/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "txXSLTNumber.h"
#include "nsReadableUtils.h"
#include "txCore.h"

class txDecimalCounter : public txFormattedCounter {
 public:
  txDecimalCounter() : mMinLength(1), mGroupSize(50) {}

  txDecimalCounter(int32_t aMinLength, int32_t aGroupSize,
                   const nsAString& mGroupSeparator);

  virtual void appendNumber(int32_t aNumber, nsAString& aDest) override;

 private:
  int32_t mMinLength;
  int32_t mGroupSize;
  nsString mGroupSeparator;
};

class txAlphaCounter : public txFormattedCounter {
 public:
  explicit txAlphaCounter(char16_t aOffset) : mOffset(aOffset) {}

  virtual void appendNumber(int32_t aNumber, nsAString& aDest) override;

 private:
  char16_t mOffset;
};

class txRomanCounter : public txFormattedCounter {
 public:
  explicit txRomanCounter(bool aUpper) : mTableOffset(aUpper ? 30 : 0) {}

  void appendNumber(int32_t aNumber, nsAString& aDest) override;

 private:
  int32_t mTableOffset;
};

nsresult txFormattedCounter::getCounterFor(const nsString& aToken,
                                           int32_t aGroupSize,
                                           const nsAString& aGroupSeparator,
                                           txFormattedCounter*& aCounter) {
  int32_t length = aToken.Length();
  NS_ASSERTION(length, "getting counter for empty token");
  aCounter = 0;

  if (length == 1) {
    char16_t ch = aToken.CharAt(0);
    switch (ch) {
      case 'i':
      case 'I':
        aCounter = new txRomanCounter(ch == 'I');
        break;

      case 'a':
      case 'A':
        aCounter = new txAlphaCounter(ch);
        break;

      case '1':
      default:
        // if we don't recognize the token then use "1"
        aCounter = new txDecimalCounter(1, aGroupSize, aGroupSeparator);
        break;
    }
    MOZ_ASSERT(aCounter);
    return NS_OK;
  }

  // for now, the only multi-char token we support are decimals
  int32_t i;
  for (i = 0; i < length - 1; ++i) {
    if (aToken.CharAt(i) != '0') break;
  }
  if (i == length - 1 && aToken.CharAt(i) == '1') {
    aCounter = new txDecimalCounter(length, aGroupSize, aGroupSeparator);
  } else {
    // if we don't recognize the token then use '1'
    aCounter = new txDecimalCounter(1, aGroupSize, aGroupSeparator);
  }
  MOZ_ASSERT(aCounter);
  return NS_OK;
}

txDecimalCounter::txDecimalCounter(int32_t aMinLength, int32_t aGroupSize,
                                   const nsAString& aGroupSeparator)
    : mMinLength(aMinLength),
      mGroupSize(aGroupSize),
      mGroupSeparator(aGroupSeparator) {
  if (mGroupSize <= 0) {
    mGroupSize = aMinLength + 10;
  }
}

void txDecimalCounter::appendNumber(int32_t aNumber, nsAString& aDest) {
  const int32_t bufsize = 10;  // must be able to fit an int32_t
  char16_t buf[bufsize];
  int32_t pos = bufsize;
  while (aNumber > 0) {
    int32_t ch = aNumber % 10;
    aNumber /= 10;
    buf[--pos] = ch + '0';
  }

  // in case we didn't get a long enough string
  int32_t end = (bufsize > mMinLength) ? bufsize - mMinLength : 0;
  while (pos > end) {
    buf[--pos] = '0';
  }

  // in case we *still* didn't get a long enough string.
  // this should be very rare since it only happens if mMinLength is bigger
  // then the length of any int32_t.
  // pos will always be zero
  int32_t extraPos = mMinLength;
  while (extraPos > bufsize) {
    aDest.Append(char16_t('0'));
    --extraPos;
    if (extraPos % mGroupSize == 0) {
      aDest.Append(mGroupSeparator);
    }
  }

  // copy string to buffer
  if (mGroupSize >= bufsize - pos) {
    // no grouping will occur
    aDest.Append(buf + pos, (uint32_t)(bufsize - pos));
  } else {
    // append chars up to first grouping separator
    int32_t len = ((bufsize - pos - 1) % mGroupSize) + 1;
    aDest.Append(buf + pos, len);
    pos += len;
    while (bufsize - pos > 0) {
      aDest.Append(mGroupSeparator);
      aDest.Append(buf + pos, mGroupSize);
      pos += mGroupSize;
    }
    NS_ASSERTION(bufsize == pos, "error while grouping");
  }
}

void txAlphaCounter::appendNumber(int32_t aNumber, nsAString& aDest) {
  char16_t buf[12];
  buf[11] = 0;
  int32_t pos = 11;
  while (aNumber > 0) {
    --aNumber;
    int32_t ch = aNumber % 26;
    aNumber /= 26;
    buf[--pos] = ch + mOffset;
  }

  aDest.Append(buf + pos, (uint32_t)(11 - pos));
}

const char* const kTxRomanNumbers[] = {
    "", "c", "cc", "ccc", "cd", "d", "dc", "dcc", "dccc", "cm",
    "", "x", "xx", "xxx", "xl", "l", "lx", "lxx", "lxxx", "xc",
    "", "i", "ii", "iii", "iv", "v", "vi", "vii", "viii", "ix",
    "", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM",
    "", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC",
    "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};

void txRomanCounter::appendNumber(int32_t aNumber, nsAString& aDest) {
  // Numbers bigger then 3999 and negative numbers can't be done in roman
  if (uint32_t(aNumber) >= 4000) {
    txDecimalCounter().appendNumber(aNumber, aDest);
    return;
  }

  while (aNumber >= 1000) {
    aDest.Append(!mTableOffset ? char16_t('m') : char16_t('M'));
    aNumber -= 1000;
  }

  int32_t posValue;

  // Hundreds
  posValue = aNumber / 100;
  aNumber %= 100;
  AppendASCIItoUTF16(
      mozilla::MakeStringSpan(kTxRomanNumbers[posValue + mTableOffset]), aDest);
  // Tens
  posValue = aNumber / 10;
  aNumber %= 10;
  AppendASCIItoUTF16(
      mozilla::MakeStringSpan(kTxRomanNumbers[10 + posValue + mTableOffset]),
      aDest);
  // Ones
  AppendASCIItoUTF16(
      mozilla::MakeStringSpan(kTxRomanNumbers[20 + aNumber + mTableOffset]),
      aDest);
}