// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/filters/decrypting_video_decoder.h"

#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/debug/trace_event.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/single_thread_task_runner.h"
#include "media/base/bind_to_current_loop.h"
#include "media/base/decoder_buffer.h"
#include "media/base/decryptor.h"
#include "media/base/pipeline.h"
#include "media/base/video_decoder_config.h"
#include "media/base/video_frame.h"

namespace media {

const char DecryptingVideoDecoder::kDecoderName[] = "DecryptingVideoDecoder";

DecryptingVideoDecoder::DecryptingVideoDecoder(
    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
    const SetDecryptorReadyCB& set_decryptor_ready_cb)
    : task_runner_(task_runner),
      state_(kUninitialized),
      set_decryptor_ready_cb_(set_decryptor_ready_cb),
      decryptor_(NULL),
      key_added_while_decode_pending_(false),
      trace_id_(0),
      weak_factory_(this) {}

std::string DecryptingVideoDecoder::GetDisplayName() const {
  return kDecoderName;
}

void DecryptingVideoDecoder::Initialize(const VideoDecoderConfig& config,
                                        bool /* low_delay */,
                                        const PipelineStatusCB& status_cb,
                                        const OutputCB& output_cb) {
  DVLOG(2) << "Initialize()";
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK(state_ == kUninitialized ||
         state_ == kIdle ||
         state_ == kDecodeFinished) << state_;
  DCHECK(decode_cb_.is_null());
  DCHECK(reset_cb_.is_null());
  DCHECK(config.IsValidConfig());
  DCHECK(config.is_encrypted());

  init_cb_ = BindToCurrentLoop(status_cb);
  output_cb_ = BindToCurrentLoop(output_cb);
  weak_this_ = weak_factory_.GetWeakPtr();
  config_ = config;

  if (state_ == kUninitialized) {
    state_ = kDecryptorRequested;
    set_decryptor_ready_cb_.Run(BindToCurrentLoop(base::Bind(
        &DecryptingVideoDecoder::SetDecryptor, weak_this_)));
    return;
  }

  // Reinitialization.
  decryptor_->DeinitializeDecoder(Decryptor::kVideo);
  state_ = kPendingDecoderInit;
  decryptor_->InitializeVideoDecoder(config, BindToCurrentLoop(base::Bind(
      &DecryptingVideoDecoder::FinishInitialization, weak_this_)));
}

void DecryptingVideoDecoder::Decode(const scoped_refptr<DecoderBuffer>& buffer,
                                    const DecodeCB& decode_cb) {
  DVLOG(3) << "Decode()";
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK(state_ == kIdle ||
         state_ == kDecodeFinished ||
         state_ == kError) << state_;
  DCHECK(!decode_cb.is_null());
  CHECK(decode_cb_.is_null()) << "Overlapping decodes are not supported.";

  decode_cb_ = BindToCurrentLoop(decode_cb);

  if (state_ == kError) {
    base::ResetAndReturn(&decode_cb_).Run(kDecodeError);
    return;
  }

  // Return empty frames if decoding has finished.
  if (state_ == kDecodeFinished) {
    base::ResetAndReturn(&decode_cb_).Run(kOk);
    return;
  }

  pending_buffer_to_decode_ = buffer;
  state_ = kPendingDecode;
  DecodePendingBuffer();
}

void DecryptingVideoDecoder::Reset(const base::Closure& closure) {
  DVLOG(2) << "Reset() - state: " << state_;
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK(state_ == kIdle ||
         state_ == kPendingDecode ||
         state_ == kWaitingForKey ||
         state_ == kDecodeFinished ||
         state_ == kError) << state_;
  DCHECK(init_cb_.is_null());  // No Reset() during pending initialization.
  DCHECK(reset_cb_.is_null());

  reset_cb_ = BindToCurrentLoop(closure);

  decryptor_->ResetDecoder(Decryptor::kVideo);

  // Reset() cannot complete if the decode callback is still pending.
  // Defer the resetting process in this case. The |reset_cb_| will be fired
  // after the decode callback is fired - see DecryptAndDecodeBuffer() and
  // DeliverFrame().
  if (state_ == kPendingDecode) {
    DCHECK(!decode_cb_.is_null());
    return;
  }

  if (state_ == kWaitingForKey) {
    DCHECK(!decode_cb_.is_null());
    pending_buffer_to_decode_ = NULL;
    base::ResetAndReturn(&decode_cb_).Run(kAborted);
  }

  DCHECK(decode_cb_.is_null());
  DoReset();
}

DecryptingVideoDecoder::~DecryptingVideoDecoder() {
  DCHECK(task_runner_->BelongsToCurrentThread());

  if (state_ == kUninitialized)
    return;

  if (decryptor_) {
    decryptor_->DeinitializeDecoder(Decryptor::kVideo);
    decryptor_ = NULL;
  }
  if (!set_decryptor_ready_cb_.is_null())
    base::ResetAndReturn(&set_decryptor_ready_cb_).Run(DecryptorReadyCB());
  pending_buffer_to_decode_ = NULL;
  if (!init_cb_.is_null())
    base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
  if (!decode_cb_.is_null())
    base::ResetAndReturn(&decode_cb_).Run(kAborted);
  if (!reset_cb_.is_null())
    base::ResetAndReturn(&reset_cb_).Run();
}

void DecryptingVideoDecoder::SetDecryptor(
    Decryptor* decryptor,
    const DecryptorAttachedCB& decryptor_attached_cb) {
  DVLOG(2) << "SetDecryptor()";
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK_EQ(state_, kDecryptorRequested) << state_;
  DCHECK(!init_cb_.is_null());
  DCHECK(!set_decryptor_ready_cb_.is_null());
  set_decryptor_ready_cb_.Reset();

  if (!decryptor) {
    base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
    state_ = kError;
    decryptor_attached_cb.Run(false);
    return;
  }

  decryptor_ = decryptor;

  state_ = kPendingDecoderInit;
  decryptor_->InitializeVideoDecoder(
      config_,
      BindToCurrentLoop(base::Bind(
          &DecryptingVideoDecoder::FinishInitialization, weak_this_)));
  decryptor_attached_cb.Run(true);
}

void DecryptingVideoDecoder::FinishInitialization(bool success) {
  DVLOG(2) << "FinishInitialization()";
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK_EQ(state_, kPendingDecoderInit) << state_;
  DCHECK(!init_cb_.is_null());
  DCHECK(reset_cb_.is_null());  // No Reset() before initialization finished.
  DCHECK(decode_cb_.is_null());  // No Decode() before initialization finished.

  if (!success) {
    base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
    decryptor_ = NULL;
    state_ = kError;
    return;
  }

  decryptor_->RegisterNewKeyCB(
      Decryptor::kVideo,
      BindToCurrentLoop(
          base::Bind(&DecryptingVideoDecoder::OnKeyAdded, weak_this_)));

  // Success!
  state_ = kIdle;
  base::ResetAndReturn(&init_cb_).Run(PIPELINE_OK);
}


void DecryptingVideoDecoder::DecodePendingBuffer() {
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK_EQ(state_, kPendingDecode) << state_;
  TRACE_EVENT_ASYNC_BEGIN0(
      "media", "DecryptingVideoDecoder::DecodePendingBuffer", ++trace_id_);

  int buffer_size = 0;
  if (!pending_buffer_to_decode_->end_of_stream()) {
    buffer_size = pending_buffer_to_decode_->data_size();
  }

  decryptor_->DecryptAndDecodeVideo(
      pending_buffer_to_decode_, BindToCurrentLoop(base::Bind(
          &DecryptingVideoDecoder::DeliverFrame, weak_this_, buffer_size)));
}

void DecryptingVideoDecoder::DeliverFrame(
    int buffer_size,
    Decryptor::Status status,
    const scoped_refptr<VideoFrame>& frame) {
  DVLOG(3) << "DeliverFrame() - status: " << status;
  DCHECK(task_runner_->BelongsToCurrentThread());
  DCHECK_EQ(state_, kPendingDecode) << state_;
  DCHECK(!decode_cb_.is_null());
  DCHECK(pending_buffer_to_decode_.get());

  TRACE_EVENT_ASYNC_END2(
      "media", "DecryptingVideoDecoder::DecodePendingBuffer", trace_id_,
      "buffer_size", buffer_size, "status", status);

  bool need_to_try_again_if_nokey_is_returned = key_added_while_decode_pending_;
  key_added_while_decode_pending_ = false;

  scoped_refptr<DecoderBuffer> scoped_pending_buffer_to_decode =
      pending_buffer_to_decode_;
  pending_buffer_to_decode_ = NULL;

  if (!reset_cb_.is_null()) {
    base::ResetAndReturn(&decode_cb_).Run(kAborted);
    DoReset();
    return;
  }

  DCHECK_EQ(status == Decryptor::kSuccess, frame.get() != NULL);

  if (status == Decryptor::kError) {
    DVLOG(2) << "DeliverFrame() - kError";
    state_ = kError;
    base::ResetAndReturn(&decode_cb_).Run(kDecodeError);
    return;
  }

  if (status == Decryptor::kNoKey) {
    DVLOG(2) << "DeliverFrame() - kNoKey";
    // Set |pending_buffer_to_decode_| back as we need to try decoding the
    // pending buffer again when new key is added to the decryptor.
    pending_buffer_to_decode_ = scoped_pending_buffer_to_decode;

    if (need_to_try_again_if_nokey_is_returned) {
      // The |state_| is still kPendingDecode.
      DecodePendingBuffer();
      return;
    }

    state_ = kWaitingForKey;
    return;
  }

  if (status == Decryptor::kNeedMoreData) {
    DVLOG(2) << "DeliverFrame() - kNeedMoreData";
    state_ = scoped_pending_buffer_to_decode->end_of_stream() ? kDecodeFinished
                                                              : kIdle;
    base::ResetAndReturn(&decode_cb_).Run(kOk);
    return;
  }

  DCHECK_EQ(status, Decryptor::kSuccess);
  // No frame returned with kSuccess should be end-of-stream frame.
  DCHECK(!frame->end_of_stream());
  output_cb_.Run(frame);

  if (scoped_pending_buffer_to_decode->end_of_stream()) {
    // Set |pending_buffer_to_decode_| back as we need to keep flushing the
    // decryptor.
    pending_buffer_to_decode_ = scoped_pending_buffer_to_decode;
    DecodePendingBuffer();
    return;
  }

  state_ = kIdle;
  base::ResetAndReturn(&decode_cb_).Run(kOk);
}

void DecryptingVideoDecoder::OnKeyAdded() {
  DVLOG(2) << "OnKeyAdded()";
  DCHECK(task_runner_->BelongsToCurrentThread());

  if (state_ == kPendingDecode) {
    key_added_while_decode_pending_ = true;
    return;
  }

  if (state_ == kWaitingForKey) {
    state_ = kPendingDecode;
    DecodePendingBuffer();
  }
}

void DecryptingVideoDecoder::DoReset() {
  DCHECK(init_cb_.is_null());
  DCHECK(decode_cb_.is_null());
  state_ = kIdle;
  base::ResetAndReturn(&reset_cb_).Run();
}

}  // namespace media