/** @file
 *
 * @par History
 * - 2009/09/05 Turley: Added struct .? and .- as shortcut for .exists() and .erase()
 */


#ifndef __EXECUTOR_H
#define __EXECUTOR_H

#include "pol_global_config.h"

#ifndef __EXECTYPE_H
#include "exectype.h"
#endif

#ifndef BSCRIPT_BOBJECT_H
#include "bobject.h"
#endif

#include <exception>
#include <map>
#include <memory>
#include <optional>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#include "../clib/refptr.h"
#include "../clib/spinlock.h"
#include "berror.h"
#include "bobject.h"
#include "continueimp.h"
#include "eprog.h"
#include "executortype.h"

#ifdef ESCRIPT_PROFILE
#include "clib/timer.h"
#include <map>
#endif

namespace Pol
{
namespace Core
{
class UOExecutor;

void list_script( UOExecutor* uoexec );
}  // namespace Core
namespace Bscript
{
class BContinuation;
class BFunctionRef;
class Executor;
class EScriptProgram;
class ExecutorModule;
class ModuleFunction;
class String;
class Token;

class ExecutorDebugListener
{
public:
  virtual void on_halt() {};
  virtual void on_destroy() {};
  virtual void on_print( const std::string& /*str*/ ) {};
};

// FIXME: how to make this a nested struct in Executor?
struct ReturnContext
{
  struct External
  {
    External( ref_ptr<EScriptProgram> program, std::vector<ExecutorModule*> modules,
              std::shared_ptr<BObjectRefVec> globals )
        : Program( std::move( program ) ),
          Modules( std::move( modules ) ),
          Globals( std::move( globals ) )
    {
    }
    ref_ptr<EScriptProgram> Program;
    std::vector<ExecutorModule*> Modules;
    std::shared_ptr<BObjectRefVec> Globals;
  };

  unsigned PC;
  unsigned ValueStackDepth;
  BObjectRef Continuation = BObjectRef();

  std::optional<External> ExternalContext;
};

struct BackupStruct
{
  std::unique_ptr<BObjectRefVec> Locals;
  ValueStackCont ValueStack;
  unsigned PC;
};

enum class ExecutorType
{
  EXECUTOR,
  POL
};

enum class ExecutorDebugState
{
  ATTACHING,
  ATTACHED,
  INS_TRACE,
  RUN,
  BREAK_INTO,
  STEP_INTO,
  STEPPING_INTO,
  STEP_OVER,
  STEPPING_OVER,
  STEP_OUT,
};

class ExecutorDebugEnvironment
{
public:
  ExecutorDebugEnvironment( std::weak_ptr<ExecutorDebugListener> listener, bool set_attaching );

  // Return `false` to skip the instruction from executing.
  bool on_instruction( Executor& );
  size_t sizeEstimate() const;

  ExecutorDebugState debug_state;
  std::set<unsigned> breakpoints;
  std::set<unsigned> tmpbreakpoints;
  struct
  {
    unsigned line;
    size_t control;
  } break_on_linechange_from;
  unsigned bp_skip;
  std::weak_ptr<ExecutorDebugListener> listener;
};

class Executor
{
public:
  static Clib::SpinLock _executor_lock;
  virtual size_t sizeEstimate() const;

  friend void Core::list_script( Core::UOExecutor* uoexec );
  int done;
  void seterror( bool err );
  bool error() const;
  bool error_;
  bool halt_;
  bool run_ok_;

  virtual ExecutorType type() { return ExecutorType::EXECUTOR; }

  enum DEBUG_LEVEL
  {
    NONE,
    SOURCELINES,
    INSTRUCTIONS
  };
  DEBUG_LEVEL debug_level;
  unsigned PC;  // program counter

  bool AttachFunctionalityModules();


  bool setProgram( EScriptProgram* prog );

  std::shared_ptr<BObjectRefVec> Globals2;

  std::vector<BObjectRefVec*> upperLocals2;

  std::vector<ReturnContext> ControlStack;

  BObjectRefVec* Locals2;

  static UninitObject* m_SharedUninitObject;


  ValueStackCont ValueStack;

  static ExecInstrFunc GetInstrFunc( const Token& token );

  /*
      These must both be deleted.  instr references _symbols, so it should be deleted first.
      FIXME: there should be a separate object, called EProgram or something,
      that owns both the instructions and the symbols.  It should be ref_counted,
      so a code repository can store programs that multiple Executors use.
      That means debugger stuff has to come out of Instruction.
      */
  unsigned nLines;

  std::vector<BObjectRef> fparams;

  friend class ExecutorModule;
  void setFunctionResult( BObjectImp* imp );

protected:
  int getParams( unsigned howMany );
  void expandParams();
  void cleanParams();

public:
  // Creates a new continuation object to call `funcref` with arguments `args`,
  // calling a core `callback` with the return value.
  //
  // Responsible for moving the arguments to the `ValueStack` stack,
  // expanding/shrinking as needed. The executor, when seeing a `BContinuation`
  // inside `ins_call_method_id`, will "translate" it to a `BFunctionRef` to
  // call. The handling of `BFunctionRef`s _inside_ `ins_call_method_id`
  // requires arguments to be on `ValueStack`.
  //
  // Since this runs inside `ins_call_method_id`, it can **only** be used in
  // `<object>.<method>` calls. Extending where this is called will require
  // changing implementation.
  //
  // Returns `BContinuation*` on success, `BError*` on failure (if provided
  // funcref is not a BFunctionRef).
  template <typename Callback>
  BObjectImp* makeContinuation( BObjectRef funcref, Callback&& callback, BObjectRefVec args = {} );

  // Runs the existing continuation object with arguments `args`.
  //
  // Responsible for moving the arguments to the `fparams` stack. The handling
  // of `BFunctionRef`s _outside_ `ins_call_method_id` requires arguments to be
  // on `fparams` (as they are moved to `ValueStack` in `ins_call_method_id`).
  BContinuation* withContinuation( BContinuation* continuation, BObjectRefVec args = {} );

  // Runs `callback( unsigned int PC )` for every frame in the call stack.
  template <typename Callback>
  void walkCallStack( Callback&& callback );

  int makeString( unsigned param );
  bool hasParams( unsigned howmany ) const { return ( fparams.size() >= howmany ); }
  size_t numParams() const { return fparams.size(); }
  BObjectImp* getParamImp( unsigned param );
  BObjectImp* getParamImp( unsigned param, BObjectImp::BObjectType type );
  BObjectImp* getParamImp2( unsigned param, BObjectImp::BObjectType type );
  BObject* getParamObj( unsigned param );

  const String* getStringParam( unsigned param );
  const BLong* getLongParam( unsigned param );

  bool getStringParam( unsigned param, const String*& pstr );
  bool getUnicodeStringParam( unsigned param, const String*& pstr );  // accepts also BLong array
  bool getParam( unsigned param, int& value );
  bool getParam( unsigned param, int& value, int maxval );
  bool getParam( unsigned param, int& value, int minval, int maxval );
  bool getRealParam( unsigned param, double& value );
  bool getObjArrayParam( unsigned param, ObjArray*& pobjarr );

  bool getParam( unsigned param, unsigned& value );

  bool getParam( unsigned param, unsigned short& value );
  bool getParam( unsigned param, unsigned short& value, unsigned short maxval );
  bool getParam( unsigned param, unsigned short& value, unsigned short minval,
                 unsigned short maxval );

  bool getParam( unsigned param, short& value );
  bool getParam( unsigned param, short& value, short maxval );
  bool getParam( unsigned param, short& value, short minval, short maxval );
  bool getParam( unsigned param, signed char& value );

  bool getParam( unsigned param, bool& value );

  BApplicObjBase* getApplicObjParam( unsigned param, const BApplicObjType* object_type );


  const char* paramAsString( unsigned param );
  double paramAsDouble( unsigned param );
  int paramAsLong( unsigned param );

protected:
  int makeDouble( unsigned param );


  BObject* getParam( unsigned param );

  BObject getValue();
  BObjectRef getObjRef();

public:
  int getToken( Token& token, unsigned position );
  BObjectRef& LocalVar( unsigned int varnum );
  BObjectRef& GlobalVar( unsigned int varnum );
  int makeGlobal( const Token& token );
  void popParam( const Token& token );
  void popParamByRef( const Token& token );
  void getArg( const Token& token );
  void pushArg( BObjectImp* arg );
  void pushArg( const BObjectRef& ref );

  static BObjectRef addmember( BObject& left, const BObject& right );
  static BObjectRef removemember( BObject& left, const BObject& right );
  static BObjectRef checkmember( BObject& left, const BObject& right );
  void addmember2( BObject& left, const BObject& right );
  static bool builtinMethodForced( const char*& methodname );

  // execmodules: modules associated with the current program.  References modules owned by
  // availmodules.
  std::vector<ExecutorModule*> execmodules;
  std::vector<ExecutorModule*> availmodules;  // owns

public:
  Executor();
  virtual ~Executor();
  Executor( const Executor& exec ) = delete;
  Executor& operator=( const Executor& exec ) = delete;

  void addModule( ExecutorModule* module );  // NOTE, executor deletes its modules when done
  ExecutorModule* findModule( const std::string& name );

  ModuleFunction* current_module_function;
  // NOTE: the debugger code expects these to be virtual..
  void execFunc( const Token& token );
  void execInstr();

  void ins_nop( const Instruction& ins );
  void ins_jmpiftrue( const Instruction& ins );
  void ins_jmpiffalse( const Instruction& ins );
  void ins_skipiftrue_else_consume( const Instruction& ins );
  void ins_globalvar( const Instruction& ins );
  void ins_localvar( const Instruction& ins );
  void ins_makeLocal( const Instruction& ins );
  void ins_declareArray( const Instruction& ins );
  void ins_bool( const Instruction& ins );
  void ins_long( const Instruction& ins );
  void ins_double( const Instruction& ins );
  void ins_classinst( const Instruction& ins );
  void ins_string( const Instruction& ins );
  void ins_regexp( const Instruction& ins );
  void ins_error( const Instruction& ins );
  void ins_struct( const Instruction& ins );
  void ins_spread( const Instruction& ins );
  void ins_array( const Instruction& ins );
  void ins_dictionary( const Instruction& ins );
  void ins_uninit( const Instruction& ins );
  void ins_ident( const Instruction& ins );
  void ins_unminus( const Instruction& ins );
  void ins_unplusplus( const Instruction& ins );
  void ins_unminusminus( const Instruction& ins );
  void ins_unplusplus_post( const Instruction& ins );
  void ins_unminusminus_post( const Instruction& ins );

  void ins_logical_and( const Instruction& ins );
  void ins_logical_or( const Instruction& ins );
  void ins_logical_not( const Instruction& ins );

  void ins_bitwise_not( const Instruction& ins );

  void ins_set_member( const Instruction& ins );
  void ins_set_member_consume( const Instruction& ins );
  void ins_get_member( const Instruction& ins );
  void ins_get_member_id( const Instruction& ins );                       // test id
  void ins_set_member_id( const Instruction& ins );                       // test id
  void ins_set_member_id_consume( const Instruction& ins );               // test id
  void ins_set_member_id_consume_plusequal( const Instruction& ins );     // test id
  void ins_set_member_id_consume_minusequal( const Instruction& ins );    // test id
  void ins_set_member_id_consume_timesequal( const Instruction& ins );    // test id
  void ins_set_member_id_consume_divideequal( const Instruction& ins );   // test id
  void ins_set_member_id_consume_modulusequal( const Instruction& ins );  // test id
  void ins_set_member_id_unplusplus( const Instruction& ins );            // test id
  void ins_set_member_id_unminusminus( const Instruction& ins );          // test id
  void ins_set_member_id_unplusplus_post( const Instruction& ins );       // test id
  void ins_set_member_id_unminusminus_post( const Instruction& ins );     // test id

  void ins_assign_localvar( const Instruction& ins );
  void ins_assign_globalvar( const Instruction& ins );
  void ins_assign_consume( const Instruction& ins );
  void ins_consume( const Instruction& ins );
  void ins_assign( const Instruction& ins );
  void ins_array_assign( const Instruction& ins );
  void ins_array_assign_consume( const Instruction& ins );
  void ins_multisubscript_assign( const Instruction& ins );
  void ins_multisubscript_assign_consume( const Instruction& ins );
  void ins_multisubscript( const Instruction& ins );

  void ins_unpack_sequence( const Instruction& ins );
  void ins_unpack_indices( const Instruction& ins );
  void ins_take_local( const Instruction& ins );
  void ins_take_global( const Instruction& ins );

  void ins_add( const Instruction& ins );
  void ins_subtract( const Instruction& ins );
  void ins_mult( const Instruction& ins );
  void ins_div( const Instruction& ins );
  void ins_modulus( const Instruction& ins );

  void ins_is( const Instruction& ins );

  void ins_interpolate_string( const Instruction& ins );
  void ins_format_expression( const Instruction& ins );

  void ins_insert_into( const Instruction& ins );

  void ins_plusequal( const Instruction& ins );
  void ins_minusequal( const Instruction& ins );
  void ins_timesequal( const Instruction& ins );
  void ins_divideequal( const Instruction& ins );
  void ins_modulusequal( const Instruction& ins );

  void ins_bitshift_right( const Instruction& ins );
  void ins_bitshift_left( const Instruction& ins );
  void ins_bitwise_and( const Instruction& ins );
  void ins_bitwise_xor( const Instruction& ins );
  void ins_bitwise_or( const Instruction& ins );

  void ins_equal( const Instruction& ins );
  void ins_notequal( const Instruction& ins );
  void ins_lessthan( const Instruction& ins );
  void ins_lessequal( const Instruction& ins );
  void ins_greaterthan( const Instruction& ins );
  void ins_greaterequal( const Instruction& ins );

  void ins_goto( const Instruction& ins );
  void ins_arraysubscript( const Instruction& ins );
  void ins_func( const Instruction& ins );
  void ins_call_method( const Instruction& ins );
  void ins_call_method_id( const Instruction& ins );
  void ins_statementbegin( const Instruction& ins );
  void ins_progend( const Instruction& ins );
  void ins_makelocal( const Instruction& ins );
  void ins_check_mro( const Instruction& ins );
  void ins_jsr_userfunc( const Instruction& ins );
  void ins_pop_param( const Instruction& ins );
  void ins_pop_param_byref( const Instruction& ins );
  void ins_get_arg( const Instruction& ins );
  void ins_leave_block( const Instruction& ins );
  void ins_gosub( const Instruction& ins );
  void ins_return( const Instruction& ins );
  void ins_exit( const Instruction& ins );

  void ins_member( const Instruction& ins );
  void ins_addmember( const Instruction& ins );
  void ins_removemember( const Instruction& ins );
  void ins_checkmember( const Instruction& ins );
  void ins_dictionary_addmember( const Instruction& ins );
  void ins_addmember2( const Instruction& ins );
  void ins_addmember_assign( const Instruction& ins );
  void ins_in( const Instruction& ins );

  void ins_initforeach( const Instruction& ins );
  void ins_stepforeach( const Instruction& ins );

  void ins_casejmp( const Instruction& ins );
  void ins_initfor( const Instruction& ins );
  void ins_nextfor( const Instruction& ins );

  void ins_funcref( const Instruction& ins );
  void ins_functor( const Instruction& ins );

  void ins_logical_jump( const Instruction& ins );
  void ins_logical_convert( const Instruction& ins );

  static int ins_casejmp_findlong( const Token& token, BLong* blong );
  static int ins_casejmp_findbool( const Token& token, BBoolean* bbool );
  static int ins_casejmp_findstring( const Token& token, String* bstringimp );
  static int ins_casejmp_finduninit( const Token& token );
  static int ins_casejmp_finddefault( const Token& token );

  bool running_to_completion() const;
  void set_running_to_completion( bool to_completion );

  bool runnable() const;
  void calcrunnable();

  bool halt() const;
  void sethalt( bool halt );

  // Takes ownership of `continuation`. If `funcref` is present, checks if jump
  // is "external" (ie. current program is different than funcref's), and if so,
  // sets up members (Globals2, nLines, prog_, execmodules) accordingly.
  void jump( int target_PC, BContinuation* continuation, BFunctionRef* funcref );

  // Returns the current execution stack of this executor. The returned object
  // is either a string containing a line for each stack frame, or an array of
  // objects representing each stack frame.
  //
  // Will load the debug symbols for the current program. If debug symbols are
  // not available, only program counter information will be available, and
  // filename+line+function name will be empty.
  BObjectImp* get_stacktrace( bool as_array );

  bool attach_debugger( std::weak_ptr<ExecutorDebugListener> listener = {},
                        bool set_attaching = true );
  void detach_debugger();
  void print_to_debugger( const std::string& message );
  std::string dbg_get_instruction( size_t atPC ) const;
  void dbg_get_instruction( size_t atPC, std::string& os ) const;
  void dbg_ins_trace();
  void dbg_step_into();
  void dbg_step_over();
  void dbg_step_out();
  void dbg_run();
  void dbg_break();
  void dbg_setbp( unsigned atPC );
  void dbg_clrbp( unsigned atPC );
  void dbg_clrbps( const std::set<unsigned>& PCs );
  void dbg_clrallbp();

  bool exec();
  void reinitExec();
  void initForFnCall( unsigned in_PC );
  void show_context( unsigned atPC );
  void show_context( std::string& os, unsigned atPC );

  void call_function_reference( BFunctionRef* funcref, BContinuation* continuation,
                                const Instruction& jmp );

  int getDebugLevel() { return debug_level; }
  void setDebugLevel( DEBUG_LEVEL level ) { debug_level = level; }
  void setViewMode( bool vm ) { viewmode_ = vm; }
  const std::string& scriptname() const;
  bool empty_scriptname();
  const EScriptProgram* prog() const;

  virtual unsigned int pid() const { return 0; };

private:
  ref_ptr<EScriptProgram> prog_;
  bool prog_ok_;
  bool viewmode_;

  bool runs_to_completion_;

  std::unique_ptr<ExecutorDebugEnvironment> dbg_env_;

  BObjectImp* func_result_;

  void printStack( const std::string& message );

protected:
  friend class BClassInstance;
  void cleanup();

  struct ClassMethodKey
  {
    ref_ptr<EScriptProgram> prog;
    unsigned index;
    std::string method_name;
    bool operator<( const ClassMethodKey& other ) const;
  };

  std::map<ClassMethodKey, BObjectRef /*function ref*/> class_methods;
};

inline const std::string& Executor::scriptname() const
{
  return prog_->name;
}

inline bool Executor::empty_scriptname()
{
  return prog_->name.get().empty();
}

inline const EScriptProgram* Executor::prog() const
{
  return prog_.get();
}

inline bool Executor::runnable() const
{
  return run_ok_;
}
inline void Executor::calcrunnable()
{
  run_ok_ = !error_ && !halt_;
}

inline void Executor::seterror( bool err )
{
  error_ = err;
  calcrunnable();
}
inline bool Executor::error() const
{
  return error_;
}

inline bool Executor::halt() const
{
  return halt_;
}

inline bool Executor::running_to_completion() const
{
  return runs_to_completion_;
}
inline void Executor::set_running_to_completion( bool to_completion )
{
  runs_to_completion_ = to_completion;
}

#ifdef ESCRIPT_PROFILE
class EscriptProfiler
{
public:
  EscriptProfiler( ExecutorModule* em, const ModuleFunction* modfunc,
                   const std::vector<BObjectRef>& fparams );

  EscriptProfiler( const Instruction& ins, const BObjectRef& leftref,
                   const std::vector<BObjectRef>& fparams );
  EscriptProfiler( const Instruction& ins, const BObjectImp* callee, const char* method_name,
                   const std::vector<BObjectRef>& fparams );
  ~EscriptProfiler();
  static std::string result();

private:
  Tools::HighPerfTimer timer_{};
  std::string name_{};
  struct profile_instr
  {
    int64_t sum;
    int64_t max;
    int64_t min;
    int64_t count;
  };
  static std::map<std::string, profile_instr> escript_profile_map_;
};
#define ESCRIPT_PROFILER EscriptProfiler escript_profiler
#else
#define ESCRIPT_PROFILER( ... )
#endif
}  // namespace Bscript
}  // namespace Pol
#endif