// Copyright 2019-present, the HuggingFace Inc. team, The Google AI Language Team and Facebook, Inc.
// Copyright 2019 Guillaume Becquin
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//     http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

extern crate anyhow;

use std::sync::{Arc, RwLock};

use rust_bert::bart::{
    BartConfigResources, BartMergesResources, BartModelResources, BartVocabResources,
};
use rust_bert::pipelines::common::ModelResource;
use rust_bert::pipelines::summarization::{SummarizationConfig, SummarizationModel};
use rust_bert::resources::{BufferResource, RemoteResource, ResourceProvider};
use tch::Device;

fn main() -> anyhow::Result<()> {
    let input = ["In findings published Tuesday in Cornell University's arXiv by a team of scientists \
from the University of Montreal and a separate report published Wednesday in Nature Astronomy by a team \
from University College London (UCL), the presence of water vapour was confirmed in the atmosphere of K2-18b, \
a planet circling a star in the constellation Leo. This is the first such discovery in a planet in its star's \
habitable zone — not too hot and not too cold for liquid water to exist. The Montreal team, led by Björn Benneke, \
used data from the NASA's Hubble telescope to assess changes in the light coming from K2-18b's star as the planet \
passed between it and Earth. They found that certain wavelengths of light, which are usually absorbed by water, \
weakened when the planet was in the way, indicating not only does K2-18b have an atmosphere, but the atmosphere \
contains water in vapour form. The team from UCL then analyzed the Montreal team's data using their own software \
and confirmed their conclusion. This was not the first time scientists have found signs of water on an exoplanet, \
but previous discoveries were made on planets with high temperatures or other pronounced differences from Earth. \
\"This is the first potentially habitable planet where the temperature is right and where we now know there is water,\" \
said UCL astronomer Angelos Tsiaras. \"It's the best candidate for habitability right now.\" \"It's a good sign\", \
said Ryan Cloutier of the Harvard–Smithsonian Center for Astrophysics, who was not one of either study's authors. \
\"Overall,\" he continued, \"the presence of water in its atmosphere certainly improves the prospect of K2-18b being \
a potentially habitable planet, but further observations will be required to say for sure. \" \
K2-18b was first identified in 2015 by the Kepler space telescope. It is about 110 light-years from Earth and larger \
but less dense. Its star, a red dwarf, is cooler than the Sun, but the planet's orbit is much closer, such that a year \
on K2-18b lasts 33 Earth days. According to The Guardian, astronomers were optimistic that NASA's James Webb space \
telescope — scheduled for launch in 2021 — and the European Space Agency's 2028 ARIEL program, could reveal more \
about exoplanets like K2-18b."];

    let weights = Arc::new(RwLock::new(get_weights()?));
    let summarization_model = SummarizationModel::new(config(Device::Cpu, weights.clone()))?;

    //    Credits: WikiNews, CC BY 2.5 license (https://en.wikinews.org/wiki/Astronomers_find_water_vapour_in_atmosphere_of_exoplanet_K2-18b)
    let output = summarization_model.summarize(&input)?;
    for sentence in output {
        println!("{sentence}");
    }

    let summarization_model =
        SummarizationModel::new(config(Device::cuda_if_available(), weights))?;

    //    Credits: WikiNews, CC BY 2.5 license (https://en.wikinews.org/wiki/Astronomers_find_water_vapour_in_atmosphere_of_exoplanet_K2-18b)
    let output = summarization_model.summarize(&input)?;
    for sentence in output {
        println!("{sentence}");
    }

    Ok(())
}

fn get_weights() -> anyhow::Result<Vec<u8>, anyhow::Error> {
    let model_resource = RemoteResource::from_pretrained(BartModelResources::DISTILBART_CNN_6_6);
    Ok(std::fs::read(model_resource.get_local_path()?)?)
}

fn config(device: Device, model_data: Arc<RwLock<Vec<u8>>>) -> SummarizationConfig {
    let config_resource = Box::new(RemoteResource::from_pretrained(
        BartConfigResources::DISTILBART_CNN_6_6,
    ));
    let vocab_resource = Box::new(RemoteResource::from_pretrained(
        BartVocabResources::DISTILBART_CNN_6_6,
    ));
    let merges_resource = Box::new(RemoteResource::from_pretrained(
        BartMergesResources::DISTILBART_CNN_6_6,
    ));
    let model_resource = ModelResource::Torch(Box::new(BufferResource { data: model_data }));

    SummarizationConfig {
        model_resource,
        config_resource,
        vocab_resource,
        merges_resource: Some(merges_resource),
        num_beams: 1,
        length_penalty: 1.0,
        min_length: 56,
        max_length: Some(142),
        device,
        ..Default::default()
    }
}