clio/src/util/config/ObjectView.hpp

#pragma once

#include "util/config/ValueView.hpp"

#include <cstddef>
#include <functional>
#include <optional>
#include <string>
#include <string_view>

namespace util::config {

class ClioConfigDefinition;
class ArrayView;

/**
 * @brief Provides a view into a subset of configuration data defined by a prefix
 *
 * Allows querying and accessing configuration values based on the provided prefix
 */
class ObjectView {
public:
    /**
     * @brief Constructs an ObjectView for the specified prefix. The view must be of type object
     *
     * @param prefix The prefix indicating the subset of configuration data to view
     * @param clioConfig Reference to the ClioConfigDefinition containing all the configuration data
     */
    ObjectView(std::string_view prefix, ClioConfigDefinition const& clioConfig);

    /**
     * @brief Constructs an ObjectView for an indexed array within the specified prefix
     *
     * @param prefix The prefix indicating the subset of configuration data to view
     * @param arrayIndex The index of the array object element to view
     * @param clioConfig Reference to the ClioConfigDefinition containing all the configuration data
     */
    ObjectView(
        std::string_view prefix,
        std::size_t arrayIndex,
        ClioConfigDefinition const& clioConfig
    );

    /**
     * @brief Checks if prefix_.key (fullkey) exists in ClioConfigDefinition
     *
     * @param key The suffix of the key
     * @return true if the full key exists, otherwise false
     */
    [[nodiscard]] bool
    containsKey(std::string_view key) const;

    /**
     * @brief Retrieves the value associated with the specified prefix._key in ClioConfigDefinition
     *
     * @param key The suffix of the key
     * @return A ValueView object representing the value associated with the key
     */
    [[nodiscard]] ValueView
    getValueView(std::string_view key) const;

    /**
     * @brief Returns the specified value of given string if value exists
     *
     * @tparam T The type T to return
     * @param key The config key to add to prefix and then search for
     * @return Value of key of type T
     */
    template <typename T>
    [[nodiscard]] T
    get(std::string_view key) const
    {
        return getValueView(key).getValueImpl<T>();
    }

    /**
     * @brief Returns the specified value of given string of type T if type and value exists
     *
     * @tparam T The type T to return
     * @param key The config key to add to prefix and then search for
     * @return The value of type T if it exists, std::nullopt otherwise.
     */
    template <typename T>
    [[nodiscard]] std::optional<T>
    maybeValue(std::string_view key) const
    {
        return getValueView(key).asOptional<T>();
    }

    /**
     * @brief Retrieves an ObjectView in ClioConfigDefinition with key that starts with prefix_.key.
     * The view must be of type object
     *
     * @param key The suffix of the key
     * @return An ObjectView representing the subset of configuration data
     */
    [[nodiscard]] ObjectView
    getObject(std::string_view key) const;

    /**
     * @brief Retrieves an ArrayView in ClioConfigDefinition with key that starts with prefix_.key.
     * The view must be of type object
     *
     * @param key The suffix of the key
     * @return An ObjectView representing the subset of configuration data
     */
    [[nodiscard]] ArrayView
    getArray(std::string_view key) const;

private:
    /**
     * @brief returns the full key (prefix.key)
     *
     * @param key The suffix of the key
     * @return the full string of the key
     */
    [[nodiscard]] std::string
    getFullKey(std::string_view key) const;

    /**
     * @brief Checks if any key in ClioConfigDefinition starts with prefix_.key
     *
     * @param key The suffix of the key
     * @return true if at least one key starts with the specified prefix_.key, otherwise false
     */
    [[nodiscard]] bool
    startsWithKey(std::string_view key) const;

    std::string prefix_;
    std::optional<size_t> arrayIndex_;
    std::reference_wrapper<ClioConfigDefinition const> clioConfig_;
};

}  // namespace util::config