package runtime

import (
	"context"
	"strings"
)

// ContainerSpec describes a container to create and run.
type ContainerSpec struct {
	Name    string   // container name, format: <service>-<component>
	Image   string   // full image reference
	Network string   // docker network name
	User    string   // container user (e.g., "0:0")
	Restart string   // restart policy (e.g., "unless-stopped")
	Ports   []string // "host:container" port mappings
	Volumes []string // "host:container" volume mounts
	Cmd     []string // command and arguments
}

// ContainerInfo describes the observed state of a running or stopped container.
type ContainerInfo struct {
	Name    string
	Image   string
	State   string // "running", "stopped", "exited", etc.
	Network string
	User    string
	Restart string
	Ports   []string
	Volumes []string
	Cmd     []string
	Version string // extracted from image tag
}

// Runtime is the container runtime abstraction.
type Runtime interface {
	Pull(ctx context.Context, image string) error
	Run(ctx context.Context, spec ContainerSpec) error
	Stop(ctx context.Context, name string) error
	Remove(ctx context.Context, name string) error
	Inspect(ctx context.Context, name string) (ContainerInfo, error)
	List(ctx context.Context) ([]ContainerInfo, error)
}

// ExtractVersion parses the tag from an image reference.
// Examples:
//
//	"registry/img:v1.2.0"       -> "v1.2.0"
//	"registry/img:latest"       -> "latest"
//	"registry/img"              -> ""
//	"registry:5000/img:v1"      -> "v1"
func ExtractVersion(image string) string {
	// Strip registry/path prefix so that a port like "registry:5000" isn't
	// mistaken for a tag separator.
	name := image
	if i := strings.LastIndex(image, "/"); i >= 0 {
		name = image[i+1:]
	}
	if i := strings.LastIndex(name, ":"); i >= 0 {
		return name[i+1:]
	}
	return ""
}