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

const winston = require('winston');

// For storing in files
// options[type] = file
// options[path] - Where to store

const FileDocumentStore = function(options){
	this.basePath = options.path || './data';
	this.expire = options.expire;
};

// Generate md5 of a string
FileDocumentStore.md5 = function(str){
	let md5sum = crypto.createHash('md5');
	md5sum.update(str);
	return md5sum.digest('hex');
};

// Save data in a file, key as md5 - since we don't know what we could
// be passed here
FileDocumentStore.prototype.set = function(key, data, callback, skipExpire){
	try {
		const _this = this;
		fs.mkdir(this.basePath, '700', function(){
			const fn = _this.basePath + '/' + FileDocumentStore.md5(key);
			fs.writeFile(fn, data, 'utf8', function(err){
				if (err){
					callback(false);
				}
				else {
					callback(true);
					if (_this.expire && !skipExpire){
						winston.warn('file store cannot set expirations on keys');
					}
				}
			});
		});
	} catch(err){
		callback(false);
	}
};

// Get data from a file from key
FileDocumentStore.prototype.get = function(key, callback, skipExpire){
	const _this = this;
	const fn = require('path').join(this.basePath, FileDocumentStore.md5(key));
	fs.readFile(fn, 'utf8', function(err, data){
		if (err){
			callback(false);
		}
		else {
			callback(data);
			if (_this.expire && !skipExpire){
				winston.warn('file store cannot set expirations on keys');
			}
		}
	});
};

module.exports = FileDocumentStore;