/**
 * main.c
 */
void main(void)
{
    WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD;     // stop watchdog timer
    set_DCO(CURRENT_FREQ);
    LCD_INIT();
    init_keypad();
    write_string("LOCKED", 0x00);
    write_string("ENTER KEY", 0x40);
    char key, index = 0;
    char key_str[4];
    char answer[4]="1234";

    while (1){
        //check initial key presses
        key=keypad_check();
        if (key != '\0'){
            if (key=='*'){ //clear screen and restart if * pressed
                index=0;
                clear_LCD();
                write_string("LOCKED", 0x00);
                write_string("ENTER KEY", 0x40);
            }
            else{ //otherwise print the character pressed and add to the answer string
                write_char_LCD(0x4A+index, key);
                key_str[index]=key;
                index++;
                delay_ms(500, CURRENT_FREQ);
            }
        }
        //once four characters have been entered check against answer string
        if (index== 4){
            index=0;
            //if code is correct, print hello world and wait for next input
            if (key_str[0]==answer[0] && key_str[1]==answer[1] && key_str[2]==answer[2] && key_str[3]==answer[3]) {
                clear_LCD();
                write_string("HELLO WORLD", 0x00);
                //once correct entered, wait for next key
                while (1){
                    key=keypad_check();
                    if (key != '\0'){
                        //if next key is *, clear and go back to locked screen
                        if (key=='*'){
                            index=0;
                            clear_LCD();
                            write_string("LOCKED", 0x00);
                            write_string("ENTER KEY", 0x40);
                            break;
                        }
                        //if next key is #, prompt for new code and
                        else if (key == '#'){
                            clear_LCD();
                            write_string("ENTER NEW CODE", 0x00);
                            while (1) {
                                key=keypad_check();
                                if (key != '\0'){
                                    //if * is pressed, clear and restart new code entry
                                    if (key=='*'){
                                        index=0;
                                        clear_LCD();
                                        write_string("ENTER NEW CODE", 0x00);
                                    }
                                    //change code to next key pressed and exit once 4 digits entered
                                    else{
                                        write_char_LCD(0x40+index, key);
                                        answer[index]=key;
                                        index++;
                                        delay_ms(500, CURRENT_FREQ);
                                        if (index == 4) {
                                            index = 0;
                                            clear_LCD();
                                            write_string("LOCKED", 0x00);
                                            write_string("ENTER KEY", 0x40);
                                            break;
                                        }
                                    }
                                }
                            }
                            break;
                        }
                    }
                }
            }
            //if code is incorrect return to locked screen
            else {
                clear_LCD();
                write_string("LOCKED", 0x00);
                write_string("ENTER KEY", 0x40);
            }
        }
    }
}