package com.typesafe.config.parser;

import com.typesafe.config.ConfigValue;

/**
 * Represents an individual HOCON or JSON file, preserving all
 * formatting and syntax details.  This can be used to replace
 * individual values and exactly render the original text of the
 * input.
 *
 * <p>
 * Because this object is immutable, it is safe to use from multiple threads and
 * there's no need for "defensive copies."
 *
 * <p>
 * <em>Do not implement interface {@code ConfigDocument}</em>; it should only be
 * implemented by the config library. Arbitrary implementations will not work
 * because the library internals assume a specific concrete implementation.
 * Also, this interface is likely to grow new methods over time, so third-party
 * implementations will break.
 */
public interface ConfigDocument {
    /**
     * Returns a new ConfigDocument that is a copy of the current ConfigDocument,
     * but with the desired value set at the desired path. If the path exists, it will
     * remove all duplicates before the final occurrence of the path, and replace the value
     * at the final occurrence of the path. If the path does not exist, it will be added. If
     * the document has an array as the root value, an exception will be thrown.
     *
     * @param path the path at which to set the desired value
     * @param newValue the value to set at the desired path, represented as a string. This
     *                 string will be parsed into a ConfigNode using the same options used to
     *                 parse the entire document, and the text will be inserted
     *                 as-is into the document. Leading and trailing comments, whitespace, or
     *                 newlines are not allowed, and if present an exception will be thrown.
     *                 If a concatenation is passed in for newValue but the document was parsed
     *                 with JSON, the first value in the concatenation will be parsed and inserted
     *                 into the ConfigDocument.
     * @return a copy of the ConfigDocument with the desired value at the desired path
     */
    ConfigDocument withValueText(String path, String newValue);

    /**
     * Returns a new ConfigDocument that is a copy of the current
     * ConfigDocument, but with the desired value set at the
     * desired path. Works like {@link #withValueText(String, String)},
     * but takes a ConfigValue instead of a string.
     *
     * @param path the path at which to set the desired value
     * @param newValue the value to set at the desired path, represented as a ConfigValue.
     *                 The rendered text of the ConfigValue will be inserted into the
     *                 ConfigDocument.
     * @return a copy of the ConfigDocument with the desired value at the desired path
     */
    ConfigDocument withValue(String path, ConfigValue newValue);

    /**
     * Returns a new ConfigDocument that is a copy of the current ConfigDocument, but with
     * all values at the desired path removed. If the path does not exist in the document,
     * a copy of the current document will be returned. If there is an array at the root, an exception
     * will be thrown.
     *
     * @param path the path to remove from the document
     * @return a copy of the ConfigDocument with the desired value removed from the document.
     */
    ConfigDocument withoutPath(String path);

    /**
     * Returns a boolean indicating whether or not a ConfigDocument has a value at the desired path.
     * null counts as a value for purposes of this check.
     * @param path the path to check
     * @return true if the path exists in the document, otherwise false
     */
    boolean hasPath(String path);

    /**
     * The original text of the input, modified if necessary with
     * any replaced or added values.
     * @return the modified original text
     */
    String render();
}
