#include "cpu.h"

#include <algorithm>
#include <utility>
#include <iterator>
#include <vector>
#include <set>
#include <map>
#include <stdlib.h>
#include <iostream>
#include <iomanip>
#include <fstream>

#include "nodes.h"
#include "addressbus.h"

//#define TRACE 1

CPU::CPU(AddressBus& addressBus) :
addressBus(addressBus) {
    std::cout << "reading segsonly";
    std::ifstream if_segs("segsonly");
    if (!if_segs.is_open()) {
        std::cerr << "error opening file: segs" << std::endl;
        exit(EXIT_FAILURE);
    }

    int i_seg(0);
    while (if_segs.good()) {
        int i_segin(-1);
        bool b_on(false);
        if_segs >> i_segin >> b_on;
        if (i_segin >= 0) {
            if (i_segin != i_seg++) {
                std::cerr << "error: mismatch in segsonly file near " << i_segin << std::endl;
                exit(EXIT_FAILURE);
            }
            std::cout << ".";
            seg s;
            s.pullup = b_on;
            s.pulldown = false;
            s.on = false;
            segs.push_back(s);
        }
    }
    std::cout << std::endl << "read " << segs.size() << " segs" << std::endl;



    std::cout << "reading trns";
    std::ifstream if_trns("trns");
    if (!if_trns.is_open()) {
        std::cerr << "error opening file: trns" << std::endl;
        exit(EXIT_FAILURE);
    }

    int i_trn(0);
    while (if_trns.good()) {
        std::cout << ".";
        int i_trnin(-1);
        int i_gate, i_c1, i_c2;
        if_trns >> i_trnin >> i_gate >> i_c1 >> i_c2;
        if (i_trnin >= 0) {
            if (i_trnin != i_trn++) {
                std::cerr << "error: mismatch in trns file near " << i_trnin << std::endl;
                exit(EXIT_FAILURE);
            }
            trn t;
            t.gate = i_gate;
            t.c1 = i_c1;
            t.c2 = i_c2;
            t.on = false;
            trns.push_back(t);
        }
    }
    std::cout << std::endl << "read " << trns.size() << " trns" << std::endl;

    for (int i = 0; i != trns.size(); ++i) {
        trn& t = trns[i];
        if (t.c1 == VSS) {
            t.c1 = t.c2;
            t.c2 = VSS;
        } else if (t.c1 == VCC) {
            t.c1 = t.c2;
            t.c2 = VCC;
        }
        segs[t.gate].gates.push_back(i);
        segs[t.c1].c1c2s.push_back(i);
        segs[t.c2].c1c2s.push_back(i);
    }
    // TODO:	init();

    std::cout << "running some..." << std::endl;
    for (int i(0); i < 100; ++i) {
        step();
    }
    std::cout << "end" << std::endl;
}

CPU::~CPU() {
}

void CPU::tick() {
    step();
    step();
}

unsigned char CPU::readByte(unsigned int b7, unsigned int b6, unsigned int b5, unsigned int b4, unsigned int b3, unsigned int b2, unsigned int b1, unsigned int b0) {
    return
    segs[b7].on << 7 |
            segs[b6].on << 6 |
            segs[b5].on << 5 |
            segs[b4].on << 4 |
            segs[b3].on << 3 |
            segs[b2].on << 2 |
            segs[b1].on << 1 |
            segs[b0].on;
}

unsigned short CPU::readWord(unsigned int b15, unsigned int b14, unsigned int b13, unsigned int b12, unsigned int b11, unsigned int b10, unsigned int b9, unsigned int b8, unsigned int b7, unsigned int b6, unsigned int b5, unsigned int b4, unsigned int b3, unsigned int b2, unsigned int b1, unsigned int b0) {
    return
    segs[b15].on << 15 |
            segs[b14].on << 14 |
            segs[b13].on << 13 |
            segs[b12].on << 12 |
            segs[b11].on << 11 |
            segs[b10].on << 10 |
            segs[b9].on << 9 |
            segs[b8].on << 8 |
            segs[b7].on << 7 |
            segs[b6].on << 6 |
            segs[b5].on << 5 |
            segs[b4].on << 4 |
            segs[b3].on << 3 |
            segs[b2].on << 2 |
            segs[b1].on << 1 |
            segs[b0].on;
}

bool CPU::isHigh(int iseg) {
    return segs[iseg].on;
}

unsigned char CPU::rData() {
    return readByte(DB7, DB6, DB5, DB4, DB3, DB2, DB1, DB0);
}

unsigned short CPU::rAddr() {
    return readWord(AB15, AB14, AB13, AB12, AB11, AB10, AB9, AB8, AB7, AB6, AB5, AB4, AB3, AB2, AB1, AB0);
}

unsigned char CPU::rA() {
    return readByte(A7, A6, A5, A4, A3, A2, A1, A0);
}

unsigned char CPU::rX() {
    return readByte(X7, X6, X5, X4, X3, X2, X1, X0);
}

unsigned char CPU::rY() {
    return readByte(Y7, Y6, Y5, Y4, Y3, Y2, Y1, Y0);
}

unsigned char CPU::rS() {
    return readByte(S7, S6, S5, S4, S3, S2, S1, S0);
}

unsigned short CPU::rPC() {
    return readWord(PCH7, PCH6, PCH5, PCH4, PCH3, PCH2, PCH1, PCH0, PCL7, PCL6, PCL5, PCL4, PCL3, PCL2, PCL1, PCL0);
}

static void pHex(unsigned char x) {
    std::cout << std::setw(2) << std::setfill('0') << std::hex << (unsigned long) x << std::dec;
}

static void pHexw(unsigned short x) {
    std::cout << std::setw(4) << std::setfill('0') << std::hex << (unsigned long) x << std::dec;
}

void CPU::dumpSegs() {
    for (int i = 0; i < segs.size(); ++i) {
        std::cout << i << " ";
        seg& s = segs[i];
        if (s.pullup) {
            std::cout << "+";
        } else if (s.pulldown) {
            std::cout << "-";
        } else {
            std::cout << "0";
        }
        if (s.on) {
            std::cout << "+";
        } else {
            std::cout << "-";
        }
        std::cout << std::endl;
    }
}

unsigned char CPU::mRead(unsigned short addr) {
    unsigned char x;
    x = this->addressBus.read(addr);
#ifdef TRACEMEM
    std::cout << "--------------------------------------------- ";
    pHex(x);
    std::cout << "<";
    pHexw(addr);
    std::cout << std::endl;
#endif
    return x;
}

void CPU::mWrite(unsigned short addr, unsigned char data) {
    this->addressBus.write(addr, data);
#ifdef TRACEMEM
    std::cout << "--------------------------------------------- ";
    pHex(data);
    std::cout << ">";
    pHexw(addr);
    std::cout << std::endl;
#endif
}

void CPU::dumpRegs() {
    std::cout << "A";
    pHex(rA());
    std::cout << " X";
    pHex(rX());
    std::cout << " Y";
    pHex(rY());
    std::cout << " ";
    std::cout << (isHigh(P7) ? "N" : "n");
    std::cout << (isHigh(P6) ? "V" : "v");
    std::cout << ".";
    std::cout << (isHigh(P4) ? "B" : "b");
    std::cout << (isHigh(P3) ? "D" : "d");
    std::cout << (isHigh(P2) ? "I" : "i");
    std::cout << (isHigh(P1) ? "Z" : "z");
    std::cout << (isHigh(P0) ? "C" : "c");
    std::cout << " S";
    pHex(rS());
    std::cout << " PC";
    pHexw(rPC());
    if (isHigh(CLK1OUT)) {
        std::cout << "  PH1  ";
    }
    if (isHigh(CLK2OUT)) {
        std::cout << "  PH2";
        if (isHigh(RW)) {
            std::cout << " R";
        } else {
            std::cout << " W";
        }
    }
    std::cout << " DB";
    pHex(rData());
    std::cout << " AB";
    pHexw(rAddr());
    std::cout << std::endl;
    //pZP();
}

static void addRecalc(int n, std::set<int>& rcl) {
    if (n == VCC || n == VSS) {
        return;
    }
    rcl.insert(n);
}

static void onTrans(trn& t, std::set<int>& rcl) {
    if (t.on) {
        return;
    }
    t.on = true;
    addRecalc(t.c1, rcl);
    //	addRecalc(t.c2,rcl); //looks like this is not necessary?
}

static void offTrans(trn& t, std::set<int>& rcl) {
    if (!t.on) {
        return;
    }
    t.on = false;
    addRecalc(t.c1, rcl);
    addRecalc(t.c2, rcl);
}

bool CPU::getGroupValue(const std::set<int>& s) {
    if (s.find(VSS) != s.end()) {
        return false;
    }
    if (s.find(VCC) != s.end()) {
        return true;
    }
    for (std::set<int>::const_iterator i = s.begin(); i != s.end(); ++i) {
        const seg& s = segs[*i];
        if (s.pullup) {
            return true;
        }
        if (s.pulldown) {
            return false;
        }
        //		if (s.on) { return true; }
    }
    for (std::set<int>::const_iterator i = s.begin(); i != s.end(); ++i) {
        const seg& s = segs[*i];
        if (s.on) {
            return true;
        }
    }
    return false;
}

void CPU::addToGroup(int n, std::set<int>& s) {
    const std::pair < std::set<int>::iterator, bool> ret = s.insert(n);
    if (!ret.second) {
        return;
    }
    if (n == VCC || n == VSS) {
        return;
    }
    //std::cout << "a: " << n << std::endl;
    const seg& sg = segs[n];
    for (std::vector<int>::const_iterator itrn = sg.c1c2s.begin(); itrn != sg.c1c2s.end(); ++itrn) {
        const trn& t = trns[*itrn];
        if (t.on) {
            if (t.c1 == n) {
                addToGroup(t.c2, s);
            } else if (t.c2 == n) {
                addToGroup(t.c1, s);
            }
        }
    }
}

void CPU::recalcNode(int n, std::set<int>& rcl) {
    if (!(n == VCC || n == VSS)) {
        std::set<int> g;
        addToGroup(n, g);
        const bool gval = getGroupValue(g);
        //std::cout << "gval: " << gval << " grp size: " << g.size() << std::endl;
        for (std::set<int>::iterator ig = g.begin(); ig != g.end(); ++ig) {
            //std::cout << "ig: " << *ig << std::endl;
            seg& seg = segs[*ig];
            if (seg.on != gval) {
                //std::cout << "change seg on " << std::endl;
                seg.on = gval;
                for (std::vector<int>::iterator igate = seg.gates.begin(); igate != seg.gates.end(); ++igate) {
                    trn& t = trns[*igate];
                    if (seg.on) {
                        onTrans(t, rcl);
                    } else {
                        offTrans(t, rcl);
                    }
                }
            }
        }
    }
}

void CPU::recalc(const std::set<int>& s) {
    std::set<int> list(s);
    //	std::set<int> done;
    for (int sane = 0; sane < 100; ++sane) {
        //std::cout << "rc: " << list.size() << std::endl;
        if (!list.size()) {
            return;
        }
        std::set<int> rcl;
        for (std::set<int>::const_iterator ilist = list.begin(); ilist != list.end(); ++ilist) {
            recalcNode(*ilist, rcl);
            //std::cout << "done recalcNode" << std::endl;
        }
        //		done.insert(rcl.begin(),rcl.end());
        //		std::set<int> v;
        //		std::set_difference(rcl.begin(),rcl.end(),done.begin(),done.end(),std::inserter(v,v.end()));
        //		list = v;
        //		if (std::equal(list.begin(),list.end(),rcl.begin())) {
        //std::cout << "hit stasis" << std::endl;
        //			return;
        //		}
        list = rcl;
    }
    std::cerr << "ERROR: reached maximum iteration limit while recalculating CPU state" << std::endl;
}

void CPU::recalc(int n) {
    std::set<int> s;
    s.insert(n);
    recalc(s);
}

void CPU::recalcAll() {
    std::set<int> s;
    for (int i = 0; i < segs.size(); ++i) {
        if (!(i == VCC || i == VSS)) {
            s.insert(i);
        }
    }
    recalc(s);
}

void CPU::setSeg(int iseg, bool up) {
    seg& s = segs[iseg];
    s.pullup = up;
    s.pulldown = !up;
}

void CPU::setHigh(int iseg) {
    setSeg(iseg, true);
}

void CPU::setLow(int iseg) {
    setSeg(iseg, false);
}

void CPU::putDataToChip(unsigned char data) {
    /*
            std::cout << "d2cpu: ";
            pHex(data);
            std::cout << std::endl;
     */
    unsigned char x = data;

    setSeg(DB0, x & 1);
    x >>= 1;
    setSeg(DB1, x & 1);
    x >>= 1;
    setSeg(DB2, x & 1);
    x >>= 1;
    setSeg(DB3, x & 1);
    x >>= 1;
    setSeg(DB4, x & 1);
    x >>= 1;
    setSeg(DB5, x & 1);
    x >>= 1;
    setSeg(DB6, x & 1);
    x >>= 1;
    setSeg(DB7, x & 1);
}

void CPU::readBus() {
    if (isHigh(RW)) {
        putDataToChip(mRead(rAddr()));
    }
}

void CPU::writeBus() {
    if (!isHigh(RW)) {
        mWrite(rAddr(), rData());
    }
}

static void addDataToRecalc(std::set<int>& s) {
    s.insert(DB0);
    s.insert(DB1);
    s.insert(DB2);
    s.insert(DB3);
    s.insert(DB4);
    s.insert(DB5);
    s.insert(DB6);
    s.insert(DB7);
}

void CPU::rw() {
    readBus();
    std::set<int> s;
    addDataToRecalc(s);
    recalc(s);
    writeBus();
}

void CPU::step() {
    if (isHigh(CLK0)) {
        setLow(CLK0);
        recalc(CLK0);
    } else {
        setHigh(CLK0);
        recalc(CLK0);
        rw();
    }
#ifdef TRACE
    dumpRegs();
#endif

}

void CPU::powerOn() {
    std::cout << "initializing CPU..." << std::endl;
    //dumpRegs();
    //dumpSegs();
    recalcAll();
    //dumpSegs();
#ifdef TRACE
    dumpRegs();
#endif
    setHigh(VCC);
    setLow(VSS);

    setHigh(CLK0);
    setHigh(IRQ);
    setLow(RES);
    setHigh(NMI);
    setHigh(RDY);
    setLow(SO);

    std::set<int> s;
    s.insert(VCC);
    s.insert(VSS);
    s.insert(CLK0);
    s.insert(IRQ);
    s.insert(RES);
    s.insert(NMI);
    s.insert(RDY);
    s.insert(SO);
    recalc(s);
    //dumpSegs();
    //	std::cout << "recalc all" << std::endl;
    //	recalcAll();
    rw();
#ifdef TRACE
    dumpRegs();
#endif
    //	std::cout << "some power-up pre-reset cycles" << std::endl;
    //	for (int i(0); i < 10; ++i) {
    //		step();
    //	}
    //
    //	std::cout << "   RESET" << std::endl;
}

void CPU::reset() {
    setHigh(RES);
    recalc(RES);
}