engine

type EngineOptions struct {
	Root            string
	UpdateFrequency tool.UpdateFrequency
}

type GetterCtor func(stoic.Stoic, stoic.Tool) (tool.Getter, error)

type RunnerCtor func(stoic.Stoic, stoic.Tool) (tool.Runner, error)

type State interface {
	// ToolId identifies the tool the instance pertains too.
	ToolId() string

	// Filename returns the filesystem path where the state is persisted.
	Filename() string

	// UpstreamVersion returns the latest upstream version of the tool that is
	// available locally, for the specified channel.
	UpstreamVersion(tc tool.Channel) tool.Version

	// LastUpstreamUpdate returns the time at which the upstream version for the
	// specified channel was last updated.
	LastUpstreamUpdate(tc tool.Channel) time.Time

	// CurrentCheckout returns the most recent checkout marked as current.
	CurrentCheckout() tool.Checkout

	// CheckoutForVersion returns the most recent checkout for the requested
	// version.
	CheckoutForVersion(version tool.Version) tool.Checkout
}

type ToolChannelInfoFormat struct {
	Version    tool.Version  `json:"version,omitempty"`
	LastUpdate UnixTimestamp `json:"last-update,omitempty"`
}

type ToolCheckoutFormat struct {
	CheckoutVersion tool.Version  `json:"version"`
	CheckoutPath    string        `json:"path"`
	Created         UnixTimestamp `json:"created"`
	SetCurrent      UnixTimestamp `json:"set-current,omitempty"`
}

type ToolStateFormat struct {
	Upstream  *ToolChannelInfoFormat                 `json:"upstream,omitempty"`
	Channels  map[tool.Channel]ToolChannelInfoFormat `json:"channels,omitempty"`
	Checkouts []ToolCheckoutFormat                   `json:"checkouts,omitempty"`
}

type UnixTimestamp int64