// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "extensions/browser/guest_view/web_view/web_view_find_helper.h"

#include <memory>
#include <utility>

#include "base/memory/scoped_refptr.h"
#include "components/guest_view/browser/guest_view_event.h"
#include "extensions/browser/guest_view/web_view/web_view_constants.h"
#include "extensions/browser/guest_view/web_view/web_view_guest.h"

using guest_view::GuestViewEvent;

namespace {

// Parameters to callback functions.
const char kFindNumberOfMatches[] = "numberOfMatches";
const char kFindActiveMatchOrdinal[] = "activeMatchOrdinal";
const char kFindSelectionRect[] = "selectionRect";
const char kFindRectLeft[] = "left";
const char kFindRectTop[] = "top";
const char kFindRectWidth[] = "width";
const char kFindRectHeight[] = "height";
const char kFindCanceled[] = "canceled";

}  // anonymous namespace

namespace extensions {

WebViewFindHelper::WebViewFindHelper(WebViewGuest* webview_guest)
    : webview_guest_(webview_guest), current_find_request_id_(0) {
}

WebViewFindHelper::~WebViewFindHelper() {
}

void WebViewFindHelper::CancelAllFindSessions() {
  current_find_session_ = nullptr;
  while (!find_info_map_.empty()) {
    find_info_map_.begin()->second->SendResponse(true /* canceled */);
    find_info_map_.erase(find_info_map_.begin());
  }
  if (find_update_event_)
    DispatchFindUpdateEvent(true /* canceled */, true /* final_update */);
  find_update_event_.reset();
}

void WebViewFindHelper::DispatchFindUpdateEvent(bool canceled,
                                                bool final_update) {
  CHECK(find_update_event_);
  base::DictValue args;
  find_update_event_->PrepareResults(args);
  args.Set(kFindCanceled, canceled);
  args.Set(webview::kFindFinalUpdate, final_update);
  CHECK(webview_guest_);
  webview_guest_->DispatchEventToView(std::make_unique<GuestViewEvent>(
      webview::kEventFindReply, std::move(args)));
}

void WebViewFindHelper::EndFindSession(int session_request_id, bool canceled) {
  auto session_iterator = find_info_map_.find(session_request_id);
  CHECK(session_iterator != find_info_map_.end());
  FindInfo* find_info = session_iterator->second.get();

  // Call the callback function of the first request of the find session.
  find_info->SendResponse(canceled);

  // For every subsequent find request of the find session.
  for (auto i = find_info->find_next_requests_.begin();
       i != find_info->find_next_requests_.end(); ++i) {
    DCHECK(i->get());

    // Do not call callbacks for subsequent find requests that have not been
    // replied to yet. These requests will get their own final updates in the
    // same order as they appear in |find_next_requests_|, i.e. the order that
    // the requests were made in. Once one request is found that has not been
    // replied to, none that follow will be replied to either, and do not need
    // to be checked.
    if (!(*i)->replied_)
      break;

    // Update the request's number of matches (if not canceled).
    if (!canceled) {
      (*i)->find_results_.number_of_matches_ =
          find_info->find_results_.number_of_matches_;
    }

    // Call the request's callback function with the find results, and then
    // delete its map entry to free the WebViewInternalFindFunction object.
    (*i)->SendResponse(canceled);
    find_info_map_.erase((*i)->request_id_);
  }

  // Erase the first find request's map entry to free the
  // WebViewInternalFindFunction
  // object.
  find_info_map_.erase(session_request_id);
}

void WebViewFindHelper::Find(content::WebContents* guest_web_contents,
                             const std::u16string& search_text,
                             blink::mojom::FindOptionsPtr options,
                             ForwardResponseCallback callback) {
  // Need a new request_id for each new find request.
  ++current_find_request_id_;

  if (current_find_session_) {
    const std::u16string& current_search_text =
        current_find_session_->search_text();
    bool current_match_case = current_find_session_->options()->match_case;
    options->new_session = current_search_text.empty() ||
                           current_search_text != search_text ||
                           current_match_case != options->match_case;
  } else {
    options->new_session = true;
  }

  // Stores the find request information by request_id so that its callback
  // function can be called when the find results are available.
  std::pair<FindInfoMap::iterator, bool> insert_result =
      find_info_map_.insert(std::make_pair(
          current_find_request_id_, base::MakeRefCounted<FindInfo>(
                                        current_find_request_id_, search_text,
                                        options.Clone(), std::move(callback))));
  // No duplicate insertions.
  CHECK(insert_result.second);

  // Link find requests that are a part of the same find session.
  if (!options->new_session && current_find_session_) {
    CHECK(current_find_request_id_ != current_find_session_->request_id());
    current_find_session_->AddFindNextRequest(
        insert_result.first->second->AsWeakPtr());
  }

  // Update the current find session, if necessary.
  if (options->new_session) {
    current_find_session_ = insert_result.first->second;
  }

  // Handle the empty |search_text| case internally.
  if (search_text.empty()) {
    guest_web_contents->StopFinding(content::STOP_FIND_ACTION_CLEAR_SELECTION);
    FindReply(current_find_request_id_, 0, gfx::Rect(), 0, true);
    return;
  }

  guest_web_contents->Find(current_find_request_id_, search_text,
                           std::move(options), /*skip_delay=*/true);
}

void WebViewFindHelper::FindReply(int request_id,
                                  int number_of_matches,
                                  const gfx::Rect& selection_rect,
                                  int active_match_ordinal,
                                  bool final_update) {
  auto find_iterator = find_info_map_.find(request_id);

  // Ignore slow replies to canceled find requests.
  if (find_iterator == find_info_map_.end())
    return;

  // This find request must be a part of an existing find session.
  CHECK(current_find_session_);

  WebViewFindHelper::FindInfo* find_info = find_iterator->second.get();
  // Handle canceled find requests.
  if (find_info->options()->new_session &&
      find_info_map_.begin()->first < request_id) {
    CHECK_NE(current_find_session_->request_id(),
             find_info_map_.begin()->first);
    if (find_update_event_)
      DispatchFindUpdateEvent(true /* canceled */, true /* final_update */);
    EndFindSession(find_info_map_.begin()->first, true /* canceled */);
  }

  // Clears the results for |findupdate| for a new find session.
  if (!find_info->replied() && find_info->options()->new_session) {
    find_update_event_ =
        std::make_unique<FindUpdateEvent>(find_info->search_text());
  }

  // Aggregate the find results.
  find_info->AggregateResults(number_of_matches, selection_rect,
                              active_match_ordinal, final_update);
  if (find_update_event_) {
    find_update_event_->AggregateResults(number_of_matches, selection_rect,
                                         active_match_ordinal, final_update);
    // Propagate incremental results to the |findupdate| event.
    DispatchFindUpdateEvent(false /* canceled */, final_update);
  }

  // Call the callback functions of completed find requests.
  if (final_update)
    EndFindSession(request_id, false /* canceled */);
}

WebViewFindHelper::FindResults::FindResults()
    : number_of_matches_(0), active_match_ordinal_(0) {
}

WebViewFindHelper::FindResults::~FindResults() {
}

void WebViewFindHelper::FindResults::AggregateResults(
    int number_of_matches,
    const gfx::Rect& selection_rect,
    int active_match_ordinal,
    bool final_update) {
  if (number_of_matches != -1)
    number_of_matches_ = number_of_matches;

  if (active_match_ordinal != -1)
    active_match_ordinal_ = active_match_ordinal;

  if (final_update && active_match_ordinal_ == 0) {
    // No match found, so the selection rectangle is empty.
    selection_rect_ = gfx::Rect();
  } else if (!selection_rect.IsEmpty()) {
    selection_rect_ = selection_rect;
  }
}

void WebViewFindHelper::FindResults::PrepareResults(base::DictValue& results) {
  results.Set(kFindNumberOfMatches, number_of_matches_);
  results.Set(kFindActiveMatchOrdinal, active_match_ordinal_);
  base::DictValue rect;
  rect.Set(kFindRectLeft, selection_rect_.x());
  rect.Set(kFindRectTop, selection_rect_.y());
  rect.Set(kFindRectWidth, selection_rect_.width());
  rect.Set(kFindRectHeight, selection_rect_.height());
  results.Set(kFindSelectionRect, std::move(rect));
}

WebViewFindHelper::FindUpdateEvent::FindUpdateEvent(
    const std::u16string& search_text)
    : search_text_(search_text) {}

WebViewFindHelper::FindUpdateEvent::~FindUpdateEvent() {
}

void WebViewFindHelper::FindUpdateEvent::AggregateResults(
    int number_of_matches,
    const gfx::Rect& selection_rect,
    int active_match_ordinal,
    bool final_update) {
  find_results_.AggregateResults(number_of_matches, selection_rect,
                                 active_match_ordinal, final_update);
}

void WebViewFindHelper::FindUpdateEvent::PrepareResults(
    base::DictValue& results) {
  results.Set(webview::kFindSearchText, search_text_);
  find_results_.PrepareResults(results);
}

WebViewFindHelper::FindInfo::FindInfo(int request_id,
                                      const std::u16string& search_text,
                                      blink::mojom::FindOptionsPtr options,
                                      ForwardResponseCallback callback)
    : request_id_(request_id),
      search_text_(search_text),
      options_(std::move(options)),
      callback_(std::move(callback)),
      replied_(false) {}

void WebViewFindHelper::FindInfo::AggregateResults(
    int number_of_matches,
    const gfx::Rect& selection_rect,
    int active_match_ordinal,
    bool final_update) {
  replied_ = true;
  find_results_.AggregateResults(number_of_matches, selection_rect,
                                 active_match_ordinal, final_update);
}

base::WeakPtr<WebViewFindHelper::FindInfo>
WebViewFindHelper::FindInfo::AsWeakPtr() {
  return weak_ptr_factory_.GetWeakPtr();
}

void WebViewFindHelper::FindInfo::SendResponse(bool canceled) {
  // Prepare the find results to pass to the callback function.
  base::DictValue results;
  find_results_.PrepareResults(results);
  results.Set(kFindCanceled, canceled);

  // Call the callback.
  std::move(callback_).Run(std::move(results));
}

WebViewFindHelper::FindInfo::~FindInfo() = default;

}  // namespace extensions