/*
    * Copyright © 2025 rosestack.github.io
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package io.github.rose.security.rest.mfa.provider.impl;
  
  import io.github.rose.core.json.JsonUtils;
  import io.github.rose.security.rest.mfa.config.OtpBasedMfaConfig;
  import io.github.rose.security.rest.mfa.provider.MfaProvider;
  import io.github.rose.security.rest.mfa.provider.OtpBasedMfaProviderConfig;
  import io.github.rose.security.util.SecurityUser;
  import org.apache.commons.lang3.RandomStringUtils;
  import org.springframework.cache.CacheManager;
  import org.springframework.stereotype.Component;
  
  import java.io.Serializable;
  import java.util.concurrent.TimeUnit;
  
  import static io.github.rose.security.CacheConstants.TWO_FA_VERIFICATION_CODE_CACHE;
  
  @Component
  public abstract class OtpBasedMfaProvider<C extends OtpBasedMfaProviderConfig, A extends OtpBasedMfaConfig>
      implements MfaProvider<C, A> {
  
      private final CacheManager cacheManager;
  
      public OtpBasedMfaProvider(CacheManager cacheManager) {
          this.cacheManager = cacheManager;
      }
  
      @Override
      public final void prepareVerificationCode(SecurityUser user, C providerConfig, A twoFaConfig) {
          String verificationCode = RandomStringUtils.randomNumeric(6);
          sendVerificationCode(user, verificationCode, providerConfig, twoFaConfig);
          cacheManager
              .getCache(TWO_FA_VERIFICATION_CODE_CACHE)
              .put(
                  TWO_FA_VERIFICATION_CODE_CACHE + ":" + user.getUsername(),
                  JsonUtils.toBytes(new Otp(System.currentTimeMillis(), verificationCode, twoFaConfig)));
      }
  
      protected abstract void sendVerificationCode(
          SecurityUser user, String verificationCode, C providerConfig, A accountConfig);
  
      @Override
      public final boolean checkVerificationCode(SecurityUser user, String code, C providerConfig, A twoFaConfig) {
          String correctVerificationCode = cacheManager
              .getCache(TWO_FA_VERIFICATION_CODE_CACHE)
              .get(TWO_FA_VERIFICATION_CODE_CACHE + ":" + user.getUsername())
              .toString();
          Otp otp = JsonUtils.fromJson(correctVerificationCode, Otp.class);
          if (correctVerificationCode != null) {
              if (System.currentTimeMillis() - otp.getTimestamp()
                  > TimeUnit.SECONDS.toMillis(providerConfig.getVerificationCodeExpireTime())) {
                  cacheManager
                      .getCache(TWO_FA_VERIFICATION_CODE_CACHE)
                      .evict(TWO_FA_VERIFICATION_CODE_CACHE + ":" + user.getUsername());
                  return false;
              }
              if (code.equals(otp.getValue()) && twoFaConfig.equals(otp.getTwoFaConfig())) {
                  cacheManager
                      .getCache(TWO_FA_VERIFICATION_CODE_CACHE)
                      .evict(TWO_FA_VERIFICATION_CODE_CACHE + ":" + user.getUsername());
                  return true;
              }
          }
          return false;
      }
  
      public static class Otp implements Serializable {
  
          private final long timestamp;
  
          private final String value;
  
          private final OtpBasedMfaConfig twoFaConfig;
  
          public Otp(long timestamp, String value, OtpBasedMfaConfig twoFaConfig) {
              this.timestamp = timestamp;
              this.value = value;
              this.twoFaConfig = twoFaConfig;
          }
  
          public long getTimestamp() {
              return timestamp;
          }
  
          public String getValue() {
             return value;
         }
 
         public OtpBasedMfaConfig getTwoFaConfig() {
             return twoFaConfig;
         }
     }
 }