#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/io.h>
#include <signal.h>
#include <string.h>

#define PORT_80 0x80
#define SCAN_DELAY 5000

const unsigned char segment_codes[] = {
    0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07,  // 0-7
    0x7F, 0x6F, 0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71,  // 8-F
    0x00, 0x40                                       // Off, horizontal bar
};

typedef struct {
    int running;
    int display_value;
} DisplayContext;

DisplayContext ctx = {1, 0};

void signal_handler(int sig) {
    printf("\nExiting...\n");
    ctx.running = 0;
    outb(0x00, PORT_80);  // Clear Display
}

// Initialize I/O permissions
int init_io() {
    if (iopl(3) < 0) {
        perror("iopl failed");
        return -1;
    }
    
    return 0;
}

// Display a single number at the specified position
void display_digit(int digit, int position) {
    unsigned char code;
    
    if (digit < 0 || digit > 15) {
        code = segment_codes[16];  // 熄灭
    } else {
        code = segment_codes[digit];
    }
    
    // Position 0 uses low 4 bits, and position 1 uses high 4 bits (depending on hardware connection)
    if (position == 0) {
        outb(code, PORT_80);
    } else {
        outb(code, PORT_80);
    }
}

// Display two digits
void display_two_digits(int num) {
    char value = num & 0xff;
    outb(value, PORT_80);
    return;
    int tens = num / 10;
    int ones = num % 10;
    int scan_count = 50; 
    
    for (int i = 0; i < scan_count && ctx.running; i++) {
        // Display ten digits
        outb(segment_codes[tens], PORT_80);
        usleep(SCAN_DELAY);
        
        //  Display one digit
        outb(segment_codes[ones], PORT_80);
        usleep(SCAN_DELAY);
    }
}

// Display a number in hexadecimal format
void display_hex(int value) {
    char values = value & 0xff;
    outb(values, PORT_80);
    return;
    // for (int i = 0; i < 50 && ctx.running; i++) {
    //     outb(segment_codes[high], PORT_80);
    //     usleep(SCAN_DELAY);
        
    //     outb(segment_codes[low], PORT_80);
    //     usleep(SCAN_DELAY);
    // }
}

// Display a number in decimal format
void blink_display(int num, int times) {
    for (int i = 0; i < times && ctx.running; i++) {
        display_two_digits(num);
        usleep(500000);  // 500ms
        
        outb(0x00, PORT_80);
        usleep(300000);  // 300ms
    }
}

// Scroll a text message across the display
void scroll_display(const char *text) {
    int len = strlen(text);
    
    for (int i = 0; i <= len && ctx.running; i++) {
        for (int j = 0; j < 20 && ctx.running; j++) {
            if (i < len) {
                int digit = text[i] - '0';
                if (digit >= 0 && digit <= 9) {
                    outb(segment_codes[digit], PORT_80);
                }
            }
            usleep(SCAN_DELAY);
        }
    }
}

int main(int argc, char *argv[]) {
    int choice = 0;
    int value;
    
    
    if (init_io() < 0) {
        printf("error\n");
        return 1;
    }
    
    signal(SIGINT, signal_handler);
    
    for (int i = 0; i < 3 && ctx.running; i++) {
        outb(0xFF, PORT_80);
        usleep(300000);
        outb(0x00, PORT_80);
        usleep(200000);
    }
    printf("test finish\n\n");
    
    while (ctx.running) {
        printf("\nPlease select a mode:\n");
        printf("1. Show Numbers (0-99)\n");
        printf("2. Display Hex (00-FF)\n");
        printf("3. Flashing display\n");
        printf("4. Scrolling\n");
        printf("5. counter\n");
        printf("6. exit\n");
        printf("select: ");
        
        if (scanf("%d", &choice) != 1) {
            while(getchar() != '\n');
            continue;
        }
        
        switch(choice) {
            case 1:
                printf("Enter numbers (0-99): ");
                scanf("%d", &value);
                if (value >= 0 && value <= 99) {
                    printf("show %d\n", value);
                    display_two_digits(value);
                }
                break;
                
            case 2:
                printf("Enter hexadecimal value (00-FF): ");
                scanf("%x", &value);
                if (value >= 0 && value <= 0xFF) {
                    printf("show 0x%02X\n", value);
                    display_hex(value);
                }
                break;
                
            case 3:
                printf("Enter numbers and flashes: ");
                scanf("%d %d", &value, &choice);
                blink_display(value, choice);
                break;
                
            case 4:
                printf("Input digital string: ");
                char text[10];
                scanf("%s", text);
                scroll_display(text);
                break;
                
            case 5:
                printf("Counter mode (press Ctrl+C to exit)\n");
                for (int i = 0; i <= 99 && ctx.running; i++) {
                    printf("\rcount: %d", i);
                    fflush(stdout);
                    display_two_digits(i);
                }
                printf("\n");
                break;
                
            case 6:
                ctx.running = 0;
                break;
                
            default:
                printf("Invalid selection\n");
        }
    }
    
    // 清理
    outb(0x00, PORT_80);
    printf("\nexit\n");
    
    return 0;
}