const (

	// CPUPhysicalPackageID is a physical package id of cpu#. Typically corresponds to a physical socket number,
	// but the actual value is architecture and platform dependent.
	CPUPhysicalPackageID = "physical_package_id"
	// CPUCoreID is the CPU core ID of cpu#. Typically it is the hardware platform's identifier
	// (rather than the kernel's). The actual value is architecture and platform dependent.
	CPUCoreID = "core_id"

	//HugePagesNrFile name of nr_hugepages file in sysfs
	HugePagesNrFile = "nr_hugepages"
)

type CacheInfo struct {
	// cache id
	Id int
	// size in bytes
	Size uint64
	// cache type - instruction, data, unified
	Type string
	// distance from cpus in a multi-level hierarchy
	Level int
	// number of cpus that can access this cache.
	Cpus int
}

type SysFs interface {
	// Get NUMA nodes paths
	GetNodesPaths() ([]string, error)
	// Get paths to CPUs in provided directory e.g. /sys/devices/system/node/node0 or /sys/devices/system/cpu
	GetCPUsPaths(cpusPath string) ([]string, error)
	// Get physical core id for specified CPU
	GetCoreID(coreIDFilePath string) (string, error)
	// Get physical package id for specified CPU
	GetCPUPhysicalPackageID(cpuPath string) (string, error)
	// Get book id for specified CPU
	GetBookID(cpuPath string) (string, error)
	// Get drawer id for specified CPU
	GetDrawerID(cpuPath string) (string, error)
	// Get total memory for specified NUMA node
	GetMemInfo(nodeDir string) (string, error)
	// Get hugepages from specified directory
	GetHugePagesInfo(hugePagesDirectory string) ([]os.FileInfo, error)
	// Get hugepage_nr from specified directory
	GetHugePagesNr(hugePagesDirectory string, hugePageName string) (string, error)
	// Get directory information for available block devices.
	GetBlockDevices() ([]os.FileInfo, error)
	// Get Size of a given block device.
	GetBlockDeviceSize(string) (string, error)
	// Get scheduler type for the block device.
	GetBlockDeviceScheduler(string) (string, error)
	// Get device major:minor number string.
	GetBlockDeviceNumbers(string) (string, error)
	// Is the device "hidden" (meaning will not have a device handle)
	// This is the case with native nvme multipathing.
	IsBlockDeviceHidden(string) (bool, error)

	GetNetworkDevices() ([]os.FileInfo, error)
	GetNetworkAddress(string) (string, error)
	GetNetworkMtu(string) (string, error)
	GetNetworkSpeed(string) (string, error)
	GetNetworkStatValue(dev string, stat string) (uint64, error)

	// Get directory information for available caches accessible to given cpu.
	GetCaches(id int) ([]os.FileInfo, error)
	// Get information for a cache accessible from the given cpu.
	GetCacheInfo(cpu int, cache string) (CacheInfo, error)

	GetSystemUUID() (string, error)

	// GetDistances returns distance array
	GetDistances(string) (string, error)

	// IsCPUOnline determines if CPU status from kernel hotplug machanism standpoint.
	// See: https://www.kernel.org/doc/html/latest/core-api/cpu_hotplug.html
	IsCPUOnline(dir string) bool
}