var (
	ErrExist          = errors.New("container with given ID already exists")
	ErrInvalidID      = errors.New("invalid container ID format")
	ErrNotExist       = errors.New("container does not exist")
	ErrPaused         = errors.New("container paused")
	ErrRunning        = errors.New("container still running")
	ErrNotRunning     = errors.New("container not running")
	ErrNotPaused      = errors.New("container not paused")
	ErrCgroupNotExist = errors.New("cgroup not exist")
)

type BaseState struct {
	// ID is the container ID.
	ID string `json:"id"`

	// InitProcessPid is the init process id in the parent namespace.
	InitProcessPid int `json:"init_process_pid"`

	// InitProcessStartTime is the init process start time in clock cycles since boot time.
	InitProcessStartTime uint64 `json:"init_process_start"`

	// Created is the unix timestamp for the creation time of the container in UTC
	Created time.Time `json:"created"`

	// Config is the container's configuration.
	Config configs.Config `json:"config"`
}

type IO struct {
	Stdin  io.WriteCloser
	Stdout io.ReadCloser
	Stderr io.ReadCloser
}

type Process struct {
	// The command to be run followed by any arguments.
	Args []string

	// Env specifies the environment variables for the process.
	Env []string

	// UID and GID of the executing process running inside the container
	// local to the container's user and group configuration.
	UID, GID int

	// AdditionalGroups specifies the gids that should be added to supplementary groups
	// in addition to those that the user belongs to.
	AdditionalGroups []int

	// Cwd will change the process's current working directory inside the container's rootfs.
	Cwd string

	// Stdin is a reader which provides the standard input stream.
	Stdin io.Reader

	// Stdout is a writer which receives the standard output stream.
	Stdout io.Writer

	// Stderr is a writer which receives the standard error stream.
	Stderr io.Writer

	// ExtraFiles specifies additional open files to be inherited by the process.
	ExtraFiles []*os.File

	// Initial size for the console.
	ConsoleWidth  uint16
	ConsoleHeight uint16

	// Capabilities specify the capabilities to keep when executing the process.
	// All capabilities not specified will be dropped from the processes capability mask.
	//
	// If not nil, takes precedence over container's [configs.Config.Capabilities].
	Capabilities *configs.Capabilities

	// AppArmorProfile specifies the profile to apply to the process and is
	// changed at the time the process is executed.
	//
	// If not empty, takes precedence over container's [configs.Config.AppArmorProfile].
	AppArmorProfile string

	// Label specifies the label to apply to the process. It is commonly used by selinux.
	//
	// If not empty, takes precedence over container's [configs.Config.ProcessLabel].
	Label string

	// NoNewPrivileges controls whether processes can gain additional privileges.
	//
	// If not nil, takes precedence over container's [configs.Config.NoNewPrivileges].
	NoNewPrivileges *bool

	// Rlimits specifies the resource limits, such as max open files, to set for the process.
	// If unset, the process will inherit rlimits from the parent process.
	//
	// If not empty, takes precedence over container's [configs.Config.Rlimit].
	Rlimits []configs.Rlimit

	// ConsoleSocket provides the masterfd console.
	ConsoleSocket *os.File

	// PidfdSocket provides process file descriptor of it own.
	PidfdSocket *os.File

	// Init specifies whether the process is the first process in the container.
	Init bool

	// LogLevel is a string containing a numeric representation of the current
	// log level (i.e. "4", but never "info"). It is passed on to runc init as
	// _LIBCONTAINER_LOGLEVEL environment variable.
	LogLevel string

	// SubCgroupPaths specifies sub-cgroups to run the process in.
	// Map keys are controller names, map values are paths (relative to
	// container's top-level cgroup).
	//
	// If empty, the default top-level container's cgroup is used.
	//
	// For cgroup v2, the only key allowed is "".
	SubCgroupPaths map[string]string

	// Scheduler represents the scheduling attributes for a process.
	//
	// If not empty, takes precedence over container's [configs.Config.Scheduler].
	Scheduler *configs.Scheduler

	// IOPriority is a process I/O priority.
	//
	// If not empty, takes precedence over container's [configs.Config.IOPriority].
	IOPriority *configs.IOPriority

	CPUAffinity *configs.CPUAffinity
	// contains filtered or unexported fields
}

type Status int

const (
	// Created is the status that denotes the container exists but has not been run yet.
	Created Status = iota
	// Running is the status that denotes the container exists and is running.
	Running
	// Paused is the status that denotes the container exists, but all its processes are paused.
	Paused
	// Stopped is the status that denotes the container does not have a created or running process.
	Stopped
)