// 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 "components/omnibox/browser/autocomplete_provider.h"

#include <algorithm>
#include <set>
#include <string>

#include "base/feature_list.h"
#include "base/i18n/case_conversion.h"
#include "base/logging.h"
#include "base/no_destructor.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/trace_event/memory_usage_estimator.h"
#include "components/bookmarks/browser/bookmark_utils.h"
#include "components/omnibox/browser/autocomplete_i18n.h"
#include "components/omnibox/browser/autocomplete_input.h"
#include "components/omnibox/browser/autocomplete_match.h"
#include "components/omnibox/browser/autocomplete_match_classification.h"
#include "components/omnibox/browser/history_provider.h"
#include "components/omnibox/browser/omnibox_field_trial.h"
#include "components/omnibox/browser/scored_history_match.h"
#include "components/omnibox/common/omnibox_features.h"
#include "components/url_formatter/url_fixer.h"
#include "url/gurl.h"

AutocompleteProvider::AutocompleteProvider(Type type)
    : provider_max_matches_(OmniboxFieldTrial::GetProviderMaxMatches(type)),
      done_(true),
      type_(type) {}

// static
const char* AutocompleteProvider::TypeToString(Type type) {
  switch (type) {
    case TYPE_BOOKMARK:
      return "Bookmark";
    case TYPE_BUILTIN:
      return "Builtin";
    case TYPE_CLIPBOARD:
      return "Clipboard";
    case TYPE_DOCUMENT:
      return "Document";
    case TYPE_HISTORY_QUICK:
      return "HistoryQuick";
    case TYPE_HISTORY_URL:
      return "HistoryURL";
    case TYPE_KEYWORD:
      return "Keyword";
    case TYPE_ON_DEVICE_HEAD:
      return "OnDeviceHead";
    case TYPE_SEARCH:
      return "Search";
    case TYPE_SHORTCUTS:
      return "Shortcuts";
    case TYPE_ZERO_SUGGEST:
      return "ZeroSuggest";
    case TYPE_ZERO_SUGGEST_LOCAL_HISTORY:
      return "LocalHistoryZeroSuggest";
    case TYPE_QUERY_TILE:
      return "QueryTile";
    case TYPE_MOST_VISITED_SITES:
      return "MostVisitedSites";
    case TYPE_VERBATIM_MATCH:
      return "VerbatimMatch";
    case TYPE_VOICE_SUGGEST:
      return "VoiceSuggest";
    default:
      NOTREACHED() << "Unhandled AutocompleteProvider::Type " << type;
      return "Unknown";
  }
}

void AutocompleteProvider::Stop(bool clear_cached_results,
                                bool due_to_user_inactivity) {
  done_ = true;
}

const char* AutocompleteProvider::GetName() const {
  return TypeToString(type_);
}

// static
ACMatchClassifications AutocompleteProvider::ClassifyAllMatchesInString(
    const base::string16& find_text,
    const base::string16& text,
    const bool text_is_search_query,
    const ACMatchClassifications& original_class) {
  // TODO (manukh) Move this function to autocomplete_match_classification
  DCHECK(!find_text.empty());

  if (text.empty())
    return original_class;

  TermMatches term_matches = FindTermMatches(find_text, text);

  ACMatchClassifications classifications;
  if (text_is_search_query) {
    classifications = ClassifyTermMatches(term_matches, text.size(),
                                          ACMatchClassification::NONE,
                                          ACMatchClassification::MATCH);
  } else
    classifications = ClassifyTermMatches(term_matches, text.size(),
                                          ACMatchClassification::MATCH,
                                          ACMatchClassification::NONE);

  return AutocompleteMatch::MergeClassifications(original_class,
                                                 classifications);
}

metrics::OmniboxEventProto_ProviderType AutocompleteProvider::
    AsOmniboxEventProviderType() const {
  switch (type_) {
    case TYPE_BOOKMARK:
      return metrics::OmniboxEventProto::BOOKMARK;
    case TYPE_BUILTIN:
      return metrics::OmniboxEventProto::BUILTIN;
    case TYPE_CLIPBOARD:
      return metrics::OmniboxEventProto::CLIPBOARD;
    case TYPE_DOCUMENT:
      return metrics::OmniboxEventProto::DOCUMENT;
    case TYPE_HISTORY_QUICK:
      return metrics::OmniboxEventProto::HISTORY_QUICK;
    case TYPE_HISTORY_URL:
      return metrics::OmniboxEventProto::HISTORY_URL;
    case TYPE_KEYWORD:
      return metrics::OmniboxEventProto::KEYWORD;
    case TYPE_ON_DEVICE_HEAD:
      return metrics::OmniboxEventProto::ON_DEVICE_HEAD;
    case TYPE_SEARCH:
      return metrics::OmniboxEventProto::SEARCH;
    case TYPE_SHORTCUTS:
      return metrics::OmniboxEventProto::SHORTCUTS;
    case TYPE_ZERO_SUGGEST:
      return metrics::OmniboxEventProto::ZERO_SUGGEST;
    case TYPE_ZERO_SUGGEST_LOCAL_HISTORY:
      return metrics::OmniboxEventProto::ZERO_SUGGEST_LOCAL_HISTORY;
    case TYPE_QUERY_TILE:
      return metrics::OmniboxEventProto::QUERY_TILE;
    case TYPE_MOST_VISITED_SITES:
      return metrics::OmniboxEventProto::ZERO_SUGGEST;
    case TYPE_VERBATIM_MATCH:
      return metrics::OmniboxEventProto::ZERO_SUGGEST;
    case TYPE_VOICE_SUGGEST:
      return metrics::OmniboxEventProto::SEARCH;
    default:
      NOTREACHED() << "Unhandled AutocompleteProvider::Type " << type_;
      return metrics::OmniboxEventProto::UNKNOWN_PROVIDER;
  }
}

void AutocompleteProvider::DeleteMatch(const AutocompleteMatch& match) {
  DLOG(WARNING) << "The AutocompleteProvider '" << GetName()
                << "' has not implemented DeleteMatch.";
}

void AutocompleteProvider::AddProviderInfo(ProvidersInfo* provider_info) const {
}

void AutocompleteProvider::ResetSession() {
}

size_t AutocompleteProvider::EstimateMemoryUsage() const {
  return base::trace_event::EstimateMemoryUsage(matches_);
}

AutocompleteProvider::~AutocompleteProvider() {
  Stop(false, false);
}

// static
AutocompleteProvider::FixupReturn AutocompleteProvider::FixupUserInput(
    const AutocompleteInput& input) {
  const base::string16& input_text = input.text();
  const FixupReturn failed(false, input_text);

  // Fixup and canonicalize user input.
  const GURL canonical_gurl(
      url_formatter::FixupURL(base::UTF16ToUTF8(input_text), std::string()));
  std::string canonical_gurl_str(canonical_gurl.possibly_invalid_spec());
  if (canonical_gurl_str.empty()) {
    // This probably won't happen, but there are no guarantees.
    return failed;
  }

  // If the user types a number, GURL will convert it to a dotted quad.
  // However, if the parser did not mark this as a URL, then the user probably
  // didn't intend this interpretation.  Since this can break history matching
  // for hostname beginning with numbers (e.g. input of "17173" will be matched
  // against "0.0.67.21" instead of the original "17173", failing to find
  // "17173.com"), swap the original hostname in for the fixed-up one.
  if ((input.type() != metrics::OmniboxInputType::URL) &&
      canonical_gurl.HostIsIPAddress()) {
    std::string original_hostname =
        base::UTF16ToUTF8(input_text.substr(input.parts().host.begin,
                                            input.parts().host.len));
    const url::Parsed& parts =
        canonical_gurl.parsed_for_possibly_invalid_spec();
    // parts.host must not be empty when HostIsIPAddress() is true.
    DCHECK(parts.host.is_nonempty());
    canonical_gurl_str.replace(parts.host.begin, parts.host.len,
                               original_hostname);
  }
  base::string16 output(base::UTF8ToUTF16(canonical_gurl_str));
  // Don't prepend a scheme when the user didn't have one.  Since the fixer
  // upper only prepends the "http" scheme, that's all we need to check for.
  if (!AutocompleteInput::HasHTTPScheme(input_text))
    TrimHttpPrefix(&output);

  // Make the number of trailing slashes on the output exactly match the input.
  // Examples of why not doing this would matter:
  // * The user types "a" and has this fixed up to "a/".  Now no other sites
  //   beginning with "a" will match.
  // * The user types "file:" and has this fixed up to "file://".  Now inline
  //   autocomplete will append too few slashes, resulting in e.g. "file:/b..."
  //   instead of "file:///b..."
  // * The user types "http:/" and has this fixed up to "http:".  Now inline
  //   autocomplete will append too many slashes, resulting in e.g.
  //   "http:///c..." instead of "http://c...".
  // NOTE: We do this after calling TrimHttpPrefix() since that can strip
  // trailing slashes (if the scheme is the only thing in the input).  It's not
  // clear that the result of fixup really matters in this case, but there's no
  // harm in making sure.
  const size_t last_input_nonslash =
      input_text.find_last_not_of(base::ASCIIToUTF16("/\\"));
  size_t num_input_slashes =
      (last_input_nonslash == base::string16::npos)
          ? input_text.length()
          : (input_text.length() - 1 - last_input_nonslash);
  // If we appended text, user slashes are irrelevant.
  if (output.length() > input_text.length() &&
      base::StartsWith(output, input_text, base::CompareCase::SENSITIVE))
    num_input_slashes = 0;
  const size_t last_output_nonslash =
      output.find_last_not_of(base::ASCIIToUTF16("/\\"));
  const size_t num_output_slashes =
      (last_output_nonslash == base::string16::npos) ?
      output.length() : (output.length() - 1 - last_output_nonslash);
  if (num_output_slashes < num_input_slashes)
    output.append(num_input_slashes - num_output_slashes, '/');
  else if (num_output_slashes > num_input_slashes)
    output.erase(output.length() - num_output_slashes + num_input_slashes);
  if (output.empty())
    return failed;

  return FixupReturn(true, output);
}

// static
size_t AutocompleteProvider::TrimHttpPrefix(base::string16* url) {
  // Find any "http:".
  if (!AutocompleteInput::HasHTTPScheme(*url))
    return 0;
  size_t scheme_pos =
      url->find(base::ASCIIToUTF16(url::kHttpScheme) + base::char16(':'));
  DCHECK_NE(base::string16::npos, scheme_pos);

  // Erase scheme plus up to two slashes.
  size_t prefix_end = scheme_pos + strlen(url::kHttpScheme) + 1;
  const size_t after_slashes = std::min(url->length(), prefix_end + 2);
  while ((prefix_end < after_slashes) && ((*url)[prefix_end] == '/'))
    ++prefix_end;
  url->erase(scheme_pos, prefix_end - scheme_pos);
  return (scheme_pos == 0) ? prefix_end : 0;
}

// static
bool AutocompleteProvider::InExplicitExperimentalKeywordMode(
    const AutocompleteInput& input,
    const base::string16& keyword) {
  return OmniboxFieldTrial::IsExperimentalKeywordModeEnabled() &&
         input.prefer_keyword() &&
         base::StartsWith(input.text(), keyword,
                          base::CompareCase::SENSITIVE) &&
         IsExplicitlyInKeywordMode(input, keyword);
}

// static
bool AutocompleteProvider::IsExplicitlyInKeywordMode(
    const AutocompleteInput& input,
    const base::string16& keyword) {
  // It is important to this method that we determine if the user entered
  // keyword mode intentionally, as we use this routine to e.g. filter
  // all but keyword results. Currently we assume that the user entered
  // keyword mode intentionally with all entry methods except with a
  // space (and disregard entry method during a backspace). However, if the
  // user has typed a char past the space, we again assume keyword mode.
  return (((input.keyword_mode_entry_method() !=
                metrics::OmniboxEventProto::SPACE_AT_END &&
            input.keyword_mode_entry_method() !=
                metrics::OmniboxEventProto::SPACE_IN_MIDDLE) &&
           !input.prevent_inline_autocomplete()) ||
          input.text().size() > keyword.size() + 1);
}