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// Simple word patterns matcher which will be used in composer objects
// for auto swtiching input mode.

#include "composer/internal/mode_switching_handler.h"

#include <cctype>
#include <string>

#include "base/logging.h"
#include "base/singleton.h"

namespace mozc {
namespace composer {

ModeSwitchingHandler::ModeSwitchingHandler() {
  // Default patterns are fixed right now.
  // AddRule(key, display_mode, input_mode);
  AddRule("google", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("Google", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("Chrome", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("chrome", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("Android", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("android", PREFERRED_ALPHANUMERIC, REVERT_TO_PREVIOUS_MODE);
  AddRule("http", HALF_ALPHANUMERIC, HALF_ALPHANUMERIC);
  AddRule("www.", HALF_ALPHANUMERIC, HALF_ALPHANUMERIC);
  AddRule("\\\\", HALF_ALPHANUMERIC, HALF_ALPHANUMERIC);
}

ModeSwitchingHandler::~ModeSwitchingHandler() {}

bool ModeSwitchingHandler::GetModeSwitchingRule(
    const std::string &key, ModeSwitching *display_mode,
    ModeSwitching *input_mode) const {
  if (display_mode == nullptr || input_mode == nullptr) {
    LOG(ERROR) << "display_mode/input_mode is nullptr.";
    return false;
  }

  auto it = patterns_.find(key);
  if (it != patterns_.end()) {
    *display_mode = it->second.first;
    *input_mode = it->second.second;
    return true;
  }

  if (IsDriveLetter(key)) {
    *display_mode = HALF_ALPHANUMERIC;
    *input_mode = HALF_ALPHANUMERIC;
    return true;
  }

  *display_mode = NO_CHANGE;
  *input_mode = NO_CHANGE;
  return false;
}

bool ModeSwitchingHandler::IsDriveLetter(const std::string &key) {
  return key.size() == 3 && isalpha(key[0]) && key[1] == ':' && key[2] == '\\';
}

void ModeSwitchingHandler::AddRule(const std::string &key,
                                   const ModeSwitching display_mode,
                                   const ModeSwitching input_mode) {
  patterns_.emplace(key, std::make_pair(display_mode, input_mode));
}

ModeSwitchingHandler *ModeSwitchingHandler::GetModeSwitchingHandler() {
  return Singleton<ModeSwitchingHandler>::get();
}

}  // namespace composer
}  // namespace mozc
