use chrono::NaiveDateTime;
use julian_day_converter::*;

fn main() {
    // Convert a sample Julian Day value to a valid NaiveDateTime object and then use to_jd() for interoperability
    // with astronomical applications
    // The return value is a result consistent with other parse functions
    // julian_day_to_datetime(jd_value) is equivalent to NaiveDateTime::from_jd(jd_value)
    let sample_julian_day = 2459827.25;
    if let Ok(date_time) = julian_day_to_datetime(sample_julian_day) {
      let formatted_date_time_string = date_time.format("%Y-%m-%dT%H:%M:%S").to_string();
      println!("The Julian day {} is {} as ISO date-time", sample_julian_day, formatted_date_time_string);
    }
    
    // Convert an approximate date-time string to a valid NaiveDateTime object and then use to_jd() for interoperability
    // with astronomical applications
    // The return value is a result consistent with other parse functions
    let approx_date_time = "2023-11-09 15"; // 3pm 
    if let Some(date_time) = NaiveDateTime::from_fuzzy_iso_string(approx_date_time) {
      let formatted_date_time_string = date_time.format("%Y-%m-%dT%H:%M:%S").to_string();
      println!("The input time of `{}` is assumed to be {} UTC and in Julian Days is {}", approx_date_time, formatted_date_time_string, date_time.to_jd());
    }
  
    let historical_jd = 2334317.39336563;
    // Convert to a NaiveDateTime object and then apply its format method
    // The return value is an options consistent with other chrono::NaiveDateTime constructors
    if let Some(date_time) = NaiveDateTime::from_jd(historical_jd) {
      let formatted_date_time_string = date_time.format("%Y-%m-%dT%H:%M:%S").to_string();
      println!("The meteorite landed on Earth at {} Julian days or {}", historical_jd, formatted_date_time_string);
    }

    let prehistoric_julian_day = -190338.875;
    // Convert to a NaiveDateTime object and then apply its format method
    // The return value is a result consistent with other parse functions
    if let Some(date_time) = NaiveDateTime::from_jd(prehistoric_julian_day) {
      let formatted_date_time_string = date_time.format("%Y-%m-%dT%H:%M:%S").to_string();
      println!("An asteroid hit the Earth at {} Julian days or {}", historical_jd, formatted_date_time_string);
    }

    let unix_timestamp = 169938309;
    // does not require conversion to a NaiveDateTime object
    let jd = unixtime_to_julian_day(unix_timestamp);
    println!("All valid 64 bit integers can be converted to Julian days, e.g. {} is {} Julian days", unix_timestamp, jd);
    
    let julian_day = 2134937.3937f64;
    // does not require conversion to a NaiveDateTime object
    let ts = julian_day_to_unixtime(julian_day);
    println!("Some historical and far-future Julian days may yield very big timestamp values e.g. {} is {} as a unix timestamp", julian_day, ts);
  
  }