FuriHalRtc refactor: new datetime lib (#3386)

* datetimelib created
* datetimelib unit tests added
* firmware fixes to new datetimelib
* typo fix
* merge artifacts fixed, datetimelib renamed to datetime

Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>

lib/datetime/datetime.c

@@ -0,0 +1,104 @@
+#include "datetime.h"
+
+#define TAG "DateTime"
+
+#define SECONDS_PER_MINUTE 60
+#define SECONDS_PER_HOUR (SECONDS_PER_MINUTE * 60)
+#define SECONDS_PER_DAY (SECONDS_PER_HOUR * 24)
+#define MONTHS_COUNT 12
+#define EPOCH_START_YEAR 1970
+
+static const uint8_t datetime_days_per_month[2][MONTHS_COUNT] = {
+    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
+
+static const uint16_t datetime_days_per_year[] = {365, 366};
+
+bool datetime_validate_datetime(DateTime* datetime) {
+    bool invalid = false;
+
+    invalid |= (datetime->second > 59);
+    invalid |= (datetime->minute > 59);
+    invalid |= (datetime->hour > 23);
+
+    invalid |= (datetime->year < 2000);
+    invalid |= (datetime->year > 2099);
+
+    invalid |= (datetime->month == 0);
+    invalid |= (datetime->month > 12);
+
+    invalid |= (datetime->day == 0);
+    invalid |= (datetime->day > 31);
+
+    invalid |= (datetime->weekday == 0);
+    invalid |= (datetime->weekday > 7);
+
+    return !invalid;
+}
+
+uint32_t datetime_datetime_to_timestamp(DateTime* datetime) {
+    uint32_t timestamp = 0;
+    uint8_t years = 0;
+    uint8_t leap_years = 0;
+
+    for(uint16_t y = EPOCH_START_YEAR; y < datetime->year; y++) {
+        if(datetime_is_leap_year(y)) {
+            leap_years++;
+        } else {
+            years++;
+        }
+    }
+
+    timestamp += ((years * datetime_days_per_year[0]) + (leap_years * datetime_days_per_year[1])) *
+                 SECONDS_PER_DAY;
+
+    bool leap_year = datetime_is_leap_year(datetime->year);
+
+    for(uint8_t m = 1; m < datetime->month; m++) {
+        timestamp += datetime_get_days_per_month(leap_year, m) * SECONDS_PER_DAY;
+    }
+
+    timestamp += (datetime->day - 1) * SECONDS_PER_DAY;
+    timestamp += datetime->hour * SECONDS_PER_HOUR;
+    timestamp += datetime->minute * SECONDS_PER_MINUTE;
+    timestamp += datetime->second;
+
+    return timestamp;
+}
+
+void datetime_timestamp_to_datetime(uint32_t timestamp, DateTime* datetime) {
+    uint32_t days = timestamp / SECONDS_PER_DAY;
+    uint32_t seconds_in_day = timestamp % SECONDS_PER_DAY;
+
+    datetime->year = EPOCH_START_YEAR;
+
+    while(days >= datetime_get_days_per_year(datetime->year)) {
+        days -= datetime_get_days_per_year(datetime->year);
+        (datetime->year)++;
+    }
+
+    datetime->month = 1;
+    while(days >=
+          datetime_get_days_per_month(datetime_is_leap_year(datetime->year), datetime->month)) {
+        days -=
+            datetime_get_days_per_month(datetime_is_leap_year(datetime->year), datetime->month);
+        (datetime->month)++;
+    }
+
+    datetime->day = days + 1;
+    datetime->hour = seconds_in_day / SECONDS_PER_HOUR;
+    datetime->minute = (seconds_in_day % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE;
+    datetime->second = seconds_in_day % SECONDS_PER_MINUTE;
+}
+
+uint16_t datetime_get_days_per_year(uint16_t year) {
+    return datetime_days_per_year[datetime_is_leap_year(year) ? 1 : 0];
+}
+
+bool datetime_is_leap_year(uint16_t year) {
+    return (((year) % 4 == 0) && ((year) % 100 != 0)) || ((year) % 400 == 0);
+}
+
+uint8_t datetime_get_days_per_month(bool leap_year, uint8_t month) {
+    return datetime_days_per_month[leap_year ? 1 : 0][month - 1];
+}