#include "MKL25Z4.h"  // Device header
#include <stdlib.h>    // For rand() and srand()
#include <stdio.h>     // For sprintf

// Pin Definitions for LCD
#define RS (1 << 1)  // PTC1
#define EN (1 << 2)  // PTC2
#define D4 (1 << 4)  // PTC4
#define D5 (1 << 5)  // PTC5
#define D6 (1 << 6)  // PTC6
#define D7 (1 << 7)  // PTC7

// Pin Definitions for Jumper
#define JUMPER_PIN 12   // Jumper connected to PTC12
#define SWITCH_PIN 4    // Button connected to PTA4
#define LED_PIN 5       // LED connected to PTA5

// Function Prototypes for LCD and SysTick
void delay_ms(unsigned int delay);
void LCD_Command(unsigned char cmd);
void LCD_Data(unsigned char data);
void LCD_Init(void);
void LCD_Print(const char *str);
void SysTick_Handler(void);

// Variables for SysTick Timer
volatile uint32_t milliseconds = 0;  // Milliseconds counter
volatile uint8_t timer_running = 0;   // Timer running flag
volatile uint32_t random_delay_time = 0;  // Store the random delay time

// Delay function (simple)
void delay_ms(unsigned int delay) {
    for (volatile unsigned int i = 0; i < delay * 6000; i++);
}

// LCD Command function
void LCD_Command(unsigned char cmd) {
    PTC->PCOR = RS;  // RS = 0 for command
    PTC->PSOR = EN;  // EN = 1
    PTC->PCOR = (D4 | D5 | D6 | D7);  // Clear data lines

    // Send higher nibble
    PTC->PSOR = ((cmd >> 4) & 0x0F) << 4;
    PTC->PCOR = EN;  // EN = 0
    delay_ms(1);
    PTC->PSOR = EN;  // EN = 1

    // Send lower nibble
    PTC->PCOR = (D4 | D5 | D6 | D7);  // Clear data lines
    PTC->PSOR = (cmd & 0x0F) << 4;
    PTC->PCOR = EN;  // EN = 0
    delay_ms(1);
}

// LCD Data function
void LCD_Data(unsigned char data) {
    PTC->PSOR = RS;  // RS = 1 for data
    PTC->PSOR = EN;  // EN = 1
    PTC->PCOR = (D4 | D5 | D6 | D7);  // Clear data lines

    // Send higher nibble
    PTC->PSOR = ((data >> 4) & 0x0F) << 4;
    PTC->PCOR = EN;  // EN = 0
    delay_ms(1);
    PTC->PSOR = EN;  // EN = 1

    // Send lower nibble
    PTC->PCOR = (D4 | D5 | D6 | D7);  // Clear data lines
    PTC->PSOR = (data & 0x0F) << 4;
    PTC->PCOR = EN;  // EN = 0
    delay_ms(1);
}

// Initialize LCD
void LCD_Init(void) {
    SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK;  // Enable clock for PORTC
    PORTC->PCR[1] = PORT_PCR_MUX(1);     // PTC1 as GPIO (RS)
    PORTC->PCR[2] = PORT_PCR_MUX(1);     // PTC2 as GPIO (EN)
    PORTC->PCR[4] = PORT_PCR_MUX(1);     // PTC4 as GPIO (D4)
    PORTC->PCR[5] = PORT_PCR_MUX(1);     // PTC5 as GPIO (D5)
    PORTC->PCR[6] = PORT_PCR_MUX(1);     // PTC6 as GPIO (D6)
    PORTC->PCR[7] = PORT_PCR_MUX(1);     // PTC7 as GPIO (D7)

    PTC->PDDR |= (RS | EN | D4 | D5 | D6 | D7);  // Set pins as output
    PTC->PCOR = (RS | EN | D4 | D5 | D6 | D7);  // Clear all pins

    delay_ms(20);       // Wait for LCD to power up
    LCD_Command(0x02);  // Initialize LCD in 4-bit mode
    LCD_Command(0x28);  // 4-bit, 2 lines, 5x7 font
    LCD_Command(0x0C);  // Display ON, cursor OFF
    LCD_Command(0x06);  // Entry mode, auto-increment cursor
    LCD_Command(0x01);  // Clear display
    delay_ms(2);
}

// Print string to LCD
void LCD_Print(const char *str) {
    while (*str) {
        LCD_Data(*str++);
    }
}

// Initialize SysTick Timer
void SysTick_Init(void) {
    SysTick->LOAD = 48000 - 1;  // 1 ms per tick (48 MHz clock)
    SysTick->VAL = 0;           // Clear current value
    SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_TICKINT_Msk | SysTick_CTRL_ENABLE_Msk;
}

// SysTick Handler (for 1 ms tick)
void SysTick_Handler(void) {
    if (timer_running) {
        milliseconds++;
    }
}

// Function to generate a random delay
void random_delay() {
    srand(milliseconds);  // Seed the random generator with the current time
    random_delay_time = rand() % 5 + 1;  // Generate a delay between 1s and 5s
    delay_ms(random_delay_time);  // Wait for the random delay
}

// Main function
int main(void) {
    // Enable clock to Port A and Port C
    SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK | SIM_SCGC5_PORTA_MASK;

    // Configure PTA5 as GPIO for LED
    PORTA->PCR[LED_PIN] = PORT_PCR_MUX(1);  // Set PTA5 as GPIO
    PTA->PDDR |= (1 << LED_PIN);            // Set PTA5 to output direction

    // Configure PTC12 as GPIO for jumper (button signal)
    PORTC->PCR[JUMPER_PIN] = PORT_PCR_MUX(1);  // Set PTC12 as GPIO
    PTC->PDDR &= ~(1 << JUMPER_PIN);  // Set PTC12 as input

    // Configure PTA4 as GPIO for the button
    PORTA->PCR[SWITCH_PIN] = PORT_PCR_MUX(1);  // Set PTA4 as GPIO
    PTA->PDDR &= ~(1 << SWITCH_PIN);  // Set PTA4 as input
    PORTA->PCR[SWITCH_PIN] |= PORT_PCR_PE(1) | PORT_PCR_PS(1);  // Enable pull-up resistor

    // Initialize LCD
    LCD_Init();
    LCD_Print("Waiting...");

    // Start SysTick Timer
    SysTick_Init();
    timer_running = 1;  // Start the timer

    // LED control with random delay
    random_delay();  // Generate a random delay
    PTA->PTOR = (1 << LED_PIN);  // Turn on the LED (toggle PTA5)
    delay_ms(1000);  // Wait for 1 second
    PTA->PTOR = (1 << LED_PIN);  // Turn off the LED (toggle PTA5)

    while (1) {
        if (PTC->PDIR & (1 << JUMPER_PIN)) {  // Check if PTC12 is high (button pressed)
            timer_running = 0;  // Stop the SysTick timer
            uint32_t total_time = milliseconds * 2;  // Double the time
            uint32_t seconds = total_time / 1000;       // Calculate seconds
            uint32_t fractional_ms = total_time % 1000; // Calculate milliseconds part

            // Subtract the random delay from the total time
            total_time -= random_delay_time * 1000; // Convert to milliseconds

            // Calculate the adjusted time (after subtracting the random delay)
            seconds = total_time / 1000;        // Adjusted seconds
            fractional_ms = total_time % 1000;  // Adjusted milliseconds part

            // Clear LCD and display the adjusted time
            LCD_Command(0x01);  // Clear the display
            delay_ms(2);
            char time_str[16];
            sprintf(time_str, "%lu.%03lu s", seconds, fractional_ms);  // Format as X.XXX seconds
            LCD_Print(time_str);  // Print elapsed time on the LCD

            // Optional: Wait before restarting
            delay_ms(2000);  // Wait 2 seconds before restarting
            LCD_Command(0x01);  // Clear the display again
            LCD_Print("Waiting...");

            milliseconds = 0;  // Reset milliseconds counter
            timer_running = 1;  // Restart the timer
        }
    }

    return 0;
}