/**
 * =========================================
 * TDV_SDK – GAME HELPER (G120)
 * =========================================
 * - KHÔNG làm SDK
 * - KHÔNG load server
 * - CHỈ quản lý UI + slot + drag
 */

var tdv_sdk = {

    // ===== DATA FROM SDK BRIDGE =====
    gameData: [],
    currentQuestionIndex: 0,
    currentQuestion: null,

    // ===== QUESTION DATA =====
    correctSentence: "",
    currentWords: [],
    correctWords: [],
    blankCount: 1,

    // ===== SLOT DATA =====
    placedWords: [],
    blankIndexes: [],
    missingWords: [],
    canSubmit: 0,

    // ===== LOAD QUESTION =====
    loadQuestions: function () {
        var q = this.gameData[this.currentQuestionIndex];
        if (!q) {
            console.warn("No question data");
            return;
        }

        this.currentQuestion = q;

        // G120 chuẩn
        this.correctSentence = q.question || "";
        this.currentWords = q.options || [];
        this.correctWords = q.correctSequence || this.currentWords.slice();
        this.blankCount = q.blank_count || 1;

        this.resetPlacedWords();
        this.generateBlankIndexes();
        this.generateMissingWords();

        console.log("🧩 Question loaded:", q);
        console.log("📝 Sentence:", this.correctSentence);
        console.log("🧩 Words:", this.currentWords);
    },

    // ===== SLOT LOGIC =====
    resetPlacedWords: function () {
        this.placedWords = new Array(this.correctWords.length).fill("");
        this.canSubmit = 0;
        console.log("🔄 Reset placedWords:", this.placedWords);
    },

    setWordAtSlot: function (word, index) {
        if (this.placedWords[index] !== "") return 0;
        this.placedWords[index] = word;
        this.updateSubmitState();
        return 1;
    },

    clearWordAtSlot: function (index) {
        this.placedWords[index] = "";
        this.updateSubmitState();
    },

    updateSubmitState: function () {
        var filled = this.placedWords.filter(w => w !== "").length;
        this.canSubmit = (filled === this.blankIndexes.length) ? 1 : 0;
    },

    // ===== BLANK LOGIC =====
    generateBlankIndexes: function () {
        this.blankIndexes = [];
        var pool = [...Array(this.correctWords.length).keys()];

        for (var i = pool.length - 1; i > 0; i--) {
            var j = Math.floor(Math.random() * (i + 1));
            [pool[i], pool[j]] = [pool[j], pool[i]];
        }

        this.blankIndexes = pool.slice(0, this.blankCount);
        console.log("🕳️ Blank indexes:", this.blankIndexes);
    },

    generateMissingWords: function () {
        this.missingWords = [];
        for (var i = 0; i < this.blankIndexes.length; i++) {
            this.missingWords.push(this.correctWords[this.blankIndexes[i]]);
        }
        console.log("🧩 Missing words:", this.missingWords);
    },

    // ===== BUILD SEQUENCE =====
    buildUserSequence: function () {
        var result = [];
        for (var i = 0; i < this.correctWords.length; i++) {
            if (this.blankIndexes.indexOf(i) !== -1) {
                result.push(this.placedWords[i] || "");
            } else {
                result.push(this.correctWords[i]);
            }
        }
        return result;
    },

    // ===== SUBMIT =====
    submitAnswer: function () {
        if (this.canSubmit !== 1) return;

        var sequence = this.buildUserSequence();
        console.log("📤 Submit sequence:", sequence);

        window.submitSequenceAnswer(sequence);
    }
};