package routinex

import (
	"runtime"
	"strconv"
	"strings"
	"sync"
)

// ------------------- goroutine id -------------------
func CurGID() uint64 {
	var buf [64]byte
	n := runtime.Stack(buf[:], false)
	line := strings.Fields(strings.TrimPrefix(string(buf[:n]), "goroutine "))[0]
	gid, _ := strconv.ParseUint(line, 10, 64)
	return gid
}

type RoutineLocal struct {
	data sync.Map // gid -> map[key]any
}

var (
	instance     *RoutineLocal
	instanceOnce sync.Once
)

func GetInstance() *RoutineLocal {
	instanceOnce.Do(func() {
		instance = &RoutineLocal{}
	})
	return instance
}

// Set 存储单条数据
func Set(key string, value any) {
	gid := CurGID()
	v, _ := GetInstance().data.LoadOrStore(gid, &sync.Map{})
	m := v.(*sync.Map)
	m.Store(key, value)
}

// Get 获取单条数据
func Get(key string) any {
	gid := CurGID()
	if v, ok := GetInstance().data.Load(gid); ok {
		m := v.(*sync.Map)
		if val, ok := m.Load(key); ok {
			return val
		}
	}
	return nil
}

// Clear 删除当前 goroutine 所有数据
func Clear() {
	GetInstance().data.Delete(CurGID())
}

// Go 封装函数，自动继承父 goroutine 数据
func Go(f func()) {
	parentGID := CurGID()
	parentData, _ := GetInstance().data.Load(parentGID)

	go func() {
		if parentData != nil {
			GetInstance().data.Store(CurGID(), parentData)
			defer Clear()
		}
		f()
	}()
}