#include <stdio.h>
#include <stdlib.h>
#include<windows.h>


int Leap (int year)                     //判断闰年
{
    return (year%4==0&&year%100!=0)||(year%400==0);
}

int Kimlareson(int year, int month, int day)
{
    if (month<3)                        //1,2月要当做去年的13,14月算
    {
        month+=12;
        year-=1;
    }
    
    int K = year % 100;
    int J = year / 100;

    
    if (year<1582||(year==1582&&(month<10||(month==10&&day<=4))))//1582年10月4日及之前
    {
        return (day+(13*(month+1))/5+K+K/4+5-J)%7;
    }
    
    else                                //1582年10月15日及之后
    {
        return (day+(13*(month+1))/5+K+K/4+J/4+5*J)%7;
    }
}
int daysinmonth(int year,int month)
{
    switch(month)
    {
        case 2:
            return Leap(year)?29:28;    //判断2月天数
        case 4: case 6: case 9: case 11:
            return 30;
        default:
            return 31;
    }
}
void print_month_calendar(int year,int month,int *start_day)//单个月的日历
{
    const char *months[]={"一月","二月","三月","四月","五月","六月","七月","八月","九月","十月","十一月","十二月"};
    printf("\n     %d %s\n",year,months[month - 1]);
    printf("日 一 二 三 四 五 六\n");
    int days_in_month=daysinmonth(year,month);

    for (int i=0;i<*start_day;i++)
    {
        printf("   ");
    }

    for (int day=1;day<=days_in_month;day++)
    {
        
        printf("%2d ",day);
        if ((*start_day+day)%7==0)
        {
            printf("\n");
        }
    }
    printf("\n");

    *start_day=(*start_day+days_in_month)%7;
}
void print_1582(int *start_day)         //单独处理1582年10月这个怪胎（？）
{
    printf("\n     十月 1582\n");
    printf("日 一 二 三 四 五 六\n");

    
    for (int i=0;i<*start_day;i++)
    {
        printf("   ");
    }

    // 打印1-4日
    for (int day=1;day<=4;day++)
    {
        printf("%2d ",day);
        if ((*start_day+day-1)%7==6)
        {
            printf("\n");
        }
    }

    
    int current_day=5;                  //跳过5-14日
    for (int day=15;day<=31;day++)
    {
        if ((*start_day+current_day-1)%7==0)
        {
            printf("\n");
        }
        printf("%2d ",day);
        current_day++;
    }
    printf("\n");

    
    *start_day=(*start_day+21)%7;       //1582年10月只有21天
}
void print_calendar(int year)           //打印单列日历
{
    int start_day=Kimlareson(year,1,1);
    for (int month=1;month<=12;month++)
    {
        if (year==1582&&month==10)
        {
            print_1582(&start_day);     //处理1582年10月
        }
        else
        {
            print_month_calendar(year,month,&start_day);
        }
    }
}

void print_calendar_double(int year)    //打印双列整年日历
{
    int start_day[12];
    start_day[0]=Kimlareson(year,1,1);

    
    for (int month=1;month<12;month++)  //计算每月起始星期几
    {
        start_day[month]=(start_day[month-1]+daysinmonth(year,month))%7;
    }

    const char *months[]={"一月", "二月", "三月", "四月", "五月", "六月","七月", "八月", "九月", "十月", "十一月", "十二月"};

    for (int i = 0; i < 6; i++)         //每行输出两个月 
    { 
        printf("\n");

        for (int j = 0; j < 2; j++)     //两个月的标题
        {
            int month = i * 2 + j + 1;
            printf("     %d  %s          ",year,months[month-1]);
        }
        printf("\n");

        
        for (int j = 0; j < 2; j++)     //星期标题
        {
            printf("日 一 二 三 四 五 六   ");
        }
        printf("\n");

        int max_days[2] = { daysinmonth(year, i * 2 + 1), daysinmonth(year, i * 2 + 2) };//获取两个月的最大天数和起始星期几
        int start_days[2] = { start_day[i * 2], start_day[i * 2 + 1] };

        //打印日期
        int day[2] = {1, 1};            //每个月的当前日期
        int printed_anything = 1;       //标记是否有剩余日期可打印

        while (printed_anything) {
            printed_anything = 0;

            for (int j = 0; j < 2; j++)
            {
                
                if (day[j] == 1)        //打印月初的空格
                {
                    for (int k = 0; k < start_days[j]; k++)
                    {
                        printf("   ");
                    }
                }

                
                while (day[j] <= max_days[j] && ((day[j] + start_days[j] - 1) % 7) != 6)//打印日期
                {
                    printf("%2d ",day[j]++);
                    printed_anything=1;
                }

                
                if (day[j] <= max_days[j])//打印最后一个日期，换行并跳到下一个月
                {
                    printf("%2d ",day[j]++);
                    printed_anything=1;
                } else
                {
                    printf("   ");      //填充空格保持对齐
                }

                printf("  ");           //每月之间的间隔
            }

            printf("\n");               //换行到下一个星期
        }
    }
}


int main()
{
    SetConsoleOutputCP(65001);
    int x;
    for(;x!=4;)
    {
    printf("          menu\n");
    printf("[1]判断是否闰年\n");
    printf("[2]输出该年份的日历\n");
    printf("[3]求这一天是星期几\n");
    printf("[4]退出\n");
    
    
    scanf("%d",&x);

    if(x==1)
    {
        int y,x;
        printf("请输入年份：");
        scanf("%d",&y);
        if (y<0)
        {
            printf("你确定你输的是对吗？\n");
        }
        else if(y>=10000)
        {
            printf("%d...你不觉得太过久远了吗?\n",y);
        }
        else
        {
            x=Leap(y);
            if(x==1)
                printf("是闰年\n");
            else
                printf("不是闰年\n");
        }
    }
    else if(x==2)
    {
        int y,x;
        printf("请输入年份：");
        scanf("%d",&y);
        if (y<0)
        {
            printf("你确定你输的是对吗？\n");
        }
        else if(y>=10000)
        {
            printf("%d...你不觉得太过久远了吗?\n",y);
        }
        else
        {
            printf("请选择单列或双列输出（1.单列 2.双列）：");
            scanf("%d",&x);
            if(x==1)
            {
                print_calendar(y);
            }
            else if(x==2)
            {
                print_calendar_double(y);
            }
            else
            {
                printf("啧...我觉得我说的很明显了呢...\n");
            }
        }
    }
    else if(x==3)
    {
        int year, month, day;
        printf("请输入日期（年 月 日）：");
        scanf("%d %d %d", &year, &month, &day);
        if(year<0||month<=0||day<=0)
        {
            printf("你是认真的吗？\n");
        }
        else if(year>=10000)
        {
            printf("%d...你不觉得太过久远了吗?\n",year);
        }
        else if(month>=13||day<=0||day>31)
        {
            printf("你是认真的吗？\n");
        }
        else if((month==2&&Leap(year)&&day>29)||(month==2&&Leap(year)==0&&day>28))
        {
            printf("你是认真的吗？\n");
        }
        else if(year==1582&&month==10&&day>4&&day<15)
        {
            printf("这一天已经被教皇大人吃掉了www\n");
        }
        else 
        {
            int weekday=Kimlareson(year, month, day);
            const char *weekdays[] = {"星期六","星期日","星期一","星期二","星期三","星期四","星期五"};
    
            printf("%d年%d月%d日是：%s\n",year,month,day,weekdays[weekday]);
        }
    }
    else if(x==4)
        exit(0);
    else if(x==99)
        printf("你先生，何时来的？\n是要时停扫地偷胖次吗？\n");
    else
    {
        printf("请不要开玩笑了，我没有这个功能哦\n");
    }
    }
    
    
    
    return 0;
}