#include <iss/arch_if.h>
#include "pctrace.h"
#include <util/logging.h>
#include <util/ities.h>
#include <rapidjson/document.h>
#include <rapidjson/istreamwrapper.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>
#include <rapidjson/ostreamwrapper.h>
#include <rapidjson/error/en.h>
#include <fstream>
#include <iostream>
#ifdef WITH_LZ4
#include <lz4frame.h>
#endif

namespace iss {
namespace plugin {

using namespace rapidjson;
using namespace std;

#ifdef WITH_LZ4
class lz4compress_steambuf: public std::streambuf {
public:
    lz4compress_steambuf(const lz4compress_steambuf&) = delete;
    lz4compress_steambuf& operator=(const lz4compress_steambuf&) = delete;
    lz4compress_steambuf(std::ostream &sink, size_t buf_size)
    : sink(sink)
    , src_buf(buf_size)
    , dest_buf(LZ4F_compressBound(buf_size, nullptr))
    {
        auto errCode = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
        if (LZ4F_isError(errCode) != 0)
            throw std::runtime_error(std::string("Failed to create LZ4 context: ") + LZ4F_getErrorName(errCode));
        size_t ret = LZ4F_compressBegin(ctx, &dest_buf.front(), dest_buf.capacity(), nullptr);
        if (LZ4F_isError(ret) != 0)
            throw std::runtime_error(std::string("Failed to start LZ4 compression: ") + LZ4F_getErrorName(ret));
        setp(src_buf.data(), src_buf.data() + src_buf.size() - 1);
        sink.write(dest_buf.data(), ret);
    }

    ~lz4compress_steambuf() {
        close();
    }

    void close() {
        if (closed)
            return;
        sync();
        auto ret = LZ4F_compressEnd(ctx, dest_buf.data(), dest_buf.capacity(), nullptr);
        if (LZ4F_isError(ret) != 0)
            throw std::runtime_error(std::string("Failed to finish LZ4 compression: ") + LZ4F_getErrorName(ret));
        sink.write(dest_buf.data(), ret);
        LZ4F_freeCompressionContext(ctx);
        closed = true;
    }

private:
    int_type overflow(int_type ch) override {
        compress_and_write();
        *pptr() = static_cast<char_type>(ch);
        pbump(1);
        return ch;
    }

    int_type sync() override {
        compress_and_write();
        return 0;
    }

    void compress_and_write() {
        if (closed)
            throw std::runtime_error("Cannot write to closed stream");
        if(auto orig_size = pptr() - pbase()){
            auto ret = LZ4F_compressUpdate(ctx, dest_buf.data(), dest_buf.capacity(), pbase(), orig_size, nullptr);
            if (LZ4F_isError(ret) != 0)
                throw std::runtime_error(std::string("LZ4 compression failed: ") + LZ4F_getErrorName(ret));
            if(ret) sink.write(dest_buf.data(), ret);
            pbump(-orig_size);
        }
    }

    std::ostream &sink;
    std::vector<char> src_buf;
    std::vector<char> dest_buf;
    LZ4F_compressionContext_t ctx{ nullptr };
    bool closed{ false };
};
#endif

cov::cov(std::string const &filename)
: instr_if(nullptr)
, filename(filename)
, output("output.trc")
#ifdef WITH_LZ4
, strbuf(new lz4compress_steambuf(output, 4096))
, ostr(strbuf.get())
#endif
{ }

cov::~cov() { }

bool cov::registration(const char *const version, vm_if& vm) {
    instr_if = vm.get_arch()->get_instrumentation_if();
    if(!instr_if) return false;
    const string  core_name = instr_if->core_type_name();
    if (filename.length() > 0) {
        ifstream is(filename);
        if (is.is_open()) {
            try {
                IStreamWrapper isw(is);
                Document d;
                ParseResult ok = d.ParseStream(isw);
                if(ok) {
                    Value& val = d[core_name.c_str()];
                    if(val.IsArray()){
                        delays.reserve(val.Size());
                        for (auto it = val.Begin(); it != val.End(); ++it) {
                            auto& name = (*it)["name"];
                            auto& size = (*it)["size"];
                            auto& delay = (*it)["delay"];
                            auto& branch = (*it)["branch"];
                            if(delay.IsArray()) {
                                auto dt = delay[0].Get<unsigned>();
                                auto dnt = delay[1].Get<unsigned>();
                                delays.push_back(instr_desc{size.Get<unsigned>(), dt, dnt, branch.Get<bool>()});
                            } else if(delay.Is<unsigned>()) {
                                auto d = delay.Get<unsigned>();
                                delays.push_back(instr_desc{size.Get<unsigned>(), d, d, branch.Get<bool>()});
                            } else
                                throw runtime_error("JSON parse error");

                        }
                    } else {
                        LOG(ERR)<<"plugin cycle_estimate: could not find an entry for "<<core_name<<" in JSON file"<<endl;
                        return false;
                    }
                } else {
                    LOG(ERR)<<"plugin cycle_estimate: could not parse in JSON file at "<< ok.Offset()<<": "<<GetParseError_En(ok.Code())<<endl;
                    return false;
                }
            } catch (runtime_error &e) {
                LOG(ERR) << "Could not parse input file " << filename << ", reason: " << e.what();
                return false;
            }
        } else {
            LOG(ERR) << "Could not open input file " << filename;
            return false;
        }
    }
    return true;
}

void cov::callback(instr_info_t iinfo, const exec_info& einfo) {
    auto delay = 0;
    size_t id = iinfo.instr_id;
    auto entry = delays[id];
    auto instr = instr_if->get_instr_word();
    auto call = (id==2 || id==3) && bit_sub<7,5>(instr)!=0;
    bool taken = einfo.branch_taken;
    if (einfo.branch_taken) {
        delay = entry.taken;
        if(entry.taken > 1)
            instr_if->set_curr_instr_cycles(entry.taken);
    } else {
        delay = entry.not_taken;
        if (entry.not_taken > 1)
            instr_if->set_curr_instr_cycles(entry.not_taken);
    }
#ifndef WITH_LZ4
    output<<std::hex <<"0x" << instr_if->get_pc() <<"," << delay <<"," << call<< "\n";
#else
    auto rdbuf=ostr.rdbuf();
    ostr<<std::hex <<"0x" << instr_if->get_pc() <<"," << delay <<"," << call<< "\n";
#endif
}
}
}