/*
 * Copyright (c) 2019-2020 Arm Limited
 * All rights reserved.
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 2003-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "base/statistics.hh"

#include <fstream>
#include <iomanip>
#include <list>
#include <map>
#include <string>

#include "base/callback.hh"
#include "base/cprintf.hh"
#include "base/debug.hh"
#include "base/hostinfo.hh"
#include "base/logging.hh"
#include "base/str.hh"
#include "base/time.hh"
#include "base/trace.hh"
#include "sim/root.hh"

using namespace std;

namespace Stats {

std::string Info::separatorString = "::";

// We wrap these in a function to make sure they're built in time.
list<Info *> &
statsList()
{
    static list<Info *> the_list;
    return the_list;
}

MapType &
statsMap()
{
    static MapType the_map;
    return the_map;
}

void
InfoAccess::setInfo(Group *parent, Info *info)
{
    panic_if(statsMap().find(this) != statsMap().end() ||
             _info != nullptr,
             "shouldn't register stat twice!");

    // New-style stats are reachable through the hierarchy and
    // shouldn't be added to the global lists.
    if (parent) {
        _info = info;
        return;
    }

    statsList().push_back(info);

#ifndef NDEBUG
    pair<MapType::iterator, bool> result =
#endif
        statsMap().insert(make_pair(this, info));
    assert(result.second && "this should never fail");
    assert(statsMap().find(this) != statsMap().end());
}

void
InfoAccess::setParams(const StorageParams *params)
{
    info()->storageParams = params;
}

void
InfoAccess::setInit()
{
    info()->flags.set(init);
}

Info *
InfoAccess::info()
{
    if (_info) {
        // New-style stats
        return _info;
    } else {
        // Legacy stats
        MapType::const_iterator i = statsMap().find(this);
        assert(i != statsMap().end());
        return (*i).second;
    }
}

const Info *
InfoAccess::info() const
{
    if (_info) {
        // New-style stats
        return _info;
    } else {
        // Legacy stats
        MapType::const_iterator i = statsMap().find(this);
        assert(i != statsMap().end());
        return (*i).second;
    }
}

StorageParams::~StorageParams()
{
}

NameMapType &
nameMap()
{
    static NameMapType the_map;
    return the_map;
}

int Info::id_count = 0;

int debug_break_id = -1;

Info::Info()
    : flags(none), precision(-1), prereq(0), storageParams(NULL)
{
    id = id_count++;
    if (debug_break_id >= 0 and debug_break_id == id)
        Debug::breakpoint();
}

Info::~Info()
{
}

bool
validateStatName(const string &name)
{
    if (name.empty())
        return false;

    vector<string> vec;
    tokenize(vec, name, '.');
    vector<string>::const_iterator item = vec.begin();
    while (item != vec.end()) {
        if (item->empty())
            return false;

        string::const_iterator c = item->begin();

        // The first character is different
        if (!isalpha(*c) && *c != '_')
            return false;

        // The rest of the characters have different rules.
        while (++c != item->end()) {
            if (!isalnum(*c) && *c != '_')
                return false;
        }

        ++item;
    }

    return true;
}

void
Info::setName(const string &name)
{
    setName(nullptr, name);
}

void
Info::setName(const Group *parent, const string &name)
{
    if (!validateStatName(name))
        panic("invalid stat name '%s'", name);

    // We only register the stat with the nameMap() if we are using
    // old-style stats without a parent group. New-style stats should
    // be unique since their names should correspond to a member
    // variable.
    if (!parent) {
        auto p = nameMap().insert(make_pair(name, this));

        if (!p.second)
            panic("same statistic name used twice! name=%s\n",
                  name);
    }

    this->name = name;
}

bool
Info::less(Info *stat1, Info *stat2)
{
    const string &name1 = stat1->name;
    const string &name2 = stat2->name;

    vector<string> v1;
    vector<string> v2;

    tokenize(v1, name1, '.');
    tokenize(v2, name2, '.');

    size_type last = min(v1.size(), v2.size()) - 1;
    for (off_type i = 0; i < last; ++i)
        if (v1[i] != v2[i])
            return v1[i] < v2[i];

    // Special compare for last element.
    if (v1[last] == v2[last])
        return v1.size() < v2.size();
    else
        return v1[last] < v2[last];

    return false;
}

bool
Info::baseCheck() const
{
    if (!(flags & Stats::init)) {
#ifdef DEBUG
        cprintf("this is stat number %d\n", id);
#endif
        panic("Not all stats have been initialized.\n"
              "You may need to add <ParentClass>::regStats() to a"
              " new SimObject's regStats() function. Name: %s",
              name);
        return false;
    }

    if ((flags & display) && name.empty()) {
        panic("all printable stats must be named");
        return false;
    }

    return true;
}

void
Info::enable()
{
}

void
VectorInfo::enable()
{
    size_type s = size();
    if (subnames.size() < s)
        subnames.resize(s);
    if (subdescs.size() < s)
        subdescs.resize(s);
}

void
VectorDistInfo::enable()
{
    size_type s = size();
    if (subnames.size() < s)
        subnames.resize(s);
    if (subdescs.size() < s)
        subdescs.resize(s);
}

void
Vector2dInfo::enable()
{
    if (subnames.size() < x)
        subnames.resize(x);
    if (subdescs.size() < x)
        subdescs.resize(x);
    if (y_subnames.size() < y)
        y_subnames.resize(y);
}

void
HistStor::grow_out()
{
    int size = cvec.size();
    int zero = size / 2; // round down!
    int top_half = zero + (size - zero + 1) / 2; // round up!
    int bottom_half = (size - zero) / 2; // round down!

    // grow down
    int low_pair = zero - 1;
    for (int i = zero - 1; i >= bottom_half; i--) {
        cvec[i] = cvec[low_pair];
        if (low_pair - 1 >= 0)
            cvec[i] += cvec[low_pair - 1];
        low_pair -= 2;
    }
    assert(low_pair == 0 || low_pair == -1 || low_pair == -2);

    for (int i = bottom_half - 1; i >= 0; i--)
        cvec[i] = Counter();

    // grow up
    int high_pair = zero;
    for (int i = zero; i < top_half; i++) {
        cvec[i] = cvec[high_pair];
        if (high_pair + 1 < size)
            cvec[i] += cvec[high_pair + 1];
        high_pair += 2;
    }
    assert(high_pair == size || high_pair == size + 1);

    for (int i = top_half; i < size; i++)
        cvec[i] = Counter();

    max_bucket *= 2;
    min_bucket *= 2;
    bucket_size *= 2;
}

void
HistStor::grow_convert()
{
    int size = cvec.size();
    int half = (size + 1) / 2; // round up!
    //bool even = (size & 1) == 0;

    int pair = size - 1;
    for (int i = size - 1; i >= half; --i) {
        cvec[i] = cvec[pair];
        if (pair - 1 >= 0)
            cvec[i] += cvec[pair - 1];
        pair -= 2;
    }

    for (int i = half - 1; i >= 0; i--)
        cvec[i] = Counter();

    min_bucket = -max_bucket;// - (even ? bucket_size : 0);
    bucket_size *= 2;
}

void
HistStor::grow_up()
{
    int size = cvec.size();
    int half = (size + 1) / 2; // round up!

    int pair = 0;
    for (int i = 0; i < half; i++) {
        cvec[i] = cvec[pair];
        if (pair + 1 < size)
            cvec[i] += cvec[pair + 1];
        pair += 2;
    }
    assert(pair == size || pair == size + 1);

    for (int i = half; i < size; i++)
        cvec[i] = Counter();

    max_bucket *= 2;
    bucket_size *= 2;
}

void
HistStor::add(HistStor *hs)
{
    int b_size = hs->size();
    assert(size() == b_size);
    assert(min_bucket == hs->min_bucket);

    sum += hs->sum;
    logs += hs->logs;
    squares += hs->squares;
    samples += hs->samples;

    while (bucket_size > hs->bucket_size)
        hs->grow_up();
    while (bucket_size < hs->bucket_size)
        grow_up();

    for (uint32_t i = 0; i < b_size; i++)
        cvec[i] += hs->cvec[i];
}

Formula::Formula(Group *parent, const char *name, const char *desc)
    : DataWrapVec<Formula, FormulaInfoProxy>(parent, name, desc)

{
}


Formula::Formula(Group *parent, const char *name, const char *desc,
                 const Temp &r)
    : DataWrapVec<Formula, FormulaInfoProxy>(parent, name, desc)
{
    *this = r;
}

const Formula &
Formula::operator=(const Temp &r)
{
    assert(!root && "Can't change formulas");
    root = r.getNodePtr();
    setInit();
    assert(size());
    return *this;
}

const Formula &
Formula::operator+=(Temp r)
{
    if (root)
        root = NodePtr(new BinaryNode<std::plus<Result> >(root, r));
    else {
        root = r.getNodePtr();
        setInit();
    }

    assert(size());
    return *this;
}

const Formula &
Formula::operator/=(Temp r)
{
    assert (root);
    root = NodePtr(new BinaryNode<std::divides<Result> >(root, r));

    assert(size());
    return *this;
}


void
Formula::result(VResult &vec) const
{
    if (root)
        vec = root->result();
}

Result
Formula::total() const
{
    return root ? root->total() : 0.0;
}

size_type
Formula::size() const
{
    if (!root)
        return 0;
    else
        return root->size();
}

void
Formula::reset()
{
}

bool
Formula::zero() const
{
    VResult vec;
    result(vec);
    for (VResult::size_type i = 0; i < vec.size(); ++i)
        if (vec[i] != 0.0)
            return false;
    return true;
}

string
Formula::str() const
{
    return root ? root->str() : "";
}

Handler resetHandler = NULL;
Handler dumpHandler = NULL;

void
registerHandlers(Handler reset_handler, Handler dump_handler)
{
    resetHandler = reset_handler;
    dumpHandler = dump_handler;
}

CallbackQueue dumpQueue;
CallbackQueue resetQueue;

void
processResetQueue()
{
    resetQueue.process();
}

void
processDumpQueue()
{
    dumpQueue.process();
}

void
registerResetCallback(const std::function<void()> &callback)
{
    resetQueue.push_back(callback);
}

bool _enabled = false;

bool
enabled()
{
    return _enabled;
}

void
enable()
{
    if (_enabled)
        fatal("Stats are already enabled");

    _enabled = true;
}

void
dump()
{
    if (dumpHandler)
        dumpHandler();
    else
        fatal("No registered Stats::dump handler");
}

void
reset()
{
    if (resetHandler)
        resetHandler();
    else
        fatal("No registered Stats::reset handler");
}

const Info *
resolve(const std::string &name)
{
    const auto &it = nameMap().find(name);
    if (it != nameMap().cend()) {
        return it->second;
    } else {
        return Root::root()->resolveStat(name);
    }
}

void
registerDumpCallback(const std::function<void()> &callback)
{
    dumpQueue.push_back(callback);
}

} // namespace Stats

void
debugDumpStats()
{
    Stats::dump();
}