// Copyright 2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.

package garray

import (
	"bytes"
	"encoding/json"
	"fmt"
	"github.com/gogf/gf/text/gstr"
	"math"
	"sort"

	"github.com/gogf/gf/internal/rwmutex"
	"github.com/gogf/gf/util/gconv"
	"github.com/gogf/gf/util/grand"
)

type Array struct {
	mu    *rwmutex.RWMutex
	array []interface{}
}

// New creates and returns an empty array.
// The parameter <safe> is used to specify whether using array in concurrent-safety,
// which is false in default.
func New(safe ...bool) *Array {
	return NewArraySize(0, 0, safe...)
}

// See New.
func NewArray(safe ...bool) *Array {
	return NewArraySize(0, 0, safe...)
}

// NewArraySize create and returns an array with given size and cap.
// The parameter <safe> is used to specify whether using array in concurrent-safety,
// which is false in default.
func NewArraySize(size int, cap int, safe ...bool) *Array {
	return &Array{
		mu:    rwmutex.New(safe...),
		array: make([]interface{}, size, cap),
	}
}

// NewArrayRange creates and returns a array by a range from <start> to <end>
// with step value <step>.
func NewArrayRange(start, end, step int, safe ...bool) *Array {
	if step == 0 {
		panic(fmt.Sprintf(`invalid step value: %d`, step))
	}
	slice := make([]interface{}, (end-start+1)/step)
	index := 0
	for i := start; i <= end; i += step {
		slice[index] = i
		index++
	}
	return NewArrayFrom(slice, safe...)
}

// See NewArrayFrom.
func NewFrom(array []interface{}, safe ...bool) *Array {
	return NewArrayFrom(array, safe...)
}

// See NewArrayFromCopy.
func NewFromCopy(array []interface{}, safe ...bool) *Array {
	return NewArrayFromCopy(array, safe...)
}

// NewArrayFrom creates and returns an array with given slice <array>.
// The parameter <safe> is used to specify whether using array in concurrent-safety,
// which is false in default.
func NewArrayFrom(array []interface{}, safe ...bool) *Array {
	return &Array{
		mu:    rwmutex.New(safe...),
		array: array,
	}
}

// NewArrayFromCopy creates and returns an array from a copy of given slice <array>.
// The parameter <safe> is used to specify whether using array in concurrent-safety,
// which is false in default.
func NewArrayFromCopy(array []interface{}, safe ...bool) *Array {
	newArray := make([]interface{}, len(array))
	copy(newArray, array)
	return &Array{
		mu:    rwmutex.New(safe...),
		array: newArray,
	}
}

// Get returns the value of the specified index,
// the caller should notice the boundary of the array.
func (a *Array) Get(index int) interface{} {
	a.mu.RLock()
	defer a.mu.RUnlock()
	value := a.array[index]
	return value
}

// Set sets value to specified index.
func (a *Array) Set(index int, value interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.array[index] = value
	return a
}

// SetArray sets the underlying slice array with the given <array>.
func (a *Array) SetArray(array []interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	a.array = array
	return a
}

// Replace replaces the array items by given <array> from the beginning of array.
func (a *Array) Replace(array []interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	max := len(array)
	if max > len(a.array) {
		max = len(a.array)
	}
	for i := 0; i < max; i++ {
		a.array[i] = array[i]
	}
	return a
}

// Sum returns the sum of values in an array.
func (a *Array) Sum() (sum int) {
	a.mu.RLock()
	defer a.mu.RUnlock()
	for _, v := range a.array {
		sum += gconv.Int(v)
	}
	return
}

// SortFunc sorts the array by custom function <less>.
func (a *Array) SortFunc(less func(v1, v2 interface{}) bool) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	sort.Slice(a.array, func(i, j int) bool {
		return less(a.array[i], a.array[j])
	})
	return a
}

// InsertBefore inserts the <value> to the front of <index>.
func (a *Array) InsertBefore(index int, value interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	rear := append([]interface{}{}, a.array[index:]...)
	a.array = append(a.array[0:index], value)
	a.array = append(a.array, rear...)
	return a
}

// InsertAfter inserts the <value> to the back of <index>.
func (a *Array) InsertAfter(index int, value interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	rear := append([]interface{}{}, a.array[index+1:]...)
	a.array = append(a.array[0:index+1], value)
	a.array = append(a.array, rear...)
	return a
}

// Remove removes an item by index.
func (a *Array) Remove(index int) interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	// Determine array boundaries when deleting to improve deletion efficiency。
	if index == 0 {
		value := a.array[0]
		a.array = a.array[1:]
		return value
	} else if index == len(a.array)-1 {
		value := a.array[index]
		a.array = a.array[:index]
		return value
	}
	// If it is a non-boundary delete,
	// it will involve the creation of an array,
	// then the deletion is less efficient.
	value := a.array[index]
	a.array = append(a.array[:index], a.array[index+1:]...)
	return value
}

// PushLeft pushes one or multiple items to the beginning of array.
func (a *Array) PushLeft(value ...interface{}) *Array {
	a.mu.Lock()
	a.array = append(value, a.array...)
	a.mu.Unlock()
	return a
}

// PushRight pushes one or multiple items to the end of array.
// It equals to Append.
func (a *Array) PushRight(value ...interface{}) *Array {
	a.mu.Lock()
	a.array = append(a.array, value...)
	a.mu.Unlock()
	return a
}

// PopRand randomly pops and return an item out of array.
func (a *Array) PopRand() interface{} {
	return a.Remove(grand.Intn(len(a.array)))
}

// PopRands randomly pops and returns <size> items out of array.
func (a *Array) PopRands(size int) []interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	if size > len(a.array) {
		size = len(a.array)
	}
	array := make([]interface{}, size)
	for i := 0; i < size; i++ {
		index := grand.Intn(len(a.array))
		array[i] = a.array[index]
		a.array = append(a.array[:index], a.array[index+1:]...)
	}
	return array
}

// PopLeft pops and returns an item from the beginning of array.
func (a *Array) PopLeft() interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	value := a.array[0]
	a.array = a.array[1:]
	return value
}

// PopRight pops and returns an item from the end of array.
func (a *Array) PopRight() interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	index := len(a.array) - 1
	value := a.array[index]
	a.array = a.array[:index]
	return value
}

// PopLefts pops and returns <size> items from the beginning of array.
func (a *Array) PopLefts(size int) []interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	length := len(a.array)
	if size > length {
		size = length
	}
	value := a.array[0:size]
	a.array = a.array[size:]
	return value
}

// PopRights pops and returns <size> items from the end of array.
func (a *Array) PopRights(size int) []interface{} {
	a.mu.Lock()
	defer a.mu.Unlock()
	index := len(a.array) - size
	if index < 0 {
		index = 0
	}
	value := a.array[index:]
	a.array = a.array[:index]
	return value
}

// Range picks and returns items by range, like array[start:end].
// Notice, if in concurrent-safe usage, it returns a copy of slice;
// else a pointer to the underlying data.
//
// If <end> is negative, then the offset will start from the end of array.
// If <end> is omitted, then the sequence will have everything from start up
// until the end of the array.
func (a *Array) Range(start int, end ...int) []interface{} {
	a.mu.RLock()
	defer a.mu.RUnlock()
	offsetEnd := len(a.array)
	if len(end) > 0 && end[0] < offsetEnd {
		offsetEnd = end[0]
	}
	if start > offsetEnd {
		return nil
	}
	if start < 0 {
		start = 0
	}
	array := ([]interface{})(nil)
	if a.mu.IsSafe() {
		array = make([]interface{}, offsetEnd-start)
		copy(array, a.array[start:offsetEnd])
	} else {
		array = a.array[start:offsetEnd]
	}
	return array
}

// SubSlice returns a slice of elements from the array as specified
// by the <offset> and <size> parameters.
// If in concurrent safe usage, it returns a copy of the slice; else a pointer.
//
// If offset is non-negative, the sequence will start at that offset in the array.
// If offset is negative, the sequence will start that far from the end of the array.
//
// If length is given and is positive, then the sequence will have up to that many elements in it.
// If the array is shorter than the length, then only the available array elements will be present.
// If length is given and is negative then the sequence will stop that many elements from the end of the array.
// If it is omitted, then the sequence will have everything from offset up until the end of the array.
//
// Any possibility crossing the left border of array, it will fail.
func (a *Array) SubSlice(offset int, length ...int) []interface{} {
	a.mu.RLock()
	defer a.mu.RUnlock()
	size := len(a.array)
	if len(length) > 0 {
		size = length[0]
	}
	if offset > len(a.array) {
		return nil
	}
	if offset < 0 {
		offset = len(a.array) + offset
		if offset < 0 {
			return nil
		}
	}
	if size < 0 {
		offset += size
		size = -size
		if offset < 0 {
			return nil
		}
	}
	end := offset + size
	if end > len(a.array) {
		end = len(a.array)
		size = len(a.array) - offset
	}
	if a.mu.IsSafe() {
		s := make([]interface{}, size)
		copy(s, a.array[offset:])
		return s
	} else {
		return a.array[offset:end]
	}
}

// See PushRight.
func (a *Array) Append(value ...interface{}) *Array {
	a.PushRight(value...)
	return a
}

// Len returns the length of array.
func (a *Array) Len() int {
	a.mu.RLock()
	length := len(a.array)
	a.mu.RUnlock()
	return length
}

// Slice returns the underlying data of array.
// Note that, if it's in concurrent-safe usage, it returns a copy of underlying data,
// or else a pointer to the underlying data.
func (a *Array) Slice() []interface{} {
	if a.mu.IsSafe() {
		a.mu.RLock()
		defer a.mu.RUnlock()
		array := make([]interface{}, len(a.array))
		copy(array, a.array)
		return array
	} else {
		return a.array
	}
}

// Interfaces returns current array as []interface{}.
func (a *Array) Interfaces() []interface{} {
	return a.Slice()
}

// Clone returns a new array, which is a copy of current array.
func (a *Array) Clone() (newArray *Array) {
	a.mu.RLock()
	array := make([]interface{}, len(a.array))
	copy(array, a.array)
	a.mu.RUnlock()
	return NewArrayFrom(array, !a.mu.IsSafe())
}

// Clear deletes all items of current array.
func (a *Array) Clear() *Array {
	a.mu.Lock()
	if len(a.array) > 0 {
		a.array = make([]interface{}, 0)
	}
	a.mu.Unlock()
	return a
}

// Contains checks whether a value exists in the array.
func (a *Array) Contains(value interface{}) bool {
	return a.Search(value) != -1
}

// Search searches array by <value>, returns the index of <value>,
// or returns -1 if not exists.
func (a *Array) Search(value interface{}) int {
	if len(a.array) == 0 {
		return -1
	}
	a.mu.RLock()
	result := -1
	for index, v := range a.array {
		if v == value {
			result = index
			break
		}
	}
	a.mu.RUnlock()

	return result
}

// Unique uniques the array, clear repeated items.
func (a *Array) Unique() *Array {
	a.mu.Lock()
	for i := 0; i < len(a.array)-1; i++ {
		for j := i + 1; j < len(a.array); j++ {
			if a.array[i] == a.array[j] {
				a.array = append(a.array[:j], a.array[j+1:]...)
			}
		}
	}
	a.mu.Unlock()
	return a
}

// LockFunc locks writing by callback function <f>.
func (a *Array) LockFunc(f func(array []interface{})) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	f(a.array)
	return a
}

// RLockFunc locks reading by callback function <f>.
func (a *Array) RLockFunc(f func(array []interface{})) *Array {
	a.mu.RLock()
	defer a.mu.RUnlock()
	f(a.array)
	return a
}

// Merge merges <array> into current array.
// The parameter <array> can be any garray or slice type.
// The difference between Merge and Append is Append supports only specified slice type,
// but Merge supports more parameter types.
func (a *Array) Merge(array interface{}) *Array {
	switch v := array.(type) {
	case *Array:
		a.Append(gconv.Interfaces(v.Slice())...)
	case *IntArray:
		a.Append(gconv.Interfaces(v.Slice())...)
	case *StrArray:
		a.Append(gconv.Interfaces(v.Slice())...)
	case *SortedArray:
		a.Append(gconv.Interfaces(v.Slice())...)
	case *SortedIntArray:
		a.Append(gconv.Interfaces(v.Slice())...)
	case *SortedStrArray:
		a.Append(gconv.Interfaces(v.Slice())...)
	default:
		a.Append(gconv.Interfaces(array)...)
	}
	return a
}

// Fill fills an array with num entries of the value <value>,
// keys starting at the <startIndex> parameter.
func (a *Array) Fill(startIndex int, num int, value interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	if startIndex < 0 {
		startIndex = 0
	}
	for i := startIndex; i < startIndex+num; i++ {
		if i > len(a.array)-1 {
			a.array = append(a.array, value)
		} else {
			a.array[i] = value
		}
	}
	return a
}

// Chunk splits an array into multiple arrays,
// the size of each array is determined by <size>.
// The last chunk may contain less than size elements.
func (a *Array) Chunk(size int) [][]interface{} {
	if size < 1 {
		return nil
	}
	a.mu.RLock()
	defer a.mu.RUnlock()
	length := len(a.array)
	chunks := int(math.Ceil(float64(length) / float64(size)))
	var n [][]interface{}
	for i, end := 0, 0; chunks > 0; chunks-- {
		end = (i + 1) * size
		if end > length {
			end = length
		}
		n = append(n, a.array[i*size:end])
		i++
	}
	return n
}

// Pad pads array to the specified length with <value>.
// If size is positive then the array is padded on the right, or negative on the left.
// If the absolute value of <size> is less than or equal to the length of the array
// then no padding takes place.
func (a *Array) Pad(size int, val interface{}) *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	if size == 0 || (size > 0 && size < len(a.array)) || (size < 0 && size > -len(a.array)) {
		return a
	}
	n := size
	if size < 0 {
		n = -size
	}
	n -= len(a.array)
	tmp := make([]interface{}, n)
	for i := 0; i < n; i++ {
		tmp[i] = val
	}
	if size > 0 {
		a.array = append(a.array, tmp...)
	} else {
		a.array = append(tmp, a.array...)
	}
	return a
}

// Rand randomly returns one item from array(no deleting).
func (a *Array) Rand() interface{} {
	a.mu.RLock()
	defer a.mu.RUnlock()
	return a.array[grand.Intn(len(a.array))]
}

// Rands randomly returns <size> items from array(no deleting).
func (a *Array) Rands(size int) []interface{} {
	a.mu.RLock()
	defer a.mu.RUnlock()
	if size > len(a.array) {
		size = len(a.array)
	}
	n := make([]interface{}, size)
	for i, v := range grand.Perm(len(a.array)) {
		n[i] = a.array[v]
		if i == size-1 {
			break
		}
	}
	return n
}

// Shuffle randomly shuffles the array.
func (a *Array) Shuffle() *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	for i, v := range grand.Perm(len(a.array)) {
		a.array[i], a.array[v] = a.array[v], a.array[i]
	}
	return a
}

// Reverse makes array with elements in reverse order.
func (a *Array) Reverse() *Array {
	a.mu.Lock()
	defer a.mu.Unlock()
	for i, j := 0, len(a.array)-1; i < j; i, j = i+1, j-1 {
		a.array[i], a.array[j] = a.array[j], a.array[i]
	}
	return a
}

// Join joins array elements with a string <glue>.
func (a *Array) Join(glue string) string {
	a.mu.RLock()
	defer a.mu.RUnlock()
	buffer := bytes.NewBuffer(nil)
	for k, v := range a.array {
		buffer.WriteString(gconv.String(v))
		if k != len(a.array)-1 {
			buffer.WriteString(glue)
		}
	}
	return buffer.String()
}

// CountValues counts the number of occurrences of all values in the array.
func (a *Array) CountValues() map[interface{}]int {
	m := make(map[interface{}]int)
	a.mu.RLock()
	defer a.mu.RUnlock()
	for _, v := range a.array {
		m[v]++
	}
	return m
}

// Iterator is alias of IteratorAsc.
func (a *Array) Iterator(f func(k int, v interface{}) bool) {
	a.IteratorAsc(f)
}

// IteratorAsc iterates the array in ascending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (a *Array) IteratorAsc(f func(k int, v interface{}) bool) {
	a.mu.RLock()
	defer a.mu.RUnlock()
	for k, v := range a.array {
		if !f(k, v) {
			break
		}
	}
}

// IteratorDesc iterates the array in descending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (a *Array) IteratorDesc(f func(k int, v interface{}) bool) {
	a.mu.RLock()
	defer a.mu.RUnlock()
	for i := len(a.array) - 1; i >= 0; i-- {
		if !f(i, a.array[i]) {
			break
		}
	}
}

// String returns current array as a string, which implements like json.Marshal does.
func (a *Array) String() string {
	a.mu.RLock()
	defer a.mu.RUnlock()
	buffer := bytes.NewBuffer(nil)
	buffer.WriteByte('[')
	s := ""
	for k, v := range a.array {
		s = gconv.String(v)
		if gstr.IsNumeric(s) {
			buffer.WriteString(s)
		} else {
			buffer.WriteString(`"` + gstr.QuoteMeta(s, `"\`) + `"`)
		}
		if k != len(a.array)-1 {
			buffer.WriteByte(',')
		}
	}
	buffer.WriteByte(']')
	return buffer.String()
}

// MarshalJSON implements the interface MarshalJSON for json.Marshal.
func (a *Array) MarshalJSON() ([]byte, error) {
	a.mu.RLock()
	defer a.mu.RUnlock()
	return json.Marshal(a.array)
}

// UnmarshalJSON implements the interface UnmarshalJSON for json.Unmarshal.
func (a *Array) UnmarshalJSON(b []byte) error {
	if a.mu == nil {
		a.mu = rwmutex.New()
		a.array = make([]interface{}, 0)
	}
	a.mu.Lock()
	defer a.mu.Unlock()
	if err := json.Unmarshal(b, &a.array); err != nil {
		return err
	}
	return nil
}