use crate::mtterror::{ErrorID, MTTError};
use isolang::Language;
use std::{collections::HashMap, fmt};
use uuid::Uuid;

#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub enum NameType {
    ID(Uuid),
    Name(Name),
    None,
}

impl From<&NameType> for NameType {
    fn from(value: &NameType) -> Self {
        value.clone()
    }
}

impl From<Name> for NameType {
    fn from(value: Name) -> Self {
        Self::Name(value)
    }
}

impl From<&Name> for NameType {
    fn from(value: &Name) -> Self {
        let name = value.clone();
        Self::from(name)
    }
}

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

impl From<&Uuid> for NameType {
    fn from(value: &Uuid) -> Self {
        let id = value.clone();
        Self::from(id)
    }
}

#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct Name {
    name: String,
    lang: Language,
}

impl Name {
    fn new(name: &str, lang: Language) -> Self {
        Self {
            name: name.to_lowercase(),
            lang: lang,
        }
    }

    fn get_language(&self) -> &Language {
        &self.lang
    }

    pub fn english(name: &str) -> Self {
        Self::new(name, Language::from_639_1("en").unwrap())
    }

    pub fn japanese(name: &str) -> Self {
        Self::new(name, Language::from_639_1("ja").unwrap())
    }
}

impl fmt::Display for Name {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.name)
    }
}

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

    pub fn random_name() -> Name {
        Name::english(Uuid::new_v4().to_string().as_str())
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct Names {
    names: HashMap<Name, Uuid>,
    ids: HashMap<Uuid, HashMap<Language, Name>>,
}

impl Names {
    pub fn new() -> Self {
        Self {
            names: HashMap::new(),
            ids: HashMap::new(),
        }
    }

    pub fn add_names(&mut self, names: Vec<Name>) -> Result<Uuid, MTTError> {
        let mut languages: Vec<&Language> = Vec::new();
        for name in names.iter() {
            let lang = name.get_language();
            if languages.contains(&lang) {
                let err = MTTError::new(ErrorID::NameLanguageNotUnique);
                return Err(err);
            } else {
                languages.push(lang);
            }
            if self.names.contains_key(&name) {
                let err = MTTError::new(ErrorID::NameAlreadyExists);
                return Err(err);
            }
        }
        let mut id = Uuid::new_v4();
        while self.ids.contains_key(&id) {
            id = Uuid::new_v4();
        }
        for name in names.iter() {
            self.names.insert(name.clone(), id.clone());
            let mut holder: HashMap<Language, Name> = HashMap::new();
            holder.insert(name.get_language().clone(), name.clone());
            self.ids.insert(id.clone(), holder);
        }
        Ok(id)
    }

    pub fn get_id<NT>(&self, name: NT) -> Result<Uuid, MTTError>
    where
        NT: Into<NameType>,
    {
        let name_type = name.into();
        match name_type.clone() {
            NameType::Name(data) => match self.names.get(&data) {
                Some(id) => Ok(id.clone()),
                None => Err(MTTError::new(ErrorID::NameNotFound(name_type))),
            },
            NameType::ID(data) => {
                if self.ids.contains_key(&data) {
                    Ok(data)
                } else {
                    if data == Uuid::nil() {
                        Ok(data)
                    } else {
                        Err(MTTError::new(ErrorID::NameNotFound(name_type)))
                    }
                }
            }
            NameType::None => Ok(Uuid::nil()),
        }
    }
}

#[cfg(test)]
mod names {
    use super::*;
    use std::collections::HashSet;

    #[test]
    fn are_names_lowercase() {
        let name1 = Name::new("session", Language::from_639_1("en").unwrap());
        let name2 = Name::new("Session", Language::from_639_1("en").unwrap());
        let name3 = Name::english("SESSION");
        assert_eq!(name1.to_string(), "session".to_string());
        assert_eq!(name1, name2);
        assert_eq!(name1, name3);
    }

    #[test]
    fn does_new_id_match_retrieval_id() {
        let name = Name::english("tester");
        let mut names = Names::new();
        let id = names.add_names(vec![name.clone()]).unwrap();
        assert_eq!(names.get_id(name).unwrap(), id);
        assert_eq!(names.get_id(id).unwrap(), id);
    }

    #[test]
    fn multiple_languages_can_stored_on_same_id() {
        let english = Name::english("tester");
        let japanese = Name::japanese("テスト");
        let mut names = Names::new();
        let id = names
            .add_names(vec![english.clone(), japanese.clone()])
            .unwrap();
        assert_eq!(names.get_id(english).unwrap(), id);
        assert_eq!(names.get_id(japanese).unwrap(), id);
    }

    #[test]
    fn are_name_ids_unique() {
        let mut names = Names::new();
        let data = ["one", "two", "three", "four", "five"];
        let mut ids: HashSet<Uuid> = HashSet::new();
        for item in data.iter() {
            let name = Name::english(item);
            ids.insert(names.add_names([name].to_vec()).unwrap());
        }
        assert_eq!(ids.len(), data.len());
    }

    #[test]
    fn errors_on_duplicates() {
        let name = Name::english("duplicate");
        let mut names = Names::new();
        names.add_names(vec![name.clone()]).unwrap();
        match names.add_names(vec![name.clone()]) {
            Ok(data) => unreachable!("got {:?}, should have been duplicate error", data),
            Err(err) => match err.get_error_ids().back().unwrap() {
                ErrorID::NameAlreadyExists => {}
                _ => unreachable!("got {:?}, should have been duplicate error", err),
            },
        }
    }

    #[test]
    fn errors_if_same_language_is_used() {
        let name1 = Name::english("test");
        let name2 = Name::japanese("テスト");
        let name3 = Name::english("tester");
        let mut names = Names::new();
        match names.add_names(vec![name1, name2, name3.clone()]) {
            Ok(data) => unreachable!("got {:?}, should have been needs to be unique", data),
            Err(err) => match err.get_error_ids().back().unwrap() {
                ErrorID::NameLanguageNotUnique => {}
                _ => unreachable!("got {:?}, should have been name needs to be unique", err),
            },
        }
    }

    #[test]
    fn errors_on_bad_name() {
        let name = Name::english(Uuid::new_v4().to_string().as_str());
        let expected: NameType = name.clone().into();
        let names = Names::new();
        match names.get_id(name.clone()) {
            Ok(data) => unreachable!("got {:?}, should have been missing error", data),
            Err(err) => match err.get_error_ids().back().unwrap() {
                ErrorID::NameNotFound(data) => assert_eq!(data, &expected),
                _ => unreachable!("got {:?}, should have been missing error", err),
            },
        }
    }

    #[test]
    fn errors_on_bad_id() {
        let id = Uuid::new_v4();
        let expected: NameType = id.clone().into();
        let names = Names::new();
        match names.get_id(id.clone()) {
            Ok(data) => unreachable!("got {:?}, should have been missing error", data),
            Err(err) => match err.get_error_ids().back().unwrap() {
                ErrorID::NameNotFound(data) => assert_eq!(data, &expected),
                _ => unreachable!("got {:?}, should have been missing error", err),
            },
        }
    }
}