/*  -*- C++ -*-

    SPDX-FileCopyrightText: 1998 Netscape Communications Corporation <developer@mozilla.org>

    SPDX-License-Identifier: MIT

*/

// for japanese encoding, observe characteristic:

// 1, kana character (or hankaku?) often have high frequency of appearance

// 2, kana character often exist in group

// 3, certain combination of kana is never used in japanese language

#include "nsEUCJPProber.h"

#include "nsMBCSSM.h"

#include <format>

namespace kencodingprober

{

nsEUCJPProber::nsEUCJPProber()

    : mCodingSM{std::make_unique<nsCodingStateMachine>(EUCJPSMModel)}

{

}

nsProbingState nsEUCJPProber::HandleData(const char *aBuf, unsigned int aLen)

{

    if (aLen == 0) {

        return mState;

    }

    for (unsigned int i = 0; i < aLen; i++) {

        const nsSMState codingState = mCodingSM->NextState(aBuf[i]);

        if (codingState == eError) {

            mState = eNotMe;

            break;

        }

        if (codingState == eItsMe) {

            mState = eFoundIt;

            break;

        }

        if (codingState == eStart) {

            const int64_t charLen = i - mLastStart;

            if (i == 0) {

                mLastChar[1] = aBuf[0];

                mContextAnalyser.HandleOneChar(mLastChar, charLen);

                mDistributionAnalyser.HandleOneChar(mLastChar, charLen);

            } else {

                mContextAnalyser.HandleOneChar(aBuf + i - 1, charLen);

                mDistributionAnalyser.HandleOneChar(aBuf + i - 1, charLen);

            }

            mLastStart = i;

        }

    }

    mLastChar[0] = aBuf[aLen - 1];

    mLastStart -= aLen;

    if (mState == eDetecting) {

        if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD) {

            mState = eFoundIt;

        }

    }

    return mState;

}

float nsEUCJPProber::GetConfidence(void)

{

    float contxtCf = mContextAnalyser.GetConfidence();

    float distribCf = mDistributionAnalyser.GetConfidence();

    return (contxtCf > distribCf ? contxtCf : distribCf);

}

std::string nsEUCJPProber::StatusOutput(uint8_t /* indent */)

{

    return std::format( //

        "{:1.3f} [{}]  {}  {}",

        GetConfidence(),

        GetCharSetName(),

        mDistributionAnalyser.StatusOutput(),

        mContextAnalyser.StatusOutput());

}

}