"use strict";

const fs = require('fs-extra');

const wrap = require('./wrap');

/**

* Takes the content of the source file and moves them to the dest, allowing you to manipulate the contents first.

* @param src A string representing the source path

* @param dest A string for representing the destination path

* @param options A required object of settings:

* transforms: A function or an array of transform functions

* replacements: An array of replacement definitions

* keeps: An Array of keep definitions

* write: writeFileSync options

*

*/

module.exports = function manipulateFileSync(src, dest, options) {

let content = fs.readFileSync(src, 'utf8');

// transforms are raw methods which will transform the content

if (options.transforms) {

wrap(options.transforms).forEach(t => content = t(content));

}

// replacements are objects which indicate how a content should be replaced.

if (options.replacements) {

wrap(options.replacements).forEach(r => content = replace(content, r));

}

// keeps are objects which indicate which content should be kept

if (options.keeps) {

wrap(options.keeps).forEach(k => content = keep(content, k));

}

fs.outputFileSync(dest, content, options.write);

return content;

};

/**

* Instead of replacing content, this method tries to determine which content should be kept

* @param content String

* @param options Object

* target: a regexp that determines which content should be targetted, if only a subset should be eligible

* select: a string regexp that determines how to select content. $keep is a special token used to indicate how keep values are included

* values: an array of strings representing capture group values

* @returns String transformed content

*/

function keep(content, options) {

const targets = options.target ? content.match(options.target) : null;

let targetContent = targets && targets.length ? targets[0] : content;

if (targetContent) {

const keepsRegex = new RegExp(options.select.replace('$keep', `(${options.values.join('|')})`), 'gm');

const cleanRegex = new RegExp(options.select.replace('$keep', '.*'), 'gm');

const keepLines = targetContent.match(keepsRegex);

const insertIndex = targetContent.search(cleanRegex);

targetContent = insert(targetContent.replace(cleanRegex, ''), insertIndex, `${keepLines.join(options.join || '')}\n`);

content = options.target ? content.replace(options.target, targetContent) : targetContent;

}

return content;

}

/**

* Replaces part of the content

* @param content String

* @param options Object

* replace: String or Regex that must be provided to determine how to replace

* content: String to use as the replacement content

* file: String of the file path to the file to be used as content for the replacement

* encoding: String the encoding of the file

*/

function replace(content, options) {

let substitute = options.content || '';

if (options.file) {

substitute = fs.readFileSync(options.file, options.encoding || 'utf8');

}

return content.replace(options.replace, substitute);

}

function insert(str, index, value) {

return str.substr(0, index) + value + str.substr(index);

}