/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2025                                                               *
 *                                                                                       *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
 * software and associated documentation files (the "Software"), to deal in the Software *
 * without restriction, including without limitation the rights to use, copy, modify,    *
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
 * permit persons to whom the Software is furnished to do so, subject to the following   *
 * conditions:                                                                           *
 *                                                                                       *
 * The above copyright notice and this permission notice shall be included in all copies *
 * or substantial portions of the Software.                                              *
 *                                                                                       *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
 ****************************************************************************************/

#ifndef __OPENSPACE_CORE___SCRIPTENGINE___H__
#define __OPENSPACE_CORE___SCRIPTENGINE___H__

#include <openspace/util/syncable.h>
#include <openspace/scripting/lualibrary.h>
#include <ghoul/lua/luastate.h>
#include <ghoul/misc/boolean.h>
#include <filesystem>
#include <mutex>
#include <optional>
#include <queue>
#include <functional>

namespace openspace { class SyncBuffer; }

namespace openspace::scripting {

/**
 * The ScriptEngine is responsible for handling the execution of custom Lua functions and
 * executing scripts (#runScript). Before usage, it has to be #initialize%d and
 * #deinitialize%d. New ScriptEngine::Library%s consisting of Library::Function%s have to
 * be added which can then be called using the `openspace` namespace prefix in Lua. The
 * same functions can be exposed to other Lua states by passing them to the
 * #initializeLuaState method.
 */
class ScriptEngine : public Syncable {
public:
    struct Script {
        BooleanType(ShouldBeSynchronized);
        BooleanType(ShouldSendToRemote);
        BooleanType(ShouldBeLogged);
        using Callback = std::function<void(ghoul::Dictionary)>;

        /// The Lua script that should be executed
        std::string code;

        /// Determines whether a script should be sent to computers that are in the same
        /// _cluster_ as the master machine that the user is interacting with. These are
        /// usually different computers that tile a bigger display area and that need to
        /// be tightly locked
        ShouldBeSynchronized synchronized = ShouldBeSynchronized::Yes;

        /// Determines whether a script should be send to a distant OpenSpace instance
        /// that is not part of the same cluster. This is used in the ParallelConnection
        /// feature that can connect OpenSpace instances in a connection that does not
        /// require instantaneous synchronization
        ShouldSendToRemote sendToRemote = ShouldSendToRemote::Yes;

        /// Determines whether the script should be logged to a local script log file.
        /// Note that this might be overwritten if the user requested a verbose log file
        ShouldBeLogged addToLog = ShouldBeLogged::Yes;

        /// A callback that will be called when the script finishes executing and that
        /// provides access to the return value of the script
        Callback callback = Callback();
    };

    static constexpr std::string_view OpenSpaceLibraryName = "openspace";

    explicit ScriptEngine(bool sandboxedLua = true);

    /**
     * Initializes the internal Lua state and registers a common set of library functions.
     *
     * \throw LuaRuntimeException If the creation of the new Lua state fails
     */
    void initialize();

    /**
     * Cleans the internal Lua state and leaves the ScriptEngine in a state to be newly
     * initialize%d.
     */
    void deinitialize();

    void initializeLuaState(lua_State* state);
    ghoul::lua::LuaState* luaState();

    void addLibrary(LuaLibrary library);
    bool hasLibrary(const std::string& name);

    virtual void preSync(bool isMaster) override;
    virtual void encode(SyncBuffer* syncBuffer) override;
    virtual void decode(SyncBuffer* syncBuffer) override;
    virtual void postSync(bool isMaster) override;

    void queueScript(Script script);
    void queueScript(std::string script);

    // Runs the `script` every `timeout` seconds wallclock time
    void registerRepeatedScript(std::string identifier, std::string script,
        double timeout, std::string preScript = "", std::string postScript = "");
    void removeRepeatedScript(std::string_view identifier);

    void scheduleScript(std::string script, double delay);

    std::vector<std::string> allLuaFunctions() const;
    const std::vector<LuaLibrary>& allLuaLibraries() const;

private:
    BooleanType(Replace);

    void writeLog(const std::string& script);

    bool registerLuaLibrary(lua_State* state, LuaLibrary& library);
    void addLibraryFunctions(lua_State* state, LuaLibrary& library, Replace replace);

    bool isLibraryNameAllowed(lua_State* state, const std::string& name);

    void addBaseLibrary();

    bool runScript(const Script& script);

    ghoul::lua::LuaState _state;
    std::vector<LuaLibrary> _registeredLibraries;

    std::queue<Script> _incomingScripts;

    // Client scripts are mutex protected since decode and rendering may happen
    // asynchronously
    std::mutex _clientScriptsMutex;
    std::queue<std::string> _clientScriptQueue;
    std::queue<Script> _masterScriptQueue;

    std::vector<std::string> _scriptsToSync;

    struct RepeatedScriptInfo {
        /// This script is run everytime `timeout` seconds have passed
        std::string script;

        /// This script is run when the repeated script is unregistered
        std::string postScript;

        std::string identifier;
        double timeout = 0.0;
        double lastRun = 0.0;
    };
    std::vector<RepeatedScriptInfo> _repeatedScripts;

    struct ScheduledScriptInfo {
        // The script that should be executed
        std::string script;

        // The application timestamp at which time the script should be executed
        double timestamp = 0.0;
    };
    std::vector<ScheduledScriptInfo> _scheduledScripts;

    // Logging variables
    bool _logFileExists = false;
    bool _logScripts = true;
    std::filesystem::path _logFilename;
};

} // namespace openspace::scripting

#endif // __OPENSPACE_CORE___SCRIPTENGINE___H__