// Copyright 2017 gf Author(https://gitee.com/johng/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://gitee.com/johng/gf.
//

package gmap

import "gitee.com/johng/gf/g/internal/rwmutex"

type StringStringMap struct {
	mu *rwmutex.RWMutex
	m  map[string]string
}

func NewStringStringMap(unsafe...bool) *StringStringMap {
	return &StringStringMap{
		m  : make(map[string]string),
        mu : rwmutex.New(unsafe...),
	}
}

// 给定回调函数对原始内容进行遍历，回调函数返回true表示继续遍历，否则停止遍历
func (this *StringStringMap) Iterator(f func (k string, v string) bool) {
	this.mu.RLock()
	defer this.mu.RUnlock()
	for k, v := range this.m {
		if !f(k, v) {
			break
		}
	}
}

// 哈希表克隆
func (this *StringStringMap) Clone() map[string]string {
    m := make(map[string]string)
    this.mu.RLock()
    for k, v := range this.m {
        m[k] = v
    }
    this.mu.RUnlock()
    return m
}

// 设置键值对
func (this *StringStringMap) Set(key string, val string) {
	this.mu.Lock()
	this.m[key] = val
	this.mu.Unlock()
}

// 批量设置键值对
func (this *StringStringMap) BatchSet(m map[string]string) {
    this.mu.Lock()
    for k, v := range m {
        this.m[k] = v
    }
    this.mu.Unlock()
}

// 获取键值
func (this *StringStringMap) Get(key string) string {
	this.mu.RLock()
	val, _ := this.m[key]
	this.mu.RUnlock()
	return val
}

// 设置kv缓存键值对，内部会对键名的存在性使用写锁进行二次检索确认，如果存在则不再写入；返回键名对应的键值。
// 在高并发下有用，防止数据写入的并发逻辑错误。
func (this *StringStringMap) doSetWithLockCheck(key string, value string) string {
	this.mu.Lock()
	if v, ok := this.m[key]; ok {
		this.mu.Unlock()
		return v
	}
	this.m[key] = value
	this.mu.Unlock()
	return value
}

// 当键名存在时返回其键值，否则写入指定的键值
func (this *StringStringMap) GetOrSet(key string, value string) string {
	this.mu.RLock()
	v, ok := this.m[key]
	this.mu.RUnlock()
	if !ok {
		return this.doSetWithLockCheck(key, value)
	} else {
		return v
	}
}

// 当键名存在时返回其键值，否则写入指定的键值，键值由指定的函数生成
func (this *StringStringMap) GetOrSetFunc(key string, f func() string) string {
	this.mu.RLock()
	v, ok := this.m[key]
	this.mu.RUnlock()
	if !ok {
		return this.doSetWithLockCheck(key, f())
	} else {
		return v
	}
}

// 与GetOrSetFunc不同的是，f是在写锁机制内执行
func (this *StringStringMap) GetOrSetFuncLock(key string, f func() string) string {
	this.mu.RLock()
	val, ok := this.m[key]
	this.mu.RUnlock()
	if !ok {
		this.mu.Lock()
		defer this.mu.Unlock()
		if v, ok := this.m[key]; ok {
			this.mu.Unlock()
			return v
		}
		val         = f()
		this.m[key] = val
		return val
	} else {
		return val
	}
}

// 当键名不存在时写入，并返回true；否则返回false。
func (this *StringStringMap) SetIfNotExist(key string, value string) bool {
	if !this.Contains(key) {
		this.doSetWithLockCheck(key, value)
		return true
	}
	return false
}

// 批量删除键值对
func (this *StringStringMap) BatchRemove(keys []string) {
    this.mu.Lock()
    for _, key := range keys {
        delete(this.m, key)
    }
    this.mu.Unlock()
}

// 返回对应的键值，并删除该键值
func (this *StringStringMap) Remove(key string) string {
	this.mu.Lock()
	val, exists := this.m[key]
	if exists {
		delete(this.m, key)
	}
	this.mu.Unlock()
	return val
}

// 返回键列表
func (this *StringStringMap) Keys() []string {
	this.mu.RLock()
	keys := make([]string, 0)
	for key, _ := range this.m {
		keys = append(keys, key)
	}
    this.mu.RUnlock()
	return keys
}

// 返回值列表(注意是随机排序)
func (this *StringStringMap) Values() []string {
	this.mu.RLock()
	vals := make([]string, 0)
	for _, val := range this.m {
		vals = append(vals, val)
	}
	this.mu.RUnlock()
	return vals
}

// 是否存在某个键
func (this *StringStringMap) Contains(key string) bool {
	this.mu.RLock()
	_, exists := this.m[key]
	this.mu.RUnlock()
	return exists
}

// 哈希表大小
func (this *StringStringMap) Size() int {
	this.mu.RLock()
	length := len(this.m)
	this.mu.RUnlock()
	return length
}

// 哈希表是否为空
func (this *StringStringMap) IsEmpty() bool {
	this.mu.RLock()
	empty := len(this.m) == 0
	this.mu.RUnlock()
	return empty
}

// 清空哈希表
func (this *StringStringMap) Clear() {
    this.mu.Lock()
    this.m = make(map[string]string)
    this.mu.Unlock()
}

// 并发安全写锁操作，使用自定义方法执行加锁修改操作
func (this *StringStringMap) LockFunc(f func(m map[string]string)) {
	this.mu.Lock(true)
	defer this.mu.Unlock(true)
	f(this.m)
}

// 并发安全读锁操作，使用自定义方法执行加锁读取操作
func (this *StringStringMap) RLockFunc(f func(m map[string]string)) {
	this.mu.RLock(true)
	defer this.mu.RUnlock(true)
	f(this.m)
}