/* exported app, utils */

const utils = {
    cloneObject: function (obj) {
        return JSON.parse(JSON.stringify(obj));
    },
    serialize: function (list) {
        return LZString.compressToEncodedURIComponent(list.map(v => v.join('|')).join('|'));
    },
    deserialize: function (rawData) {
        const data = LZString.decompressFromBase64(rawData) ?? LZString.decompressFromEncodedURIComponent(rawData);
        try {
            return JSON.parse(data);
        } catch {
            let output = [];
            data.split('|').forEach((v, i) => {
                if (i % 2 === 0) {
                    output.push([ v, '' ]);
                } else {
                    output[output.length - 1][1] = v;
                }
            });
            return output;
        }
    },
    randint: function (min, max) {
        return Math.floor(Math.random() * (max - min)) + min;
    },
    randindex: function (array, ...toIgnore) {
        let index;
        do {
            index = this.randint(0, array.length);
        } while (this.contains(toIgnore, index));
        return index;
    },
    randitem: function (array) {
        return array[this.randindex(array)];
    },
    randindexes: function (array, number, ...toIgnore) {
        const output = [];
        for (let i = 0; i < number; i++) {
            output.push(this.randindex(array, ...output, ...toIgnore));
        }
        return output;
    },
    shuffle: function (array) {
        const output = [ ...array ];
        if (output.length < 2) {
            return output;
        }
        for (let i = 0; i < array.length; i++) {
            const i1 = this.randindex(array);
            const i2 = this.randindex(array, i1);
            [ output[i1], output[i2] ] = [ output[i2], output[i1] ];
        }
        return output;
    },
    contains: function (array, item) {
        return array.indexOf(item) >= 0;
    },
};

let app = {
    data() {
        return {
            question: '',
            answer: '',
            showAnswer: false,
            available: [],
            current: { a2q: [], q2a: [] },
            failed: { a2q: [], q2a: [] },
            done: { a2q: [], q2a: [] },
            newRow: [ '', '' ],
            showConfig: true,
            q2a: true,
            a2q: false,
            size: 0,
            mode: 'q2a',
        };
    },
    computed: {
        currentYear() {
            return new Date().getFullYear();
        },
        doneDisplay() {
            return (this.q2a ? this.done['q2a'].length : 0) + (this.a2q ? this.done['a2q'].length : 0);
        },
        availableDisplay() {
            return (this.q2a ? this.available.length : 0) + (this.a2q ? this.available.length : 0);
        },
    },
    methods: {
        showApp() {
            document.getElementById('app').setAttribute('style', '');
        },
        show() {
            this.showAnswer = true;
        },
        right() {
            this.done[this.mode].push(this.current[this.mode].shift());
            this.nextQuestion();
        },
        wrong() {
            this.failed[this.mode].push(this.current[this.mode].shift());
            this.nextQuestion();
        },
        deleteRow(i) {
            this.available.splice(i, 1);
            this.reset();
        },
        addRow() {
            if (this.newRow[0] && this.newRow[1]) {
                this.available.push(utils.cloneObject(this.newRow));
                this.newRow = [ '', '' ];
            }
            this.reset();
        },
        reset() {
            this.current = {
                a2q: utils.shuffle(utils.cloneObject(this.available)),
                q2a: utils.shuffle(utils.cloneObject(this.available)),
            };
            this.done = { a2q: [], q2a: [] };
            this.failed = { a2q: [], q2a: [] };
            this.nextQuestion();
        },
        nextQuestion() {
            this.showAnswer = false;

            if (this.current['a2q'].length === 0 && this.failed['a2q'].length > 0) {
                this.current['a2q'] = utils.shuffle(utils.cloneObject(this.failed['a2q']));
                this.failed['a2q'] = [];
            }

            if (this.current['q2a'].length === 0 && this.failed['q2a'].length > 0) {
                this.current['q2a'] = utils.shuffle(utils.cloneObject(this.failed['q2a']));
                this.failed['q2a'] = [];
            }

            if ((this.a2q && !this.q2a) || (this.a2q === this.q2a && this.current['a2q'].length > 0 && (this.current['q2a'].length === 0 || utils.randint(0, 2) === 1))) {
                this.mode = 'a2q';
            } else {
                this.mode = 'q2a';
            }

            if (this.current[this.mode].length > 0) {
                if (this.mode === 'a2q') {
                    this.answer = this.current[this.mode][0][0];
                    this.question = this.current[this.mode][0][1];
                } else {
                    this.question = this.current[this.mode][0][0];
                    this.answer = this.current[this.mode][0][1];
                }
            }
        },
        getLetter() {
            if (this.q2a && !this.a2q) {
                return 'd';
            }
            if (this.a2q && !this.q2a) {
                return 'e';
            }
            return 'f';
        },
    },
    beforeMount() {
        const url = new URL(window.location);
        if (url.searchParams.get('d') || url.searchParams.get('e') || url.searchParams.get('f')) {
            if (url.searchParams.get('d')) {
                this.q2a = true;
                this.a2q = false;
            } else if (url.searchParams.get('e')) {
                this.q2a = false;
                this.a2q = true;
            } else {
                this.q2a = true;
                this.a2q = true;
            }
            this.available = utils.deserialize(url.searchParams.get(this.getLetter()));
            this.showConfig = false;
            this.reset();
        }
        this.size = url.href.length;
    },
    updated() {
        const data = utils.serialize(this.available);
        const url = new URL(window.location);
        if (url.searchParams.get(this.getLetter()) !== data) {
            url.searchParams.delete('d');
            url.searchParams.delete('e');
            url.searchParams.delete('f');
            url.searchParams.set(this.getLetter(), data);
            window.history.pushState({}, '', url);
        }
        this.size = url.href.length;
    },
    mounted: function () {
        setTimeout(this.showApp);
    },
};

window.onload = () => {
    app = Vue.createApp(app);
    app.mount('#app');
};