Fix decryption function

app/src/main/java/com/github/mondei1/offpass/QRSchema.kt

@@ -1,12 +1,12 @@
 package com.github.mondei1.offpass
 
 import android.content.Context
+import android.util.Base64
 import android.util.Log
 import com.github.mondei1.offpass.entities.Compression
 import com.github.mondei1.offpass.entities.CompressionHelper
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.async
-import kotlinx.coroutines.channels.broadcast
 import kotlinx.coroutines.runBlocking
 import java.lang.Error
 
@@ -71,7 +71,7 @@ class QRSchema {
                     fields[0] = fields[0].replace("%", "")
                     session_key = fields[0].substring(0, 10) // Get first 10 chars, which are the
                                                             // session key
-                    this.title = fields[0].substring(11, fields[0].length)
+                    this.title = fields[0].substring(10, fields[0].length)
                 } else {
                     this.title = fields[0]
                 }
@@ -121,18 +121,110 @@ class QRSchema {
                             + fields[i].toString())
                 }
             }
-
-            // Final step is to resolve any compressed values
         }
         Log.i("QR-Code schema", "Found: $session_key, $title, $username, $password, " +
                 "$email, $website_url. ${custom.toString()} and ${question_awnser.toString()}")
+
         return true
     }
 
     /**
-     * This function will take all defined variables and converts them into the QR-Code schema
+     * This function will take an raw string input and will decrypt it.
+     *
+     * @return It returns the raw decrypted raw value.
      */
-    fun build() {
+    fun decrypt(raw: String, passphrase: String): String {
+        val parts = raw.split(":")
+        val iv = parts[1]
+        val salt = parts[2]
+        val encrypted_content = parts[3]
+        Log.i("Decrypt schema", "Give data: $encrypted_content")
+
+        this.decrypted_raw = CryptoOperations().decrypt(
+            encrypted_content, passphrase,
+            iv.toByteArray(), salt.toByteArray())
+
+        return this.decrypted_raw
+    }
+
+    /**
+     * This function will take all defined variables and converts them into the QR-Code schema.
+     *
+     * @param compress_values Takes an string array where a entry can be `website_url` in case of an URL or
+     * the key of an optional field. For a security question take the question as key.
+     */
+    fun build(compress_values: Array<String>, passphrase: String): String {
+        /* First phase is to construct the encrypted data. */
+        val session_key = CryptoOperations().nextString(10) // used for
+        var used_compression: Boolean = false
+
+        var url_copy = website_url
+        if (compress_values.contains("website_url")) {
+            used_compression = true
+            val email_key = CryptoOperations().nextString(4)
+            this.db?.add(session_key, Compression(email_key, website_url, null, null))
+            url_copy = "\$$email_key"
+        }
+        var encrypted_content: String =
+            "${this.title}|${this.username}|${this.password}|${this.email}|${url_copy}|"
+
+        // Loop thought optional/custom fields
+        for (i in this.custom) {
+            if (compress_values.contains(i.key)) {
+                used_compression = true
+                var key_key = CryptoOperations().nextString(4)
+                var key_value = CryptoOperations().nextString(4)
+
+                this.db?.add(session_key,
+                    Compression(key_key, i.key, null, null))
+                this.db?.add(session_key,
+                    Compression(key_value, i.value, null, null))
+
+                encrypted_content += "(\$$key_key)\$$key_value|"
+            } else {
+                encrypted_content += "(${i.key})${i.value}|"
+            }
+        }
+
+        // Loop thought security questions
+        for (i in this.question_awnser) {
+            used_compression = true
+            if (compress_values.contains(i.key)) {
+                var key_key = CryptoOperations().nextString(4)
+                var key_value = CryptoOperations().nextString(4)
+
+                this.db?.add(session_key,
+                    Compression(key_key, i.key, null, null))
+                this.db?.add(session_key,
+                    Compression(key_value, i.value, null, null))
+
+                encrypted_content += "()\$$key_key%\$$key_value|"
+            } else {
+                encrypted_content += "()${i.key}%${i.value}|"
+            }
+        }
+        encrypted_content = encrypted_content.dropLast(1)
+        if (used_compression) encrypted_content = "%$session_key%$encrypted_content"
+
+        Log.i("QR-Code Builder", "Constructed encrypted content: $encrypted_content")
+
+        // Now, let's encrypt that
+        val enc = runBlocking {
+            CryptoOperations().encrypt(passphrase, encrypted_content)
+        }
+
+        // TODO: Make schema version dynamic (currently hardcoded)
+        var final = "op1:" +
+                "${String(enc.iv)}:" +
+                "${String(enc.salt)}:" +
+                enc.result
+                    .replace("\n", "")
+
+        Log.i("QR-Code Builder", "Returning final result: $final")
+
+        this.raw = final
+
+        return final
 
     }