// Copyright 2018-2019 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 gvar provides an universal variable type, like generics.
package gvar

import (
	"encoding/json"
	"time"

	"github.com/gogf/gf/internal/empty"

	"github.com/gogf/gf/container/gtype"
	"github.com/gogf/gf/os/gtime"
	"github.com/gogf/gf/util/gconv"
)

// Var is an universal variable type.
type Var struct {
	value interface{} // Underlying value.
	safe  bool        // Concurrent safe or not.
}

// New creates and returns a new *Var with given <value>.
// The optional parameter <safe> specifies whether Var is used in concurrent-safety,
// which is false in default.
func New(value interface{}, safe ...bool) *Var {
	v := Create(value, safe...)
	return &v
}

// Create creates and returns a new Var with given <value>.
// The optional parameter <safe> specifies whether Var is used in concurrent-safety,
// which is false in default.
func Create(value interface{}, safe ...bool) Var {
	v := Var{}
	if len(safe) > 0 && !safe[0] {
		v.safe = true
		v.value = gtype.NewInterface(value)
	} else {
		v.value = value
	}
	return v
}

// Set sets <value> to <v>, and returns the old value.
func (v *Var) Set(value interface{}) (old interface{}) {
	if v.safe {
		old = v.value.(*gtype.Interface).Set(value)
	} else {
		old = v.value
		v.value = value
	}
	return
}

// Val returns the current value of <v>.
func (v *Var) Val() interface{} {
	if v == nil {
		return nil
	}
	if v.safe {
		return v.value.(*gtype.Interface).Val()
	}
	return v.value
}

// Interface is alias of Val.
func (v *Var) Interface() interface{} {
	return v.Val()
}

// IsNil checks whether <v> is nil.
func (v *Var) IsNil() bool {
	return v.Val() == nil
}

// IsEmpty checks whether <v> is empty.
func (v *Var) IsEmpty() bool {
	return empty.IsEmpty(v.Val())
}

// Bytes converts and returns <v> as []byte.
func (v *Var) Bytes() []byte {
	return gconv.Bytes(v.Val())
}

// String converts and returns <v> as string.
func (v *Var) String() string {
	return gconv.String(v.Val())
}

// Bool converts and returns <v> as bool.
func (v *Var) Bool() bool {
	return gconv.Bool(v.Val())
}

// Int converts and returns <v> as int.
func (v *Var) Int() int {
	return gconv.Int(v.Val())
}

// Ints converts and returns <v> as []int.
func (v *Var) Ints() []int {
	return gconv.Ints(v.Val())
}

// Int8 converts and returns <v> as int8.
func (v *Var) Int8() int8 {
	return gconv.Int8(v.Val())
}

// Int16 converts and returns <v> as int16.
func (v *Var) Int16() int16 {
	return gconv.Int16(v.Val())
}

// Int32 converts and returns <v> as int32.
func (v *Var) Int32() int32 {
	return gconv.Int32(v.Val())
}

// Int64 converts and returns <v> as int64.
func (v *Var) Int64() int64 {
	return gconv.Int64(v.Val())
}

// Uint converts and returns <v> as uint.
func (v *Var) Uint() uint {
	return gconv.Uint(v.Val())
}

// Uints converts and returns <v> as []uint.
func (v *Var) Uints() []uint {
	return gconv.Uints(v.Val())
}

// Uint8 converts and returns <v> as uint8.
func (v *Var) Uint8() uint8 {
	return gconv.Uint8(v.Val())
}

// Uint16 converts and returns <v> as uint16.
func (v *Var) Uint16() uint16 {
	return gconv.Uint16(v.Val())
}

// Uint32 converts and returns <v> as uint32.
func (v *Var) Uint32() uint32 {
	return gconv.Uint32(v.Val())
}

// Uint64 converts and returns <v> as uint64.
func (v *Var) Uint64() uint64 {
	return gconv.Uint64(v.Val())
}

// Float32 converts and returns <v> as float32.
func (v *Var) Float32() float32 {
	return gconv.Float32(v.Val())
}

// Float64 converts and returns <v> as float64.
func (v *Var) Float64() float64 {
	return gconv.Float64(v.Val())
}

// Floats converts and returns <v> as []float64.
func (v *Var) Floats() []float64 {
	return gconv.Floats(v.Val())
}

// Strings converts and returns <v> as []string.
func (v *Var) Strings() []string {
	return gconv.Strings(v.Val())
}

// Interfaces converts and returns <v> as []interfaces{}.
func (v *Var) Interfaces() []interface{} {
	return gconv.Interfaces(v.Val())
}

// Slice is alias of Interfaces.
func (v *Var) Slice() []interface{} {
	return v.Interfaces()
}

// Array is alias of Interfaces.
func (v *Var) Array() []interface{} {
	return v.Interfaces()
}

// Vars converts and returns <v> as []*Var.
func (v *Var) Vars() []*Var {
	array := gconv.Interfaces(v.Val())
	if len(array) == 0 {
		return nil
	}
	vars := make([]*Var, len(array))
	for k, v := range array {
		vars[k] = New(v)
	}
	return vars
}

// Time converts and returns <v> as time.Time.
// The parameter <format> specifies the format of the time string using gtime,
// eg: Y-m-d H:i:s.
func (v *Var) Time(format ...string) time.Time {
	return gconv.Time(v.Val(), format...)
}

// Duration converts and returns <v> as time.Duration.
// If value of <v> is string, then it uses time.ParseDuration for conversion.
func (v *Var) Duration() time.Duration {
	return gconv.Duration(v.Val())
}

// GTime converts and returns <v> as *gtime.Time.
// The parameter <format> specifies the format of the time string using gtime,
// eg: Y-m-d H:i:s.
func (v *Var) GTime(format ...string) *gtime.Time {
	return gconv.GTime(v.Val(), format...)
}

// Map converts <v> to map[string]interface{}.
func (v *Var) Map(tags ...string) map[string]interface{} {
	return gconv.Map(v.Val(), tags...)
}

// MapStrStr converts <v> to map[string]string.
func (v *Var) MapStrStr(tags ...string) map[string]string {
	m := v.Map(tags...)
	if len(m) > 0 {
		vMap := make(map[string]string)
		for k, v := range m {
			vMap[k] = gconv.String(v)
		}
		return vMap
	}
	return nil
}

// MapStrVar converts <v> to map[string]*Var.
func (v *Var) MapStrVar(tags ...string) map[string]*Var {
	m := v.Map(tags...)
	if len(m) > 0 {
		vMap := make(map[string]*Var)
		for k, v := range m {
			vMap[k] = New(v)
		}
		return vMap
	}
	return nil
}

// MapDeep converts <v> to map[string]interface{} recursively.
func (v *Var) MapDeep(tags ...string) map[string]interface{} {
	return gconv.MapDeep(v.Val(), tags...)
}

// MapDeep converts <v> to map[string]string recursively.
func (v *Var) MapStrStrDeep(tags ...string) map[string]string {
	m := v.MapDeep(tags...)
	if len(m) > 0 {
		vMap := make(map[string]string)
		for k, v := range m {
			vMap[k] = gconv.String(v)
		}
		return vMap
	}
	return nil
}

// MapStrVarDeep converts <v> to map[string]*Var recursively.
func (v *Var) MapStrVarDeep(tags ...string) map[string]*Var {
	m := v.MapDeep(tags...)
	if len(m) > 0 {
		vMap := make(map[string]*Var)
		for k, v := range m {
			vMap[k] = New(v)
		}
		return vMap
	}
	return nil
}

// Struct maps value of <v> to <pointer>.
// The parameter <pointer> should be a pointer to a struct instance.
// The parameter <mapping> is used to specify the key-to-attribute mapping rules.
func (v *Var) Struct(pointer interface{}, mapping ...map[string]string) error {
	return gconv.Struct(v.Val(), pointer, mapping...)
}

// Struct maps value of <v> to <pointer> recursively.
// The parameter <pointer> should be a pointer to a struct instance.
// The parameter <mapping> is used to specify the key-to-attribute mapping rules.
func (v *Var) StructDeep(pointer interface{}, mapping ...map[string]string) error {
	return gconv.StructDeep(v.Val(), pointer, mapping...)
}

// Structs converts <v> to given struct slice.
func (v *Var) Structs(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.Structs(v.Val(), pointer, mapping...)
}

// StructsDeep converts <v> to given struct slice recursively.
func (v *Var) StructsDeep(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.StructsDeep(v.Val(), pointer, mapping...)
}

// MapToMap converts map type variable <params> to another map type variable <pointer>.
// The elements of <pointer> should be type of struct/*struct.
func (v *Var) MapToMap(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.MapToMap(v.Val(), pointer, mapping...)
}

// MapToMapDeep recursively converts map type variable <params> to another map type variable <pointer>.
// The elements of <pointer> should be type of struct/*struct.
func (v *Var) MapToMapDeep(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.MapToMapDeep(v.Val(), pointer, mapping...)
}

// MapToMaps converts map type variable <params> to another map type variable <pointer>.
// The elements of <pointer> should be type of []struct/[]*struct.
func (v *Var) MapToMaps(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.MapToMaps(v.Val(), pointer, mapping...)
}

// MapToMapsDeep recursively converts map type variable <params> to another map type variable <pointer>.
// The elements of <pointer> should be type of []struct/[]*struct.
func (v *Var) MapToMapsDeep(pointer interface{}, mapping ...map[string]string) (err error) {
	return gconv.MapToMapsDeep(v.Val(), pointer, mapping...)
}

// MarshalJSON implements the interface MarshalJSON for json.Marshal.
func (v *Var) MarshalJSON() ([]byte, error) {
	return json.Marshal(v.Val())
}

// UnmarshalJSON implements the interface UnmarshalJSON for json.Unmarshal.
func (v *Var) UnmarshalJSON(b []byte) error {
	var i interface{}
	err := json.Unmarshal(b, &i)
	if err != nil {
		return err
	}
	v.Set(i)
	return nil
}