class EncryptV

# File lib/encryptvigen/encryptv.rb, line 11
def decrypt(encrypted_msg, key)
    # Metodo para desencriptar un mensaje
    new_key = extend_key(encrypted_msg, key)
    algorithm_decrypt_v(encrypted_msg,new_key)
end

# File lib/encryptvigen/encryptv.rb, line 6
def encrypt(msg, key)
    # Metodo para encriptar un mensaje
    algorithm_encrypt_v(msg,key)
end

# File lib/encryptvigen/encryptv.rb, line 80
def algorithm_decrypt_v(encrypted_msg, new_key)
    msg_len = encrypted_msg.length
    decrypted_msg = gen_ch_array(msg_len)

    #Desencriptacion
    available_chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 ".split("")
    encrypted_msg.split("").each_with_index{ |c,i|
        if validate(c) || (c.eql? ' ')
            decrypted_msg[i] = available_chars[(((index(encrypted_msg.split("")[i]) - index(new_key.split("")[i])) + available_chars.length()) % available_chars.length())]
        else
            decrypted_msg[i] = decrypted_msg.split("")[i]
        end
    }
    return decrypted_msg.join("");
end

# File lib/encryptvigen/encryptv.rb, line 59
def algorithm_encrypt_v(msg, key)
    # Encrypta un mensaje utilizando el algoritmo vigenere
    msg_len = msg.length
    key_len = key.length
    encrypted_msg = gen_ch_array(msg_len)
    
    new_key = extend_key(msg, key)

    # Encriptacion
    available_chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 ".split("") 
    msg.split("").each_with_index{ |c,i|
        if validate(c) || (c.eql? ' ')
            encrypted_msg[i] = available_chars[((index(msg.split("")[i]) + index(new_key.split("")[i])) % available_chars.length())]
        else
            encrypted_msg[i] = msg.split("")[i]
        end
    }

    return encrypted_msg.join("")
end

# File lib/encryptvigen/encryptv.rb, line 37
def extend_key(msg, key)
    # Generar une nueva clave a base del mensage y la clave original
    msg_len = msg.length
    new_key = gen_ch_array(msg_len)
    key_len = key.length
    j = 0
    msg.split("").each_with_index{ |c,i|
        if j.eql? key_len
            j = 0
        end
        new_key[i] = key.split("")[j]
        j = j + 1
    }
    return new_key.join("")
end

# File lib/encryptvigen/encryptv.rb, line 32
def gen_ch_array(len)
    # Devuelve un array de tamaño 'len' de caracteres 'x'
    ('x'*len).split("")
end

# File lib/encryptvigen/encryptv.rb, line 21
def index(ch)
    # Devuelve la posicion del caracter en el hash
    available_chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 ".split("")
    available_chars.each_with_index { |c,i|
        if c.eql? ch
            return i
        end
    }
    return -1
end

# File lib/encryptvigen/encryptv.rb, line 53
def validate(str)
    # Devuelve verdadero si el str es alfa-numerico
    chars = ('a'..'z').to_a + ('A'..'Z').to_a + (0..9).to_a
    str.chars.detect {|ch| !chars.include?(ch)}.nil?
end