use serde::{Serialize, Deserialize, Deserializer};
use std::fmt;
use rand::{thread_rng, Rng};
use chrono::prelude::{DateTime, Utc, NaiveDate};

/// ID
#[derive(Clone, Deserialize, Serialize, Debug, PartialEq, Eq, Hash)]
pub struct Id(pub u64);

impl Into<String> for Id {
    fn into(self) -> String {
        format!("{:x}", self.0)
    }
}
impl fmt::Display for Id {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.0)
    }
}

pub fn generate_id() -> Id {
    Id(thread_rng().gen())
}


/// https://serde.rs/field-attrs.html
pub fn deserialize_datetime<'de, D>(deserializer: D) -> Result<DateTime<Utc>, D::Error>
where
    D: Deserializer<'de>,
{
    let s = String::deserialize(deserializer)?;
    DateTime::parse_from_rfc3339(&s)
        .map_err(serde::de::Error::custom)
        .map(|dt| dt.with_timezone(&Utc))
}

pub fn deserialize_date<'de, D>(deserializer: D) -> Result<NaiveDate, D::Error>
where
    D: Deserializer<'de>,
{
    let s = String::deserialize(deserializer)?;
    NaiveDate::parse_from_str(&s, "%Y-%m-%d")
        .map_err(serde::de::Error::custom)
}


pub fn parse_datetime(inp: &str) -> Option<DateTime<Utc>> {
    let date = NaiveDate::parse_from_str(inp, "%d/%m/%Y").ok()?;
    Some(DateTime::<Utc>::from_naive_utc_and_offset(
        date.and_hms_opt(0, 0, 0).unwrap(),
        Utc
    ))
}

pub fn parse_datetime_american(inp: &str) -> Option<DateTime<Utc>> {
    let date = NaiveDate::parse_from_str(inp, "%m/%d/%Y").ok()?;
    Some(DateTime::<Utc>::from_naive_utc_and_offset(
        date.and_hms_opt(0, 0, 0).unwrap(),
        Utc
    ))
}