From a605b781f429952160e281274f87de68fa1f7a2b Mon Sep 17 00:00:00 2001
From: Divlo <contact@divlo.fr>
Date: Fri, 20 Mar 2020 11:45:19 +0100
Subject: [PATCH] backend: AJout de Heap's algorithm + .env.example

---
 backend/.env.example                          |  1 +
 backend/assets/functions/functionObject.js    |  4 +-
 .../assets/functions/main/convertDistance.js  |  2 +-
 .../assets/functions/main/heapAlgorithm.js    | 46 +++++++++++++++++++
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 backend/.env.example
 create mode 100644 backend/assets/functions/main/heapAlgorithm.js

diff --git a/backend/.env.example b/backend/.env.example
new file mode 100644
index 0000000..86648e1
--- /dev/null
+++ b/backend/.env.example
@@ -0,0 +1 @@
+OpenWeatherMap_API_KEY = ""
\ No newline at end of file
diff --git a/backend/assets/functions/functionObject.js b/backend/assets/functions/functionObject.js
index fd7d290..a785f5d 100644
--- a/backend/assets/functions/functionObject.js
+++ b/backend/assets/functions/functionObject.js
@@ -6,6 +6,7 @@ const { armstrongNumberOutput }                                  = require('./ma
 const { weatherRequestOutput }                                   = require('./main/weatherRequest');
 const { convertCurrencyOutput }                                  = require('./main/convertCurrency');
 const { calculateAgeOutput }                                     = require('./main/calculateAge');
+const { heapAlgorithmOutput }                                    = require('./main/heapAlgorithm');
 
 const functionObject = {
     randomNumber        : randomNumberOutput,
@@ -16,7 +17,8 @@ const functionObject = {
     armstrongNumber     : armstrongNumberOutput,
     weatherRequest      : weatherRequestOutput,
     convertCurrency     : convertCurrencyOutput,
-    calculateAge        : calculateAgeOutput
+    calculateAge        : calculateAgeOutput,
+    heapAlgorithm       : heapAlgorithmOutput
 };
 
 // Choisi la fonction à exécuter
diff --git a/backend/assets/functions/main/convertDistance.js b/backend/assets/functions/main/convertDistance.js
index 0662944..3ce5d73 100644
--- a/backend/assets/functions/main/convertDistance.js
+++ b/backend/assets/functions/main/convertDistance.js
@@ -43,7 +43,7 @@ exports.convertDistanceOutput = ({ res, next }, argsObject) => {
 
     const result = convertDistance(number, numberUnit, finalUnit);
     if (!result) {
-        return sendResponse(res, generalError);
+        return errorHandling(next, generalError);
     }
 
     return res.status(200).json(result);
diff --git a/backend/assets/functions/main/heapAlgorithm.js b/backend/assets/functions/main/heapAlgorithm.js
new file mode 100644
index 0000000..dc505a4
--- /dev/null
+++ b/backend/assets/functions/main/heapAlgorithm.js
@@ -0,0 +1,46 @@
+const errorHandling      = require('../../utils/errorHandling');
+const { requiredFields } = require('../../config/errors');
+
+/** 
+ * @description Retourne un tableau contenant toutes les possibilités d'anagramme d'un mot.
+ * @param {String} string - La chaîne de caractère à permuter
+ * @returns {Array}
+ * @examples heapAlgorithm('abc') → ["abc", "acb", "bac", "bca", "cab", "cba"]
+ */
+function heapAlgorithm(string) {
+    let results = [];
+
+    if (string.length === 1) {
+        results.push(string);
+        return results;
+    }
+
+    for (let indexString = 0; indexString < string.length; indexString++) {
+        const firstChar = string[indexString];
+        const charsLeft = string.substring(0, indexString) + string.substring(indexString + 1);
+        const innerPermutations = heapAlgorithm(charsLeft);
+        for (let indexPermutation = 0; indexPermutation < innerPermutations.length; indexPermutation++) {
+            results.push(firstChar + innerPermutations[indexPermutation]);
+        }
+    }
+    return results;
+} 
+
+/* OUTPUTS */
+exports.heapAlgorithmOutput = ({ res, next }, argsObject) => {
+    let { string } = argsObject;
+    
+    // S'il n'y a pas les champs obligatoire
+    if (!(string)) {
+        return errorHandling(next, requiredFields);
+    }
+
+    // Si la chaîne de caractère dépasse LIMIT_CHARACTERS caractères
+    const LIMIT_CHARACTERS = 8;
+    if (string.length > LIMIT_CHARACTERS) {
+        return errorHandling(next, { message: `Par souci de performance, vous ne pouvez pas exécuter cette fonction avec un mot dépassant ${LIMIT_CHARACTERS} caractères.`, statusCode: 400 });
+    }
+
+    const result = heapAlgorithm(string);
+    return res.status(200).json(result);
+}
\ No newline at end of file