// Copyright 2014 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 "chrome/browser/autocomplete/keyword_extensions_delegate_impl.h"

#include "base/strings/utf_string_conversions.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/extensions/api/omnibox/omnibox_api.h"
#include "chrome/browser/extensions/extension_service.h"
#include "chrome/browser/extensions/extension_util.h"
#include "chrome/browser/profiles/profile.h"
#include "content/public/browser/notification_details.h"
#include "content/public/browser/notification_source.h"
#include "extensions/browser/extension_system.h"

namespace omnibox_api = extensions::api::omnibox;

int KeywordExtensionsDelegateImpl::global_input_uid_ = 0;

KeywordExtensionsDelegateImpl::KeywordExtensionsDelegateImpl(
    KeywordProvider* provider)
    : KeywordExtensionsDelegate(provider),
      provider_(provider) {
  DCHECK(provider_);

  current_input_id_ = 0;
  // Extension suggestions always come from the original profile, since that's
  // where extensions run. We use the input ID to distinguish whether the
  // suggestions are meant for us.
  registrar_.Add(
      this, chrome::NOTIFICATION_EXTENSION_OMNIBOX_SUGGESTIONS_READY,
      content::Source<Profile>(profile()->GetOriginalProfile()));
  registrar_.Add(
      this, chrome::NOTIFICATION_EXTENSION_OMNIBOX_DEFAULT_SUGGESTION_CHANGED,
      content::Source<Profile>(profile()->GetOriginalProfile()));
  registrar_.Add(
      this, chrome::NOTIFICATION_EXTENSION_OMNIBOX_INPUT_ENTERED,
      content::Source<Profile>(profile()));
}

KeywordExtensionsDelegateImpl::~KeywordExtensionsDelegateImpl() {
}

void  KeywordExtensionsDelegateImpl::IncrementInputId() {
  current_input_id_ = ++global_input_uid_;
}

bool KeywordExtensionsDelegateImpl::IsEnabledExtension(
    Profile* profile,
    const std::string& extension_id) {
  ExtensionService* extension_service =
      extensions::ExtensionSystem::Get(profile)->extension_service();
  const extensions::Extension* extension =
      extension_service->GetExtensionById(extension_id, false);
  return extension &&
      (!profile->IsOffTheRecord() ||
       !extensions::util::IsIncognitoEnabled(extension_id, profile));
}

bool KeywordExtensionsDelegateImpl::Start(
    const AutocompleteInput& input,
    bool minimal_changes,
    const TemplateURL* template_url,
    const base::string16& remaining_input) {
  DCHECK(template_url);

  if (input.want_asynchronous_matches()) {
    std::string extension_id = template_url->GetExtensionId();
    if (extension_id != current_keyword_extension_id_)
      MaybeEndExtensionKeywordMode();
    if (current_keyword_extension_id_.empty())
      EnterExtensionKeywordMode(extension_id);
  }

  extensions::ApplyDefaultSuggestionForExtensionKeyword(
      profile(), template_url, remaining_input, &matches()->front());

  if (minimal_changes) {
    // If the input hasn't significantly changed, we can just use the
    // suggestions from last time. We need to readjust the relevance to
    // ensure it is less than the main match's relevance.
    for (size_t i = 0; i < extension_suggest_matches_.size(); ++i) {
      matches()->push_back(extension_suggest_matches_[i]);
      matches()->back().relevance = matches()->front().relevance - (i + 1);
    }
  } else if (input.want_asynchronous_matches()) {
    extension_suggest_last_input_ = input;
    extension_suggest_matches_.clear();

    // We only have to wait for suggest results if there are actually
    // extensions listening for input changes.
    if (extensions::ExtensionOmniboxEventRouter::OnInputChanged(
            profile(), template_url->GetExtensionId(),
            base::UTF16ToUTF8(remaining_input), current_input_id_))
      set_done(false);
  }
  return input.want_asynchronous_matches();
}

void KeywordExtensionsDelegateImpl::EnterExtensionKeywordMode(
    const std::string& extension_id) {
  DCHECK(current_keyword_extension_id_.empty());
  current_keyword_extension_id_ = extension_id;

  extensions::ExtensionOmniboxEventRouter::OnInputStarted(
      profile(), current_keyword_extension_id_);
}

void KeywordExtensionsDelegateImpl::MaybeEndExtensionKeywordMode() {
  if (!current_keyword_extension_id_.empty()) {
    extensions::ExtensionOmniboxEventRouter::OnInputCancelled(
        profile(), current_keyword_extension_id_);
    current_keyword_extension_id_.clear();
  }
}

void KeywordExtensionsDelegateImpl::Observe(
    int type,
    const content::NotificationSource& source,
    const content::NotificationDetails& details) {
  TemplateURLService* model = provider_->GetTemplateURLService();
  const AutocompleteInput& input = extension_suggest_last_input_;

  switch (type) {
    case chrome::NOTIFICATION_EXTENSION_OMNIBOX_INPUT_ENTERED:
      // Input has been accepted, so we're done with this input session. Ensure
      // we don't send the OnInputCancelled event, or handle any more stray
      // suggestions_ready events.
      current_keyword_extension_id_.clear();
      current_input_id_ = 0;
      return;

    case chrome::NOTIFICATION_EXTENSION_OMNIBOX_DEFAULT_SUGGESTION_CHANGED: {
      // It's possible to change the default suggestion while not in an editing
      // session.
      base::string16 keyword, remaining_input;
      if (matches()->empty() || current_keyword_extension_id_.empty() ||
          !KeywordProvider::ExtractKeywordFromInput(
              input, &keyword, &remaining_input))
        return;

      const TemplateURL* template_url(
          model->GetTemplateURLForKeyword(keyword));
      extensions::ApplyDefaultSuggestionForExtensionKeyword(
          profile(), template_url, remaining_input, &matches()->front());
      OnProviderUpdate(true);
      return;
    }

    case chrome::NOTIFICATION_EXTENSION_OMNIBOX_SUGGESTIONS_READY: {
      const omnibox_api::SendSuggestions::Params& suggestions =
          *content::Details<
              omnibox_api::SendSuggestions::Params>(details).ptr();
      if (suggestions.request_id != current_input_id_)
        return;  // This is an old result. Just ignore.

      base::string16 keyword, remaining_input;
      bool result = KeywordProvider::ExtractKeywordFromInput(
          input, &keyword, &remaining_input);
      DCHECK(result);
      const TemplateURL* template_url =
          model->GetTemplateURLForKeyword(keyword);

      // TODO(mpcomplete): consider clamping the number of suggestions to
      // AutocompleteProvider::kMaxMatches.
      for (size_t i = 0; i < suggestions.suggest_results.size(); ++i) {
        const omnibox_api::SuggestResult& suggestion =
            *suggestions.suggest_results[i];
        // We want to order these suggestions in descending order, so start with
        // the relevance of the first result (added synchronously in Start()),
        // and subtract 1 for each subsequent suggestion from the extension.
        // We recompute the first match's relevance; we know that |complete|
        // is true, because we wouldn't get results from the extension unless
        // the full keyword had been typed.
        int first_relevance = KeywordProvider::CalculateRelevance(
            input.type(), true, true, input.prefer_keyword(),
            input.allow_exact_keyword_match());
        // Because these matches are async, we should never let them become the
        // default match, lest we introduce race conditions in the omnibox user
        // interaction.
        extension_suggest_matches_.push_back(
            provider_->CreateAutocompleteMatch(
                template_url, input, keyword.length(),
                base::UTF8ToUTF16(suggestion.content), false,
                first_relevance - (i + 1)));

        AutocompleteMatch* match = &extension_suggest_matches_.back();
        match->contents.assign(base::UTF8ToUTF16(suggestion.description));
        match->contents_class =
            extensions::StyleTypesToACMatchClassifications(suggestion);
      }

      set_done(true);
      matches()->insert(matches()->end(),
                        extension_suggest_matches_.begin(),
                        extension_suggest_matches_.end());
      OnProviderUpdate(!extension_suggest_matches_.empty());
      return;
    }

    default:
      NOTREACHED();
      return;
  }
}

void KeywordExtensionsDelegateImpl::OnProviderUpdate(bool updated_matches) {
  provider_->listener_->OnProviderUpdate(updated_matches);
}