/*
 * This file is a part of the SteamWar software.
 *
 * Copyright (C) 2023  SteamWar.de-Serverteam
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package de.steamwar.command;

import lombok.Getter;

import java.lang.annotation.*;
import java.lang.reflect.Method;
import java.lang.reflect.Parameter;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.function.Function;

public interface Handler {

    default Optional<Class<?>> getGenericTypeOfReturn(Method method) {
        Type type;
        try {
            type = method.getGenericReturnType();
        } catch (Exception e) {
            return Optional.empty();
        }
        if (!(type instanceof ParameterizedType)) {
            return Optional.empty();
        }
        ParameterizedType parameterizedType = (ParameterizedType) type;
        Type[] generics = parameterizedType.getActualTypeArguments();
        if (generics.length != 1 && generics.length != 2) {
            return Optional.empty();
        }
        Type genericType = generics[generics.length - 1];
        try {
            return Optional.of(Class.forName(genericType.getTypeName()));
        } catch (Exception e) {
            return Optional.empty();
        }
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.ANNOTATION_TYPE)
    @interface Implementation {
        Class<? extends Handler> value();
    }

    class HandlerException extends Exception {
        public HandlerException(String message) {
            super(message);
        }
    }

    interface DataCheckable {
        boolean hasExecutorMapper(Class<?> clazz);

        boolean hasMapper(String key);

        boolean hasValidator(String key);

        boolean hasSupplier(String key);
    }

    interface DataReadable {
        Function<?, ?> getExecutorMapper(Class<?> clazz);

        <A, B> AbstractTypeMapper<A, B> getMapper(String key);

        <A, B> AbstractTypeValidator<A, B> getValidator(String key);

        <A, B> AbstractTypeSupplier<A, B> getSupplier(String key);
    }

    interface DataWritable {
        Function<?, ?> getExecutorMapper(Class<?> clazz);

        <A, B> void addMapper(String key, boolean local, AbstractTypeMapper<A, B> mapper);

        <A, B> void addValidator(String key, boolean local, AbstractTypeValidator<A, B> validator);

        <A, B> void addSupplier(String key, boolean local, AbstractTypeSupplier<A, B> supplier);

        /**
         * Invoking the same method twice will result in the exact same result.
         */
        <T> T invoke(Method method);

        void addCommand(Method method, String[] subCommand, String[] description, boolean noTabComplete);
    }

    interface HandlerMethod<T extends Annotation> extends Handler {
        default void check(T annotation, Method method, DataCheckable dataCheckable) throws Exception {
            check(annotation, new MethodWrapper.ForMethod(method), dataCheckable);
        }

        default void check(T annotation, MethodWrapper method, DataCheckable dataCheckable) throws HandlerException {
        }

        int getRunPriority();

        void run(T annotation, Method method, DataWritable dataWritable);
    }

    interface HandlerParameter<T extends Annotation, A, B> extends Handler {
        default void check(T annotation, Parameter parameter, int index, DataCheckable dataCheckable) throws Exception {
            check(annotation, new MethodWrapper.ForMethod((Method) parameter.getDeclaringExecutable()), new ParameterWrapper.ForParameter(parameter), index, dataCheckable);
        }

        default void check(T annotation, MethodWrapper methodWrapper, ParameterWrapper parameter, int index, DataCheckable dataCheckable) throws HandlerException {
        }

        default boolean needsParentTypeMapper() {
            return false;
        }

        /**
         * Null values are allowed to be returned.
         */
        default AbstractTypeMapper<A, B> getTypeMapper(T annotation, Parameter parameter, int index, DataReadable dataReadable, AbstractTypeMapper<A, B> parentTypeMapper) {
            return null;
        }

        default int getValidatorPriority() {
            return 0;
        }

        /**
         * Null values are allowed to be returned.
         */
        default AbstractTypeValidator<A, B> getValidator(T annotation, Parameter parameter, int index, DataReadable dataReadable) {
            return null;
        }
    }

    interface MethodWrapper {
        String getName();

        int getParameterCount();

        TypeWrapper getReturnType();

        ParameterWrapper[] getParameters();

        class ForMethod implements MethodWrapper {

            @Getter
            private final Method method;

            public ForMethod(Method method) {
                this.method = method;
            }

            @Override
            public String getName() {
                return method.getName();
            }

            @Override
            public int getParameterCount() {
                return method.getParameterCount();
            }

            @Override
            public TypeWrapper getReturnType() {
                return new TypeWrapper.ForClass(method.getReturnType());
            }

            @Override
            public ParameterWrapper[] getParameters() {
                return Arrays.stream(method.getParameters()).map(ParameterWrapper.ForParameter::new).toArray(ParameterWrapper[]::new);
            }
        }
    }

    interface ParameterWrapper {
        TypeWrapper getType();

        boolean isVarArgs();

        boolean isAnnotationPresent(Class<? extends Annotation> annotation);

        <A extends Annotation> A getAnnotation(Class<A> annotation);

        String getName();

        List<Annotation> getAnnotations();

        class ForParameter implements ParameterWrapper {

            @Getter
            private final Parameter parameter;

            public ForParameter(Parameter parameter) {
                this.parameter = parameter;
            }

            @Override
            public TypeWrapper getType() {
                return new TypeWrapper.ForClass(this.parameter.getType());
            }

            @Override
            public boolean isVarArgs() {
                return parameter.isVarArgs();
            }

            @Override
            public boolean isAnnotationPresent(Class<? extends Annotation> annotation) {
                return parameter.isAnnotationPresent(annotation);
            }

            @Override
            public <A extends Annotation> A getAnnotation(Class<A> annotation) {
                return parameter.getAnnotation(annotation);
            }

            @Override
            public String getName() {
                return parameter.getName();
            }

            @Override
            public List<Annotation> getAnnotations() {
                return CommandUtils.getAnnotations(parameter);
            }
        }
    }

    interface TypeWrapper {

        boolean isAssignableTo(Class<?> clazz);

        boolean isAssignableTo(TypeWrapper type);

        boolean isPrimitive();

        boolean isArray();

        boolean isEnum();

        boolean is(Class<?> clazz);

        boolean is(TypeWrapper type);

        TypeWrapper getComponentType();

        String getName();

        class ForClass implements TypeWrapper {
            @Getter
            private final Class<?> clazz;

            public ForClass(Class<?> clazz) {
                this.clazz = clazz;
            }

            @Override
            public boolean isAssignableTo(Class<?> clazz) {
                return clazz.isAssignableFrom(this.clazz);
            }

            @Override
            public boolean isAssignableTo(TypeWrapper type) {
                if (type instanceof ForClass) {
                    return ((ForClass) type).getClazz().isAssignableFrom(clazz);
                }
                return false;
            }

            @Override
            public boolean isPrimitive() {
                return clazz.isPrimitive();
            }

            @Override
            public boolean isArray() {
                return clazz.isArray();
            }

            @Override
            public boolean isEnum() {
                return clazz.isEnum();
            }

            @Override
            public boolean is(Class<?> clazz) {
                return this.clazz == clazz;
            }

            @Override
            public boolean is(TypeWrapper type) {
                if (type instanceof ForClass) {
                    return ((ForClass) type).getClazz() == this.clazz;
                }
                return false;
            }

            @Override
            public TypeWrapper getComponentType() {
                return new TypeWrapper.ForClass(this.clazz.getComponentType());
            }

            @Override
            public String getName() {
                return this.clazz.getName();
            }
        }
    }
}