package host

import (
	"log"
	"strings"
)

// URI is a string type, accessed via the pre-defined variables, and represent
// the URI pattern used to connect to a host.
// Example:
// Driver[+Transport]://<host or empty for local>[:PORT]/<path>[?Options&in=uri&format]
type URI struct {
	Driver    string
	Transport string
	Path      string
	Options   []string
}

// CustomURI create and return a custom URI method, following RFC2396,
// keeping in mind that the hostname will be inserted between the transport and path
func CustomURI(driver, transport, path string, options ...string) *URI {
	return &URI{
		Driver:    driver,
		Transport: transport,
		Path:      path,
		Options:   options,
	}
}

// URIs available to build connections to a libvirt host
var (
	// URI for connecting to a remote QEMU system over SSH
	URI_QEMU_SSH_SYSTEM = &URI{Driver: "qemu", Transport: "ssh", Path: "system"}
	// URI for connecting to a remote	QEMU system over TLS
	// Builds the URI qemu://<host:port>/system
	URI_QEMU_TLS_SYSTEM = &URI{Driver: "qemu", Transport: "", Path: "system"}
	// URI for connecting to a remote QEMU session over SSH
	URI_QEMU_SSH_SESSION = &URI{Driver: "qemu", Transport: "ssh", Path: "session"}
	// URI for connecting to a local QEMU system over a UNIX socket
	URI_QEMU_UNIX_SYSTEM = &URI{Driver: "qemu", Transport: "unix", Path: "system"}
	// URI for connecting to a remote QEMU system over unsecured TCP
	URI_QEMU_TCP_SYSTEM = &URI{Driver: "qemu", Transport: "tcp", Path: "system"}

	// URI for connecting to a remote XEN system with SSH
	URI_XEN_SSH_SYSTEM = &URI{Driver: "xen", Transport: "ssh", Path: "system"}
	// URI for connecting to a remote XEN system over TLS
	URI_XEN_TLS_SYSTEM = &URI{Driver: "xen", Transport: "", Path: "system"}
)

// ConnectionString takes a host name to interpolate into a URI and returns the string
func (u *URI) ConnectionString(h string) string {
	var sb strings.Builder
	optlen := len(u.Options)
	sb.WriteString(u.Driver)
	if u.Transport != "" {
		sb.WriteRune('+')
		sb.WriteString(u.Transport)
	}
	sb.WriteString("://")
	if h != "" {
		sb.WriteString(h)
	}
	sb.WriteRune('/')
	sb.WriteString(u.Path)

	if optlen > 0 {
		sb.WriteRune('?')
		for i, o := range u.Options {
			sb.WriteString(o)
			if optlen != i+1 {
				sb.WriteRune('&')
			}
		}
	}
	log.Printf("Connection URI: %s", sb.String())
	return sb.String()
}

// AddOpt adds more options to the option list
func (u *URI) AddOpt(opt string) {
	u.Options = append(u.Options, opt)
}