// Copyright © 2023 OpenIM. All rights reserved.
//
// 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 utils

import (
	"encoding/json"
	"sort"
)

// SliceSub a中存在,b中不存在 (a-b)
func SliceSub[E comparable](a, b []E) []E {
	k := make(map[E]struct{})
	for i := 0; i < len(b); i++ {
		k[b[i]] = struct{}{}
	}
	t := make(map[E]struct{})
	rs := make([]E, 0, len(a))
	for i := 0; i < len(a); i++ {
		e := a[i]
		if _, ok := t[e]; ok {
			continue
		}
		if _, ok := k[e]; ok {
			continue
		}
		rs = append(rs, e)
		t[e] = struct{}{}
	}
	return rs
}

// SliceSubAny a中存在,b中不存在 (a-b)
func SliceSubAny[E comparable, T any](a []E, b []T, fn func(t T) E) []E {
	return SliceSub(a, Slice(b, fn))
}

// SliceAnySub a中存在,b中不存在 (a-b) fn 返回的是uuid
func SliceAnySub[E any, T comparable](a, b []E, fn func(t E) T) []E {
	m := make(map[T]E)
	for i := 0; i < len(b); i++ {
		v := b[i]
		m[fn(v)] = v
	}
	var es []E
	for i := 0; i < len(a); i++ {
		v := a[i]
		if _, ok := m[fn(v)]; !ok {
			es = append(es, v)
		}
	}
	return es
}

// DistinctAny 去重
func DistinctAny[E any, K comparable](es []E, fn func(e E) K) []E {
	v := make([]E, 0, len(es))
	tmp := map[K]struct{}{}
	for i := 0; i < len(es); i++ {
		t := es[i]
		k := fn(t)
		if _, ok := tmp[k]; !ok {
			tmp[k] = struct{}{}
			v = append(v, t)
		}
	}
	return v
}

func DistinctAnyGetComparable[E any, K comparable](es []E, fn func(e E) K) []K {
	v := make([]K, 0, len(es))
	tmp := map[K]struct{}{}
	for i := 0; i < len(es); i++ {
		t := es[i]
		k := fn(t)
		if _, ok := tmp[k]; !ok {
			tmp[k] = struct{}{}
			v = append(v, k)
		}
	}
	return v
}

// Distinct 去重
func Distinct[T comparable](ts []T) []T {
	if len(ts) < 2 {
		return ts
	} else if len(ts) == 2 {
		if ts[0] == ts[1] {
			return ts[:1]
		} else {
			return ts
		}
	}
	return DistinctAny(ts, func(t T) T {
		return t
	})
}

// Delete 删除切片元素, 支持负数删除倒数第几个
func Delete[E any](es []E, index ...int) []E {
	switch len(index) {
	case 0:
		return es
	case 1:
		i := index[0]
		if i < 0 {
			i = len(es) + i
		}
		if len(es) <= i {
			return es
		}
		return append(es[:i], es[i+1:]...)
	default:
		tmp := make(map[int]struct{})
		for _, i := range index {
			if i < 0 {
				i = len(es) + i
			}
			tmp[i] = struct{}{}
		}
		v := make([]E, 0, len(es))
		for i := 0; i < len(es); i++ {
			if _, ok := tmp[i]; !ok {
				v = append(v, es[i])
			}
		}
		return v
	}
}

// DeleteAt 删除切片元素, 支持负数删除倒数第几个
func DeleteAt[E any](es *[]E, index ...int) []E {
	v := Delete(*es, index...)
	*es = v
	return v
}

// IndexAny get the index of the element
func IndexAny[E any, K comparable](e E, es []E, fn func(e E) K) int {
	k := fn(e)
	for i := 0; i < len(es); i++ {
		if fn(es[i]) == k {
			return i
		}
	}
	return -1
}

// IndexOf get the index of the element
func IndexOf[E comparable](e E, es ...E) int {
	return IndexAny(e, es, func(t E) E {
		return t
	})
}

// Contain 是否包含
func Contain[E comparable](e E, es ...E) bool {
	return IndexOf(e, es...) >= 0
}

// DuplicateAny 是否有重复的
func DuplicateAny[E any, K comparable](es []E, fn func(e E) K) bool {
	t := make(map[K]struct{})
	for _, e := range es {
		k := fn(e)
		if _, ok := t[k]; ok {
			return true
		}
		t[k] = struct{}{}
	}
	return false
}

// Duplicate 是否有重复的
func Duplicate[E comparable](es []E) bool {
	return DuplicateAny(es, func(e E) E {
		return e
	})
}

// SliceToMapOkAny slice to map (自定义类型, 筛选)
func SliceToMapOkAny[E any, K comparable, V any](es []E, fn func(e E) (K, V, bool)) map[K]V {
	kv := make(map[K]V)
	for i := 0; i < len(es); i++ {
		t := es[i]
		if k, v, ok := fn(t); ok {
			kv[k] = v
		}
	}
	return kv
}

// SliceToMapAny slice to map (自定义类型)
func SliceToMapAny[E any, K comparable, V any](es []E, fn func(e E) (K, V)) map[K]V {
	return SliceToMapOkAny(es, func(e E) (K, V, bool) {
		k, v := fn(e)
		return k, v, true
	})
}

// SliceToMap slice to map
func SliceToMap[E any, K comparable](es []E, fn func(e E) K) map[K]E {
	return SliceToMapOkAny(es, func(e E) (K, E, bool) {
		k := fn(e)
		return k, e, true
	})
}

// SliceSetAny slice to map[K]struct{}
func SliceSetAny[E any, K comparable](es []E, fn func(e E) K) map[K]struct{} {
	return SliceToMapAny(es, func(e E) (K, struct{}) {
		return fn(e), struct{}{}
	})
}

func Filter[E, T any](es []E, fn func(e E) (T, bool)) []T {
	rs := make([]T, 0, len(es))
	for i := 0; i < len(es); i++ {
		e := es[i]
		if t, ok := fn(e); ok {
			rs = append(rs, t)
		}
	}
	return rs
}

// Slice 批量转换切片类型
func Slice[E any, T any](es []E, fn func(e E) T) []T {
	v := make([]T, len(es))
	for i := 0; i < len(es); i++ {
		v[i] = fn(es[i])
	}
	return v
}

// SliceSet slice to map[E]struct{}
func SliceSet[E comparable](es []E) map[E]struct{} {
	return SliceSetAny(es, func(e E) E {
		return e
	})
}

// HasKey get whether the map contains key
func HasKey[K comparable, V any](m map[K]V, k K) bool {
	if m == nil {
		return false
	}
	_, ok := m[k]
	return ok
}

// Min get minimum value
func Min[E Ordered](e ...E) E {
	v := e[0]
	for _, t := range e[1:] {
		if v > t {
			v = t
		}
	}
	return v
}

// Max get maximum value
func Max[E Ordered](e ...E) E {
	v := e[0]
	for _, t := range e[1:] {
		if v < t {
			v = t
		}
	}
	return v
}

func Paginate[E any](es []E, pageNumber int, showNumber int) []E {
	if pageNumber <= 0 {
		return []E{}
	}
	if showNumber <= 0 {
		return []E{}
	}
	start := (pageNumber - 1) * showNumber
	end := start + showNumber
	if start >= len(es) {
		return []E{}
	}
	if end > len(es) {
		end = len(es)
	}
	return es[start:end]
}

// BothExistAny 获取切片中共同存在的元素(交集)
func BothExistAny[E any, K comparable](es [][]E, fn func(e E) K) []E {
	if len(es) == 0 {
		return []E{}
	}
	var idx int
	ei := make([]map[K]E, len(es))
	for i := 0; i < len(ei); i++ {
		e := es[i]
		if len(e) == 0 {
			return []E{}
		}
		kv := make(map[K]E)
		for j := 0; j < len(e); j++ {
			t := e[j]
			k := fn(t)
			kv[k] = t
		}
		ei[i] = kv
		if len(kv) < len(ei[idx]) {
			idx = i
		}
	}
	v := make([]E, 0, len(ei[idx]))
	for k := range ei[idx] {
		all := true
		for i := 0; i < len(ei); i++ {
			if i == idx {
				continue
			}
			if _, ok := ei[i][k]; !ok {
				all = false
				break
			}
		}
		if !all {
			continue
		}
		v = append(v, ei[idx][k])
	}
	return v
}

// BothExist 获取切片中共同存在的元素(交集)
func BothExist[E comparable](es ...[]E) []E {
	return BothExistAny(es, func(e E) E {
		return e
	})
}

//// CompleteAny a中存在b的所有元素, 同时b中的所有元素a
//func CompleteAny[K comparable, E any](ks []K, es []E, fn func(e E) K) bool {
//	if len(ks) == 0 && len(es) == 0 {
//		return true
//	}
//	kn := make(map[K]uint8)
//	for _, e := range Distinct(ks) {
//		kn[e]++
//	}
//	for k := range SliceSetAny(es, fn) {
//		kn[k]++
//	}
//	for _, n := range kn {
//		if n != 2 {
//			return false
//		}
//	}
//	return true
//}

// Complete a和b去重后是否相等(忽略顺序)
func Complete[E comparable](a []E, b []E) bool {
	return len(Single(a, b)) == 0
}

// Keys get map keys
func Keys[K comparable, V any](kv map[K]V) []K {
	ks := make([]K, 0, len(kv))
	for k := range kv {
		ks = append(ks, k)
	}
	return ks
}

// Values get map values
func Values[K comparable, V any](kv map[K]V) []V {
	vs := make([]V, 0, len(kv))
	for k := range kv {
		vs = append(vs, kv[k])
	}
	return vs
}

// Sort basic type sorting
func Sort[E Ordered](es []E, asc bool) []E {
	SortAny(es, func(a, b E) bool {
		if asc {
			return a < b
		} else {
			return a > b
		}
	})
	return es
}

// SortAny custom sort method
func SortAny[E any](es []E, fn func(a, b E) bool) {
	sort.Sort(&sortSlice[E]{
		ts: es,
		fn: fn,
	})
}

// If true -> a, false -> b
func If[T any](isa bool, a, b T) T {
	if isa {
		return a
	}
	return b
}

func ToPtr[T any](t T) *T {
	return &t
}

// Equal 比较切片是否相对(包括元素顺序)
func Equal[E comparable](a []E, b []E) bool {
	if len(a) != len(b) {
		return false
	}
	for i := 0; i < len(a); i++ {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

// Single a中存在,b中不存在 或 b中存在,a中不存在
func Single[E comparable](a, b []E) []E {
	kn := make(map[E]uint8)
	for _, e := range Distinct(a) {
		kn[e]++
	}
	for _, e := range Distinct(b) {
		kn[e]++
	}
	v := make([]E, 0, len(kn))
	for k, n := range kn {
		if n == 1 {
			v = append(v, k)
		}
	}
	return v
}

// Order 将ts按es排序
func Order[E comparable, T any](es []E, ts []T, fn func(t T) E) []T {
	if len(es) == 0 || len(ts) == 0 {
		return ts
	}
	kv := make(map[E][]T)
	for i := 0; i < len(ts); i++ {
		t := ts[i]
		k := fn(t)
		kv[k] = append(kv[k], t)
	}
	rs := make([]T, 0, len(ts))
	for _, e := range es {
		vs := kv[e]
		delete(kv, e)
		rs = append(rs, vs...)
	}
	for k := range kv {
		rs = append(rs, kv[k]...)
	}
	return rs
}

func OrderPtr[E comparable, T any](es []E, ts *[]T, fn func(t T) E) []T {
	*ts = Order(es, *ts, fn)
	return *ts
}

func UniqueJoin(s ...string) string {
	data, _ := json.Marshal(s)
	return string(data)
}

type sortSlice[E any] struct {
	ts []E
	fn func(a, b E) bool
}

func (o *sortSlice[E]) Len() int {
	return len(o.ts)
}

func (o *sortSlice[E]) Less(i, j int) bool {
	return o.fn(o.ts[i], o.ts[j])
}

func (o *sortSlice[E]) Swap(i, j int) {
	o.ts[i], o.ts[j] = o.ts[j], o.ts[i]
}

// Ordered types that can be sorted
type Ordered interface {
	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64 | ~string
}

func Unwrap(err error) error {
	for err != nil {
		unwrap, ok := err.(interface {
			Unwrap() error
		})
		if !ok {
			break
		}
		err = unwrap.Unwrap()
	}
	return err
}

// NotNilReplace 当new_不为空时, 将old设置为new_
func NotNilReplace[T any](old, new_ *T) {
	if new_ == nil {
		return
	}
	*old = *new_
}

func Batch[T any, V any](fn func(T) V, ts []T) []V {
	if ts == nil {
		return nil
	}
	res := make([]V, 0, len(ts))
	for i := range ts {
		res = append(res, fn(ts[i]))
	}
	return res
}

func InitSlice[T any](val *[]T) {
	if val != nil && *val == nil {
		*val = []T{}
	}
}

func InitMap[K comparable, V any](val *map[K]V) {
	if val != nil && *val == nil {
		*val = map[K]V{}
	}
}