//DingusPPC
//Written by divingkatae and maximum
//(c)2018-20 (theweirdo)     spatium
//Please ask for permission
//if you want to distribute this.
//(divingkatae#1017 or powermax#2286 on Discord)

//The main runfile - main.cpp
//This is where the magic begins

#include <iostream>
#include <map>
#include <cstring>
#include <cinttypes>
#include <array>
#include <stdio.h>
#include <fstream>
#include <stdexcept>
#include "ppcemu.h"
#include "ppcmmu.h"
#include "memreadwrite.h"
#include "devices/mpc106.h"
#include "debugger/debugger.h"
#include "devices/machineid.h"
#include "devices/macio.h"
#include "devices/mpc106.h"

using namespace std;

/**
    Power Macintosh ROM identification string

    is located in the ConfigInfo structure starting at 0x30D064 (PCI Macs)
    or 0x30C064 (Nubus Macs). This helps a lot to determine which
    hardware is to be used.
*/
static const map<string,string> PPCMac_ROMIdentity = { //Codename Abbreviation for...
    {"Alch", "Performa 6400"},                         //Alchemy
    {"Come", "PowerBook 2400"},                        //Comet
    {"Cord", "Power Mac 5200/6200 series"},            //Cordyceps
    {"Gaze", "Power Mac 6500"},                        //Gazelle
    {"Goss", "Power Mac G3 Beige"},                    //Gossamer
    {"GRX ", "PowerBook G3 Wallstreet"},               //(Unknown)
    {"Hoop", "PowerBook 3400"},                        //Hooper
    {"PBX ", "PowerBook Pre-G3"},                      //(Unknown)
    {"PDM ", "Nubus Power Mac or WGS"},                //Piltdown Man (6100/7100/8100)
    {"Pip ", "Pippin... uh... yeah..."},               //Pippin
    {"Powe", "Generic Power Mac"},                     //PowerMac?
    {"Spar", "20th Anniversay Mac, you lucky thing."}, //Spartacus
    {"Tanz", "Power Mac 4400"},                        //Tanzania
    {"TNT ", "Power Mac 7xxxx/8xxx series"},           //Trinitrotoluene :-)
    {"Zanz", "A complete engima."},                    //Zanzibar (mentioned in Sheepshaver's code, but no match to any known ROM)
    {"????", "A clone, perhaps?"}                      //N/A (Placeholder ID)
};


SetPRS ppc_state;

bool is_nubus = 0;

bool grab_branch;
bool grab_exception;
bool grab_return;
bool grab_breakpoint;

uint32_t ppc_cur_instruction; //Current instruction for the PPC
uint32_t ppc_effective_address;
uint32_t ppc_real_address;
uint32_t ppc_next_instruction_address; //Used for branching, setting up the NIA

uint32_t return_value;

MemCtrlBase *mem_ctrl_instance = 0;
HeathrowIC  *heathrow = 0;
GossamerID  *machine_id;

unsigned char * machine_sysram_mem;
unsigned char * machine_sysrom_mem;

uint32_t grab_sysram_size;
uint32_t grab_iocont_size;
uint32_t grab_sysrom_size;

uint32_t ram_size_set;

uint32_t prev_msr_state = 0;
uint32_t cur_msr_state = 0;

//MSR Flags
bool msr_es_change; //Check Endian

uint32_t rom_file_begin; //where to start storing ROM files in memory
uint32_t pci_io_end;

uint32_t rom_filesize;

uint32_t write_opcode;
uint8_t write_char;

//Initialize the PPC's registers.
void reg_init(){
    for (uint32_t i = 0; i < 32; i++){
        ppc_state.ppc_fpr[i] = 0;
    }
    ppc_state.ppc_pc = 0;
    for (uint32_t i = 0; i < 32; i++){
        ppc_state.ppc_gpr[i] = 0;
    }
    ppc_state.ppc_cr = 0;
    ppc_state.ppc_fpscr = 0;
    ppc_state.ppc_tbr[0] = 0;
    ppc_state.ppc_tbr[1] = 0;

    for (uint32_t i = 0; i < 1024; i++){
        switch(i){
            case 287:
               //Identify as a G3
               //Processor IDS
               // 601 v1  -  00010001
               // 603 v1  -  00030001
               // 604 v1  -  00040001
               // 603e v1 -  00060101
               // 750 v1  -  00080200
                ppc_state.ppc_spr[i] = 0x00080200;
                break;
                /**
            case 528:
            case 536:
                ppc_state.ppc_spr[i] = 0x00001FFE;
                break;
            case 530:
            case 538:
                ppc_state.ppc_spr[i] = 0xC0001FFE;
                break;
            case 532:
            case 540:
                ppc_state.ppc_spr[i] = 0xE0001FFE;
                break;
            case 534:
            case 542:
                ppc_state.ppc_spr[i] = 0xF0001FFE;
                break;
            case 529:
            case 531:
            case 537:
            case 539:
                ppc_state.ppc_spr[i] = 0x00000002;
                break;
            case 533:
            case 541:
                ppc_state.ppc_spr[i] = 0xE0000002;
                break;
            case 535:
                ppc_state.ppc_spr[i] = 0xF0000002;
                break;
            case 543:
                ppc_state.ppc_spr[i] = 0x00000002;
                break;
            **/
            default:
                ppc_state.ppc_spr[i] = 0;
        }
    }


    //Only bit 25 of the MSR is initially set on bootup.
    ppc_state.ppc_msr = 0x40;
    for (uint32_t i = 0; i < 16; i++){
        ppc_state.ppc_sr[i] = 0;
    }
}

//Debugging Functions
uint32_t reg_print(){
    for (uint32_t i = 0; i < 32; i++){
        printf("FPR %d : %" PRIx64 "", i, ppc_state.ppc_fpr[i]);
    }
    ppc_state.ppc_pc = 0;
    for (uint32_t i = 0; i < 32; i++){
        printf("GPR %d : %x", i, ppc_state.ppc_gpr[i]);
    }
    printf("CR : %x", ppc_state.ppc_cr);
    printf("FPSCR : %x", ppc_state.ppc_fpscr);
    printf("TBR 0 : %x", ppc_state.ppc_tbr[0]);
    printf("TBR 1 : %x", ppc_state.ppc_tbr[1]);

    for (uint32_t i = 0; i < 1024; i++){
        printf("SPR %d  : %x", i, ppc_state.ppc_spr[i]);
    }

    printf("CR  : %x", ppc_state.ppc_cr);

    printf("MSR : %x", ppc_state.ppc_msr);

    for (uint32_t i = 0; i < 16; i++){
        printf("SR %d : %x", i, ppc_state.ppc_sr[i]);
    }

    return 0;
}

uint32_t reg_read(){
    uint32_t grab_me = 0;
    std::cout << hex << "TODO: Decide which register to read from; for now, which GPR?" << endl;
    //printf("Which register to read from? 0 - GPR, 1 = FPR, 2 = CR, 3 = FPSCR");
    std::cin >> hex >> grab_me;
    if (grab_me < 32){
        printf("GPR value: %d", ppc_state.ppc_gpr[grab_me]);
    }
    return 0;
}

uint32_t reg_write(){
    uint32_t grab_me = 0;
    std::cout << hex << "TODO: Decide which register to write to; for now, which GPR?" << endl;
    //printf("Which register to write to? 0 - GPR, 1 = FPR, 2 = CR, 3 = FPSCR");
    std::cin >> hex >> grab_me;
    if (grab_me < 32){
        printf("GPR value: %d", ppc_state.ppc_gpr[grab_me]);
    }
    return 0;
}

int main(int argc, char **argv)
{
    ram_size_set = 0x4000000; //64 MB of RAM for the Mac

    rom_file_begin = 0xFFF00000; //where to start storing ROM files in memory
    pci_io_end = 0x83FFFFFF;
    rom_filesize = 0x400000;

    //Init virtual CPU.
    reg_init();

    //0xFFF00100 is where the reset vector is.
    //In other words, begin executing code here.
    ppc_state.ppc_pc = 0xFFF00100;

    uint32_t opcode_entered = 0; //used for testing opcodes in playground

    std::cout << "DingusPPC - Prototype 5bf4 (7/14/2019)       " << endl;
    std::cout << "Written by divingkatae, (c) 2019.            " << endl;
    std::cout << "This is not intended for general use.        " << endl;
    std::cout << "Use at your own discretion.                  " << endl;

    //Open the ROM File.
    ifstream romFile;

    romFile.open("rom.bin", ios::in|ios::binary);

    if (romFile.fail()){
        cerr << "rom.bin not present. Please provide an appropriate ROM file"
             << " and restart this program.\n";

        romFile.close();
        return 1;
    }

    //Calculate and validate ROM file size.
    romFile.seekg(0, romFile.end);
    rom_filesize = (uint32_t) romFile.tellg();
    printf("Rom SIZE: %d \n", rom_filesize);
    romFile.seekg (0, romFile.beg);

    if (rom_filesize != 0x400000){
        cerr << "Unsupported ROM File size. Expected size is 4 megabytes.\n";
        romFile.close();
        return 1;
    }

    machine_sysram_mem = (unsigned char*) calloc (67108864, 1);
    machine_sysrom_mem = (unsigned char*) calloc (rom_filesize, 1);

    memset(machine_sysram_mem, 0x0, 67108864);

    grab_sysram_size = sizeof(machine_sysram_mem);
    grab_sysrom_size = rom_filesize;

    //Sanity checks - Prevent the input files being too small or too big.
    //Also prevent the ROM area from overflow.
    if (ram_size_set < 0x800000){
        cerr << "The RAM size must be at least 8 MB to function.\n";
        return 1;
    }
    else if (ram_size_set > 0x20000000){
        cerr << "RAM too big. Must be no more than 2 GB.\n";
        return 1;
    }

    rom_file_begin = 0xFFFFFFFF - grab_sysrom_size + 1;

    char configGrab = 0;
    uint32_t configInfoOffset = 0;

    romFile.seekg (0x300082, ios::beg); //This is where the place to get the offset is
    romFile.get(configGrab); //just one byte to determine ConfigInfo location
    configInfoOffset = (uint32_t)(configGrab & 0xff);

    if (configInfoOffset == 0xC0){
        is_nubus = 1;
    }

    uint32_t configInfoAddr = 0x300000 + (configInfoOffset << 8) + 0x69; //address to check the identifier string
    char memPPCBlock[5]; //First four chars are enough to distinguish between codenames
    romFile.seekg (configInfoAddr, ios::beg);
    romFile.read(memPPCBlock, 4);
    memPPCBlock[4] = 0;
    uint32_t rom_id = READ_DWORD_BE_A(memPPCBlock);

    std::string string_test = std::string(memPPCBlock);

    //Just auto-iterate through the list
    for (auto iter = PPCMac_ROMIdentity.begin(); iter != PPCMac_ROMIdentity.end(); ){

        string redo_me = iter->first;

        if (string_test.compare(redo_me) == 0){
            cout << "The machine is identified as..." << iter->second << endl;
            romFile.seekg (0x0, ios::beg);
            break;
        }
        else{
            iter++;
        }
    }

    switch(rom_id) {
    case 0x476F7373: {
            cout << "Initialize Gossamer hardware..." << endl;
            MPC106 *mpc106 = new MPC106();
            mem_ctrl_instance = mpc106;
            if (!mem_ctrl_instance->add_rom_region(0xFFC00000, 0x400000)) {
                cout << "failure!\n" << endl;
                delete(mem_ctrl_instance);
                romFile.close();
                return 1;
            }
            machine_id = new GossamerID(0x3d8c);
            mpc106->add_mmio_region(0xFF000004, 4096, machine_id);

            heathrow = new HeathrowIC();
            mpc106->pci_register_device(16, heathrow);
            cout << "done" << endl;
        }
        break;
    default:
        cout << "This machine not supported yet." << endl;
        return 1;
    }

    //Read ROM file content and transfer it to the dedicated ROM region
    romFile.read ((char *)machine_sysrom_mem,grab_sysrom_size);
    mem_ctrl_instance->set_data(0xFFC00000, machine_sysrom_mem, rom_filesize);
    romFile.close();

    if (argc > 1){
        string checker = argv[1];
        cout << checker << endl;
        if (checker == "fuzzer"){
            //Brute force every instruction that the PPC can interpret.
            //TODO: Change this so that this goes through user-specified instructions.
            ppc_cur_instruction = 0xFFFFFFFF;
            std::cout << "Testing Opcode: " << ppc_cur_instruction  << endl;
            while (ppc_cur_instruction > 0x00000000){
                ppc_main_opcode();
                ppc_cur_instruction--;
            }
        }
        else if ((checker=="1")|(checker=="realtime")|(checker=="/realtime")|(checker=="-realtime")){
            ppc_exec();
        }
        else if ((checker=="e")|(checker=="loadelf")|(checker=="/loadelf")|(checker=="-loadelf")){
            ifstream elfFile;
            uint32_t elf_file_setsize = 0;

            char elf_headerchk [4];
            char elf_bformat [1];
            char elf_machine [2];
            char elf_memoffset [4];

            elfFile.seekg(0, elfFile.end);
            elf_file_setsize = (uint32_t) elfFile.tellg();
            elfFile.seekg (0, elfFile.beg);

            if (elf_file_setsize < 45){
                cerr << "Elf File TOO SMALL. Please make sure it's a legitimate file.";

                return 1;
            }
            else if (elf_file_setsize > ram_size_set){
                cerr << "Elf File TOO BIG. Please make sure it fits within memory.";

                return 1;
            }

            //There's got to be a better way to get fields of info from an ELF file.
            elfFile.seekg(0x0, ios::beg); //ELF file begins here
            elfFile.read(elf_headerchk, 4);
            elfFile.seekg(0x4, ios::cur);
            elfFile.read(elf_bformat, 1);
            elfFile.seekg(0x8, ios::cur);
            elfFile.read(elf_machine, 2);
            elfFile.seekg(0x6, ios::cur);
            elfFile.read(elf_memoffset, 4);
            elfFile.seekg (0, elfFile.beg);

            bool elf_valid_check = (atoi(elf_headerchk) == 0x7F454C46) && (atoi(elf_bformat) == 1) &&\
                                   ((atoi(elf_machine) == 0) | (atoi(elf_machine) == 20));

            if (!elf_valid_check){
                cerr << "The ELF file inserted was not legitimate. Please try again." << endl;
                return 1;
            }

            elfFile.read ((char *)machine_sysram_mem,ram_size_set);

            if (argc > 2){
                string elfname = string(argv[1]);
                elfname = elfname + ".elf";
                elfFile.open(elfname, ios::in|ios::binary);
            }
            else{
                elfFile.open("test.elf", ios::in|ios::binary);
            }
            if (elfFile.fail()){
                cerr << "Please insert the elf file before continuing.\n";

                return 1;
            }

            ppc_state.ppc_pc = atoi(elf_memoffset);

            ppc_exec();
        }
        else if ((checker=="until")|(checker=="/until")|(checker=="-until")){
            uint32_t grab_bp = 0x0;

            std::cout << hex << "Enter the address in hex for where to stop execution." << endl;
            cin >> hex >> grab_bp;

            ppc_exec_until(grab_bp);
        }
        else if (checker=="disas"){
            if (argc > 2){
                checker = argv[1];
            }
            else{
                checker = "\\compile.txt";
            }
            ifstream inFile (checker, ios::binary | ios::ate);
            if (!inFile) {
                cerr << "Unable to open file for assembling.";
                exit(1);
            }
        }
        else if ((checker=="stepi")|(checker=="/stepi")|(checker=="-stepi")){
            std::cout << hex << "Ready to execute an opcode?" << endl;

            string check_q;
            cin >> check_q;
            getline (cin, check_q);

            if (check_q != "No"){
                quickinstruction_translate(ppc_state.ppc_pc);
                ppc_main_opcode();
                if (grab_branch & !grab_exception){
                    ppc_state.ppc_pc = ppc_next_instruction_address;
                    grab_branch = 0;
                    ppc_tbr_update();
                }
                else if (grab_return | grab_exception){
                    ppc_state.ppc_pc = ppc_next_instruction_address;
                    grab_exception = 0;
                    grab_return = 0;
                    ppc_tbr_update();
                }
                else{
                    ppc_state.ppc_pc += 4;
                    ppc_tbr_update();
                }
            }
        }
        else if ((checker=="stepp")|(checker=="/stepp")|(checker=="-stepp")){
            std::cout << hex << "Ready to execute a page of opcodes?" << endl;

            string check_q;
            cin >> check_q;
            getline (cin, check_q);

            if (check_q != "No"){
                for (int instructions_to_do = 0; instructions_to_do < 256; instructions_to_do++){
                    quickinstruction_translate(ppc_state.ppc_pc);
                    ppc_main_opcode();
                    if (grab_branch & !grab_exception){
                        ppc_state.ppc_pc = ppc_next_instruction_address;
                        grab_branch = 0;
                        ppc_tbr_update();
                    }
                    else if (grab_return | grab_exception){
                        ppc_state.ppc_pc = ppc_next_instruction_address;
                        grab_exception = 0;
                        grab_return = 0;
                        ppc_tbr_update();
                    }
                    else{
                        ppc_state.ppc_pc += 4;
                        ppc_tbr_update();
                    }
                }
            }
        }
        else if ((checker=="play")|(checker=="playground")|(checker=="/playground")|(checker=="-playground")){
            std::cout << hex << "Enter any opcodes for the PPC you want here." << endl;

            while (power_on){
                cin >> hex >> opcode_entered;
                //power off the PPC
                if (opcode_entered == 0x00000000){
                    power_on = 0;
                }
                //print registers
                else if (opcode_entered == 0x00000001){
                    reg_print();
                }
                else if (opcode_entered == 0x00000002){
                    reg_read();
                }
                else if (opcode_entered == 0x00000003){
                    reg_write();
                }
                //test another opcode
                else{
                    ppc_cur_instruction = opcode_entered;
                    quickinstruction_translate(ppc_state.ppc_pc);
                    ppc_main_opcode();
                    if (grab_branch & !grab_exception){
                        ppc_state.ppc_pc = ppc_next_instruction_address;
                        grab_branch = 0;
                        ppc_tbr_update();
                    }
                    else if (grab_return | grab_exception){
                        ppc_state.ppc_pc = ppc_next_instruction_address;
                        grab_exception = 0;
                        grab_return = 0;
                        ppc_tbr_update();
                    }
                    else{
                        ppc_state.ppc_pc += 4;
                        ppc_tbr_update();
                    }
                }
            }
        } else if (checker == "debugger") {
            enter_debugger();
        }
    }
    else{
        std::cout << "                    " << endl;
        std::cout << "Please enter one of the following commands when " << endl;
        std::cout << "booting up DingusPPC...                         " << endl;
        std::cout << "                    " << endl;
        std::cout << "                    " << endl;
        std::cout << "realtime - Run the emulator in real-time.       " << endl;
        std::cout << "loadelf - Load an ELF file to run from RAM.     " << endl;
        std::cout << "debugger - Enter the interactive debugger.      " << endl;
        std::cout << "fuzzer - Test every single PPC opcode.          " << endl;
        std::cout << "stepp - Execute a page of opcodes per key press." << endl;
        std::cout << "playground - Mess around with and opcodes.      " << endl;
    }

    delete(heathrow);
    delete(machine_id);
    delete(mem_ctrl_instance);

    //Free memory after the emulation is completed.
    free(machine_sysram_mem);
    free(machine_sysrom_mem);

    return 0;
}