import fs = require('fs');

import { Storage } from './storage';

export class StorageNode implements Storage {

    private prefix: string;

    constructor(id:string) {
        try {
            fs.mkdirSync("data");
        } catch (e) {
            // ignore
        }
        const safeId = id.replace(/[^A-Za-z0-9]/g, "");
        if (safeId === '') {
            throw new Error("must have non-empty id");
        }
        this.prefix = safeId;
    }

    public async getValues() {
        return Object.values(this.getMap());
    }

    public async get(key:string) {
        return this.getMap()[key];
    }

    public async set(key:string, value:any) {
        const filename = "data/storage_" + this.prefix;
        let map;
        try {
            const contents = fs.readFileSync(filename, {encoding: 'utf-8'});
            map = JSON.parse(contents);
        } catch(e) {
            map = {};
        }
        map[key] = value;
        fs.writeFileSync(filename, JSON.stringify(map));
    }

    private getMap() {
        try {
            const filename = "data/storage_" + this.prefix;
            const contents = fs.readFileSync(filename, {encoding: 'utf-8'});
            return JSON.parse(contents);
        } catch (e) {
            return {};
        }
    }
}