// Copyright 2018 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 "ash/assistant/model/assistant_response.h"

#include "ash/assistant/model/assistant_ui_element.h"
#include "base/bind.h"

namespace ash {

// AssistantResponse -----------------------------------------------------------

AssistantResponse::AssistantResponse() = default;

AssistantResponse::~AssistantResponse() = default;

void AssistantResponse::AddUiElement(
    std::unique_ptr<AssistantUiElement> ui_element) {
  ui_elements_.push_back(std::move(ui_element));
}

const std::vector<std::unique_ptr<AssistantUiElement>>&
AssistantResponse::GetUiElements() const {
  return ui_elements_;
}

void AssistantResponse::AddSuggestions(
    std::vector<AssistantSuggestionPtr> suggestions) {
  for (AssistantSuggestionPtr& suggestion : suggestions)
    suggestions_.push_back(std::move(suggestion));
}

const chromeos::assistant::mojom::AssistantSuggestion*
AssistantResponse::GetSuggestionById(int id) const {
  // We consider the index of a suggestion within our backing vector to be its
  // unique identifier.
  DCHECK_GE(id, 0);
  DCHECK_LT(id, static_cast<int>(suggestions_.size()));
  return suggestions_.at(id).get();
}

std::map<int, const chromeos::assistant::mojom::AssistantSuggestion*>
AssistantResponse::GetSuggestions() const {
  std::map<int, const AssistantSuggestion*> suggestions;

  // We use index within our backing vector to represent the unique identifier
  // for a suggestion.
  int id = 0;
  for (const AssistantSuggestionPtr& suggestion : suggestions_)
    suggestions[id++] = suggestion.get();

  return suggestions;
}

void AssistantResponse::Process(
    mojo::Remote<content::mojom::NavigableContentsFactory> contents_factory,
    ProcessingCallback callback) {
  processor_ = std::make_unique<Processor>(*this, std::move(contents_factory),
                                           std::move(callback));
  processor_->Process();
}

// AssistantResponse::Processor ------------------------------------------------

AssistantResponse::Processor::Processor(
    AssistantResponse& response,
    mojo::Remote<content::mojom::NavigableContentsFactory> contents_factory,
    ProcessingCallback callback)
    : response_(response),
      contents_factory_(std::move(contents_factory)),
      callback_(std::move(callback)) {}

AssistantResponse::Processor::~Processor() {
  if (callback_)
    std::move(callback_).Run(/*success=*/false);
}

void AssistantResponse::Processor::Process() {
  // Responses should only be processed once.
  DCHECK_EQ(ProcessingState::kUnprocessed, response_.processing_state());
  response_.set_processing_state(ProcessingState::kProcessing);

  for (const auto& ui_element : response_.GetUiElements()) {
    switch (ui_element->GetType()) {
      case AssistantUiElementType::kCard:
        ++processing_count_;
        // Start asynchronous processing of the card element.
        static_cast<AssistantCardElement*>(ui_element.get())
            ->Process(contents_factory_.get(),
                      base::BindOnce(
                          &AssistantResponse::Processor::OnFinishedProcessing,
                          base::Unretained(this)));
        break;
      case AssistantUiElementType::kText:
        // No processing necessary.
        break;
    }
  }

  // If any elements are processing asynchronously this will no-op.
  TryFinishing();
}

void AssistantResponse::Processor::OnFinishedProcessing(bool success) {
  // We handle success/failure cases the same because failures will skipped in
  // view handling. We decrement our |processing_count_| and attempt to finish
  // response processing. This will no-op if elements are still processing.
  --processing_count_;
  TryFinishing();
}

void AssistantResponse::Processor::TryFinishing() {
  // No-op if we are already finished or if elements are still processing.
  if (!callback_ || processing_count_ > 0)
    return;

  // Notify processing success.
  response_.set_processing_state(ProcessingState::kProcessed);
  std::move(callback_).Run(/*success=*/true);
}

}  // namespace ash