package cloudstack

import (
	"fmt"
	"log"
	"regexp"
	"time"

	"github.com/hashicorp/terraform/helper/schema"
	"github.com/xanzy/go-cloudstack/cloudstack"
)

// CloudStack uses a "special" ID of -1 to define an unlimited resource
const UnlimitedResourceID = "-1"

type retrieveError struct {
	name  string
	value string
	err   error
}

func (e *retrieveError) Error() error {
	return fmt.Errorf("Error retrieving ID of %s %s: %s", e.name, e.value, e.err)
}

func setValueOrID(d *schema.ResourceData, key string, value string, id string) {
	if isID(d.Get(key).(string)) {
		// If the given id is an empty string, check if the configured value matches
		// the UnlimitedResourceID in which case we set id to UnlimitedResourceID
		if id == "" && d.Get(key).(string) == UnlimitedResourceID {
			id = UnlimitedResourceID
		}

		d.Set(key, id)
	} else {
		d.Set(key, value)
	}
}

func retrieveID(cs *cloudstack.CloudStackClient, name, value string) (id string, e *retrieveError) {
	// If the supplied value isn't a ID, try to retrieve the ID ourselves
	if isID(value) {
		return value, nil
	}

	log.Printf("[DEBUG] Retrieving ID of %s: %s", name, value)

	var err error
	switch name {
	case "disk_offering":
		id, err = cs.DiskOffering.GetDiskOfferingID(value)
	case "virtual_machine":
		id, err = cs.VirtualMachine.GetVirtualMachineID(value)
	case "service_offering":
		id, err = cs.ServiceOffering.GetServiceOfferingID(value)
	case "network_offering":
		id, err = cs.NetworkOffering.GetNetworkOfferingID(value)
	case "project":
		id, err = cs.Project.GetProjectID(value)
	case "vpc_offering":
		id, err = cs.VPC.GetVPCOfferingID(value)
	case "vpc":
		id, err = cs.VPC.GetVPCID(value)
	case "network":
		id, err = cs.Network.GetNetworkID(value)
	case "zone":
		id, err = cs.Zone.GetZoneID(value)
	case "ipaddress":
		p := cs.Address.NewListPublicIpAddressesParams()
		p.SetIpaddress(value)
		l, e := cs.Address.ListPublicIpAddresses(p)
		if e != nil {
			err = e
			break
		}
		if l.Count == 1 {
			id = l.PublicIpAddresses[0].Id
			break
		}
		err = fmt.Errorf("Could not find ID of IP address: %s", value)
	case "os_type":
		p := cs.GuestOS.NewListOsTypesParams()
		p.SetDescription(value)
		l, e := cs.GuestOS.ListOsTypes(p)
		if e != nil {
			err = e
			break
		}
		if l.Count == 1 {
			id = l.OsTypes[0].Id
			break
		}
		err = fmt.Errorf("Could not find ID of OS Type: %s", value)
	default:
		return id, &retrieveError{name: name, value: value,
			err: fmt.Errorf("Unknown request: %s", name)}
	}

	if err != nil {
		return id, &retrieveError{name: name, value: value, err: err}
	}

	return id, nil
}

func retrieveTemplateID(cs *cloudstack.CloudStackClient, zoneid, value string) (id string, e *retrieveError) {
	// If the supplied value isn't a ID, try to retrieve the ID ourselves
	if isID(value) {
		return value, nil
	}

	log.Printf("[DEBUG] Retrieving ID of template: %s", value)

	id, err := cs.Template.GetTemplateID(value, "executable", zoneid)
	if err != nil {
		return id, &retrieveError{name: "template", value: value, err: err}
	}

	return id, nil
}

// ID can be either a UUID or a UnlimitedResourceID
func isID(id string) bool {
	re := regexp.MustCompile(`^([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}|-1)$`)
	return re.MatchString(id)
}

// RetryFunc is the function retried n times
type RetryFunc func() (interface{}, error)

// Retry is a wrapper around a RetryFunc that will retry a function
// n times or until it succeeds.
func Retry(n int, f RetryFunc) (interface{}, error) {
	var lastErr error

	for i := 0; i < n; i++ {
		r, err := f()
		if err == nil {
			return r, nil
		}

		lastErr = err
		time.Sleep(30 * time.Second)
	}

	return nil, lastErr
}