#pragma once

#include <xrpl/beast/utility/Journal.h>
#include <xrpl/nodestore/Backend.h>
#include <xrpl/nodestore/Database.h>
#include <xrpl/nodestore/Factory.h>
#include <xrpl/nodestore/Scheduler.h>

#include <cstddef>
#include <memory>
#include <string>

namespace xrpl::node_store {

/**
 * Singleton for managing NodeStore factories and back ends.
 */
class Manager
{
public:
    virtual ~Manager() = default;
    Manager() = default;
    Manager(Manager const&) = delete;
    Manager&
    operator=(Manager const&) = delete;

    /**
     * Returns the instance of the manager singleton.
     */
    static Manager&
    instance();

    /**
     * Add a factory.
     */
    virtual void
    insert(Factory& factory) = 0;

    /**
     * Remove a factory.
     */
    virtual void
    erase(Factory& factory) = 0;

    /**
     * Return a pointer to the matching factory if it exists.
     * @param  name The name to match, performed case-insensitive.
     * @return `nullptr` if a match was not found.
     */
    virtual Factory*
    find(std::string const& name) = 0;

    /**
     * Create a backend.
     */
    virtual std::unique_ptr<Backend>
    makeBackend(
        Section const& parameters,
        std::size_t burstSize,
        Scheduler& scheduler,
        beast::Journal journal) = 0;

    /**
     * Construct a NodeStore database.
     *
     * The parameters are key value pairs passed to the backend. The
     * 'type' key must exist, it defines the choice of backend. Most
     * backends also require a 'path' field.
     *
     * Some choices for 'type' are:
     *     HyperLevelDB, LevelDBFactory, SQLite, MDB
     *
     * If the fastBackendParameter is omitted or empty, no ephemeral database
     * is used. If the scheduler parameter is omitted or unspecified, a
     * synchronous scheduler is used which performs all tasks immediately on
     * the caller's thread.
     *
     * @note If the database cannot be opened or created, an exception is
     * thrown.
     *
     * @param name A diagnostic label for the database.
     * @param burstSize Backend burst size in bytes.
     * @param scheduler The scheduler to use for performing asynchronous tasks.
     * @param readThreads The number of async read threads to create
     * @param backendParameters The parameter string for the persistent
     * backend.
     * @param fastBackendParameters [optional] The parameter string for the
     * ephemeral backend.
     *
     * @return The opened database.
     */
    virtual std::unique_ptr<Database>
    makeDatabase(
        std::size_t burstSize,
        Scheduler& scheduler,
        int readThreads,
        Section const& backendParameters,
        beast::Journal journal) = 0;
};

}  // namespace xrpl::node_store