package environment

import (
	"fmt"
	"github.com/docker/go-connections/nat"
	"strconv"
)

// Defines the allocations available for a given server. When using the Docker environment
// driver these correspond to mappings for the container that allow external connections.
type Allocations struct {
	// Defines the default allocation that should be used for this server. This is
	// what will be used for {SERVER_IP} and {SERVER_PORT} when modifying configuration
	// files or the startup arguments for a server.
	DefaultMapping struct {
		Ip   string `json:"ip"`
		Port int    `json:"port"`
	} `json:"default"`

	// Mappings contains all of the ports that should be assigned to a given server
	// attached to the IP they correspond to.
	Mappings map[string][]int `json:"mappings"`
}

// Converts the server allocation mappings into a format that can be understood by Docker. While
// we do strive to support multiple environments, using Docker's standardized format for the
// bindings certainly makes life a little easier for managing things.
func (a *Allocations) Bindings() nat.PortMap {
	var out = nat.PortMap{}

	for ip, ports := range a.Mappings {
		for _, port := range ports {
			// Skip over invalid ports.
			if port < 1 || port > 65535 {
				continue
			}

			binding := []nat.PortBinding{
				{
					HostIP:   ip,
					HostPort: strconv.Itoa(port),
				},
			}

			out[nat.Port(fmt.Sprintf("%d/tcp", port))] = binding
			out[nat.Port(fmt.Sprintf("%d/udp", port))] = binding
		}
	}

	return out
}

// Converts the server allocation mappings into a PortSet that can be understood
// by Docker. This formatting is slightly different than "Bindings" as it should
// return an empty struct rather than a binding.
//
// To accomplish this, we'll just get the values from "Bindings" and then set them
// to empty structs. Because why not.
func (a *Allocations) Exposed() nat.PortSet {
	var out = nat.PortSet{}

	for port := range a.Bindings() {
		out[port] = struct{}{}
	}

	return out
}