// Copyright 2018 Stefan Kroboth
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

//! # Write parameter vectors somewhere
//!
//! This is very basic and needs much more work. The idea is that parameter vectors are written to
//! disk (or anywhere, essentially) on a regular basis, or on certain events (new best parameter
//! vector found for instance).
//! Several standard implementations should be provided (like writing an image as a PNG) as well as
//! the possibility to implement such a writer for custom types. This will require a bit of
//! thinking.

pub mod file;

use crate::ArgminWrite;
use crate::Error;
use serde::{Deserialize, Serialize};
use std::default::Default;
use std::sync::Arc;

// naming is somewhat inconsistent... maybe ArgminWriteMode ?
#[derive(Copy, Clone, Serialize, Deserialize, Debug, Eq, PartialEq, Ord, PartialOrd)]
pub enum WriterMode {
    Never,
    Always,
    Every(u64),
    NewBest,
}

impl Default for WriterMode {
    fn default() -> WriterMode {
        WriterMode::Always
    }
}

#[derive(Clone, Default)]
pub struct ArgminWriter<T> {
    writers: Vec<Arc<ArgminWrite<Param = T>>>,
}

impl<T> ArgminWriter<T> {
    pub fn new() -> Self {
        ArgminWriter { writers: vec![] }
    }

    pub fn push(&mut self, writer: Arc<ArgminWrite<Param = T>>) -> &mut Self {
        self.writers.push(writer);
        self
    }
}

impl<T: Clone> ArgminWrite for ArgminWriter<T> {
    type Param = T;

    fn write(&self, param: &T, iter: u64, new_best: bool) -> Result<(), Error> {
        for w in self.writers.iter() {
            w.write(param, iter, new_best)?;
        }
        Ok(())
    }
}

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

    send_sync_test!(argmin_write, ArgminWriter<Vec<f64>>);
}