// Copyright (c) 2008-2022 the Urho3D project
// License: MIT

#pragma once

#include "../Core/Context.h"
#include "../Core/Object.h"
#include "../LuaScript/LuaScriptEventListener.h"

struct lua_State;

namespace Urho3D
{

extern const char* LOGIC_CATEGORY;

class LuaFunction;
class LuaScriptEventInvoker;
class Scene;

/// Lua script subsystem.
class URHO3D_API LuaScript : public Object, public LuaScriptEventListener
{
    URHO3D_OBJECT(LuaScript, Object);

public:
    /// Construct.
    explicit LuaScript(Context* context);
    /// Destruct.
    ~LuaScript() override;

    /// Add a scripted event handler by function at the given stack index.
    void AddEventHandler(const String& eventName, int index) override;
    /// Add a scripted event handler by function name.
    void AddEventHandler(const String& eventName, const String& functionName) override;
    /// Add a scripted event handler by function at the given stack index for a specific sender.
    void AddEventHandler(Object* sender, const String& eventName, int index) override;
    /// Add a scripted event handler by function name for a specific sender.
    void AddEventHandler(Object* sender, const String& eventName, const String& functionName) override;
    /// Remove a scripted event handler.
    void RemoveEventHandler(const String& eventName) override;
    /// Remove a scripted event handler for a specific sender.
    void RemoveEventHandler(Object* sender, const String& eventName) override;
    /// Remove all scripted event handlers for a specific sender.
    void RemoveEventHandlers(Object* sender) override;
    /// Remove all scripted event handlers.
    void RemoveAllEventHandlers() override;
    /// Remove all scripted event handlers, except those listed.
    void RemoveEventHandlersExcept(const Vector<String>& exceptionNames) override;
    /// Return whether has subscribed to an event.
    bool HasEventHandler(const String& eventName) const override;
    /// Return whether has subscribed to a specific sender's event.
    bool HasEventHandler(Object* sender, const String& eventName) const override;

    /// Execute script file. Return true if successful.
    bool ExecuteFile(const String& fileName);
    /// Execute script string. Return true if successful.
    bool ExecuteString(const String& string);
    /// Load script file on file system (i.e. not from resource cache). Return true if successful.
    bool LoadRawFile(const String& fileName);
    /// Load and execute script file on file system (i.e. not from resource cache). Return true if successful.
    bool ExecuteRawFile(const String& fileName);
    /// Execute script function.
    bool ExecuteFunction(const String& functionName);
    /// Set whether to execute engine console commands as script code.
    void SetExecuteConsoleCommands(bool enable);

    /// Return Lua state.
    lua_State* GetState() const { return luaState_; }

    /// Return Lua function at the given stack index.
    LuaFunction* GetFunction(int index);
    /// Return Lua function by function name.
    LuaFunction* GetFunction(const String& functionName, bool silentIfNotFound = false);

    /// Return whether is executing engine console commands as script code.
    bool GetExecuteConsoleCommands() const { return executeConsoleCommands_; }

    /// Push Lua function to stack. Return true if is successful. Return false on any error and an error string is pushed instead.
    static bool PushLuaFunction(lua_State* L, const String& functionName);

private:
    /// Register loader.
    void RegisterLoader();
    /// Replace print.
    void ReplacePrint();
    /// Handle post update.
    void HandlePostUpdate(StringHash eventType, VariantMap& eventData);
    /// Handle a console command event.
    void HandleConsoleCommand(StringHash eventType, VariantMap& eventData);

    /// At panic.
    static int AtPanic(lua_State* L);
    /// Loader.
    static int Loader(lua_State* L);
    /// Print function.
    static int Print(lua_State* L);

    /// Lua state.
    lua_State* luaState_;
    /// Procedural event invoker.
    SharedPtr<LuaScriptEventInvoker> eventInvoker_;
    /// Coroutine update function.
    LuaFunction* coroutineUpdate_;
    /// Flag for executing engine console commands as script code. Default to true.
    bool executeConsoleCommands_;
    /// Function pointer to function map.
    HashMap<const void*, SharedPtr<LuaFunction>> functionPointerToFunctionMap_;
    /// Function name to function map.
    HashMap<String, SharedPtr<LuaFunction>> functionNameToFunctionMap_;
};

/// Register Lua script library objects.
void URHO3D_API RegisterLuaScriptLibrary(Context* context);

}