From 5ebe0bcd00c8ad70f28fdaa5081459717f56ef02 Mon Sep 17 00:00:00 2001
From: ENGO150 <v.smejkal06@gmail.com>
Date: Tue, 8 Mar 2022 19:35:24 +0100
Subject: [PATCH] created working decrypter

---
 src/decrypter.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 87 insertions(+), 3 deletions(-)

diff --git a/src/decrypter.c b/src/decrypter.c
index 7a80f3f..cbb17c4 100644
--- a/src/decrypter.c
+++ b/src/decrypter.c
@@ -1,12 +1,96 @@
 #include "../include/decrypter.h"
 
 #include <stdio.h>
+#include <string.h>
 #include <stdlib.h>
 
 char *decryptText(char *text, char *key)
 {
-    printf("fuk of\n");
+    //CONSTS
+    const int KEY_LENGTH = strlen(key);
 
-    exit(0);
-    return NULL;
+    //VARIABLES
+    char *returningText;
+    int numberBuffer;
+    char *textBuffer;
+
+    numberBuffer = 1;
+
+    //GET LENTGH OF returningText AND textKeyChain
+    for (int i = 0; i < strlen(text); i++)
+    {
+        if (text[i] == '.') numberBuffer++;
+    }
+
+    //SET LENGTH
+    returningText = malloc(numberBuffer);
+    int textKeyChain[numberBuffer];
+    int encryptedTextKeyChain[numberBuffer];
+
+    //LOAD textKeyChain
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer = i;
+
+        //CHECK, IF numberBuffer ISN'T GREATER THAN KEY_LENGTH AND CUT UNUSED LENGTH
+        while (numberBuffer >= KEY_LENGTH)
+        {
+            numberBuffer -= KEY_LENGTH;
+        }
+
+        //FILL textKeyChain
+        if ((numberBuffer + 1) % 3 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] * key[numberBuffer + 1];
+        } else if ((numberBuffer + 1) % 2 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] - key[numberBuffer + 1];
+        } else
+        {
+            textKeyChain[i] = key[numberBuffer] + key[numberBuffer + 1];
+        }
+    }
+
+    //LOAD encryptedTextKeyChain
+    for (int i = 0; i < (sizeof(encryptedTextKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer = 0;
+
+        //GET LENGTH OF EACH CHARACTER
+        for (int j = 0; j < strlen(text); j++)
+        {
+            if (text[j] == '.') break;
+
+            numberBuffer++;
+        }
+
+        textBuffer = malloc(numberBuffer);
+
+        //LOAD textBuffer
+        for (int j = 0; j < strlen(text); j++)
+        {
+            textBuffer[j] = text[j];
+
+            if (numberBuffer == j) break;
+        }
+
+        encryptedTextKeyChain[i] = atoi(textBuffer);
+
+        text += numberBuffer + 1;
+        free(textBuffer);
+    }
+
+    //DECRYPT TEXT
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        textKeyChain[i] -= encryptedTextKeyChain[i];
+    }
+
+    //LOAD returningText
+    for (int i = 0; i < sizeof(textKeyChain) / sizeof(int); i++)
+    {
+        returningText[i] = (char) textKeyChain[i];
+    }
+
+    return returningText;
 }
\ No newline at end of file