/*
    * Copyright 2019-2020 the original author or authors.
    *
    * 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 org.bremersee.web;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.stream.Collectors;
  import javax.validation.constraints.NotEmpty;
  import javax.validation.constraints.NotNull;
  import lombok.EqualsAndHashCode;
  import lombok.Getter;
  import lombok.Setter;
  import lombok.ToString;
  import org.springframework.boot.context.properties.ConfigurationProperties;
  import org.springframework.util.StringUtils;
  import org.springframework.validation.annotation.Validated;
  
  /**
   * The cors properties.
   *
   * @author Christian Bremer
   */
  @ConfigurationProperties(prefix = "bremersee.cors")
  @Setter
  @ToString
  @EqualsAndHashCode
  @Validated
  public class CorsProperties {
  
    @Getter
    private boolean enable = true;
  
    @Getter
    private boolean allowAll = true;
  
    @NotNull
    private List<CorsConfiguration> configs = new ArrayList<>();
  
    /**
     * Allow all configuration.
     *
     * @return the allow all configuration
     */
    @NotEmpty
    public static List<CorsConfiguration> allowAllConfiguration() {
      return Collections
          .singletonList(CorsConfiguration.allowAllConfiguration());
    }
  
    /**
     * Gets configs.
     *
     * @return the configs
     */
    @NotNull
    public List<CorsConfiguration> getConfigs() {
      if (configs == null) {
        configs = new ArrayList<>();
      }
      if (enable && allowAll && configs.isEmpty()) {
        return allowAllConfiguration();
      }
      return configs.stream()
          .filter(config -> StringUtils.hasText(config.getPathPattern()))
          .collect(Collectors.toList());
    }
  
    /**
     * The cors configuration.
     */
    @Setter
    @ToString
    @EqualsAndHashCode
    @Validated
    public static class CorsConfiguration {
  
      @Getter
      private String pathPattern;
  
      private List<String> allowedOrigins = new ArrayList<>();
  
      private List<String> allowedMethods = new ArrayList<>();
  
      private List<String> allowedHeaders = new ArrayList<>();
 
     @Getter
     @NotNull
     private List<String> exposedHeaders = new ArrayList<>();
 
     @Getter
     private boolean allowCredentials;
 
     @Getter
     private long maxAge = 1800L;
 
     /**
      * Allow all configuration.
      *
      * @return the allow all configuration
      */
     static CorsConfiguration allowAllConfiguration() {
       CorsConfiguration configuration = new CorsConfiguration();
       configuration.pathPattern = "/**";
       configuration.allowedOrigins = Collections.singletonList("*");
       configuration.allowedMethods = Collections.singletonList("*");
       configuration.allowedHeaders = Collections.singletonList("*");
       configuration.allowCredentials = false;
       return configuration;
     }
 
     /**
      * Gets allowed origins.
      *
      * @return the allowed origins
      */
     @NotEmpty
     public List<String> getAllowedOrigins() {
       if (allowedOrigins == null) {
         allowedOrigins = new ArrayList<>();
       }
       if (allowedOrigins.isEmpty()) {
         allowedOrigins.add("*");
       }
       return allowedOrigins;
     }
 
     /**
      * Gets allowed methods.
      *
      * @return the allowed methods
      */
     @NotEmpty
     public List<String> getAllowedMethods() {
       if (allowedMethods == null) {
         allowedMethods = new ArrayList<>();
       }
       if (allowedMethods.isEmpty()) {
         allowedMethods.add("*");
       }
       return allowedMethods;
     }
 
     /**
      * Gets allowed headers.
      *
      * @return the allowed headers
      */
     @NotEmpty
     public List<String> getAllowedHeaders() {
       if (allowedHeaders == null) {
         allowedHeaders = new ArrayList<>();
       }
       if (allowedHeaders.isEmpty()) {
         allowedHeaders.add("*");
       }
       return allowedHeaders;
     }
   }
 }