// Copyright 2013 Cloudera Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "runtime/timestamp-parse-util.h"
#include <boost/assign/list_of.hpp>

namespace assign = boost::assign;
using boost::unordered_map;

namespace impala {

bool TimestampParser::initialized_ = false;
unordered_map<StringValue, int> TimestampParser::REV_MONTH_INDEX;
DateTimeFormatContext TimestampParser::DEFAULT_SHORT_DATE_TIME_CTX;
DateTimeFormatContext TimestampParser::DEFAULT_SHORT_ISO_DATE_TIME_CTX;
DateTimeFormatContext TimestampParser::DEFAULT_DATE_CTX;
DateTimeFormatContext TimestampParser::DEFAULT_TIME_CTX;
DateTimeFormatContext TimestampParser::DEFAULT_DATE_TIME_CTX[10];
DateTimeFormatContext TimestampParser::DEFAULT_ISO_DATE_TIME_CTX[10];
DateTimeFormatContext TimestampParser::DEFAULT_TIME_FRAC_CTX[10];

void TimestampParser::Init() {
  if (TimestampParser::initialized_) return;
  // This needs to be lazily init'd because a StringValues hash function will be invoked
  // for each entry that's placed in the map. The hash function expects that
  // CpuInfo::Init() has already been called.
  REV_MONTH_INDEX = assign::map_list_of
    (StringValue("jan"), 1)(StringValue("feb"), 2)(StringValue("mar"), 3)
    (StringValue("apr"), 4)(StringValue("may"), 5)(StringValue("jun"), 6)
    (StringValue("jul"), 7)(StringValue("aug"), 8)(StringValue("sep"), 9)
    (StringValue("oct"), 10)(StringValue("nov"), 11)(StringValue("dec"), 12);

  // Setup the default date/time context yyyy-MM-dd HH:mm:ss.SSSSSSSSS
  const char* DATE_TIME_CTX_FMT = "yyyy-MM-dd HH:mm:ss.SSSSSSSSS";
  const int FRACTIONAL_MAX_LEN = 9;
  for (int i = FRACTIONAL_MAX_LEN; i >= 0; --i) {
    DEFAULT_DATE_TIME_CTX[i].Reset(DATE_TIME_CTX_FMT,
        DEFAULT_DATE_TIME_FMT_LEN - (FRACTIONAL_MAX_LEN - i));
    ParseFormatTokens(&DEFAULT_DATE_TIME_CTX[i]);
  }

  // Setup the default ISO date/time context yyyy-MM-ddTHH:mm:ss.SSSSSSSSS
  for (int i = FRACTIONAL_MAX_LEN; i >= 0; --i) {
    DEFAULT_ISO_DATE_TIME_CTX[i].Reset("yyyy-MM-ddTHH:mm:ss.SSSSSSSSS",
        DEFAULT_DATE_TIME_FMT_LEN - (FRACTIONAL_MAX_LEN - i));
    ParseFormatTokens(&DEFAULT_ISO_DATE_TIME_CTX[i]);
  }

  // Setup the short default date/time context yyyy-MM-dd HH:mm:ss
  DEFAULT_SHORT_DATE_TIME_CTX.Reset("yyyy-MM-dd HH:mm:ss",
      DEFAULT_SHORT_DATE_TIME_FMT_LEN);
  ParseFormatTokens(&DEFAULT_SHORT_DATE_TIME_CTX);

  // Setup the short default ISO date/time context yyyy-MM-ddTHH:mm:ss
  DEFAULT_SHORT_ISO_DATE_TIME_CTX.Reset("yyyy-MM-ddTHH:mm:ss",
      DEFAULT_SHORT_DATE_TIME_FMT_LEN);
  ParseFormatTokens(&DEFAULT_SHORT_ISO_DATE_TIME_CTX);

  // Setup the default short date context yyyy-MM-dd
  DEFAULT_DATE_CTX.Reset("yyyy-MM-dd", DEFAULT_DATE_FMT_LEN);
  ParseFormatTokens(&DEFAULT_DATE_CTX);

  // Setup the default short time context HH:mm:ss
  DEFAULT_TIME_CTX.Reset("HH:mm:ss", DEFAULT_TIME_FMT_LEN);
  ParseFormatTokens(&DEFAULT_TIME_CTX);

  // Setup the default short time context with fractional seconds HH:mm:ss.SSSSSSSSS
  for (int i = FRACTIONAL_MAX_LEN; i >= 0; --i) {
    DEFAULT_TIME_FRAC_CTX[i].Reset(DATE_TIME_CTX_FMT + 11,
        DEFAULT_TIME_FRAC_FMT_LEN - (FRACTIONAL_MAX_LEN - i));
    ParseFormatTokens(&DEFAULT_TIME_FRAC_CTX[i]);
  }
  // Flag that the parser is ready.
  TimestampParser::initialized_ = true;
}

}