//! Convert most of the [Time Strings](http://sqlite.org/lang_datefunc.html) to chrono types.
extern crate chrono;

use std::error;
use self::chrono::{NaiveDate, NaiveTime, NaiveDateTime, DateTime, TimeZone, UTC, Local};
use libc::c_int;

use {Error, Result};
use types::{FromSql, ToSql};

use ffi;
use ffi::sqlite3_stmt;
use ffi::sqlite3_column_type;

const JULIAN_DAY: f64 = 2440587.5; // 1970-01-01 00:00:00 is JD 2440587.5
const DAY_IN_SECONDS: f64 = 86400.0;
const JULIAN_DAY_GREGORIAN: f64 = 1721424.5; // Jan 1, 1 proleptic Gregorian calendar

/// ISO 8601 calendar date without timezone => "YYYY-MM-DD"
impl ToSql for NaiveDate {
    unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int {
        let date_str = self.format("%Y-%m-%d").to_string();
        date_str.bind_parameter(stmt, col)
    }
}

/// "YYYY-MM-DD" or Julian Day => ISO 8601 calendar date without timezone.
impl FromSql for NaiveDate {
    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveDate> {
        match sqlite3_column_type(stmt, col) {
            ffi::SQLITE_TEXT => {
                let s = try!(String::column_result(stmt, col));
                match NaiveDate::parse_from_str(&s, "%Y-%m-%d") {
                    Ok(dt) => Ok(dt),
                    Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
                }
            }
            ffi::SQLITE_FLOAT => {
                // if column affinity is REAL and an integer/unix timestamp is inserted => unexpected result
                let mut jd = ffi::sqlite3_column_double(stmt, col);
                jd -= JULIAN_DAY_GREGORIAN;
                if jd < i32::min_value() as f64 || jd > i32::max_value() as f64 {
                    let err: Box<error::Error + Sync + Send> = "out-of-range date".into();
                    return Err(Error::FromSqlConversionFailure(err));
                }
                match NaiveDate::from_num_days_from_ce_opt(jd as i32) {
                    Some(dt) => Ok(dt),
                    None => {
                        let err: Box<error::Error + Sync + Send> = "out-of-range date".into();
                        Err(Error::FromSqlConversionFailure(err))
                    }
                }
            }
            _ => Err(Error::InvalidColumnType),
        }
    }

    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
        let sqlite_type = sqlite3_column_type(stmt, col);
        sqlite_type == ffi::SQLITE_TEXT || sqlite_type == ffi::SQLITE_FLOAT
    }
}

/// ISO 8601 time without timezone => "HH:MM:SS.SSS"
impl ToSql for NaiveTime {
    unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int {
        let date_str = self.format("%H:%M:%S.3f").to_string();
        date_str.bind_parameter(stmt, col)
    }
}

/// "HH:MM"/"HH:MM:SS"/"HH:MM:SS.SSS" => ISO 8601 time without timezone.
impl FromSql for NaiveTime {
    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveTime> {
        match sqlite3_column_type(stmt, col) {
            ffi::SQLITE_TEXT => {
                let s = try!(String::column_result(stmt, col));
                let fmt = match s.len() {
                    5 => "%H:%M",
                    8 => "%H:%M:%S",
                    _ => "%H:%M:%S%.3f",
                };
                match NaiveTime::parse_from_str(&s, fmt) {
                    Ok(dt) => Ok(dt),
                    Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
                }
            }
            _ => Err(Error::InvalidColumnType),
        }
    }

    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
        sqlite3_column_type(stmt, col) == ffi::SQLITE_TEXT
    }
}

/// ISO 8601 combined date and time without timezone => "YYYY-MM-DD HH:MM:SS.SSS"
impl ToSql for NaiveDateTime {
    unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int {
        let date_str = self.format("%Y-%m-%d %H:%M:%S%.3f").to_string();
        date_str.bind_parameter(stmt, col)
    }
}

/// "YYYY-MM-DD HH:MM"/"YYYY-MM-DD HH:MM:SS"/"YYYY-MM-DD HH:MM:SS.SSS"/ Julian Day / Unix Time => ISO 8601 combined date and time without timezone.
/// ("YYYY-MM-DDTHH:MM"/"YYYY-MM-DDTHH:MM:SS"/"YYYY-MM-DDTHH:MM:SS.SSS" also supported)
impl FromSql for NaiveDateTime {
    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveDateTime> {
        match sqlite3_column_type(stmt, col) {
            ffi::SQLITE_TEXT => {
                let s = try!(String::column_result(stmt, col));
                let fmt = match s.len() {
                    16 => {
                        match s.as_bytes()[10] {
                            b'T' => "%Y-%m-%dT%H:%M",
                            _ => "%Y-%m-%d %H:%M",
                        }
                    }
                    19 => {
                        match s.as_bytes()[10] {
                            b'T' => "%Y-%m-%dT%H:%M:%S",
                            _ => "%Y-%m-%d %H:%M:%S",
                        }
                    }
                    _ => {
                        match s.as_bytes()[10] {
                            b'T' => "%Y-%m-%dT%H:%M:%S%.3f",
                            _ => "%Y-%m-%d %H:%M:%S%.3f",
                        }
                    }
                };
                match NaiveDateTime::parse_from_str(&s, fmt) {
                    Ok(dt) => Ok(dt),
                    Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
                }
            }
            ffi::SQLITE_INTEGER => {
                match NaiveDateTime::from_timestamp_opt(ffi::sqlite3_column_int64(stmt, col), 0) {
                    Some(dt) => Ok(dt),
                    None => {
                        let err: Box<error::Error + Sync + Send> = "out-of-range number of seconds"
                                                                       .into();
                        Err(Error::FromSqlConversionFailure(err))
                    }
                }
            }
            ffi::SQLITE_FLOAT => {
                // if column affinity is REAL and an integer/unix timestamp is inserted => unexpected result
                let mut jd = ffi::sqlite3_column_double(stmt, col);
                jd -= JULIAN_DAY;
                jd *= DAY_IN_SECONDS;
                let ns = jd.fract() * 10f64.powi(9);
                match NaiveDateTime::from_timestamp_opt(jd as i64, ns as u32) {
                    Some(dt) => Ok(dt),
                    None => {
                        let err: Box<error::Error + Sync + Send> = "out-of-range number of \
                                                                    seconds and/or invalid \
                                                                    nanosecond"
                                                                       .into();
                        Err(Error::FromSqlConversionFailure(err))
                    }
                }
            }
            _ => Err(Error::InvalidColumnType),
        }
    }

    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
        let sqlite_type = sqlite3_column_type(stmt, col);
        sqlite_type == ffi::SQLITE_TEXT || sqlite_type == ffi::SQLITE_INTEGER ||
        sqlite_type == ffi::SQLITE_FLOAT
    }
}

/// ISO 8601 date and time with time zone => "YYYY-MM-DD HH:MM:SS.SSS[+-]HH:MM"
impl ToSql for DateTime<UTC> {
    unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int {
        let date_str = self.format("%Y-%m-%dT%H:%M:%S%.3f%:z").to_string();
        date_str.bind_parameter(stmt, col)
    }
}

/// "YYYY-MM-DD HH:MM:SS.SSS[+-]HH:MM"/"YYYY-MM-DD HH:MM"/"YYYY-MM-DD HH:MM:SS"/"YYYY-MM-DD HH:MM:SS.SSS"/ Julian Day / Unix Time => ISO 8601 date and time with time zone.
/// ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM"/"YYYY-MM-DDTHH:MM"/"YYYY-MM-DDTHH:MM:SS"/"YYYY-MM-DDTHH:MM:SS.SSS" also supported)
/// When the timezone is not specified, UTC is used.
impl FromSql for DateTime<UTC> {
    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<DateTime<UTC>> {
        match sqlite3_column_type(stmt, col) {
            ffi::SQLITE_TEXT => {
                let s = try!(String::column_result(stmt, col));
                if s.len() > 23 {
                    let fmt = if s.as_bytes()[10] == b'T' {
                        "%Y-%m-%dT%H:%M:%S%.3f%:z"
                    } else {
                        "%Y-%m-%d %H:%M:%S%.3f%:z"
                    };
                    match UTC.datetime_from_str(fmt, &s) {
                        Ok(dt) => Ok(dt),
                        Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
                    }
                } else {
                    NaiveDateTime::column_result(stmt, col).map(|dt| UTC.from_utc_datetime(&dt))
                }
            }
            ffi::SQLITE_INTEGER => {
                NaiveDateTime::column_result(stmt, col).map(|dt| UTC.from_utc_datetime(&dt))
            }
            ffi::SQLITE_FLOAT => {
                NaiveDateTime::column_result(stmt, col).map(|dt| UTC.from_utc_datetime(&dt))
            }
            _ => Err(Error::InvalidColumnType),
        }
    }

    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
        NaiveDateTime::column_has_valid_sqlite_type(stmt, col)
    }
}


/// ISO 8601 date and time with time zone => "YYYY-MM-DD HH:MM:SS.SSS[+-]HH:MM"
impl ToSql for DateTime<Local> {
    unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int {
        let date_str = self.format("%Y-%m-%dT%H:%M:%S%.3f%:z").to_string();
        date_str.bind_parameter(stmt, col)
    }
}

/// "YYYY-MM-DD HH:MM:SS.SSS[+-]HH:MM"/"YYYY-MM-DD HH:MM"/"YYYY-MM-DD HH:MM:SS"/"YYYY-MM-DD HH:MM:SS.SSS"/ Julian Day / Unix Time => ISO 8601 date and time with time zone.
/// ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM"/"YYYY-MM-DDTHH:MM"/"YYYY-MM-DDTHH:MM:SS"/"YYYY-MM-DDTHH:MM:SS.SSS" also supported)
/// When the timezone is not specified, Local is used.
impl FromSql for DateTime<Local> {
    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<DateTime<Local>> {
        match sqlite3_column_type(stmt, col) {
            ffi::SQLITE_TEXT => {
                let s = try!(String::column_result(stmt, col));
                if s.len() > 23 {
                    let fmt = if s.as_bytes()[10] == b'T' {
                        "%Y-%m-%dT%H:%M:%S%.3f%:z"
                    } else {
                        "%Y-%m-%d %H:%M:%S%.3f%:z"
                    };
                    match Local.datetime_from_str(fmt, &s) {
                        Ok(dt) => Ok(dt),
                        Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
                    }
                } else {
                    NaiveDateTime::column_result(stmt, col).map(|dt| Local.from_utc_datetime(&dt))
                }
            }
            ffi::SQLITE_INTEGER => {
                NaiveDateTime::column_result(stmt, col).map(|dt| Local.from_utc_datetime(&dt))
            }
            ffi::SQLITE_FLOAT => {
                NaiveDateTime::column_result(stmt, col).map(|dt| Local.from_utc_datetime(&dt))
            }
            _ => Err(Error::InvalidColumnType),
        }
    }

    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
        NaiveDateTime::column_has_valid_sqlite_type(stmt, col)
    }
}

// struct UnixTime(NaiveDateTime);
// struct JulianTime(NaiveDateTime)