// Copyright 2019 Yunion
//
// 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.

package bitmap

// Uint2IntArray transfer bitmap displayed as n to int array
func Uint2IntArray(n uint32) []int {
	return Uint64ToIntArray(uint64(n))
}

// IntArray2Uint transfer int array nums to bitmap number
func IntArray2Uint(nums []int) uint32 {
	return uint32(IntArrayToUint64(nums))
}

func Uint64ToIntArray(n uint64) []int {
	ret := make([]int, 0, 2)
	var i uint = 0
	for n != 0 {
		if n&(1<<i) != 0 {
			n &= uint64(^(1 << i))
			ret = append(ret, int(i))
		}
		i++
	}
	return ret
}

func IntArrayToUint64(nums []int) uint64 {
	var ret uint64 = 0
	for _, i := range nums {
		ret |= (1 << uint(i))
	}
	return ret
}

// Determine if int slice a euqals b
func IntSliceEqual(a, b []int) bool {
	if len(a) != len(b) {
		return false
	}
	for i := 0; i < len(a); i++ {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

type BitMap struct {
	bits []byte
	size int64
}

func (bm *BitMap) Set(idx int64) {
	if idx > bm.size {
		return
	}
	subscript := idx / 8
	var pos = uint64(idx % 8)
	bm.bits[subscript] = (bm.bits[subscript] | 1<<pos)
}

func (bm *BitMap) Has(idx int64) bool {
	if idx > bm.size {
		return false
	}
	subscript := idx / 8
	var pos = uint64(idx % 8)
	return bm.bits[subscript]&(1<<pos) > 0
}

func (bm *BitMap) Clean(idx int64) {
	if idx > bm.size {
		return
	}
	subscript := idx / 8
	var pos = uint64(idx % 8)
	bm.bits[subscript] &= ^(1 << pos)
}

func NewBitMap(size int64) *BitMap {
	bits := make([]byte, (size>>3)+1)
	return &BitMap{bits: bits, size: size}
}