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package org.apache.juneau.rest.arg;

import static org.apache.juneau.internal.CollectionUtils.*;
import static org.apache.juneau.common.internal.StringUtils.*;
import static org.apache.juneau.http.annotation.FormDataAnnotation.*;

import java.util.*;

import org.apache.juneau.*;
import org.apache.juneau.annotation.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.http.annotation.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.reflect.*;
import org.apache.juneau.rest.*;
import org.apache.juneau.rest.annotation.*;
import org.apache.juneau.rest.httppart.*;

/**
 * Resolves method parameters and parameter types annotated with {@link FormData} on {@link RestOp}-annotated Java methods.
 *
 * <p>
 * The parameter value is resolved using:
 * <p class='bjava'>
 *    <jv>opSession</jv>
 *       .{@link RestOpSession#getRequest() getRequest}()
 *       .{@link RestRequest#getFormParams() getFormParams}()
 *       .{@link RequestFormParams#get(String) get}(<jv>name</jv>)
 *       .{@link RequestFormParam#as(Class) as}(<jv>type</jv>);
 * </p>
 *
 * <p>
 * {@link HttpPartSchema schema} is derived from the {@link FormData} annotation.
 *
 * <p>
 * If the {@link Schema#collectionFormat()} value is {@link HttpPartCollectionFormat#MULTI}, then the data type can be a {@link Collection} or array.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="../../../../../index.html#jrs.JavaMethodParameters">Java Method Parameters</a>
 * </ul>
 */
public class FormDataArg implements RestOpArg {
   private final boolean multi;
   private final HttpPartParser partParser;
   private final HttpPartSchema schema;
   private final String name, def;
   private final ClassInfo type;

   /**
    * Static creator.
    *
    * @param paramInfo The Java method parameter being resolved.
    * @param annotations The annotations to apply to any new part parsers.
    * @return A new {@link FormDataArg}, or <jk>null</jk> if the parameter is not annotated with {@link FormData}.
    */
   public static FormDataArg create(ParamInfo paramInfo, AnnotationWorkList annotations) {
      if (paramInfo.hasAnnotation(FormData.class) || paramInfo.getParameterType().hasAnnotation(FormData.class))
         return new FormDataArg(paramInfo, annotations);
      return null;
   }

   /**
    * Constructor.
    *
    * @param pi The Java method parameter being resolved.
    * @param annotations The annotations to apply to any new part parsers.
    */
   protected FormDataArg(ParamInfo pi, AnnotationWorkList annotations) {
      this.name = findName(pi).orElseThrow(()->new ArgException(pi, "@FormData used without name or value"));
      this.def = findDef(pi).orElse(null);
      this.type = pi.getParameterType();
      this.schema = HttpPartSchema.create(FormData.class, pi);
      Class<? extends HttpPartParser> pp = schema.getParser();
      this.partParser = pp != null ? HttpPartParser.creator().type(pp).apply(annotations).create() : null;
      this.multi = schema.getCollectionFormat() == HttpPartCollectionFormat.MULTI;

      if (multi && ! type.isCollectionOrArray())
         throw new ArgException(pi, "Use of multipart flag on @FormData parameter that is not an array or Collection");
   }

   @SuppressWarnings({ "rawtypes", "unchecked" })
   @Override /* RestOpArg */
   public Object resolve(RestOpSession opSession) throws Exception {
      RestRequest req = opSession.getRequest();
      HttpPartParserSession ps = partParser == null ? req.getPartParserSession() : partParser.getPartSession();
      RequestFormParams rh = req.getFormParams();
      BeanSession bs = req.getBeanSession();
      ClassMeta<?> cm = bs.getClassMeta(type.innerType());

      if (multi) {
         Collection c = cm.isArray() ? list() : (Collection)(cm.canCreateNewInstance() ? cm.newInstance() : new JsonList());
         rh.getAll(name).stream().map(x -> x.parser(ps).schema(schema).as(cm.getElementType()).orElse(null)).forEach(x -> c.add(x));
         return cm.isArray() ? ArrayUtils.toArray(c, cm.getElementType().getInnerClass()) : c;
      }

      if (cm.isMapOrBean() && isOneOf(name, "*", "")) {
         JsonMap m = new JsonMap();
         rh.forEach(e -> m.put(e.getName(), e.parser(ps).schema(schema == null ? null : schema.getProperty(e.getName())).as(cm.getValueType()).orElse(null)));
         return req.getBeanSession().convertToType(m, cm);
      }

      return rh.getLast(name).parser(ps).schema(schema).def(def).as(type.innerType()).orElse(null);
   }
}