calendar.c

// Calendar - original code by NDRAEY for SayoriOS (c) 2023
 
#include "common.h"
#include "drv/cmos.h"
#include "io/tty.h"
 
#define printf(M, ...) _tty_printf(M, ##__VA_ARGS__)
 
unsigned int days_in_months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
char* months[12] = {
    "January",
    "February",
    "March",
    "April",
    "May",
    "June",
    "July",
    "August",
    "September",
    "October",
    "November",
    "December"
};
 
unsigned int dayofweek(unsigned int d, unsigned int m, unsigned int y) {
    int t[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
    
    y -= m < 3;
    
    return (y + y / 4 - y / 100 + y / 400 + t[m - 1] + d) % 7;
}
 
bool is_leap(uint32_t year) {
    return (year & 3) == 0 && ((year % 25) != 0 || (year & 15) == 0);
}
 
unsigned int days_in_month(unsigned int month, unsigned int year) {
    if(month == 1) {
        return is_leap(year) ? 29 : 28;
    }
 
    return days_in_months[month];
}
 
int month_by_name(char* name, int fallback) {
    for(int i = 0; i < 12; i++) {
        if(strcmp(months[i], name) == 0) {
            return i;
        }
    }
 
    return fallback;
}
 
void calendar(int argc, char** argv) {
    sayori_time_t tm = get_time();
 
    // In SayoriOS month starts from 1, not 0.
    tm.month -= 1;
 
    int month = tm.month;
 
    if(argc == 2) {
        month = month_by_name(argv[argc - 1], month);
    }
 
    char* days_of_week[7] = {
        "Sunday",
        "Monday",
        "Tuesday",
        "Wednesday",
        "Thursday",
        "Friday",
        "Saturday"  
    };
 
    int year = tm.year;
 
    printf("%10s %d\n", months[month], year);
 
    for(int i = 0; i < 7; i++) {
        // printf("%.2s ", days_of_week[i]);
        printf("%c%c ", days_of_week[i][0], days_of_week[i][1]);
    }
 
    printf("\n");
 
    unsigned int first_day = dayofweek(1, month + 1, year);
 
    printf("%*s", 3 * (first_day), "");
 
    for(unsigned int i = 1; i <= days_in_month(month, year); i++) {
        unsigned int dow = dayofweek(i, month + 1, year);
 
        if(dow == 0 && i != 1) {
            printf("\n");
        }
 
        if((int)i == tm.day && tm.month == month) {
            // printf("\033[7m%2d\033[0m ", i);
 
            tty_setcolor(0xff00ff);
            printf("%2d ", i);
            tty_setcolor(VESA_WHITE);
 
            continue;
        }
 
        printf("%2d ", i);
    }
 
    printf("\n\n");
}