/*
 * 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.jdbi.v3.stringtemplate4;

import static org.jdbi.v3.stringtemplate4.StringTemplateSqlLocator.findStringTemplateGroup;

import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.jdbi.v3.core.config.ConfigRegistry;
import org.jdbi.v3.core.statement.SqlStatements;
import org.jdbi.v3.core.rewriter.ColonPrefixStatementRewriter;
import org.jdbi.v3.core.rewriter.StatementRewriter;
import org.jdbi.v3.sqlobject.internal.SqlAnnotations;
import org.jdbi.v3.sqlobject.SqlObjects;
import org.jdbi.v3.sqlobject.config.Configurer;
import org.jdbi.v3.sqlobject.config.ConfiguringAnnotation;
import org.jdbi.v3.sqlobject.locator.SqlLocator;
import org.stringtemplate.v4.ST;
import org.stringtemplate.v4.STGroup;

/**
 * Configures SQL Object to locate SQL using the {@link StringTemplateSqlLocator#findStringTemplate(Class, String)}
 * method. If the SQL annotation (e.g. <code>@SqlQuery</code>) defines a value (e.g. <code>@SqlQuery("hello")</code>),
 * that value (<code>"hello"</code>) will be used for the <code>name</code> parameter; if undefined, the name of the SQL
 * object method will be used:
 *
 * <pre>
 *     @UseStringTemplateSqlLocator
 *     interface Viccini {
 *         @SqlUpdate
 *         void doTheThing(long id);     // => StringTemplateSqlLocator.findStringTemplateSql(Viccini.class, "doTheThing")
 *
 *         @SqlUpdate("thatOtherThing")
 *         void doTheThing(String name); // => StringTemplateSqlLocator.findStringTemplateSql(Viccini.class, "thatOtherThing")
 *     }
 * </pre>
 */
@ConfiguringAnnotation(UseStringTemplateSqlLocator.Impl.class)
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
public @interface UseStringTemplateSqlLocator {
    Class<? extends StatementRewriter> value() default ColonPrefixStatementRewriter.class;

    class Impl implements Configurer {
        @Override
        public void configureForType(ConfigRegistry registry, Annotation annotation, Class<?> sqlObjectType) {
            UseStringTemplateSqlLocator useStringTemplateSqlLocator = (UseStringTemplateSqlLocator) annotation;
            SqlLocator locator = (type, method) -> {
                String templateName = SqlAnnotations.getAnnotationValue(method).orElseGet(method::getName);
                STGroup group = findStringTemplateGroup(type);
                if (!group.isDefined(templateName)) {
                    throw new IllegalStateException("No StringTemplate group " + templateName + " for class " + sqlObjectType);
                }

                return templateName;
            };
            StatementRewriter delegate = createDelegate(useStringTemplateSqlLocator.value());
            StatementRewriter locatingRewriter = (sql, params, ctx) -> {
                String templateName = sql;

                STGroup group = findStringTemplateGroup(sqlObjectType);
                ST template = group.getInstanceOf(templateName);
                ctx.getAttributes().forEach(template::add);
                String rewritten = template.render();

                return delegate.rewrite(rewritten, params, ctx);
            };
            registry.get(SqlObjects.class).setSqlLocator(locator);
            registry.get(SqlStatements.class).setStatementRewriter(locatingRewriter);
        }

        @Override
        public void configureForMethod(ConfigRegistry registry, Annotation annotation, Class<?> sqlObjectType, Method method) {
            configureForType(registry, annotation, sqlObjectType);
        }

        private StatementRewriter createDelegate(Class<? extends StatementRewriter> type) {
            try {
                return type.getConstructor().newInstance();
            } catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
                throw new IllegalStateException("Error instantiating delegate statement rewriter: " + type, e);
            }
        }
    }
}