const (
	// TaskCreateEventTopic for task create
	TaskCreateEventTopic = "/tasks/create"
	// TaskStartEventTopic for task start
	TaskStartEventTopic = "/tasks/start"
	// TaskOOMEventTopic for task oom
	TaskOOMEventTopic = "/tasks/oom"
	// TaskExitEventTopic for task exit
	TaskExitEventTopic = "/tasks/exit"
	// TaskDeleteEventTopic for task delete
	TaskDeleteEventTopic = "/tasks/delete"
	// TaskExecAddedEventTopic for task exec create
	TaskExecAddedEventTopic = "/tasks/exec-added"
	// TaskExecStartedEventTopic for task exec start
	TaskExecStartedEventTopic = "/tasks/exec-started"
	// TaskPausedEventTopic for task pause
	TaskPausedEventTopic = "/tasks/paused"
	// TaskResumedEventTopic for task resume
	TaskResumedEventTopic = "/tasks/resumed"
	// TaskCheckpointedEventTopic for task checkpoint
	TaskCheckpointedEventTopic = "/tasks/checkpointed"
	// TaskUnknownTopic for unknown task events
	TaskUnknownTopic = "/tasks/?"
)

var (
	// ErrTaskNotExists is returned when a task does not exist
	ErrTaskNotExists = errors.New("task does not exist")
	// ErrTaskAlreadyExists is returned when a task already exists
	ErrTaskAlreadyExists = errors.New("task already exists")
)

type ConsoleSize struct {
	Width  uint32
	Height uint32
}

type CreateOpts struct {
	// Spec is the OCI runtime spec
	Spec *types.Any
	// Rootfs mounts to perform to gain access to the container's filesystem
	Rootfs []mount.Mount
	// IO for the container's main process
	IO IO
	// Checkpoint digest to restore container state
	Checkpoint string
	// RuntimeOptions for the runtime
	RuntimeOptions *types.Any
	// TaskOptions received for the task
	TaskOptions *types.Any
	// Runtime to use
	Runtime string
}

type ExecOpts struct {
	Spec *types.Any
	IO   IO
}

type Exit struct {
	Pid       uint32
	Status    uint32
	Timestamp time.Time
}

type IO struct {
	Stdin    string
	Stdout   string
	Stderr   string
	Terminal bool
}

type PlatformRuntime interface {
	// ID of the runtime
	ID() string
	// Create creates a task with the provided id and options.
	Create(ctx context.Context, id string, opts CreateOpts) (Task, error)
	// Get returns a task.
	Get(context.Context, string) (Task, error)
	// Tasks returns all the current tasks for the runtime.
	// Any container runs at most one task at a time.
	Tasks(context.Context, bool) ([]Task, error)
	// Add adds a task into runtime.
	Add(context.Context, Task) error
	// Delete remove a task.
	Delete(context.Context, string)
}

type Process interface {
	ID() string
	// State returns the process state
	State(context.Context) (State, error)
	// Kill signals a container
	Kill(context.Context, uint32, bool) error
	// Pty resizes the processes pty/console
	ResizePty(context.Context, ConsoleSize) error
	// CloseStdin closes the processes stdin
	CloseIO(context.Context) error
	// Start the container's user defined process
	Start(context.Context) error
	// Wait for the process to exit
	Wait(context.Context) (*Exit, error)
	// Delete deletes the process
	Delete(context.Context) (*Exit, error)
}

type ProcessInfo struct {
	// Pid is the process ID
	Pid uint32
	// Info includes additional process information
	// Info varies by platform
	Info interface{}
}

type State struct {
	// Status is the current status of the container
	Status Status
	// Pid is the main process id for the container
	Pid uint32
	// ExitStatus of the process
	// Only valid if the Status is Stopped
	ExitStatus uint32
	// ExitedAt is the time at which the process exited
	// Only valid if the Status is Stopped
	ExitedAt time.Time
	Stdin    string
	Stdout   string
	Stderr   string
	Terminal bool
}

type Status int

const (
	// CreatedStatus when a process has been created
	CreatedStatus Status = iota + 1
	// RunningStatus when a process is running
	RunningStatus
	// StoppedStatus when a process has stopped
	StoppedStatus
	// DeletedStatus when a process has been deleted
	DeletedStatus
	// PausedStatus when a process is paused
	PausedStatus
	// PausingStatus when a process is currently pausing
	PausingStatus
)

type Task interface {
	Process

	// Namespace that the task exists in
	Namespace() string
	// Pause pauses the container process
	Pause(context.Context) error
	// Resume unpauses the container process
	Resume(context.Context) error
	// Exec adds a process into the container
	Exec(context.Context, string, ExecOpts) (Process, error)
	// Pids returns all pids
	Pids(context.Context) ([]ProcessInfo, error)
	// Checkpoint checkpoints a container to an image with live system data
	Checkpoint(context.Context, string, *types.Any) error
	// Update sets the provided resources to a running task
	Update(context.Context, *types.Any) error
	// Process returns a process within the task for the provided id
	Process(context.Context, string) (Process, error)
	// Stats returns runtime specific metrics for a task
	Stats(context.Context) (*types.Any, error)
}

type TaskInfo struct {
	ID        string
	Runtime   string
	Spec      []byte
	Namespace string
}

type TaskList struct {
	// contains filtered or unexported fields
}

type TaskMonitor interface {
	// Monitor adds the provided container to the monitor
	Monitor(Task) error
	// Stop stops and removes the provided container from the monitor
	Stop(Task) error
}