/*
 * Copyright (c) 2010, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.server.model;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;
import java.util.stream.Collectors;

import javax.ws.rs.NameBinding;
import javax.ws.rs.container.AsyncResponse;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.core.MediaType;

import org.glassfish.jersey.message.internal.MediaTypes;
import org.glassfish.jersey.model.NameBound;
import org.glassfish.jersey.process.Inflector;
import org.glassfish.jersey.uri.PathPattern;

/**
 * Model of a method available on a resource. Covers resource method, sub-resource
 * method and sub-resource locator.
 *
 * @author Marek Potociar
 */
public final class ResourceMethod implements ResourceModelComponent, Producing, Consuming, Suspendable, NameBound {

    /**
     * Resource method classification based on the recognized JAX-RS
     * resource method types.
     */
    public static enum JaxrsType {
        /**
         * JAX-RS resource method.
         * <p/>
         * Does not have a path template assigned. Is assigned to a particular HTTP method.
         */
        RESOURCE_METHOD {
            @Override
            PathPattern createPatternFor(String pathTemplate) {
                // template is ignored.
                return PathPattern.END_OF_PATH_PATTERN;
            }
        },
        /**
         * JAX-RS sub-resource method.
         * <p/>
         * Has a sub-path template assigned and is assigned to a particular HTTP method.
         */
        SUB_RESOURCE_METHOD {
            @Override
            PathPattern createPatternFor(String pathTemplate) {
                return new PathPattern(pathTemplate, PathPattern.RightHandPath.capturingZeroSegments);
            }
        },
        /**
         * JAX-RS sub-resource locator.
         * <p/>
         * Has a sub-path template assigned but is not assigned to any particular HTTP method.
         * Instead it produces a sub-resource instance that should be further
         * used in the request URI matching.
         */
        SUB_RESOURCE_LOCATOR {
            @Override
            PathPattern createPatternFor(String pathTemplate) {
                return new PathPattern(pathTemplate, PathPattern.RightHandPath.capturingZeroOrMoreSegments);
            }
        };

        /**
         * Create a proper matching path pattern from the provided template for
         * the selected method type.
         *
         * @param pathTemplate method path template.
         * @return method matching path pattern.
         */
        /* package */
        abstract PathPattern createPatternFor(String pathTemplate);

        private static JaxrsType classify(String httpMethod) {
            if (httpMethod != null && !httpMethod.isEmpty()) {
                return RESOURCE_METHOD;
            } else {
                return SUB_RESOURCE_LOCATOR;
            }
        }
    }

    /**
     * Resource method model builder.
     */
    public static final class Builder {

        private final Resource.Builder parent;

        // HttpMethod
        private String httpMethod;
        // Consuming & Producing
        private final Set<MediaType> consumedTypes;
        private final Set<MediaType> producedTypes;
        // Suspendable
        private boolean managedAsync;
        private boolean sse;
        private boolean suspended;
        private long suspendTimeout;
        private TimeUnit suspendTimeoutUnit;
        // Invocable
        private Class<?> handlerClass;
        private Object handlerInstance;
        private final Collection<Parameter> handlerParameters;

        // method (can be also interface method). Specific method to execute is defined by handlingMethod
        private Method definitionMethod;

        // this can be either equal to definitionMethod or child of definitionMethod
        private Method handlingMethod;
        private boolean encodedParams;
        private Type routingResponseType;
        // NameBound
        private final Collection<Class<? extends Annotation>> nameBindings;
        private boolean extended;

        /**
         * Create a resource method builder.
         * <p>
         * The supplied parent resource model builder will be called to register
         * the newly created resource method instance as part of the {@link #build()}
         * method invocation.
         * </p>
         * <p>
         * Note that the {@link #build()} method does not have to be invoked manually
         * as the registration will happen automatically as part of the
         * {@link org.glassfish.jersey.server.model.Resource.Builder#build()} method
         * invocation.
         * </p>
         *
         * @param parent parent resource model builder.
         */
        /* package */ Builder(final Resource.Builder parent) {
            this.parent = parent;

            this.httpMethod = null;

            this.consumedTypes = new LinkedHashSet<>();
            this.producedTypes = new LinkedHashSet<>();
            this.suspended = false;
            this.suspendTimeout = AsyncResponse.NO_TIMEOUT;
            this.suspendTimeoutUnit = TimeUnit.MILLISECONDS;

            this.handlerParameters = new LinkedList<>();

            this.encodedParams = false;

            this.nameBindings = new LinkedHashSet<>();
        }

        /**
         * Create a builder from an existing resource method model.
         *
         * @param parent         parent resource model builder.
         * @param originalMethod existing resource method model to create the builder from.
         */
        /* package */ Builder(final Resource.Builder parent, ResourceMethod originalMethod) {
            this.parent = parent;
            this.consumedTypes = new LinkedHashSet<>(originalMethod.getConsumedTypes());
            this.producedTypes = new LinkedHashSet<>(originalMethod.getProducedTypes());
            this.suspended = originalMethod.isSuspendDeclared();
            this.suspendTimeout = originalMethod.getSuspendTimeout();
            this.suspendTimeoutUnit = originalMethod.getSuspendTimeoutUnit();
            this.handlerParameters = new LinkedHashSet<>(originalMethod.getInvocable().getHandler().getParameters());
            this.nameBindings = originalMethod.getNameBindings();
            this.httpMethod = originalMethod.getHttpMethod();
            this.managedAsync = originalMethod.isManagedAsyncDeclared();

            Invocable invocable = originalMethod.getInvocable();
            this.handlingMethod = invocable.getHandlingMethod();
            this.encodedParams = false;
            this.routingResponseType = invocable.getRoutingResponseType();
            this.extended = originalMethod.isExtended();
            Method handlerMethod = invocable.getDefinitionMethod();
            MethodHandler handler = invocable.getHandler();
            if (handler.isClassBased()) {
                handledBy(handler.getHandlerClass(), handlerMethod);
            } else {
                handledBy(handler.getHandlerInstance(), handlerMethod);
            }
        }

        /**
         * Set the associated HTTP method name.
         *
         * @param name HTTP method name.
         * @return updated builder object.
         */
        public Builder httpMethod(String name) {
            this.httpMethod = name;
            return this;
        }

        /**
         * Add produced media types supported by the component.
         *
         * @param types produced media types.
         * @return updated builder object.
         */
        public Builder produces(String... types) {
            return produces(MediaTypes.createFrom(types));
        }

        /**
         * Add produced media types supported by the component.
         *
         * @param types produced media types.
         * @return updated builder object.
         */
        public Builder produces(MediaType... types) {
            return produces(Arrays.asList(types));
        }

        /**
         * Add produced media types supported by the component.
         *
         * @param types produced media types.
         * @return updated builder object.
         */
        public Builder produces(Collection<MediaType> types) {
            this.producedTypes.addAll(types);
            return this;
        }

        /**
         * Add consumed media types supported by the component.
         *
         * @param types consumed media types.
         * @return updated builder object.
         */
        public Builder consumes(String... types) {
            return consumes(MediaTypes.createFrom(types));
        }

        /**
         * Add consumed media types supported by the component.
         *
         * @param types consumed media types.
         * @return updated builder object.
         */
        public Builder consumes(MediaType... types) {
            return consumes(Arrays.asList(types));
        }

        /**
         * Add consumed media types supported by the component.
         *
         * @param types consumed media types.
         * @return updated builder object.
         */
        public Builder consumes(Collection<MediaType> types) {
            this.consumedTypes.addAll(types);
            return this;
        }

        /**
         * Adds name bindings. The passed annotation types not annotated with {@link javax.ws.rs.NameBinding}
         * meta-annotation will be ignored.
         *
         * @param nameBindings collection of name binding annotation types.
         * @return updated builder object.
         */
        public Builder nameBindings(final Collection<Class<? extends Annotation>> nameBindings) {
            for (Class<? extends Annotation> nameBinding : nameBindings) {
                if (nameBinding.getAnnotation(NameBinding.class) != null) {
                    this.nameBindings.add(nameBinding);
                }
            }
            return this;
        }

        /**
         * Adds name bindings. The passed annotation types not annotated with {@link javax.ws.rs.NameBinding}
         * meta-annotation will be ignored.
         *
         * @param nameBindings name binding annotation types.
         * @return updated builder object.
         */
        @SafeVarargs
        public final Builder nameBindings(final Class<? extends Annotation>... nameBindings) {
            return nameBindings(Arrays.asList(nameBindings));
        }

        /**
         * Adds name bindings. The passed annotations not annotated with {@link javax.ws.rs.NameBinding}
         * meta-annotation will be ignored.
         *
         * @param nameBindings name binding annotations.
         * @return updated builder object.
         */
        public Builder nameBindings(final Annotation... nameBindings) {
            return nameBindings(
                    Arrays.stream(nameBindings)
                          .map((Function<Annotation, Class<? extends Annotation>>) Annotation::annotationType)
                          .collect(Collectors.toList())
            );
        }

        /**
         * Mark the component for suspending.
         * <p/>
         * An invocation of a component (resource or sub-resource method) marked
         * for suspending will be automatically suspended by the Jersey runtime.
         *
         * @param timeout suspend timeout value.
         * @param unit    suspend timeout time unit.
         * @return updated builder object.
         */
        public Builder suspended(long timeout, TimeUnit unit) {
            suspended = true;
            suspendTimeout = timeout;
            suspendTimeoutUnit = unit;

            return this;
        }

        /**
         * Set the SSE flag on the method model to {@code true}.
         *
         * @return updated builder object.
         */
        public Builder sse() {
            sse = true;

            return this;
        }

        /**
         * Set the managed async required flag on the method model to {@code true}.
         *
         * @return updated builder object.
         */
        public Builder managedAsync() {
            managedAsync = true;

            return this;
        }

        /**
         * If set to {@code true}, the parameter values will not be automatically
         * decoded.
         * <p/>
         * Defaults to {@code false}.
         *
         * @param value {@code true} if the automatic parameter decoding should be
         *              disabled, false otherwise.
         * @return updated builder object.
         * @see javax.ws.rs.Encoded
         */
        public Builder encodedParameters(boolean value) {
            encodedParams = value;
            return this;
        }

        /**
         * Define a resource method handler binding.
         *
         * @param handlerClass concrete resource method handler class.
         * @param method       method that will be executed as a resource method. The parameters initializes
         *                     {@link org.glassfish.jersey.server.model.Invocable#getDefinitionMethod() invocable
         *                     definition method}.
         * @return updated builder object.
         */
        public Builder handledBy(Class<?> handlerClass, Method method) {
            this.handlerInstance = null;

            this.handlerClass = handlerClass;
            this.definitionMethod = method;

            return this;
        }

        /**
         * Define a resource method handler binding.
         *
         * @param handlerInstance concrete resource method handler instance.
         * @param method          handling method.
         * @return updated builder object.
         */
        public Builder handledBy(Object handlerInstance, Method method) {
            this.handlerClass = null;

            this.handlerInstance = handlerInstance;
            this.definitionMethod = method;

            return this;
        }

        /**
         * Define an inflector-based resource method handler binding.
         *
         * @param inflector inflector handling the resource method.
         * @return updated builder object.
         */
        public Builder handledBy(Inflector<ContainerRequestContext, ?> inflector) {
            return handledBy(inflector, Invocable.APPLY_INFLECTOR_METHOD);
        }

        /**
         * Define an inflector-based resource method handler binding.
         *
         * @param inflectorClass class of the inflector handling the resource method.
         * @return updated builder object.
         */
        public Builder handledBy(Class<? extends Inflector> inflectorClass) {
            return handledBy(inflectorClass, Invocable.APPLY_INFLECTOR_METHOD);
        }

        /**
         * Parameters defined on the handler (i.e. not in the handling method), e.g. via property setters or fields.
         *
         * @param parameters handler parameters to be added to the set of handler parameters for the method.
         * @return updated builder object.
         * @since 2.20
         */
        public Builder handlerParameters(Collection<Parameter> parameters) {
            this.handlerParameters.addAll(parameters);
            return this;
        }

        /**
         * Define a specific method of the handling class that will be executed. If the method
         * is not defined then the method will be equal to the method initialized by
         * one of the {@code handledBy()} builder methods.
         *
         * @param handlingMethod specific handling method.
         * @return updated builder object.
         */
        public Builder handlingMethod(final Method handlingMethod) {
            this.handlingMethod = handlingMethod;

            return this;
        }

        /**
         * Define the response entity type used during the routing for
         * selection of the resource methods. If this method is not called then
         * the {@link Invocable#getRoutingResponseType()} will be equal to
         * {@link org.glassfish.jersey.server.model.Invocable#getResponseType()} which
         * is the default configuration state.
         *
         * @param routingResponseType Routing response type.
         * @return updated builder object.
         * @see org.glassfish.jersey.server.model.Invocable#getRoutingResponseType()
         */
        public Builder routingResponseType(Type routingResponseType) {
            this.routingResponseType = routingResponseType;

            return this;
        }

        /**
         * Get the flag indicating whether the resource method is extended or is a core of exposed RESTful API.
         * The method defines the
         * flag available at {@link org.glassfish.jersey.server.model.ResourceMethod#isExtended()}.
         * <p>
         * Extended resource model components are helper components that are not considered as a core of a
         * RESTful API. These can be for example {@code OPTIONS} {@link ResourceMethod resource methods}
         * added by {@link org.glassfish.jersey.server.model.ModelProcessor model processors}
         * or {@code application.wadl} resource producing the WADL. Both resource are rather supportive
         * than the core of RESTful API.
         * </p>
         *
         * @param extended If {@code true} then resource method is marked as extended.
         * @return updated builder object.
         * @see org.glassfish.jersey.server.model.ExtendedResource
         * @since 2.5.1
         */
        public Builder extended(boolean extended) {
            this.extended = extended;
            return this;
        }

        /**
         * Build the resource method model and register it with the parent
         * {@link Resource.Builder Resource.Builder}.
         *
         * @return new resource method model.
         */
        public ResourceMethod build() {

            final Data methodData = new Data(
                    httpMethod,
                    consumedTypes,
                    producedTypes,
                    managedAsync,
                    suspended,
                    sse,
                    suspendTimeout,
                    suspendTimeoutUnit,
                    createInvocable(),
                    nameBindings,
                    parent.isExtended() || extended);

            parent.onBuildMethod(this, methodData);

            return new ResourceMethod(null, methodData);
        }

        private Invocable createInvocable() {
            assert handlerClass != null || handlerInstance != null;

            final MethodHandler handler;
            if (handlerClass != null) {
                handler = MethodHandler.create(handlerClass, encodedParams, handlerParameters);
            } else { // instance based
                handler = MethodHandler.create(handlerInstance, handlerParameters);
            }

            return Invocable.create(handler, definitionMethod, handlingMethod, encodedParams, routingResponseType);
        }
    }

    /**
     * Immutable resource method data.
     */
    /* package */ static class Data {

        // JAX-RS method type
        private final JaxrsType type;
        // HttpMethod
        private final String httpMethod;
        // Consuming & Producing
        private final List<MediaType> consumedTypes;
        private final List<MediaType> producedTypes;
        // SuspendableComponent
        private final boolean managedAsync;
        private final boolean suspended;
        private final boolean sse;
        private final long suspendTimeout;
        private final TimeUnit suspendTimeoutUnit;
        // Invocable
        private final Invocable invocable;
        // NameBound
        private final Collection<Class<? extends Annotation>> nameBindings;

        private final boolean extended;

        private Data(final String httpMethod,
                     final Collection<MediaType> consumedTypes,
                     final Collection<MediaType> producedTypes,
                     boolean managedAsync, final boolean suspended, boolean sse,
                     final long suspendTimeout,
                     final TimeUnit suspendTimeoutUnit,
                     final Invocable invocable,
                     final Collection<Class<? extends Annotation>> nameBindings,
                     final boolean extended) {
            this.managedAsync = managedAsync;
            this.type = JaxrsType.classify(httpMethod);

            this.httpMethod = (httpMethod == null) ? httpMethod : httpMethod.toUpperCase(Locale.ROOT);

            this.consumedTypes = Collections.unmodifiableList(new ArrayList<>(consumedTypes));
            this.producedTypes = Collections.unmodifiableList(new ArrayList<>(producedTypes));
            this.invocable = invocable;
            this.suspended = suspended;
            this.sse = sse;
            this.suspendTimeout = suspendTimeout;
            this.suspendTimeoutUnit = suspendTimeoutUnit;

            this.nameBindings = Collections.unmodifiableCollection(new ArrayList<>(nameBindings));
            this.extended = extended;
        }

        /**
         * Get the JAX-RS method type.
         *
         * @return the JAX-RS method type.
         */
        /* package */ JaxrsType getType() {
            return type;
        }

        /**
         * Get the associated HTTP method.
         * <p>
         * May return {@code null} in case the method represents a sub-resource
         * locator.
         * </p>
         *
         * @return the associated HTTP method, or {@code null} in case this method
         * represents a sub-resource locator.
         */
        /* package */ String getHttpMethod() {
            return httpMethod;
        }

        /**
         * Get consumable media types.
         *
         * @return consumable media types.
         */
        /* package */ List<MediaType> getConsumedTypes() {
            return consumedTypes;
        }

        /**
         * Get produced media types.
         *
         * @return produced media types.
         */
        /* package */ List<MediaType> getProducedTypes() {
            return producedTypes;
        }

        /**
         * Flag indicating whether managed async support declared on the method.
         *
         * @return {@code true} if managed async support is declared on the method, {@code false} otherwise.
         */
        /* package */ boolean isManagedAsync() {
            return managedAsync;
        }

        /**
         * Flag indicating whether the method requires injection of suspended response context.
         *
         * @return {@code true} if the method requires injection of suspended response context, {@code false} otherwise.
         */
        /* package */ boolean isSuspended() {
            return suspended;
        }

        /**
         * Flag indicating whether the method requires injection of Sse Event Sink.
         *
         * @return {@code true} if the method requires injection of Sse Event Sink, {@code false} otherwise.
         */
        /* package */ boolean isSse() {
            return sse;
        }

        /**
         * Get the suspended timeout value for the method.
         *
         * @return the suspended timeout value for the method.
         */
        /* package */ long getSuspendTimeout() {
            return suspendTimeout;
        }

        /**
         * Get the suspended timeout time unit for the method.
         *
         * @return the suspended timeout time unit for the method.
         */
        /* package */ TimeUnit getSuspendTimeoutUnit() {
            return suspendTimeoutUnit;
        }

        /**
         * Get the invocable method model.
         *
         * @return invocable method model.
         */
        /* package */ Invocable getInvocable() {
            return invocable;
        }

        /**
         * Get the flag indicating whether the resource method is extended or is a core of exposed RESTful API.
         *
         * @return {@code true} if resource is extended.
         */
        /* package */ boolean isExtended() {
            return extended;
        }

        /**
         * Get the collection of name bindings attached to this method.
         *
         * @return collection of name binding annotation types attached to the method.
         */
        /* package */ Collection<Class<? extends Annotation>> getNameBindings() {
            return nameBindings;
        }

        @Override
        public String toString() {
            return "httpMethod=" + httpMethod
                    + ", consumedTypes=" + consumedTypes
                    + ", producedTypes=" + producedTypes
                    + ", suspended=" + suspended
                    + ", suspendTimeout=" + suspendTimeout
                    + ", suspendTimeoutUnit=" + suspendTimeoutUnit
                    + ", invocable=" + invocable
                    + ", nameBindings=" + nameBindings;
        }
    }

    /**
     * Transform a collection of resource method data into resource method models.
     *
     * @param parent parent resource model.
     * @param list   resource method data collection.
     * @return transformed resource method models.
     */
    static List<ResourceMethod> transform(final Resource parent, final List<Data> list) {
        return list.stream()
                   .map(data1 -> (data1 == null) ? null : new ResourceMethod(parent, data1))
                   .collect(Collectors.toList());
    }

    private final Data data;
    private final Resource parent;

    /**
     * Create new resource method model instance.
     *
     * @param parent parent resource model.
     * @param data   resource method model data.
     */
    ResourceMethod(final Resource parent, final Data data) {
        this.parent = parent;
        this.data = data;
    }

    /**
     * Get model data represented by this resource method.
     *
     * @return model data represented by this resource method.
     */
    /* package */ Data getData() {
        return data;
    }

    /**
     * Get the parent resource for this resource method model.
     * <p>
     * May return {@code null} in case the resource method is not bound to an existing resource.
     * This is typical for resource method models returned directly from the
     * {@link ResourceMethod.Builder#build() ResourceMethod.Builder.build()} method.
     * </p>
     *
     * @return parent resource, or {@code null} if there is no parent resource associated with the method.
     * @since 2.1
     */
    public Resource getParent() {
        return parent;
    }

    /**
     * Get the JAX-RS method type.
     *
     * @return the JAX-RS method type.
     */
    public JaxrsType getType() {
        return data.getType();
    }

    /**
     * Get the associated HTTP method.
     * <p>
     * May return {@code null} in case the method represents a sub-resource
     * locator.
     * </p>
     *
     * @return the associated HTTP method, or {@code null} in case this method
     * represents a sub-resource locator.
     */
    public String getHttpMethod() {
        return data.getHttpMethod();
    }

    /**
     * Get the invocable method model.
     *
     * @return invocable method model.
     */
    public Invocable getInvocable() {
        return data.getInvocable();
    }

    /**
     * Get the flag indicating whether the resource method is extended or is a core of exposed RESTful API.
     * <p>
     * Extended resource model components are helper components that are not considered as a core of a
     * RESTful API. These can be for example {@code OPTIONS} resource methods
     * added by {@link org.glassfish.jersey.server.model.ModelProcessor model processors}
     * or {@code application.wadl} resource producing the WADL. Both resource are rather supportive
     * than the core of RESTful API.
     * </p>
     * <p>
     * If not set the resource will not be defined as extended by default.
     * </p>
     *
     * @return {@code true} if the method is extended.
     * @see org.glassfish.jersey.server.model.ExtendedResource
     * @since 2.5.1
     */
    public boolean isExtended() {
        return data.extended;
    }

    // Consuming
    @Override
    public List<MediaType> getConsumedTypes() {
        return data.getConsumedTypes();
    }

    // Producing
    @Override
    public List<MediaType> getProducedTypes() {
        return data.getProducedTypes();
    }

    // Suspendable
    @Override
    public long getSuspendTimeout() {
        return data.getSuspendTimeout();
    }

    @Override
    public TimeUnit getSuspendTimeoutUnit() {
        return data.getSuspendTimeoutUnit();
    }

    @Override
    public boolean isSuspendDeclared() {
        return data.isSuspended();
    }

    /**
     * Check whether the resource method will be producing Server-sent event stream.
     *
     * @return {@code true} if the resource method produces Server-sent event stream, {@code false} otherwise.
     */
    public boolean isSse() {
        return data.isSse();
    }

    @Override
    public boolean isManagedAsyncDeclared() {
        return data.isManagedAsync();
    }

    // ResourceModelComponent
    @Override
    public List<? extends ResourceModelComponent> getComponents() {
        return Arrays.asList(data.getInvocable());
    }

    @Override
    public void accept(ResourceModelVisitor visitor) {
        visitor.visitResourceMethod(this);
    }

    // NameBound
    @Override
    public boolean isNameBound() {
        return !data.getNameBindings().isEmpty();
    }

    @Override
    public Collection<Class<? extends Annotation>> getNameBindings() {
        return data.getNameBindings();
    }

    @Override
    public String toString() {
        return "ResourceMethod{" + data.toString() + '}';
    }
}
