const fs = require('fs');
const path = require('path');

const file = path.join(__dirname, '..', 'database.json');
if (!fs.existsSync(file)) {
    fs.writeFileSync(file, '{}');
}

let cache = {};

try {
    cache = JSON.parse(fs.readFileSync(file, 'utf8'));
} catch (e) {
    cache = {};
}

function save() {
    fs.writeFileSync(file, JSON.stringify(cache, null, 2));
}

module.exports = {
    get(key) {
        return cache[key] ?? null;
    },
    set(key, value) {
        cache[key] = value;
        save();
        return value;
    },
    delete(key) {
        const existed = key in cache;
        delete cache[key];
        save();
        return existed;
    },
    fetch(key) {
        return cache[key] ?? null;
    },
    add(key, num) {
        cache[key] = (cache[key] || 0) + num;
        save();
        return cache[key];
    },
    subtract(key, num) {
        cache[key] = (cache[key] || 0) - num;
        save();
        return cache[key];
    },
    push(key, value) {
        if (!Array.isArray(cache[key])) cache[key] = [];
        cache[key].push(value);
        save();
        return cache[key];
    },
    has(key) {
        return key in cache;
    },
    all() {
        return Object.entries(cache).map(([ID, data]) => ({ ID, data }));
    }
};