#include "PikaStdDevice_Time.h"
#include "BaseObj.h"

void PikaStdDevice_Time_sleep_ms(PikaObj* self, int ms) {
    obj_setErrorCode(self, 1);
    obj_setSysOut(self, "[error] platform method need to be override.");
}
void PikaStdDevice_Time_sleep_s(PikaObj* self, int s) {
    obj_setErrorCode(self, 1);
    obj_setSysOut(self, "[error] platform method need to be override.");
}

/*
 * @Author: Once day
 * @LastEditTime: 2022-06-04 12:10:52
 * Encoder=utf-8,Email:once_day@qq.com
 */

#include "stdio.h"
#include "stdint.h"

//结构体时间类型定义(来源c标准库corect_wtime.h)
//无论是16位整数还是32位整数都满足需求
typedef struct __tm
{
    int tm_sec;   // seconds after the minute - [0, 60] including leap second
    int tm_min;   // minutes after the hour - [0, 59]
    int tm_hour;  // hours since midnight - [0, 23]
    int tm_mday;  // day of the month - [1, 31]
    int tm_mon;   // months since January - [0, 11]
    int tm_year;  // years since 1900
    int tm_wday;  // days since Sunday - [0, 6]
    int tm_yday;  // days since January 1 - [0, 365]
    int tm_isdst; // daylight savings time flag
}_tm;

//时间戳时间类型定义(来源c标准库time.h)
//直接支持64位秒数时间，附加时间精度为ns，根据设备决定，需要1GHz及以上时钟频率才能支持1ns级别时间精度
//内部时间比对数据类型，传递给外界的时候会使用浮点数，所以精度会降低
//但内部使用复合数据类型比对，以实现平台支持的最小时间精度比较
typedef struct __timespec
{
    int64_t tv_sec;  // Seconds - >= 0
    int32_t tv_nsec; // Nanoseconds - [0, 999999999]
}_timespec;

//错误处理
typedef int status;

#define TIME_OK                 0
#define TIME_ERROR              -1
#define TIME_GET_TIME_FAIL      1
#define TIME_GET_TICK_FAIL      2
#define TIME_LESS_THAN_ZERO     3
#define TIME_OVER_3200          4
#define TIME_LESS_THAN_1970     5
#define TIME_ERROR_STRUCT_TIME  6

//错误状态处理函数
void status_deal(status s)
{

    //输出异常信息
    #define time_printf(...) __platform_printf(__VA_ARGS__)

    time_printf("\n[Error-info]Checking a exception : ");
    switch (s)
    {
    case TIME_ERROR:            time_printf("Unknow error!!!\n");break;
    case TIME_GET_TIME_FAIL :   time_printf("Fail to get Unix-time from hardware !\n");break;
    case TIME_GET_TICK_FAIL :   time_printf("Fail to get Tick-time from hardware !\n");break;
    case TIME_LESS_THAN_ZERO :  time_printf("Input a negative Unix timestamp !\n");break;
    case TIME_OVER_3200 :       time_printf("The time point exceeds 3200 AD !\n");break;
    case TIME_LESS_THAN_1970 :  time_printf("The time point less-than 1970 AD !\n");break;
    case TIME_ERROR_STRUCT_TIME:time_printf("The struct-time's range is wrong !\n");break;
    default:break;
    }
    time_printf("\n");
}

//获取硬件平台的Unix时间戳,时间精度为1s级别，
status time_get_unix_time(_timespec* this_timespec)
{
    this_timespec->tv_sec=(int64_t)(obj_getInt((void*)0, "tick")/1000);
    return TIME_OK;
}

//获取硬件平台的Tick时间,时间精度为1s级别以下
//即1s的小数部分
status time_get_tick_ns(_timespec* this_timespec)
{
    this_timespec->tv_nsec=(obj_getInt((void*)0, "tick") %1000) * 1000000;
    return TIME_OK;
}

//标准time()方法，返回以浮点数表示的从 epoch 开始的秒数的时间值。
// epoch 是 1970 年 1 月 1 日 00:00:00 (UTC)，
double time_time(void)
{
    status res = 0;//状态响应
    _timespec temp_timespec={0};
    //调用硬件平台函数，获取当前时间
    res = time_get_unix_time(&temp_timespec);
    if(res){status_deal(res);}//异常处理
    res = time_get_tick_ns(&temp_timespec);
    if(res){status_deal(res);}//异常处理
    //以浮点数返回时间，float
    return temp_timespec.tv_sec + (double)temp_timespec.tv_nsec/1000000000;
}

//标准time_ns()方法，返回以整数表示的从 epoch 开始的纳秒数的时间值。
// epoch 是 1970 年 1 月 1 日 00:00:00 (UTC)，
int64_t time_time_ns(void)
{
    status res = 0;//状态响应
    _timespec temp_timespec={0};
    //调用硬件平台函数，获取当前时间
    res = time_get_unix_time(&temp_timespec);
    if(res){status_deal(res);}//异常处理
    res = time_get_tick_ns(&temp_timespec);
    if(res){status_deal(res);}//异常处理
    //以浮点数返回时间，float
    return temp_timespec.tv_sec*1000000000 + temp_timespec.tv_nsec;
}

//利用基姆拉尔森计算公式计算星期
int time_get_week(const _tm* this_tm)
{
    //月份要+1
    int month=this_tm->tm_mon+1;
    int year=this_tm->tm_year;
    int day=this_tm->tm_mday;
    int w;
    if(month==1||month==2)
    {
        month+=12;
        year-=1;
        w=day+2*month+3*(month+1)/5+year+year/4-year/100+year/400+1;//0~6,星期日 ~ 星期六
        w = w%7;
    }
    else
    {
        w=day+2*month+3*(month+1)/5+year+year/4-year/100+year/400+1;//0~6,星期日 ~ 星期六
        w=w%7;
    }
    return w;
}

//由Unix时间戳计算标准UTC时间
status unix_time_to_utc_struct_time(_tm* this_tm,int64_t unix_time)
{
    int32_t total_day ;
    int32_t extra_second ;
    int year_400,year_100,year_4,year_1;
    int february_offset,temp;//二月偏移量,零时变量

    //判断是否输入小于0的时间戳
    if(unix_time < 0)
    {
        //暂不支持小于0的时间戳
        return TIME_LESS_THAN_ZERO;
    }

    //Unix时间戳每天秒数是固定的 62*60*24
    #define DAY_SECOND   (86400)

    total_day = unix_time / DAY_SECOND;
    extra_second = unix_time - total_day * DAY_SECOND;

    //为了减少额外闰年判断，把时间往前推到1600年，即闰年最大的一次公倍数开始计算判断
    //1970-1600 = 370 年 ，370/4 -(370/100-1)=90 个闰年
    //1600 DAY_OFFSET 365*(1970-1600)+90 = 135140,7为修正天数
    #define  YEAR_START  (1600)    //初始年份
    #define  DAY_OFFSET  (135140)  //时间偏移量

    total_day += DAY_OFFSET ;

    //从1600年到3200年有1600/4-(1600/100-1600/400)=388个闰年
    //即 MAX_DAY  1600*365+388=584388 day
    #define MAX_DAY (584388) //最大可判断时间天数

    if(total_day>MAX_DAY)
    {
        //超过3200年的换算暂不支持
        return TIME_OVER_3200;
    }
    else
    {
        //从1600年开始，天数都要多减一天，因为1600年是闰年
        //但是由于日期不包含当天时间，即2月2号，实际是2月1号+时:分:秒
        //所以算出来的日期要加上一天
        //两者配合，无需加减

        //从400年，100年，4年逐渐缩小范围
        //400个公历年天数为365*400+97=146097天
        //400年内的100个公历年天数为365*100+24=36524天
        //100年内的4年365*4+1=1461天
        #define DAY_OF_400Y (146097)
        #define DAY_OF_100Y (36524)
        #define DAY_OF_4Y   (1461)
        #define DAY_OF_1Y   (365)
        year_400 = total_day / DAY_OF_400Y; 
        total_day -= year_400 * DAY_OF_400Y;
        //计算400年内的情况
        year_100 = total_day / DAY_OF_100Y;
        total_day -= year_100 * DAY_OF_100Y;
        //计算100年内的情况
        year_4 = total_day / DAY_OF_4Y;
        total_day -= year_4 * DAY_OF_4Y;
        //计算4年内的情况
        year_1 = total_day / DAY_OF_1Y;
        total_day -= year_1 * DAY_OF_1Y;

        //计算出当前年份
        this_tm->tm_year = (year_400*400+year_100*100+year_4*4+year_1)+YEAR_START;
        //保存一年的天数
        this_tm->tm_yday = total_day;

        //剩下的天数为1年内的天数,直接计算月和日
        //根据当前是否为闰年设置二月偏移量是否为1
        //能被4整除且不被100整除或者能被400整除
        february_offset = (!year_1)&&((year_4)||(!year_100));
        //闰年需要减去一天再计算
        total_day -= february_offset;
        //使用二分法快速定位月份，使用平年计算，在月份确定到2月时，再考虑闰年
        //判断是否在1-6月里面
        //31, 28, 31, 30, 31, 30,    31, 31, 30, 31, 30, 31
        if(total_day<=181)
        {
            //判断是否在1-3月里面
            if(total_day<=90)
            {
                //判断是否在1-2月里面
                if(total_day<=59)
                {
                    total_day += february_offset;//去掉二月的偏置
                    if(total_day <=31)
                    {
                        //1月
                        temp = 0;
                    }
                    else
                    {
                        //2月
                        temp = 1;
                    }
                }
                else
                {
                    total_day -= 59;
                    //3月
                    temp = 2;
                }
            }
            else
            {
                //4-6月
                total_day -= 90;
                //是否在4月里面
                if(total_day<=30)
                {
                    //4月
                    temp = 3;
                }
                else
                {
                    //5-6月
                    total_day -= 30;
                    if(total_day <=31)
                    {
                        //5月
                        temp = 4;
                    }
                    else
                    {
                        total_day -= 31;
                        //6月
                        temp = 5;
                    }

                }
            }
        }
        else
        {
            total_day -= 181;
            //判断是否在7-9月里面
            if(total_day<=92)
            {
                //是否在7-8月
                if(total_day <= 62)
                {
                    if(total_day <= 31)
                    {
                        //7月
                        temp = 6 ;
                    }
                    else
                    {
                        total_day -= 31;
                        //8月
                        temp = 7;
                    }
                }
                else
                {
                    //9月
                    total_day -= 62;
                    temp = 8;
                }
            }
            else
            {
                //10-12月
                total_day -= 92;
                //是否在10-11月
                if(total_day <= 61)
                {
                    if(total_day <= 31)
                    {
                        //10月
                        temp = 9;
                    }
                    else
                    {
                        //11 月
                        total_day -= 31;
                        temp = 10;
                    }
                }
                else
                {
                    //12月
                    total_day -= 61;
                    temp = 11;
                }
            }                                                                       
        }

        //记录当前月份和天数
        this_tm->tm_mon = temp;//月份 [0,11]
        this_tm->tm_mday = total_day;//天数

        //利用额外秒数计算时-分-秒
        temp = extra_second / 3600;
        this_tm->tm_hour = temp;
        extra_second = extra_second - temp * 3600;

        temp = extra_second / 60;
        this_tm->tm_min = temp;
        extra_second = extra_second - temp * 60;

        this_tm->tm_sec = extra_second;

        //计算出当前日期的星期数
        this_tm->tm_wday = time_get_week(this_tm);

        //夏令时不明
        this_tm->tm_isdst = -1;
    }
    return TIME_OK;
}

//由标准UTC时间生成Unix时间戳
status utc_struct_time_to_unix_time(const _tm* this_tm,int64_t* unix_time)
{
    int32_t total_day,total_leap_year,dyear;
    int february_offset;//二月偏移量,零时变量
    //31, 28, 31, 30, 31, 30,    31, 31, 30, 31, 30, 31
    //每个月份对应前面所有月的天数
    const int month_day[]={0,31,59,90,120,151,181,212,243,273,304,334};

    //每天总秒数一定，将UTC时间（年月）转换成天数
    //为了减少额外闰年判断，把时间往前推到1600年，即闰年最大的一次公倍数开始计算判断
    //1970-1600 = 370 年 ，370/4 -(370/100-1)=90 个闰年
    //1600 DAY_OFFSET 365*(1970-1600)+90 = 135140,7为修正天数

    if(this_tm->tm_year<1970)
    {
        //暂不支持1970之前的时间
        *unix_time = 0;
        return TIME_LESS_THAN_1970;
    }
    if(this_tm->tm_year>=3200)
    {
        //暂不支持3200及以后的时间
        *unix_time = 0;
        return TIME_OVER_3200;
    }

    //先计算到相对1600年的天数，再转换到1970年
    dyear = this_tm->tm_year - YEAR_START;
    total_leap_year =  dyear/4 - (dyear/100 - dyear/400 -1);
    total_day = dyear * 365 + total_leap_year ;

    //减去1970到1600的总天数
    total_day -= DAY_OFFSET;

    //增加月和日的总天数
    //判断是否是闰年
    //能被4整除且不被100整除或者能被400整除
    if(((dyear%4 == 0)&&(dyear%100 != 0))||(dyear%400 == 0))
    {
        //闰年
        february_offset = 1; 
    }
    else
    {
        february_offset = 0; 
    }

    //计算含月和日的总天数,日期要减去当天
    total_day += month_day[this_tm->tm_mon] + this_tm->tm_mday - 1 ;
    //二月以上需要加上偏移量
    if(this_tm->tm_mon>1)
    {
        total_day += february_offset;
    }

    //根据天数以及时分秒计算Unix时间戳
    *unix_time = total_day * DAY_SECOND + this_tm->tm_hour * 3600 + this_tm->tm_min *60 + this_tm->tm_sec;

    return TIME_OK;
}

void time_struct_format(const _tm* this_tm , char * str)
{
    sprintf(str,"time.struct_time(tm_year=%d, tm_mon=%d,tm_mday=%d, tm_hour=%d, tm_min=%d, tm_sec=%d, tm_wday=%d,tm_yday=%d, tm_isdst=%d)",\
     this_tm->tm_year,this_tm->tm_mon+1,this_tm->tm_mday,\
     this_tm->tm_hour,this_tm->tm_min,this_tm->tm_sec,this_tm->tm_wday,\
     this_tm->tm_yday,this_tm->tm_isdst);
}

//标准库函数gmtime,将以自 epoch 开始的秒数表示的时间转换为 UTC 的 struct_time
void time_gmtime(double unix_time, _tm* this_tm)
{
    status res;
    char str[200];
    //转化时间
    res = unix_time_to_utc_struct_time(this_tm,(int64_t)unix_time);
    if(res)
    {
        status_deal(res);//异常情况处理
        //返回默认值
        //note: 异常情况返回默认时间起始点
        unix_time_to_utc_struct_time(this_tm,(int64_t)0);
    }
    
    //格式化字符
    time_struct_format(this_tm , str);

    //显示出来
    time_printf("%s\n",str);

}

//标准库函数localtime,将以自 epoch 开始的秒数表示的时间转换为当地时间的 struct_time
void time_localtime(double unix_time, _tm* this_tm,int locale)
{
    status res;
    int local_offset;
    char str[200];

    //获取本地时间偏移量(小时)
    local_offset =  locale*60*60;

    //转化时间
    res = unix_time_to_utc_struct_time(this_tm,(int64_t)unix_time+local_offset);
    if(res)
    {
        status_deal(res);//异常情况处理
        //这里处理的策略和标准库不同，标准库最初始的时间是1970-1-1,00:00:00，对于不同时区来说，其值是不一样的
        //但本函数是要求各时区的起始时间不超过1970-1-1,00:00:00，实际上UTC时间可以更前，可靠的最早时间可到1600年
        //对于西时区来说，时间会缺失
        unix_time_to_utc_struct_time(this_tm,(int64_t)0);
    }

    //格式化字符
    time_struct_format(this_tm , str);

    //显示出来
    time_printf("%s\n",str);

}

//检测结构体时间是否在合适的范围内，但不检查它的正确性
status time_check_struct_time(const _tm* this_tm)
{
    if(this_tm->tm_sec<0 || this_tm->tm_sec >60)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_min<0 || this_tm->tm_min >59)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_hour<0 || this_tm->tm_hour >23)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_mday<1 || this_tm->tm_sec >31)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_mon<0 || this_tm->tm_sec >11)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_wday<0 || this_tm->tm_wday >6)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    if(this_tm->tm_yday<0 || this_tm->tm_yday >365)
    {
        return TIME_ERROR_STRUCT_TIME;
    }
    return TIME_OK;
}


//标准库函数mktime(t),将当地时间的 struct_time转换为以自epoch开始的秒数表示的时间
int64_t time_mktime(const _tm* this_tm,int locale)
{
    status res;
    int local_offset;
    int64_t unix_time;

    //获取本地时间偏移量(小时)
    local_offset =  locale*60*60;

    //检测时间结构体范围正确性
    res=time_check_struct_time(this_tm);
    if(res){status_deal(res);return 0;}//异常情况返回时间零点

    //转化时间
    res = utc_struct_time_to_unix_time(this_tm,&unix_time);
    if(res){status_deal(res);return 0;}//异常情况返回时间零点
    //减去本地偏移时间
    //可能出现负数，严格来说，这不影响什么！
    unix_time -= local_offset;

    //显示出来
    //time_printf("%I64d\n",unix_time);

    //返回数据
    return unix_time;
}

//标准库函数asctime()
//把结构化时间struct_time元组表示为以下形式的字符串: `'Sun Jun 20 23:21:05 1993'`。
void time_asctime(const _tm* this_tm)
{
    //星期缩写，python标准库是三个字母，这里并不相同
    const char* week[]={"Sun","Mon","Tues","Wed","Thur","Fri","Sat"};
    //月份缩写
    const char* month[]={"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sept","Oct","Nov","Dec"};

    char str[100];

    sprintf(str,"%s %s %d %02d:%02d:%02d %d",\
     week[this_tm->tm_wday],month[this_tm->tm_mon],this_tm->tm_mday,\
     this_tm->tm_hour,this_tm->tm_min,this_tm->tm_sec,\
     this_tm->tm_year);
    time_printf("%s\n",str);
}

float PikaStdDevice_Time_time(PikaObj *self)
{
    return time_time();
}
int PikaStdDevice_Time_time_ns(PikaObj *self)
{
    return time_time_ns();
}

void time_set_tm_value(PikaObj *self,const _tm* this_tm)
{
    obj_setInt(self,"tm_sec",this_tm->tm_sec);
    obj_setInt(self,"tm_min",this_tm->tm_min);
    obj_setInt(self,"tm_hour",this_tm->tm_hour);
    obj_setInt(self,"tm_mday",this_tm->tm_mday);
    obj_setInt(self,"tm_mon",this_tm->tm_mon);
    obj_setInt(self,"tm_year",this_tm->tm_year);
    obj_setInt(self,"tm_wday",this_tm->tm_wday);
    obj_setInt(self,"tm_yday",this_tm->tm_yday);
    obj_setInt(self,"tm_isdst",this_tm->tm_isdst);
}

void PikaStdDevice_Time_gmtime(PikaObj *self, float unix_time)
{
    _tm this_tm;
    time_gmtime(unix_time,&this_tm);
    time_set_tm_value(self,&this_tm);
}
void PikaStdDevice_Time_localtime(PikaObj *self, float unix_time)
{
    _tm this_tm;
    int locale = obj_getInt(self,"locale");
    time_localtime(unix_time,&this_tm,locale);
    time_set_tm_value(self,&this_tm);
}

void time_get_tm_value(PikaObj *self,_tm* this_tm)
{
    this_tm->tm_sec=obj_getInt(self,"tm_sec");
    this_tm->tm_min=obj_getInt(self,"tm_min");
    this_tm->tm_hour=obj_getInt(self,"tm_hour");
    this_tm->tm_mday=obj_getInt(self,"tm_mday");
    this_tm->tm_mon=obj_getInt(self,"tm_mon");
    this_tm->tm_year=obj_getInt(self,"tm_year");
    this_tm->tm_wday=obj_getInt(self,"tm_wday");
    this_tm->tm_yday=obj_getInt(self,"tm_yday");
    this_tm->tm_isdst=obj_getInt(self,"tm_isdst");
}

int PikaStdDevice_Time_mktime(PikaObj *self)
{
    _tm this_tm;
    int locale = obj_getInt(self,"locale");
    time_get_tm_value(self,&this_tm);
    return time_mktime(&this_tm, locale);
}

void PikaStdDevice_Time_asctime(PikaObj *self)
{
    _tm this_tm;
    time_get_tm_value(self,&this_tm);
    time_asctime(&this_tm);
}
void PikaStdDevice_Time_ctime(PikaObj *self, float unix_time)
{
    _tm this_tm;
    int locale = obj_getInt(self,"locale");
    time_localtime(unix_time,&this_tm,locale);
    time_asctime(&this_tm);
}

void PikaStdDevice_Time___init__(PikaObj *self)
{
    obj_setInt(self,"locale",8);
    PikaStdDevice_Time_localtime(self, 0.0);
}