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/*
 * Copyright 2011-2024 Lime Mojito Pty Ltd
 *
 *    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 com.limemojito.json;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.SneakyThrows;

import java.io.InputStream;


/**
 * A utility class for loading JSON data from a resource using the Jackson library.
 * Uses an instance of ObjectMapper to perform the deserialization.
 */
public class JsonLoader {

    private final ObjectMapper objectMapper;

    /**
     * A utility class for loading JSON data from a resource using the Jackson library.
     * Uses an instance of ObjectMapper to perform the deserialization.
     *
     * @param objectMapper Jackson Object mapper to delegate JSON operations to.
     */
    public JsonLoader(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }

    /**
     * Load JSON data from a resource using the Jackson library and deserialize it into an object of the specified class.
     *
     * @param resourcePath The path of the resource from which to load the JSON data.
     * @param aClass       The Class object representing the type of the target object.
     * @param           The type of the target object.
     * @return The deserialized object of the specified class.
     */
    @SneakyThrows
    public  T loadFrom(String resourcePath, Class aClass) {
        try (InputStream resourceAsStream = getClass().getResourceAsStream(resourcePath)) {
            assertStreamFound(resourcePath, resourceAsStream);
            return objectMapper.readValue(resourceAsStream, aClass);
        }
    }

    /**
     * Load JSON data from a resource using the Jackson library and deserialize it into an object of the specified type.
     *
     * @param resourcePath  The path of the resource from which to load the JSON data.
     * @param typeReference The TypeReference object representing the type of the target object.
     * @param            The type of the target object.
     * @return The deserialized object of the specified type.
     */
    @SneakyThrows
    public  T loadFrom(String resourcePath, TypeReference typeReference) {
        try (InputStream resourceAsStream = getClass().getResourceAsStream(resourcePath)) {
            assertStreamFound(resourcePath, resourceAsStream);
            return objectMapper.readValue(resourceAsStream, typeReference);
        }
    }

    private static void assertStreamFound(String resourcePath, InputStream resourceAsStream) {
        if (resourceAsStream == null) {
            throw new IllegalArgumentException("Could not load %s from classpath.".formatted(resourcePath));
        }
    }
}