/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */

package thrift

import (
	"math"
	"strconv"
)

type Numeric interface {
	Int64() int64
	Int32() int32
	Int16() int16
	Byte() byte
	Int() int
	Float64() float64
	Float32() float32
	String() string
	isNull() bool
}

type numeric struct {
	iValue int64
	dValue float64
	sValue string
	isNil  bool
}

var (
	INFINITY          Numeric
	NEGATIVE_INFINITY Numeric
	NAN               Numeric
	ZERO              Numeric
	NUMERIC_NULL      Numeric
)

func NewNumericFromDouble(dValue float64) Numeric {
	if math.IsInf(dValue, 1) {
		return INFINITY
	}
	if math.IsInf(dValue, -1) {
		return NEGATIVE_INFINITY
	}
	if math.IsNaN(dValue) {
		return NAN
	}
	iValue := int64(dValue)
	sValue := strconv.FormatFloat(dValue, 'g', 10, 64)
	isNil := false
	return &numeric{iValue: iValue, dValue: dValue, sValue: sValue, isNil: isNil}
}

func NewNumericFromI64(iValue int64) Numeric {
	dValue := float64(iValue)
	sValue := strconv.FormatInt(iValue, 10)
	isNil := false
	return &numeric{iValue: iValue, dValue: dValue, sValue: sValue, isNil: isNil}
}

func NewNumericFromI32(iValue int32) Numeric {
	dValue := float64(iValue)
	sValue := strconv.FormatInt(int64(iValue), 10)
	isNil := false
	return &numeric{iValue: int64(iValue), dValue: dValue, sValue: sValue, isNil: isNil}
}

func NewNumericFromString(sValue string) Numeric {
	if sValue == INFINITY.String() {
		return INFINITY
	}
	if sValue == NEGATIVE_INFINITY.String() {
		return NEGATIVE_INFINITY
	}
	if sValue == NAN.String() {
		return NAN
	}
	iValue, _ := strconv.ParseInt(sValue, 10, 64)
	dValue, _ := strconv.ParseFloat(sValue, 64)
	isNil := len(sValue) == 0
	return &numeric{iValue: iValue, dValue: dValue, sValue: sValue, isNil: isNil}
}

func NewNumericFromJSONString(sValue string, isNull bool) Numeric {
	if isNull {
		return NewNullNumeric()
	}
	if sValue == JSON_INFINITY {
		return INFINITY
	}
	if sValue == JSON_NEGATIVE_INFINITY {
		return NEGATIVE_INFINITY
	}
	if sValue == JSON_NAN {
		return NAN
	}
	iValue, _ := strconv.ParseInt(sValue, 10, 64)
	dValue, _ := strconv.ParseFloat(sValue, 64)
	return &numeric{iValue: iValue, dValue: dValue, sValue: sValue, isNil: isNull}
}

func NewNullNumeric() Numeric {
	return &numeric{iValue: 0, dValue: 0.0, sValue: "", isNil: true}
}

func (p *numeric) Int64() int64 {
	return p.iValue
}

func (p *numeric) Int32() int32 {
	return int32(p.iValue)
}

func (p *numeric) Int16() int16 {
	return int16(p.iValue)
}

func (p *numeric) Byte() byte {
	return byte(p.iValue)
}

func (p *numeric) Int() int {
	return int(p.iValue)
}

func (p *numeric) Float64() float64 {
	return p.dValue
}

func (p *numeric) Float32() float32 {
	return float32(p.dValue)
}

func (p *numeric) String() string {
	return p.sValue
}

func (p *numeric) isNull() bool {
	return p.isNil
}

func init() {
	INFINITY = &numeric{iValue: 0, dValue: math.Inf(1), sValue: "Infinity", isNil: false}
	NEGATIVE_INFINITY = &numeric{iValue: 0, dValue: math.Inf(-1), sValue: "-Infinity", isNil: false}
	NAN = &numeric{iValue: 0, dValue: math.NaN(), sValue: "NaN", isNil: false}
	ZERO = &numeric{iValue: 0, dValue: 0, sValue: "0", isNil: false}
	NUMERIC_NULL = &numeric{iValue: 0, dValue: 0, sValue: "0", isNil: true}
}