#ifndef MACHINE_H
#define MACHINE_H

#include <string>
#include <iostream>
#include <vector>

#include "device.h"
#include "input_device.h"
#include "output_device.h"
#include "file_device.h"
#include "opcode.h"

#include <memory>

#define MEMORY_SIZE 65536
#define NUM_DEVICES 256


using std::string;
using std::cerr;
using std::endl;
using std::cout;


class Machine {
public:
    Machine();
    ~Machine();

    // Accessor methods for registers
    int getA() const { return A; }
    void setA(int value) { A = value; }

    int getB() const { return B; }
    void setB(int value) { B = value; }

    int getX() const { return X; }
    void setX(int value) { X = value; }

    int getL() const { return L; }
    void setL(int value) { L = value; }

    int getS() const { return S; }
    void setS(int value) { S = value; }

    int getT() const { return T; }
    void setT(int value) { T = value; }

    int getPC() const { return PC; }
    void setPC(int value) { PC = value; }

    int getSW() const { return SW; }
    void setSW(int value) { SW = value; }

    double getF() const { return F; }
    void setF(double value) { F = value; }

    int getReg(int regNum) const;
    void setReg(int regNum, int value);

    // Memory access methods
    int getByte(int address);
    void setByte(int address, int value);

    int getWord(int address);
    void setWord(int address, int value);

    double getFloat(int address);
    void setFloat(int address, double value);


    // Device access methods
    Device& getDevice(int num);
    void setDevice(int num, std::shared_ptr<Device> device);
    // Set a file device at index `num` using the provided filename.
    void setFileDevice(int num, const std::string &filename);


    // Fetch and execute instructions
    int fetch();
    void execute();

    bool execF1(int opcode);
    bool execF2(int opcode, int operand);
    bool execSICF3F4(int opcode, int ni, int operand);

    // error handling methods
    void notImplemented(string mnemonic);
    void invalidOpcode(int opcode);
    void invalidAddressing();
    void divisionByZero(int opcode);
    void undefinedHandler(int opcode);

private:
    // registers
    int A, B, X, L, S, T, PC, SW;
    double F;

    // memory
    unsigned char memory[MEMORY_SIZE];

    // devices
    std::vector<std::shared_ptr<Device>> devices;
    // fallback device returned when device slot is empty/invalid
    Device fallbackDevice;
};

    // Convert integer to 24-bit signed SIC representation
inline int toSIC24(int value) {
    value &= 0xFFFFFF;
    if (value & 0x800000) {
        value -= 0x1000000;
    }
    return value;
}

inline int setCC(int sw, int cc) {
    sw &= ~CC_MASK;     
    sw |= (cc & CC_MASK);
    return sw;
}

inline int sic_comp(int a, int b, int sw) {
    int sa = toSIC24(a);
    int sb = toSIC24(b);

    int cc;
    if (sa < sb) {
        cc = CC_LT;
    } else if (sa == sb) {
        cc = CC_EQ;
    } else {
        cc = CC_GT;
    }

    return setCC(sw, cc);
}

inline int getCC(int sw) {
    return sw & CC_MASK;
}


#endif // MACHINE_H