use chrono::prelude::*;
use std::{
    cmp::Ordering,
    ops::{Add, AddAssign},
    time::Duration,
};
use uuid::Uuid;

#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq)]
pub enum Field {
    Boolean(bool),
    DateTime(DateTime<Utc>),
    Duration(Duration),
    Integer(i128),
    None,
    Revision(Revision),
    StaticString(String),
    Uuid(Uuid),
}

impl Field {
    pub fn get_type(&self) -> FieldType {
        self.into()
    }
}

impl Add for Field {
    type Output = Self;

    fn add(self, other: Self) -> Self {
        match self {
            Field::DateTime(value1) => match other {
                Field::Duration(value2) => { value1 + value2 }.into(),
                _ => Field::None,
            },
            Field::Duration(value1) => match other {
                Field::Duration(value2) => { value1 + value2 }.into(),
                _ => Field::None,
            },
            Field::Integer(value1) => match other {
                Field::Integer(value2) => { value1 + value2 }.into(),
                _ => Field::None,
            },
            _ => Self::None,
        }
    }
}

impl AddAssign for Field {
    fn add_assign(&mut self, other: Self) {
        *self = self.clone().add(other);
    }
}

impl From<bool> for Field {
    fn from(value: bool) -> Self {
        Self::Boolean(value)
    }
}

impl From<DateTime<Utc>> for Field {
    fn from(value: DateTime<Utc>) -> Self {
        Self::DateTime(value)
    }
}

impl From<Duration> for Field {
    fn from(value: Duration) -> Self {
        Self::Duration(value)
    }
}

impl From<Revision> for Field {
    fn from(value: Revision) -> Self {
        Self::Revision(value)
    }
}

impl From<String> for Field {
    fn from(value: String) -> Self {
        Self::StaticString(value)
    }
}

impl From<&str> for Field {
    fn from(value: &str) -> Self {
        Self::from(value.to_string())
    }
}

impl From<Uuid> for Field {
    fn from(value: Uuid) -> Self {
        Self::Uuid(value)
    }
}

impl From<i128> for Field {
    fn from(value: i128) -> Self {
        Self::Integer(value)
    }
}

impl From<isize> for Field {
    fn from(value: isize) -> Self {
        let data: i128 = value.try_into().unwrap();
        Self::from(data)
    }
}

impl From<i32> for Field {
    fn from(value: i32) -> Self {
        let data: i128 = value.into();
        Self::from(data)
    }
}

impl PartialOrd for Field {
    fn partial_cmp(&self, other: &Field) -> Option<Ordering> {
        match (self, other) {
            (Self::Boolean(d1), Self::Boolean(d2)) => d1.partial_cmp(d2),
            (Self::DateTime(d1), Self::DateTime(d2)) => d1.partial_cmp(d2),
            (Self::Duration(d1), Self::Duration(d2)) => d1.partial_cmp(d2),
            (Self::Integer(d1), Self::Integer(d2)) => d1.partial_cmp(d2),
            (Self::Revision(d1), Self::Revision(d2)) => d1.partial_cmp(d2),
            (Self::StaticString(d1), Self::StaticString(d2)) => d1.partial_cmp(d2),
            (Self::Uuid(d1), Self::Uuid(d2)) => d1.partial_cmp(d2),
            (_, _) => None,
        }
    }
}

#[cfg(test)]
mod fields {
    use super::*;
    use rand::random;

    #[test]
    fn can_create_static_string() {
        let data = Uuid::new_v4().to_string();
        let result: Field = data.clone().into();
        match result.clone() {
            Field::StaticString(output) => assert_eq!(output, data),
            _ => unreachable!("got {:?}: should have been static string", result),
        }
        assert_eq!(result.get_type(), FieldType::StaticString);
    }

    #[test]
    fn can_create_from_str() {
        let holder = ["one", "two"];
        for data in holder.into_iter() {
            let result: Field = data.into();
            match result.clone() {
                Field::StaticString(output) => assert_eq!(output, data),
                _ => unreachable!("got {:?}: should have been static string", result),
            }
            assert_eq!(result.get_type(), FieldType::StaticString);
        }
    }

    #[test]
    fn create_from_uuid() {
        let data = Uuid::new_v4();
        let result: Field = data.clone().into();
        match result.clone() {
            Field::Uuid(output) => assert_eq!(output, data),
            _ => unreachable!("got {:?}: should have been uuid", result),
        }
        assert_eq!(result.get_type(), FieldType::Uuid);
    }

    #[test]
    fn create_from_datatime() {
        let data = Utc::now();
        let result: Field = data.into();
        match result.clone() {
            Field::DateTime(output) => assert_eq!(output, data),
            _ => unreachable!("got {:?}: should have been uuid", result),
        }
        assert_eq!(result.get_type(), FieldType::DateTime);
    }

    #[test]
    fn does_adding_return_none_for_things_that_cannot_add() {
        let value1: Field = Uuid::new_v4().into();
        let value2: Field = Uuid::new_v4().into();
        assert_eq!(value1 + value2, Field::None);
    }

    #[test]
    fn can_integers_be_added() {
        let value1: i128 = random::<u8>().into();
        let value2: i128 = random::<u8>().into();
        let expected: Field = { value1 + value2 }.into();
        let value1: Field = value1.into();
        let value2: Field = value2.into();
        assert_eq!(value1 + value2, expected);
    }

    #[test]
    fn can_integer_add_mismatch_returns_none() {
        let value1: Field = 5.into();
        let value2: Field = "nope".into();
        assert_eq!(value1 + value2, Field::None);
    }

    #[test]
    fn can_durations_be_added() {
        let data1: u64 = random::<u8>().into();
        let data2: u64 = random::<u8>().into();
        let value1: Field = Duration::from_secs(data1).into();
        let value2: Field = Duration::from_secs(data2).into();
        let expected: Field = Duration::from_secs(data1 + data2).into();
        assert_eq!(value1 + value2, expected);
    }

    #[test]
    fn does_duration_mismatch_return_none() {
        let value1: Field = Duration::from_secs(20).into();
        let value2: Field = "nope".into();
        assert_eq!(value1 + value2, Field::None);
    }

    #[test]
    fn can_durations_be_added_to_datetimes() {
        let timestamp = Utc::now();
        let data: u64 = random::<u8>().into();
        let duration = Duration::from_secs(data);
        let expected: Field = { timestamp + duration }.into();
        let value1: Field = timestamp.into();
        let value2: Field = duration.into();
        assert_eq!(value1 + value2, expected);
    }

    #[test]
    fn does_datetime_mismatch_return_none() {
        let value1: Field = Utc::now().into();
        let value2: Field = "nope".into();
        assert_eq!(value1 + value2, Field::None);
    }

    #[test]
    fn do_comparason_functions_work() {
        let fields = [Field::Integer(0), Field::Integer(1), Field::Integer(2)];
        assert!(fields[1] == fields[1], "equal did not work");
        assert!(fields[1] < fields[2], "less than did not work");
        assert!(fields[1] <= fields[2], "less than equal to did not work");
        assert!(fields[1] <= fields[1], "less tahn equal 50 did not work");
        assert!(fields[1] > fields[0], "greater than did not work");
        assert!(fields[1] >= fields[0], "greater than equal to did not work");
        assert!(fields[1] >= fields[1], "greater than equal to did not work");
    }

    #[test]
    fn does_mismatched_comparason_fields_return_false() {
        let fields = [Field::Integer(0), Field::Uuid(Uuid::nil())];
        assert!(!(fields[0] == fields[1]), "equal did not work");
        assert!(!(fields[0] < fields[1]), "less than did not work");
        assert!(!(fields[0] <= fields[1]), "less than equal to did not work");
        assert!(!(fields[0] <= fields[1]), "less tahn equal 50 did not work");
        assert!(!(fields[1] > fields[0]), "greater than did not work");
        assert!(
            !(fields[1] >= fields[0]),
            "greater than equal to did not work"
        );
        assert!(
            !(fields[1] >= fields[0]),
            "greater than equal to did not work"
        );
    }
}

#[derive(Clone, Debug, PartialEq)]
pub enum FieldType {
    Boolean,
    DateTime,
    Duration,
    Integer,
    None,
    Revision,
    StaticString,
    Uuid,
}

impl FieldType {
    pub fn get_default(&self) -> Field {
        match self {
            FieldType::Boolean => false.into(),
            FieldType::DateTime => Utc::now().into(),
            FieldType::Duration => Duration::from_secs(0).into(),
            FieldType::Integer => 0.into(),
            FieldType::None => Field::None,
            FieldType::Revision => Revision::new().into(),
            FieldType::StaticString => "".into(),
            FieldType::Uuid => Uuid::new_v4().into(),
        }
    }
}

impl From<&Field> for FieldType {
    fn from(value: &Field) -> Self {
        match value {
            Field::Boolean(_) => Self::Boolean,
            Field::DateTime(_) => Self::DateTime,
            Field::Duration(_) => Self::Duration,
            Field::Integer(_) => Self::Integer,
            Field::None => Self::None,
            Field::Revision(_) => Self::Revision,
            Field::StaticString(_) => Self::StaticString,
            Field::Uuid(_) => Self::Uuid,
        }
    }
}

#[cfg(test)]
mod fieldtypes {
    use super::*;

    #[test]
    fn can_get_defaults_for_uuid() {
        let ftype = FieldType::Uuid;
        let mut ids: Vec<Uuid> = Vec::new();
        for _ in 0..5 {
            let result = ftype.get_default();
            match result {
                Field::Uuid(data) => {
                    assert!(
                        !ids.contains(&data),
                        "found duplicate id {:?} in {:?}",
                        data,
                        ids
                    );
                    ids.push(data.clone());
                }
                _ => unreachable!("got {:?}: should have been uuid", result),
            }
        }
    }

    #[test]
    fn can_get_defaults_for_static_string() {
        let ftype = FieldType::StaticString;
        let result = ftype.get_default();
        match result {
            Field::StaticString(data) => assert_eq!(data, ""),
            _ => unreachable!("got {:?}: should have been static string", result),
        }
    }
}

#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
struct Revision;

impl Revision {
    fn new() -> Self {
        Self {}
    }

    fn revision(&self) -> isize {
        0
    }
}

#[cfg(test)]
mod revisions {
    use super::*;

    #[test]
    fn can_create_empty_revision() {
        let rev = Revision::new();
        assert_eq!(rev.revision(), 0);
    }
}