package extra

import (
	"github.com/json-iterator/go"
	"unsafe"
	"encoding/json"
	"strings"
	"math"
)

const MaxUint = ^uint(0)
const MaxInt = int(MaxUint >> 1)
const MinInt = -MaxInt - 1

func RegisterFuzzyDecoders() {
	jsoniter.RegisterTypeDecoder("string", &FuzzyStringDecoder{})
	jsoniter.RegisterTypeDecoder("float32", &FuzzyFloat32Decoder{})
	jsoniter.RegisterTypeDecoder("float64", &FuzzyFloat64Decoder{})
	jsoniter.RegisterTypeDecoder("int", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(MaxInt) || val < float64(MinInt) {
				iter.ReportError("fuzzy decode int", "exceed range")
				return
			}
			*((*int)(ptr)) = int(val)
		} else {
			*((*int)(ptr)) = iter.ReadInt()
		}
	}})
	jsoniter.RegisterTypeDecoder("uint", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(MaxUint) || val < 0 {
				iter.ReportError("fuzzy decode uint", "exceed range")
				return
			}
			*((*uint)(ptr)) = uint(val)
		} else {
			*((*uint)(ptr)) = iter.ReadUint()
		}
	}})
	jsoniter.RegisterTypeDecoder("int8", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxInt8) || val < float64(math.MinInt8) {
				iter.ReportError("fuzzy decode int8", "exceed range")
				return
			}
			*((*int8)(ptr)) = int8(val)
		} else {
			*((*int8)(ptr)) = iter.ReadInt8()
		}
	}})
	jsoniter.RegisterTypeDecoder("uint8", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxUint8) || val < 0 {
				iter.ReportError("fuzzy decode uint8", "exceed range")
				return
			}
			*((*uint8)(ptr)) = uint8(val)
		} else {
			*((*uint8)(ptr)) = iter.ReadUint8()
		}
	}})
	jsoniter.RegisterTypeDecoder("int16", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxInt16) || val < float64(math.MinInt16) {
				iter.ReportError("fuzzy decode int16", "exceed range")
				return
			}
			*((*int16)(ptr)) = int16(val)
		} else {
			*((*int16)(ptr)) = iter.ReadInt16()
		}
	}})
	jsoniter.RegisterTypeDecoder("uint16", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxUint16) || val < 0 {
				iter.ReportError("fuzzy decode uint16", "exceed range")
				return
			}
			*((*uint16)(ptr)) = uint16(val)
		} else {
			*((*uint16)(ptr)) = iter.ReadUint16()
		}
	}})
	jsoniter.RegisterTypeDecoder("int32", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxInt32) || val < float64(math.MinInt32) {
				iter.ReportError("fuzzy decode int32", "exceed range")
				return
			}
			*((*int32)(ptr)) = int32(val)
		} else {
			*((*int32)(ptr)) = iter.ReadInt32()
		}
	}})
	jsoniter.RegisterTypeDecoder("uint32", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxUint32) || val < 0 {
				iter.ReportError("fuzzy decode uint32", "exceed range")
				return
			}
			*((*uint32)(ptr)) = uint32(val)
		} else {
			*((*uint32)(ptr)) = iter.ReadUint32()
		}
	}})
	jsoniter.RegisterTypeDecoder("int64", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxInt64) || val < float64(math.MinInt64) {
				iter.ReportError("fuzzy decode int64", "exceed range")
				return
			}
			*((*int64)(ptr)) = int64(val)
		} else {
			*((*int64)(ptr)) = iter.ReadInt64()
		}
	}})
	jsoniter.RegisterTypeDecoder("uint64", &FuzzyIntegerDecoder{func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator) {
		if isFloat {
			val := iter.ReadFloat64()
			if val > float64(math.MaxUint64) || val < 0 {
				iter.ReportError("fuzzy decode uint64", "exceed range")
				return
			}
			*((*uint64)(ptr)) = uint64(val)
		} else {
			*((*uint64)(ptr)) = iter.ReadUint64()
		}
	}})
}

type FuzzyStringDecoder struct {
}

func (decoder *FuzzyStringDecoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
	valueType := iter.WhatIsNext()
	switch valueType {
	case jsoniter.Number:
		var number json.Number
		iter.ReadVal(&number)
		*((*string)(ptr)) = string(number)
	case jsoniter.String:
		*((*string)(ptr)) = iter.ReadString()
	default:
		iter.ReportError("FuzzyStringDecoder", "not number or string")
	}
}

type FuzzyIntegerDecoder struct {
	fun func(isFloat bool, ptr unsafe.Pointer, iter *jsoniter.Iterator)
}

func (decoder *FuzzyIntegerDecoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
	valueType := iter.WhatIsNext()
	var str string
	switch valueType {
	case jsoniter.Number:
		var number json.Number
		iter.ReadVal(&number)
		str = string(number)
	case jsoniter.String:
		str = iter.ReadString()
	default:
		iter.ReportError("FuzzyIntegerDecoder", "not number or string")
	}
	newIter := iter.Config().BorrowIterator([]byte(str))
	defer iter.Config().ReturnIterator(newIter)
	isFloat := strings.IndexByte(str, '.') != -1
	decoder.fun(isFloat, ptr, newIter)
	if newIter.Error != nil {
		iter.Error = newIter.Error
	}
}

type FuzzyFloat32Decoder struct {
}

func (decoder *FuzzyFloat32Decoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
	valueType := iter.WhatIsNext()
	var str string
	switch valueType {
	case jsoniter.Number:
		*((*float32)(ptr)) = iter.ReadFloat32()
	case jsoniter.String:
		str = iter.ReadString()
		newIter := iter.Config().BorrowIterator([]byte(str))
		defer iter.Config().ReturnIterator(newIter)
		*((*float32)(ptr)) = newIter.ReadFloat32()
		if newIter.Error != nil {
			iter.Error = newIter.Error
		}
	default:
		iter.ReportError("FuzzyFloat32Decoder", "not number or string")
	}
}

type FuzzyFloat64Decoder struct {
}

func (decoder *FuzzyFloat64Decoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
	valueType := iter.WhatIsNext()
	var str string
	switch valueType {
	case jsoniter.Number:
		*((*float64)(ptr)) = iter.ReadFloat64()
	case jsoniter.String:
		str = iter.ReadString()
		newIter := iter.Config().BorrowIterator([]byte(str))
		defer iter.Config().ReturnIterator(newIter)
		*((*float64)(ptr)) = newIter.ReadFloat64()
		if newIter.Error != nil {
			iter.Error = newIter.Error
		}
	default:
		iter.ReportError("FuzzyFloat32Decoder", "not number or string")
	}
}