package chill

import (
	"bytes"
	"context"
	"errors"
	"os"
	"strconv"
	"time"
)

var TempFile string = "/sys/class/thermal/thermal_zone2/temp"
var MaxTemp int = 72500
var Sleep = time.Second * 10
var ErrChilledOut = errors.New("temperature dropped below threshold")

func getCurrentTemp() (o int, err error) {
	var by []byte
	by, err = os.ReadFile(TempFile)
	if err != nil {
		return
	}
	by = bytes.TrimSpace(by)
	o, err = strconv.Atoi(string(by))
	return
}

func Chill(baseCtx context.Context) context.Context {
	ctx, cancel := context.WithCancelCause(baseCtx)

	ret := func(e error) context.Context {
		cancel(e)
		return ctx
	}

	current, err := getCurrentTemp()
	if err != nil {
		return ret(err)
	}

	if current < MaxTemp {
		return ret(ErrChilledOut)
	}

	go runChill(current, cancel)

	return ctx
}

func runChill(current int, cancel context.CancelCauseFunc) {
	var err error
	for current >= MaxTemp && err == nil {
		time.Sleep(Sleep)
		current, err = getCurrentTemp()
	}
	if err == nil {
		err = ErrChilledOut
	}
	cancel(err)

}