/* jslint node: true */
'use strict';

//  ENiGMA½
const EnigAssert    = require('./enigma_assert.js');

//  deps
const fse           = require('fs-extra');
const paths         = require('path');
const async         = require('async');

exports.moveFileWithCollisionHandling       = moveFileWithCollisionHandling;
exports.copyFileWithCollisionHandling       = copyFileWithCollisionHandling;
exports.pathWithTerminatingSeparator        = pathWithTerminatingSeparator;

function moveOrCopyFileWithCollisionHandling(src, dst, operation, cb) {
    operation           = operation || 'copy';
    const dstPath       = paths.dirname(dst);
    const dstFileExt    = paths.extname(dst);
    const dstFileSuffix = paths.basename(dst, dstFileExt);

    EnigAssert('move' === operation || 'copy' === operation);

    let renameIndex     = 0;
    let opOk            = false;
    let tryDstPath;

    function tryOperation(src, dst, callback) {
        if('move' === operation) {
            fse.move(src, tryDstPath, err => {
                return callback(err);
            });
        } else if('copy' === operation) {
            fse.copy(src, tryDstPath, { overwrite : false, errorOnExist : true }, err => {
                return callback(err);
            });
        }
    }

    async.until(
        (callback) => callback(null, opOk), //  until moved OK
        (cb) => {
            if(0 === renameIndex) {
                //  try originally supplied path first
                tryDstPath = dst;
            } else {
                tryDstPath = paths.join(dstPath, `${dstFileSuffix}(${renameIndex})${dstFileExt}`);
            }

            tryOperation(src, tryDstPath, err => {
                if(err) {
                    //  for some reason fs-extra copy doesn't pass err.code
                    //  :TODO: this is dangerous: submit a PR to fs-extra to set EEXIST
                    if('EEXIST' === err.code || 'dest already exists.' === err.message) {
                        renameIndex += 1;
                        return cb(null);    //  keep trying
                    }

                    return cb(err);
                }

                opOk = true;
                return cb(null, tryDstPath);
            });
        },
        (err, finalPath) => {
            return cb(err, finalPath);
        }
    );
}

//
//  Move |src| -> |dst| renaming to file(1).ext, file(2).ext, etc.
//  in the case of collisions.
//
function moveFileWithCollisionHandling(src, dst, cb) {
    return moveOrCopyFileWithCollisionHandling(src, dst, 'move', cb);
}

function copyFileWithCollisionHandling(src, dst, cb) {
    return moveOrCopyFileWithCollisionHandling(src, dst, 'copy', cb);
}

function pathWithTerminatingSeparator(path) {
    if(path && paths.sep !== path.charAt(path.length - 1)) {
        path = path + paths.sep;
    }
    return path;
}