .resize({ width: 800 })
            .sharpen({ sigma: 1.5 })
            .threshold(140);
    } else {
        pipeline = pipeline
            .resize({ height: 100 })
            .sharpen({ sigma: 2.0 })
            .median(1)
            .threshold(128);
    }

    return await pipeline.toBuffer();
}

async function ocr(imageBuffer, psmMode = '6') {
    try {
        const result = await Tesseract.recognize(imageBuffer, "eng", {
            tessedit_char_whitelist: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-*=@!$,.:;",
            tessedit_pageseg_mode: psmMode
        });
        return result.data.text.trim();
    } catch (e) {
        console.error("OCR Failed: ", e);
        return "";
    }
}

module.exports = async (data) => {
    try {
        console.log("🚀 Starting AntiBot Analysis...");

        const mainBuffer = buf(data.main);
        const processedMain = await preprocessImage(mainBuffer, 'main');
        const rawMainText = await ocr(processedMain, '7'); 
        
        const mainWords = rawMainText.replace(/[,.]/g, ' ').split(/\s+/).filter(w => w.length > 0);
        console.log("📝 Raw Main Text: ", rawMainText);
        console.log("📝 Parsed Words: ", mainWords);

        let targetConcepts = [];
        for (const word of mainWords) {
            const match = findBestMatch(word);
            if (match.type !== 'unknown') {
                targetConcepts.push(match);
            }
        }
        
        if (targetConcepts.length === 0) {
            targetConcepts = mainWords.map(w => ({ type: 'raw', value: normalize(w) }));
        }

        console.log("🎯 Target Concepts: ", targetConcepts.map(t => t.value));

        const botResults = [];
        for (const bot of data.bots) {
            const botBuffer = buf(bot.img);
            const processedBot = await preprocessImage(botBuffer, 'bot');
            const rawBotText = await ocr(processedBot, '6'); 
            const cleanBotText = normalize(rawBotText);
            
            const botAnalysis = findBestMatch(cleanBotText);
            
            botResults.push({
                id: bot.id,
                raw: rawBotText,
                clean: cleanBotText,
                analysis: botAnalysis
            });
        }

        const finalResult = [];
        const usedBots = new Set();

        for (const target of targetConcepts) {
            let bestBotId = null;
            let minDistance = 999;

            for (const bot of botResults) {
                if (usedBots.has(bot.id)) continue;

                if (target.value === bot.analysis.value || target.value === bot.clean) {
                    bestBotId = bot.id;
                    minDistance = -1;
                    break;
                }

                const dist = levenshtein(target.value, bot.clean);
                if (dist < minDistance && dist <= 2) {
                    minDistance = dist;
                    bestBotId = bot.id;
                }
            }

            if (bestBotId) {
                finalResult.push(bestBotId);
                usedBots.add(bestBotId);
            } else {
                finalResult.push(null);
            }
        }

        for (let i = 0; i < finalResult.length; i++) {
            if (finalResult[i] === null) {
                for (const bot of botResults) {
                    if (!usedBots.has(bot.id)) {
                        finalResult[i] = bot.id;
                        usedBots.add(bot.id);
                        break;
                    }
                }
            }
        }

        console.log("✅ Final Result IDs: ", finalResult);

        return {
            success: true,
            soal: mainWords,
            bots_analysis: botResults.map(b => ({ id: b.id, text: b.clean })),
            result: finalResult.filter(x => x !== null)
        };

    } catch (error) {
        console.error("💥 Antibot Error: ", error);
        return {
            success: false,
            error: error.message,
            result: []
        };
    }
};