Minimax going in order(Tic Tac Toe) - c

Question

I'm currently trying to make use of the Minimax Algorithm and create a "Unbeatable Computer Player". I'm banging my head with this one for hours now and I cant seem to figure out why the "Computer" is going in order and not making the right decisions. Does anybody have an idea? maybe something sticks out for you I can't put my finger on what's wrong honestly. I bet it has something to do with the recursive call but I'm lost here.
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
char BOARD[9][4];
void createBoard(){
for(int i = 0;i < 9;i++){
strcpy(BOARD[i], "[]");
}
strcpy(BOARD[6], "[X]");
strcpy(BOARD[1], "[O]");
strcpy(BOARD[3], "[X]");
}
void printBoard(){
printf("\n\n");
for(int i = 0;i < 9;i++){
printf("%s", BOARD[i]);
if((i + 1) % 3 == 0){
printf("\n");
}
}
printf("\n\n");
}
void makeMove(char* player, int position){
char playerFinal[5];
strcpy(playerFinal, "[");
strcat(playerFinal, player);
strcat(playerFinal, "]");
if(strcmp(BOARD[position], "[]") == 0){
strcpy(BOARD[position], playerFinal);
}
}
bool movesLeft(){
for(int i = 0;i < 9;i++){
if(strcmp(BOARD[i], "[]") == 0){
return true;
}
}
return false;
}
char* isWinner(){
for(int i = 0;i < 9;i = i + 3){
if(strcmp(BOARD[i], BOARD[i + 1]) == 0 && strcmp(BOARD[i + 1], BOARD[i + 2]) == 0){
if(strcmp(BOARD[i], "[X]") == 0){
return "X";
}
else if(strcmp(BOARD[i], "[O]") == 0){
return "O";
}
}
}
for(int i = 0;i < 3;i++){
if(strcmp(BOARD[i], BOARD[i + 3]) == 0 && strcmp(BOARD[i + 3], BOARD[i + 6]) == 0){
if(strcmp(BOARD[i], "[X]") == 0){
return "X";
}
else if(strcmp(BOARD[i], "[O]") == 0){
return "O";
}
}
}
if(strcmp(BOARD[0], BOARD[4]) == 0 && strcmp(BOARD[4], BOARD[8]) == 0){
if(strcmp(BOARD[0], "[X]") == 0){
return "X";
}
else if(strcmp(BOARD[0], "[O]") == 0){
return "O";
}
}
if(strcmp(BOARD[2], BOARD[4]) == 0 && strcmp(BOARD[4], BOARD[6]) == 0){
if(strcmp(BOARD[2], "[X]") == 0){
return "X";
}
else if(strcmp(BOARD[2], "[O]") == 0){
return "O";
}
}
if(!movesLeft()){
return "tie";
}
return "";
}
int minimax(bool isMaximizing){
char* winner = isWinner();
printf("Function Called\n");
printf("%s", winner);
if(strcmp(winner, "O") == 0){
return 10;
}
if(strcmp(winner, "X") == 0){
return -10;
}
if(strcmp(winner, "tie") == 0){
return 0;
}
if(isMaximizing){
int score;
int bestScore = -1000000;
for(int i = 0;i < 9;i++){
if(strcmp(BOARD[i], "[]") == 0){
makeMove("O", i);
score = minimax(false);
strcpy(BOARD[i], "[]");
if(score > bestScore){
bestScore = score;
}
}
}
return bestScore;
}
else{
int score;
int bestScore = 1000000;
for(int i = 0;i < 9;i++){
if(strcmp(BOARD[i], "[]") == 0){
makeMove("X", i);
score = minimax(true);
strcpy(BOARD[i], "[]");
if(score < bestScore){
bestScore = score;
}
}
}
return bestScore;
}
}
void bestMove(){
int bestScore = -1000;
int position;
for(int i = 0;i < 9;i++){
if(strcmp(BOARD[i], "[]") == 0){
int score;
makeMove("O", i);
score = minimax(false);
strcpy(BOARD[i], "[]");
printf("Position %d\n", i);
printf("Best Score %d\n", bestScore);
printf("Score %d\n", score);
if(score > bestScore){
bestScore = score;
position = i;
}
}
}
makeMove("O", position);
}
int main(){
int position;
createBoard();
printBoard();
bool player = true;
char* winner = "";
while(strcmp(winner, "") == 0){
if(player){
printf("Its the Players Turn\nChoose a Position: ");
scanf("%d", &position);
makeMove("X", position -1);
player = false;
winner = isWinner();
}
else{
printf("Its the Computers Turn");
bestMove();
player = true;
winner = isWinner();
}
printBoard();
}
printf("The Winner is: %s\n", winner);
return 0;
}