sys-datetime 1.1.0

use std::{
    fmt::Display,
    time::{Duration, SystemTime},
};

use regex::Regex;
use serde::{Deserialize, Deserializer, Serialize, Serializer};

/// Datetime
/// # Example
/// ```no_run
/// let mut dt = Datetime::default();
/// dt.add_years(1970).add_months(1).add_days(1);
/// dt.add_seconds(Datetime::timestamp().as_secs() as i64);
///
/// let now = Datetime::now();
///
/// assert!(dt == now);
/// ```
#[derive(Clone, Copy, Default, Debug, PartialEq, PartialOrd)]
pub struct Datetime {
    year: i64,
    month: u8,
    day: u8,
    hour: u8,
    minute: u8,
    second: u8,
}

impl Datetime {
    /// plus years
    pub fn add_years(&mut self, years: i64) -> &mut Self {
        if self.year < 0 {
            self.year += years;
            if self.year >= 0 {
                self.year += 1;
            }
        } else if self.year > 0 {
            self.year += years;
            if self.year <= 0 {
                self.year -= 1;
            }
        } else {
            self.year = years;
        }

        if self.month == 2 && self.day > 28 {
            let yz = if self.year < 0 {
                self.year + 1
            } else {
                self.year
            };

            if self.day >= 29 && yz % 4 == 0 && (yz % 100 != 0 || yz % 400 == 0) {
                self.day = 29;
            } else {
                self.day = 28;
            }
        }

        self
    }

    /// plus months
    pub fn add_months(&mut self, months: i64) -> &mut Self {
        let ys = (self.month as i64 + months) / 12;
        let mut ms = (self.month as i64 + months) % 12;

        if ms < 1 {
            ms += 12;
            self.month = ms as u8;

            self.add_years(ys - 1);
        } else {
            self.month = ms as u8;

            self.add_years(ys);
        }

        match self.month {
            4 | 6 | 9 | 11 if self.day > 30 => {
                self.day = 30;
            }
            _ => {}
        }

        self
    }

    /// plus days
    pub fn add_days(&mut self, days: i64) -> &mut Self {
        let mut ds = self.day as i64 + days;

        self.day = 1;

        if ds >= 1 {
            loop {
                let mut yz = if self.year < 0 {
                    self.year + 1
                } else {
                    self.year
                };

                if self.month > 2 {
                    yz += 1;
                }

                if yz % 4 == 0 && (yz % 100 != 0 || yz % 400 == 0) {
                    if ds <= 366 {
                        break;
                    }
                    ds -= 366;
                } else {
                    if ds <= 365 {
                        break;
                    }
                    ds -= 365;
                }

                self.add_years(1);
            }

            loop {
                let yz = if self.year < 0 {
                    self.year + 1
                } else {
                    self.year
                };

                match self.month {
                    1 | 3 | 5 | 7 | 8 | 10 | 12 => {
                        if ds <= 31 {
                            break;
                        }
                        ds -= 31;
                    }
                    2 => {
                        if yz % 4 == 0 && (yz % 100 != 0 || yz % 400 == 0) {
                            if ds <= 29 {
                                break;
                            }
                            ds -= 29;
                        } else {
                            if ds <= 28 {
                                break;
                            }
                            ds -= 28;
                        }
                    }
                    4 | 6 | 9 | 11 => {
                        if ds <= 30 {
                            break;
                        }
                        ds -= 30;
                    }
                    _ => {}
                }

                self.add_months(1);
            }
        } else {
            loop {
                let mut yz = if self.year < 0 {
                    self.year + 1
                } else {
                    self.year
                };

                if self.month <= 2 {
                    yz -= 1;
                }

                if yz % 4 == 0 && (yz % 100 != 0 || yz % 400 == 0) {
                    if ds >= -366 {
                        break;
                    }
                    ds += 366;
                } else {
                    if ds >= -365 {
                        break;
                    }
                    ds += 365;
                }

                self.add_years(-1);
            }

            loop {
                if ds >= 1 {
                    break;
                }

                self.add_months(-1);

                let yz = if self.year < 0 {
                    self.year + 1
                } else {
                    self.year
                };

                match self.month {
                    1 | 3 | 5 | 7 | 8 | 10 | 12 => {
                        ds += 31;
                    }
                    2 => {
                        if yz % 4 == 0 && (yz % 100 != 0 || yz % 400 == 0) {
                            ds += 29;
                        } else {
                            ds += 28;
                        }
                    }
                    4 | 6 | 9 | 11 => {
                        ds += 30;
                    }
                    _ => {}
                }
            }
        }

        self.day = ds as u8;

        self
    }

    /// plus hours
    /// ```no_run
    /// let mut dt = Datetime::now();
    /// dt.add_hours(8);
    /// println!("{}", dt);
    /// ```
    pub fn add_hours(&mut self, hours: i64) -> &mut Self {
        let mut hs = (self.hour as i64 + hours) % 24;

        if hs < 0 {
            hs += 24;

            self.add_days((self.hour as i64 + hours) / 24 - 1);
        } else {
            self.add_days((self.hour as i64 + hours) / 24);
        }

        self.hour = hs as u8;

        self
    }

    /// plus minutes
    pub fn add_minutes(&mut self, minutes: i64) -> &mut Self {
        let mut ms = (self.minute as i64 + minutes) % 60;

        if ms < 0 {
            ms += 60;

            self.add_hours((self.minute as i64 + minutes) / 60 - 1);
        } else {
            self.add_hours((self.minute as i64 + minutes) / 60);
        }

        self.minute = ms as u8;

        self
    }

    /// plus seconds
    pub fn add_seconds(&mut self, seconds: i64) -> &mut Self {
        let mut ss = (self.second as i64 + seconds) % 60;

        if ss < 0 {
            ss += 60;

            self.add_minutes((self.second as i64 + seconds) / 60 - 1);
        } else {
            self.add_minutes((self.second as i64 + seconds) / 60);
        }

        self.second = ss as u8;

        self
    }

    #[inline(always)]
    pub fn year(&self) -> i64 {
        self.year
    }

    #[inline(always)]
    pub fn month(&self) -> i64 {
        self.month as i64
    }

    #[inline(always)]
    pub fn day(&self) -> i64 {
        self.day as i64
    }

    #[inline(always)]
    pub fn hour(&self) -> i64 {
        self.hour as i64
    }

    #[inline(always)]
    pub fn minute(&self) -> i64 {
        self.minute as i64
    }

    #[inline(always)]
    pub fn second(&self) -> i64 {
        self.second as i64
    }

    /// may be used to obtain the day of the week for dates on or after 0000-03-01
    /// ```no_run
    /// assert_eq!(
    ///     Datetime::from_rfc3339("1970-01-01").unwrap().day_of_week(),
    ///     "Thursday"
    /// );
    /// ```
    pub fn day_of_week(&self) -> &'static str {
        let mut year = self.year();
        let mut month = self.month();
        let day = self.day();

        let dayofweek = [
            "Sunday",
            "Monday",
            "Tuesday",
            "Wednesday",
            "Thursday",
            "Friday",
            "Saturday",
        ];

        // adjust months so February is the last one
        month -= 2;
        if month < 1 {
            month += 12;
            year -= 1;
        }

        // split by century
        let cent = year / 100;
        year %= 100;

        dayofweek
            [((26 * month - 2) / 10 + day + year + year / 4 + cent / 4 + 5 * cent) as usize % 7]
    }

    /// the number of seconds between two Datetime
    /// ```no_run
    /// assert_eq!(
    ///     Datetime::now().seconds_since(Datetime::from_rfc3339("1970-01-01").unwrap()),
    ///     Datetime::timestamp().as_secs() as i64
    /// );
    /// ```
    pub fn seconds_since(&self, earlier: Datetime) -> i64 {
        let stop = Self {
            year: self.year,
            month: self.month,
            day: self.day,
            hour: 0,
            minute: 0,
            second: 0,
        };
        let mut start = Self {
            year: earlier.year,
            month: earlier.month,
            day: earlier.day,
            hour: 0,
            minute: 0,
            second: 0,
        };

        let mut ss =
            (stop.year() - start.year()) * 365 + (stop.month() - start.month()) * 30 + stop.day()
                - start.day();
        start.add_days(ss);

        while stop > start {
            start.add_days(1);
            ss += 1;
        }
        while stop < start {
            start.add_days(-1);
            ss -= 1;
        }

        ss = ss * 24 + self.hour() - earlier.hour();
        ss = ss * 60 + self.minute() - earlier.minute();
        ss = ss * 60 + self.second() - earlier.second();

        ss
    }

    /// create from string
    pub fn from_str(dt: &str) -> Option<Self> {
        if let Ok(re) = Regex::new("(\\d+)\\D+(\\d+)\\D+(\\d+)\\D*(\\d*)\\D*(\\d*)\\D*(\\d*)(\\D*)")
        {
            if let Some(caps) = re.captures(dt) {
                let year = if matches!(caps.get(7),Some(b) if b.as_str().contains("BC")) {
                    -caps
                        .get(1)
                        .map_or(0, |m| m.as_str().parse().unwrap_or_default())
                } else {
                    caps.get(1)
                        .map_or(0, |m| m.as_str().parse().unwrap_or_default())
                };
                let month = caps
                    .get(2)
                    .map_or(0, |m| m.as_str().parse().unwrap_or_default());
                let day = caps
                    .get(3)
                    .map_or(0, |m| m.as_str().parse().unwrap_or_default());
                let hour = caps
                    .get(4)
                    .map_or(0, |m| m.as_str().parse().unwrap_or_default());
                let minute = caps
                    .get(5)
                    .map_or(0, |m| m.as_str().parse().unwrap_or_default());
                let second = caps
                    .get(6)
                    .map_or(0, |m| m.as_str().parse().unwrap_or_default());

                return Some(Self {
                    year,
                    month,
                    day,
                    hour,
                    minute,
                    second,
                });
            }
        }

        None
    }

    /// create from rfc3339 string
    /// ```no_run
    /// assert_eq!(
    ///     Datetime::from_rfc3339("2020-01-01 08:00:00+08:00")
    ///         .unwrap()
    ///         .to_string(),
    ///     "2020-01-01 00:00:00"
    /// );
    /// ```
    pub fn from_rfc3339(rfc: &str) -> Option<Self> {
        if rfc.len() >= 10 {
            let mut dt = Datetime::default();
            dt.add_years(rfc[0..4].parse().ok()?);
            dt.add_months(rfc[5..7].parse().ok()?);
            dt.add_days(rfc[8..10].parse().ok()?);

            if rfc.len() >= 19 {
                dt.add_hours(rfc[11..13].parse().ok()?);
                dt.add_minutes(rfc[14..16].parse().ok()?);
                dt.add_seconds(rfc[17..19].parse().ok()?);

                if rfc.len() > 19 {
                    let tail = &rfc[19..];
                    if let Some(p) = tail.find(&['+', '-']) {
                        let z: Vec<&str> = tail[p + 1..].split(':').collect();
                        if z.len() > 0 {
                            if &tail[p..p + 1] == "+" {
                                dt.add_hours(-z[0].parse().ok()?);
                                if z.len() > 1 {
                                    dt.add_minutes(-z[1].parse().ok()?);
                                }
                            } else if &tail[p..p + 1] == "-" {
                                dt.add_hours(z[0].parse::<i64>().ok()?);
                                if z.len() > 1 {
                                    dt.add_minutes(z[1].parse::<i64>().ok()?);
                                }
                            }
                        }
                    }
                }
            }

            return Some(dt);
        }
        None
    }

    /// current system timestamp
    pub fn timestamp() -> Duration {
        SystemTime::now()
            .duration_since(SystemTime::UNIX_EPOCH)
            .unwrap_or_default()
    }

    /// current time
    pub fn now() -> Self {
        let mut epoch = Self {
            year: 1970,
            month: 1,
            day: 1,
            hour: 0,
            minute: 0,
            second: 0,
        };
        epoch.add_seconds(Datetime::timestamp().as_secs() as i64);
        epoch
    }
}

impl Display for Datetime {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        if self.year >= 0 {
            write!(
                f,
                "{:0>4}-{:0>2}-{:0>2} {:0>2}:{:0>2}:{:0>2}",
                self.year, self.month, self.day, self.hour, self.minute, self.second
            )
        } else {
            write!(
                f,
                "{:0>4}-{:0>2}-{:0>2} {:0>2}:{:0>2}:{:0>2} BC",
                -self.year, self.month, self.day, self.hour, self.minute, self.second
            )
        }
    }
}

impl Serialize for Datetime {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let s = self.to_string();
        String::serialize(&s, serializer)
    }
}

impl<'de> Deserialize<'de> for Datetime {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let s = String::deserialize(deserializer)?;
        if s.len() == 0 {
            Ok(Datetime::default())
        } else {
            if let Some(r) = Datetime::from_rfc3339(&s) {
                Ok(r)
            } else if let Some(r) = Datetime::from_str(&s) {
                Ok(r)
            } else {
                Err(serde::de::Error::custom("The data format is not correct"))
            }
        }
    }
}

#[cfg(feature = "postgres")]
impl sqlx::Type<sqlx::Postgres> for Datetime {
    fn type_info() -> sqlx::postgres::PgTypeInfo {
        sqlx::postgres::PgTypeInfo::with_name("TIMESTAMP")
    }

    fn compatible(ty: &sqlx::postgres::PgTypeInfo) -> bool {
        matches!(
            ty.to_string().as_str(),
            "TIMESTAMP" | "TIMESTAMPTZ" | "DATE" | "VARCHAR" | "TEXT"
        )
    }
}

#[cfg(feature = "postgres")]
impl sqlx::Encode<'_, sqlx::Postgres> for Datetime {
    fn encode_by_ref(
        &self,
        buf: &mut sqlx::postgres::PgArgumentBuffer,
    ) -> Result<sqlx::encode::IsNull, sqlx::error::BoxDynError> {
        let s = self.seconds_since(Self {
            year: 2000,
            month: 1,
            day: 1,
            hour: 0,
            minute: 0,
            second: 0,
        }) * 1000000;
        sqlx::Encode::<sqlx::Postgres>::encode_by_ref(&s, buf)
    }

    fn size_hint(&self) -> usize {
        8
    }
}

#[cfg(feature = "postgres")]
impl<'r> sqlx::Decode<'r, sqlx::Postgres> for Datetime
where
    i64: sqlx::Decode<'r, sqlx::Postgres>,
    i32: sqlx::Decode<'r, sqlx::Postgres>,
    &'r str: sqlx::Decode<'r, sqlx::Postgres>,
{
    /// when using TIMESTAMPTZ please pay attention to time zone conversion such as your_timestamp AT TIME ZONE 'your_timezone'
    fn decode(value: sqlx::postgres::PgValueRef<'r>) -> Result<Self, sqlx::error::BoxDynError> {
        match sqlx::ValueRef::type_info(&value)
            .as_ref()
            .to_string()
            .as_str()
        {
            "TIMESTAMP" | "TIMESTAMPTZ" => {
                let mut epoch = Self {
                    year: 2000,
                    month: 1,
                    day: 1,
                    hour: 0,
                    minute: 0,
                    second: 0,
                };
                epoch.add_seconds(i64::decode(value)? / 1000000);
                Ok(epoch)
            }
            "DATE" => {
                let mut epoch = Self {
                    year: 2000,
                    month: 1,
                    day: 1,
                    hour: 0,
                    minute: 0,
                    second: 0,
                };
                epoch.add_days(i32::decode(value)? as i64);
                Ok(epoch)
            }
            _ => {
                let s = <&str>::decode(value)?;
                let res = if let Some(r) = Datetime::from_rfc3339(s) {
                    r
                } else if let Some(r) = Datetime::from_str(s) {
                    r
                } else {
                    Datetime::default()
                };
                Ok(res)
            }
        }
    }
}

#[cfg(all(feature = "sqlx", not(feature = "postgres")))]
impl<'r, DB: sqlx::Database> sqlx::Type<DB> for Datetime
where
    DB: sqlx::Database,
    &'r str: sqlx::Type<DB>,
{
    fn type_info() -> <DB as sqlx::Database>::TypeInfo {
        <&str>::type_info()
    }

    fn compatible(ty: &DB::TypeInfo) -> bool {
        matches!(
            ty.to_string().as_str(),
            "TIMESTAMP" | "DATETIME" | "DATE" | "VARCHAR" | "TEXT"
        )
    }
}

#[cfg(all(feature = "sqlx", not(feature = "postgres")))]
impl<'r, DB> sqlx::Encode<'r, DB> for Datetime
where
    DB: sqlx::Database,
    String: sqlx::Encode<'r, DB>,
{
    fn encode_by_ref(
        &self,
        buf: &mut <DB as sqlx::Database>::ArgumentBuffer<'r>,
    ) -> Result<sqlx::encode::IsNull, sqlx::error::BoxDynError> {
        <String>::encode(self.to_string(), buf)
    }
}

#[cfg(all(feature = "sqlx", not(feature = "postgres")))]
impl<'r, DB> sqlx::Decode<'r, DB> for Datetime
where
    DB: sqlx::Database,
    &'r [u8]: sqlx::Decode<'r, DB>,
    &'r str: sqlx::Decode<'r, DB>,
{
    fn decode(
        value: <DB as sqlx::Database>::ValueRef<'r>,
    ) -> Result<Self, sqlx::error::BoxDynError> {
        match sqlx::ValueRef::type_info(&value)
            .as_ref()
            .to_string()
            .as_str()
        {
            #[cfg(feature = "mysql")]
            "TIMESTAMP" | "DATETIME" | "DATE" => {
                let buf = <&[u8]>::decode(value)?;
                let len = buf[0];
                let mut dt = Self {
                    year: ((buf[2] as i64) << 8) + buf[1] as i64,
                    month: buf[3],
                    day: buf[4],
                    hour: 0,
                    minute: 0,
                    second: 0,
                };
                if len > 4 {
                    dt.hour = buf[5];
                    dt.minute = buf[6];
                    dt.second = buf[7];
                }
                Ok(dt)
            }
            _ => {
                let s = <&str>::decode(value)?;
                let res = if let Some(r) = Datetime::from_rfc3339(s) {
                    r
                } else if let Some(r) = Datetime::from_str(s) {
                    r
                } else {
                    Datetime::default()
                };
                Ok(res)
            }
        }
    }
}