/*jshint esversion: 6 */
const Block = module.exports;
const Util = require("../common-util");
const Path = require("path");
const Fs = require("fs");
const Fse = require("fs-extra");
const nThen = require("nthen");

Block.mkPath = function (Env, publicKey) {
    // prepare publicKey to be used as a file name
    var safeKey = Util.escapeKeyCharacters(publicKey);

    // validate safeKey
    if (typeof(safeKey) !== 'string') { return; }

    // derive the full path
    // /home/cryptpad/cryptpad/block/fg/fg32kefksjdgjkewrjksdfksjdfsdfskdjfsfd
    return Path.join(Env.paths.block, safeKey.slice(0, 2), safeKey);
};

Block.mkArchivePath = function (Env, publicKey) {
    // prepare publicKey to be used as a file name
    var safeKey = Util.escapeKeyCharacters(publicKey);

    // validate safeKey
    if (typeof(safeKey) !== 'string') {
        return;
    }

    // derive the full path
    // /home/cryptpad/cryptpad/block/fg/fg32kefksjdgjkewrjksdfksjdfsdfskdjfsfd
    return Path.join(Env.paths.archive, 'block', safeKey.slice(0, 2), safeKey);
};

Block.archive = function (Env, publicKey, _cb) {
    var cb = Util.once(Util.mkAsync(_cb));

    // derive the filepath
    var currentPath = Block.mkPath(Env, publicKey);

    // make sure the path is valid
    if (typeof(currentPath) !== 'string') {
        return void cb('E_INVALID_BLOCK_PATH');
    }

    var archivePath = Block.mkArchivePath(Env, publicKey);
    // make sure the path is valid
    if (typeof(archivePath) !== 'string') {
        return void cb('E_INVALID_BLOCK_ARCHIVAL_PATH');
    }

    Fse.move(currentPath, archivePath, {
        overwrite: true,
    }, cb);
};

Block.check = function (Env, publicKey, _cb) { // 'check' because 'exists' implies boolean
    var cb = Util.once(Util.mkAsync(_cb));
    var path = Block.mkPath(Env, publicKey);
    Fs.access(path, Fs.constants.F_OK, cb);
};

Block.write = function (Env, publicKey, buffer, _cb) {
    var cb = Util.once(Util.mkAsync(_cb));
    var path = Block.mkPath(Env, publicKey);
    if (typeof(path) !== 'string') { return void cb('INVALID_PATH'); }
    var parsed = Path.parse(path);

    nThen(function (w) {
        Fse.mkdirp(parsed.dir, w(function (err) {
            if (!err) { return; }
            w.abort();
            cb(err);
        }));
    }).nThen(function () {
        // XXX BLOCK check whether this overwrites a block
        // XXX archive the old one if so
        Fs.writeFile(path, buffer, { encoding: 'binary' }, cb);
    });
};

/*
Block.create = function (opt, _cb) {
    var cb = Util.once(Util.mkAsync(_cb));

    var env = {
        root: opt.root || '', // XXX


    };
};
*/