// 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.

#ifndef COMPONENTS_SPELLCHECK_RENDERER_SPELLCHECK_H_
#define COMPONENTS_SPELLCHECK_RENDERER_SPELLCHECK_H_

#include <memory>
#include <set>
#include <string>
#include <vector>

#include "base/files/file.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/strings/string16.h"
#include "components/spellcheck/common/spellcheck.mojom.h"
#include "components/spellcheck/renderer/custom_dictionary_engine.h"
#include "components/spellcheck/spellcheck_buildflags.h"
#include "mojo/public/cpp/bindings/binding_set.h"
#include "services/service_manager/public/cpp/binder_registry.h"

class SpellcheckLanguage;
struct SpellCheckResult;

namespace blink {
class WebTextCheckingCompletion;
struct WebTextCheckingResult;
template <typename T> class WebVector;
class WebString;
}

namespace service_manager {
class LocalInterfaceProvider;
}

class DictionaryUpdateObserver {
 public:
  virtual ~DictionaryUpdateObserver() = default;
  // |words_added| is newly added words to dictionary as correct words.
  // OnDictionaryUpdated should be called even if |words_added| empty.
  virtual void OnDictionaryUpdated(
      const blink::WebVector<blink::WebString>& words_added) = 0;
};

// TODO(morrita): Needs reorg with SpellCheckProvider.
// See http://crbug.com/73699.
// Shared spellchecking logic/data for a RenderProcess. All RenderViews use
// this object to perform spellchecking tasks.
class SpellCheck : public base::SupportsWeakPtr<SpellCheck>,
                   public spellcheck::mojom::SpellChecker {
 public:
  // TODO(groby): I wonder if this can be private, non-mac only.
  class SpellcheckRequest;
  enum ResultFilter {
    DO_NOT_MODIFY = 1,  // Do not modify results.
    USE_NATIVE_CHECKER,  // Use native checker to double-check.
  };

  SpellCheck(service_manager::BinderRegistry* registry,
             service_manager::LocalInterfaceProvider* embedder_provider);
  ~SpellCheck() override;

  void AddSpellcheckLanguage(base::File file, const std::string& language);

  // If there are no dictionary files, then this requests them from the browser
  // and does not block. In this case it returns true.
  // If there are dictionary files, but their Hunspell has not been loaded, then
  // this loads their Hunspell.
  // If each dictionary file's Hunspell is already loaded, this does nothing. In
  // both the latter cases it returns false, meaning that it is OK to continue
  // spellchecking.
  bool InitializeIfNeeded();

  // SpellCheck a word.
  // Returns true if spelled correctly for any language in |languages_|, false
  // otherwise.
  // If any spellcheck languages failed to initialize, always returns true.
  // The |tag| parameter should either be a unique identifier for the document
  // that the word came from (if the current platform requires it), or 0.
  // In addition, finds the suggested words for a given word
  // and puts them into |*optional_suggestions|.
  // If the word is spelled correctly, the vector is empty.
  // If optional_suggestions is NULL, suggested words will not be looked up.
  // Note that doing suggest lookups can be slow.
  bool SpellCheckWord(const base::char16* text_begin,
                      int position_in_text,
                      int text_length,
                      int tag,
                      int* misspelling_start,
                      int* misspelling_len,
                      std::vector<base::string16>* optional_suggestions);

  // SpellCheck a paragraph.
  // Returns true if |text| is correctly spelled, false otherwise.
  // If the spellchecker failed to initialize, always returns true.
  bool SpellCheckParagraph(
      const base::string16& text,
      blink::WebVector<blink::WebTextCheckingResult>* results);

  // Requests to spellcheck the specified text in the background. This function
  // posts a background task and calls SpellCheckParagraph() in the task.
#if !BUILDFLAG(USE_BROWSER_SPELLCHECKER)
  void RequestTextChecking(const base::string16& text,
                           blink::WebTextCheckingCompletion* completion);
#endif

  // Creates a list of WebTextCheckingResult objects (used by WebKit) from a
  // list of SpellCheckResult objects (used by Chrome). This function also
  // checks misspelled words returned by the Spelling service and changes the
  // underline colors of contextually-misspelled words.
  void CreateTextCheckingResults(
      ResultFilter filter,
      int line_offset,
      const base::string16& line_text,
      const std::vector<SpellCheckResult>& spellcheck_results,
      blink::WebVector<blink::WebTextCheckingResult>* textcheck_results);

  bool IsSpellcheckEnabled();

  // Add observer on dictionary update event.
  void AddDictionaryUpdateObserver(DictionaryUpdateObserver* observer);
  // Remove observer on dictionary update event.
  void RemoveDictionaryUpdateObserver(DictionaryUpdateObserver* observer);

 private:
   friend class SpellCheckTest;
   FRIEND_TEST_ALL_PREFIXES(SpellCheckTest, GetAutoCorrectionWord_EN_US);
   FRIEND_TEST_ALL_PREFIXES(SpellCheckTest,
       RequestSpellCheckMultipleTimesWithoutInitialization);

   // Evenly fill |optional_suggestions| with a maximum of |kMaxSuggestions|
   // suggestions from |suggestions_list|. suggestions_list[i][j] is the j-th
   // suggestion from the i-th language's suggestions. |optional_suggestions|
   // cannot be null.
   static void FillSuggestions(
       const std::vector<std::vector<base::string16>>& suggestions_list,
       std::vector<base::string16>* optional_suggestions);

   // Binds requests for the SpellChecker interface.
   void SpellCheckerRequest(spellcheck::mojom::SpellCheckerRequest request);

   // spellcheck::mojom::SpellChecker:
   void Initialize(
       std::vector<spellcheck::mojom::SpellCheckBDictLanguagePtr> dictionaries,
       const std::vector<std::string>& custom_words,
       bool enable) override;
   void CustomDictionaryChanged(
       const std::vector<std::string>& words_added,
       const std::vector<std::string>& words_removed) override;

   // Performs dictionary update notification.
   void NotifyDictionaryObservers(
       const blink::WebVector<blink::WebString>& words_added);

#if !BUILDFLAG(USE_BROWSER_SPELLCHECKER)
  // Posts delayed spellcheck task and clear it if any.
  // Takes ownership of |request|.
  void PostDelayedSpellCheckTask(SpellcheckRequest* request);

  // Performs spell checking from the request queue.
  void PerformSpellCheck(SpellcheckRequest* request);

  // The parameters of a pending background-spellchecking request. When WebKit
  // sends a background-spellchecking request before initializing hunspell,
  // we save its parameters and start spellchecking after we finish initializing
  // hunspell. (When WebKit sends two or more requests, we cancel the previous
  // requests so we do not have to use vectors.)
  std::unique_ptr<SpellcheckRequest> pending_request_param_;
#endif

  // Bindings for SpellChecker clients.
  mojo::BindingSet<spellcheck::mojom::SpellChecker> bindings_;

  // A vector of objects used to actually check spelling, one for each enabled
  // language.
  std::vector<std::unique_ptr<SpellcheckLanguage>> languages_;

  // Custom dictionary spelling engine.
  CustomDictionaryEngine custom_dictionary_;

  service_manager::LocalInterfaceProvider* embedder_provider_;

  // Remember state for spellchecking.
  bool spellcheck_enabled_;

  // Observers of update dictionary events.
  base::ObserverList<DictionaryUpdateObserver> dictionary_update_observers_;

  base::WeakPtrFactory<SpellCheck> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(SpellCheck);
};

#endif  // COMPONENTS_SPELLCHECK_RENDERER_SPELLCHECK_H_