// This file is part of bsv.
//
// bsv is free software: you can redistribute it and/or modify it under the
// terms of the GNU Affero General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// bsv is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for
// more details.
//
// You should have received a copy of the Affero GNU General Public License
// along with bsv.  If not, see <https://www.gnu.org/licenses/>.


use camino::Utf8Path;

use super::err;
use super::error::{Error, Result};
use super::object_id::ObjectId;
use super::object_type::ObjectType;
use super::object_metadata::ObjectMetadata;
use super::pipeline::{Reader, Writer};


// pub struct ObjectIdIterator;


pub trait Cas {
    fn object_id_from_string(&self, hex: &str) -> Result<ObjectId>;

    fn has_object_id(&self, oid: &ObjectId) -> Result<bool>;
    fn iter_object_id<'s>(&'s self) -> Result<Box<dyn 's + Iterator<Item = Result<ObjectId>>>>;

    fn open_object(&self, oid: &ObjectId) -> Result<(ObjectMetadata, Box<dyn Reader>)>;
    fn new_writer(&mut self, otype: &ObjectType, size: u64) -> Result<Box<dyn Writer>>;

    fn read_object(&self, oid: &ObjectId) -> Result<(ObjectMetadata, Vec<u8>)> {
        let (metadata, mut reader) = self.open_object(oid)?;
        let mut data = Vec::new();

        reader.read_to_end(&mut data).or_else(|err|
            err!("failed to read object {}: {}", oid, err))?;

        let result_oid = reader.finalize()?;
        if &result_oid == oid {
            Ok((metadata, data))
        }
        else {
            err!("object id mismatch: requested {}, read {}", oid, result_oid)
        }
    }

    fn write_object(&mut self, otype: &ObjectType, data: &[u8]) -> Result<ObjectId> {
        let mut writer = self.new_writer(otype, data.len() as u64)?;
        writer.write_all(data).or_else(|err|
            err!("failed to write object: {}", err))?;
        writer.finalize()
    }

    fn remove_object(&mut self, oid: &ObjectId) -> Result<()>;
}

pub trait RefStore {
    fn get_ref<P: AsRef<Utf8Path>>(&self, key: P) -> Result<ObjectId>;
    fn set_ref<P: AsRef<Utf8Path>>(&mut self, key: P, value: &ObjectId) -> Result<()>;
    fn remove_ref<P: AsRef<Utf8Path>>(&mut self, key: P) -> Result<()>;
}