Break the code and win the game

Bulls & Cows is a logical game for kids and adults, also known as Mastermind, 4digits or 1A2B. Your goal is to find the computer's secret number with a minimum number of suggestions.

On each guess the game announces the number of "cows" and "bulls" in your suggestion. If the matching digits are on their right positions, they are "bulls", if they are on different positions, they are "cows". To win you must reveal the secret number.

Example: secret number is 8207

1st guess: 1234 (1 Bull)

The bull is 2 - digit is in the number and in the correct position

2nd guess: 1705 (1 Bull 1 Cow)

The bull is 0 - digit is in the number and in the correct position

The cow is 7 - digit is in the number and but in the wrong position

3rd guess: 8207 (4 Bulls)

All digits are bulls because they are all in the number and in the correct positions