package net.kdt.pojavlaunch.utils;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

public class GsonJsonUtils {
    /**
     * Safely converts a JsonElement into a JsonObject.
     * @param element the input JsonElement
     * @return the JsonObject if:
     *         the JsonElement is not null
     *         the JsonElement is not Json null
     *         the JsonElement is a JsonObjet
     *         null otherwise
     */
    public static JsonObject getJsonObjectSafe(JsonElement element) {
        if(element == null) return null;
        if(element.isJsonNull() || !element.isJsonObject()) return null;
        return element.getAsJsonObject();
    }

    /**
     * Safely gets a JsonElement from a JsonObject
     * @param jsonObject the input JsonObject
     * @param memberName the member name of the JsonElement
     * @return the JsonElement if:
     *         the input JsonObject is not null
     *         the input JsonObject contains an element with the specified memberName
     *         the JsonElement is not Json null
     *         null otherwise
     */
    public static JsonElement getElementSafe(JsonObject jsonObject, String memberName) {
        if(jsonObject == null) return null;
        if(!jsonObject.has(memberName)) return null;
        JsonElement element = jsonObject.get(memberName);
        if(element.isJsonNull()) return null;
        return element;
    }

    /**
     * Safely gets a JsonObject from a JsonObject
     * @param jsonObject the input JsonObject
     * @param memberName the member name of the output JsonObject
     * @return the output JsonObject if:
     *         the input JsonObject is not null
     *         the input JsonObject contains an element with the specified memberName
     *         the output JsonObject is not Json null
     *         the output JsonObject is a JsonObjet
     *         null otherwise
     */
    public static JsonObject getJsonObjectSafe(JsonObject jsonObject, String memberName) {
        return getJsonObjectSafe(getElementSafe(jsonObject, memberName));
    }

    /**
     * Safely gets a JsonArray from a JsonObject
     * @param jsonObject the input JsonObject
     * @param memberName the member name of the JsonArray
     * @return the JsonArray if:
     *         the input JsonObject is not null
     *         the input JsonObject contains an element with the specified memberName
     *         the JsonArray is not Json null
     *         the JsonArray is a JsonArray
     *         null otherwise
     */
    public static JsonArray getJsonArraySafe(JsonObject jsonObject, String memberName) {
        JsonElement jsonElement = getElementSafe(jsonObject, memberName);
        if(jsonElement == null || !jsonElement.isJsonArray()) return null;
        return jsonElement.getAsJsonArray();
    }

    /**
     * Safely gets an int from a JsonObject
     * @param jsonObject the input JsonObject
     * @param memberName the member name of the int
     * @param onNullValue the value that will be returned if any of the checks fail
     * @return the int if:
     *         the input JsonObject is not null
     *         the input JsonObject contains an element with the specified memberName
     *         the int is not Json null
     *         the int is an actual integer
     *         onNullValue otherwise
     */
    public static int getIntSafe(JsonObject jsonObject, String memberName, int onNullValue) {
        JsonElement jsonElement = getElementSafe(jsonObject, memberName);
        if(jsonElement == null || !jsonElement.isJsonPrimitive()) return onNullValue;
        try {
            return jsonElement.getAsInt();
        }catch (ClassCastException e) {
            return onNullValue;
        }
    }

    /**
     * Safely gets a String from a JsonObject
     * @param jsonObject the input JsonObject
     * @param memberName the member name of the int
     * @return the String if:
     *         the input JsonObject is not null
     *         the input JsonObject contains an element with the specified memberName
     *         the String is not a Json null
     *         the String is an actual String
     *         null otherwise
     */
    public static String getStringSafe(JsonObject jsonObject, String memberName) {
        JsonElement jsonElement = getElementSafe(jsonObject, memberName);
        if(jsonElement == null || !jsonElement.isJsonPrimitive()) return null;
        try {
            return jsonElement.getAsString();
        }catch (ClassCastException e) {
            return null;
        }
    }
}