// Copyright 2022 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

//! This file contains a dummy backend whose only purpose is to let the decoder
//! run so we can test it in isolation.

use std::cell::RefCell;
use std::rc::Rc;

use crate::backend::dummy::decoder::Backend;
use crate::backend::dummy::decoder::Handle;
use crate::codec::h264::dpb::Dpb;
use crate::codec::h264::dpb::DpbEntry;
use crate::codec::h264::parser::Pps;
use crate::codec::h264::parser::Slice;
use crate::codec::h264::parser::SliceHeader;
use crate::codec::h264::parser::Sps;
use crate::codec::h264::picture::PictureData;
use crate::decoder::stateless::h264::StatelessH264DecoderBackend;
use crate::decoder::stateless::h264::H264;
use crate::decoder::stateless::NewPictureResult;
use crate::decoder::stateless::NewStatelessDecoderError;
use crate::decoder::stateless::StatelessBackendResult;
use crate::decoder::stateless::StatelessDecoder;
use crate::decoder::BlockingMode;

impl StatelessH264DecoderBackend for Backend {
    fn new_sequence(&mut self, _: &Rc<Sps>) -> StatelessBackendResult<()> {
        Ok(())
    }

    fn start_picture(
        &mut self,
        _: &mut Self::Picture,
        _: &PictureData,
        _: &Sps,
        _: &Pps,
        _: &Dpb<Self::Handle>,
        _: &SliceHeader,
    ) -> StatelessBackendResult<()> {
        Ok(())
    }

    fn new_field_picture(&mut self, _: u64, _: &Self::Handle) -> NewPictureResult<()> {
        Ok(())
    }

    fn decode_slice(
        &mut self,
        _: &mut Self::Picture,
        _: &Slice,
        _: &Sps,
        _: &Pps,
        _: &[&DpbEntry<Self::Handle>],
        _: &[&DpbEntry<Self::Handle>],
    ) -> StatelessBackendResult<()> {
        Ok(())
    }

    fn submit_picture(&mut self, _: Self::Picture) -> StatelessBackendResult<Self::Handle> {
        Ok(Handle { handle: Rc::new(RefCell::new(Default::default())) })
    }

    fn new_picture(&mut self, _: u64) -> NewPictureResult<()> {
        Ok(())
    }
}

impl StatelessDecoder<H264, Backend> {
    // Creates a new instance of the decoder using the dummy backend.
    pub fn new_dummy(blocking_mode: BlockingMode) -> Result<Self, NewStatelessDecoderError> {
        Self::new(Backend::new(), blocking_mode)
    }
}