use crate::{
    action::Field,
    mtterror::{ErrorID, MTTError},
    name::{Name, NameType, Names},
};
use std::collections::HashMap;
use uuid::Uuid;

#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct Oid {
    oid: Uuid,
}

impl Oid {
    pub fn new() -> Self {
        Self {
            oid: Uuid::new_v4(),
        }
    }
}

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

    #[test]
    fn are_oids_random() {
        let count = 10;
        let mut holder: Vec<Oid> = Vec::new();
        while holder.len() < count {
            let result = Oid::new();
            assert!(!holder.contains(&result));
            holder.push(result);
        }
    }
}

#[derive(Clone, Debug)]
pub struct InternalRecord {
    data: HashMap<Uuid, Field>,
}

impl InternalRecord {
    pub fn new() -> Self {
        Self {
            data: HashMap::new(),
        }
    }

    pub fn insert<F>(&mut self, id: Uuid, data: F) -> Field
    where
        F: Into<Field>,
    {
        match self.data.insert(id, data.into()) {
            Some(data) => data.clone(),
            None => Field::None,
        }
    }

    pub fn get(&self, id: &Uuid) -> Option<&Field> {
        self.data.get(id)
    }

    pub fn is_empty(&self) -> bool {
        self.data.is_empty()
    }
}

#[derive(Clone, Debug)]
pub struct InternalRecords {
    data: HashMap<Oid, InternalRecord>,
}

impl InternalRecords {
    pub fn new() -> Self {
        Self {
            data: HashMap::new(),
        }
    }

    pub fn insert(&mut self, oid: Oid, record: InternalRecord) -> Option<InternalRecord> {
        self.data.insert(oid, record)
    }

    pub fn get(&self, oid: &Oid) -> Option<&InternalRecord> {
        self.data.get(oid)
    }

    pub fn remove(&mut self, oid: &Oid) -> Option<InternalRecord> {
        self.data.remove(oid)
    }

    pub fn iter(&self) -> impl Iterator<Item = (&Oid, &InternalRecord)> {
        self.data.iter()
    }

    pub fn keys(&self) -> impl Iterator<Item = &Oid> {
        self.data.keys()
    }

    pub fn values(&self) -> impl Iterator<Item = &InternalRecord> {
        self.data.values()
    }

    pub fn contains_key(&self, oid: &Oid) -> bool {
        self.data.contains_key(oid)
    }

    pub fn len(&self) -> usize {
        self.data.len()
    }
}

#[derive(Clone, Debug)]
pub struct Record {
    names: Names,
    data: InternalRecord,
}

impl Record {
    pub fn with_data(names: Names, rec: InternalRecord) -> Self {
        Self {
            names: names,
            data: rec,
        }
    }

    pub fn get<NT>(&self, field_id: NT) -> Result<Field, MTTError>
    where
        NT: Into<NameType>,
    {
        let id = match self.names.get_id(field_id) {
            Ok(data) => data,
            Err(err) => return Err(err),
        };
        match self.data.get(&id) {
            Some(data) => Ok(data.clone()),
            None => Err(MTTError::new(NameType::None, ErrorID::FieldMissingData)),
        }
    }
}

#[derive(Clone, Debug)]
pub struct Records {
    names: Names,
    data: InternalRecords,
}

impl Records {
    pub fn new(names: Names) -> Self {
        Self {
            names: names,
            data: InternalRecords::new(),
        }
    }

    pub fn with_data(names: Names, records: InternalRecords) -> Self {
        Self {
            names: names,
            data: records,
        }
    }

    pub fn insert(&mut self, oid: Oid, record: InternalRecord) -> Option<InternalRecord> {
        self.data.insert(oid, record)
    }

    pub fn len(&self) -> usize {
        self.data.len()
    }

    pub fn iter(&self) -> impl Iterator<Item = Record> {
        RecordIter::new(self)
    }

    pub fn get_internal_records(&self) -> &InternalRecords {
        &self.data
    }
}

struct RecordIter {
    names: Names,
    recs: Vec<InternalRecord>,
}

impl RecordIter {
    fn new(records: &Records) -> Self {
        Self {
            names: records.names.clone(),
            recs: records.data.values().cloned().collect(),
        }
    }
}

impl Iterator for RecordIter {
    type Item = Record;

    fn next(&mut self) -> Option<Self::Item> {
        match self.recs.pop() {
            Some(rec) => Some(Record::with_data(self.names.clone(), rec.clone())),
            None => None,
        }
    }
}