package cloudstack

import (
	"crypto/sha1"
	"encoding/base64"
	"encoding/hex"
	"fmt"
	"log"
	"strings"

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

func resourceCloudStackInstance() *schema.Resource {
	return &schema.Resource{
		Create: resourceCloudStackInstanceCreate,
		Read:   resourceCloudStackInstanceRead,
		Update: resourceCloudStackInstanceUpdate,
		Delete: resourceCloudStackInstanceDelete,

		Schema: map[string]*schema.Schema{
			"name": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},

			"display_name": &schema.Schema{
				Type:     schema.TypeString,
				Optional: true,
				Computed: true,
			},

			"service_offering": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
			},

			"network": &schema.Schema{
				Type:     schema.TypeString,
				Optional: true,
				ForceNew: true,
			},

			"ipaddress": &schema.Schema{
				Type:     schema.TypeString,
				Optional: true,
				Computed: true,
				ForceNew: true,
			},

			"template": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},

			"zone": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},

			"user_data": &schema.Schema{
				Type:     schema.TypeString,
				Optional: true,
				ForceNew: true,
				StateFunc: func(v interface{}) string {
					switch v.(type) {
					case string:
						hash := sha1.Sum([]byte(v.(string)))
						return hex.EncodeToString(hash[:])
					default:
						return ""
					}
				},
			},

			"expunge": &schema.Schema{
				Type:     schema.TypeBool,
				Optional: true,
				Default:  false,
			},
		},
	}
}

func resourceCloudStackInstanceCreate(d *schema.ResourceData, meta interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)

	// Retrieve the service_offering UUID
	serviceofferingid, e := retrieveUUID(cs, "service_offering", d.Get("service_offering").(string))
	if e != nil {
		return e.Error()
	}

	// Retrieve the zone object
	zone, _, err := cs.Zone.GetZoneByName(d.Get("zone").(string))
	if err != nil {
		return err
	}

	// Retrieve the template UUID
	templateid, e := retrieveTemplateUUID(cs, zone.Id, d.Get("template").(string))
	if e != nil {
		return e.Error()
	}

	// Create a new parameter struct
	p := cs.VirtualMachine.NewDeployVirtualMachineParams(serviceofferingid, templateid, zone.Id)

	// Set the name
	name := d.Get("name").(string)
	p.SetName(name)

	// Set the display name
	if displayname, ok := d.GetOk("display_name"); ok {
		p.SetDisplayname(displayname.(string))
	} else {
		p.SetDisplayname(name)
	}

	if zone.Networktype == "Advanced" {
		// Retrieve the network UUID
		networkid, e := retrieveUUID(cs, "network", d.Get("network").(string))
		if e != nil {
			return e.Error()
		}
		// Set the default network ID
		p.SetNetworkids([]string{networkid})
	}

	// If there is a ipaddres supplied, add it to the parameter struct
	if ipaddres, ok := d.GetOk("ipaddress"); ok {
		p.SetIpaddress(ipaddres.(string))
	}

	// If the user data contains any info, it needs to be base64 encoded and
	// added to the parameter struct
	if userData, ok := d.GetOk("user_data"); ok {
		ud := base64.StdEncoding.EncodeToString([]byte(userData.(string)))
		if len(ud) > 2048 {
			return fmt.Errorf(
				"The supplied user_data contains %d bytes after encoding, "+
					"this exeeds the limit of 2048 bytes", len(ud))
		}
		p.SetUserdata(ud)
	}

	// Create the new instance
	r, err := cs.VirtualMachine.DeployVirtualMachine(p)
	if err != nil {
		return fmt.Errorf("Error creating the new instance %s: %s", name, err)
	}

	d.SetId(r.Id)

	return resourceCloudStackInstanceRead(d, meta)
}

func resourceCloudStackInstanceRead(d *schema.ResourceData, meta interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)

	// Get the virtual machine details
	vm, count, err := cs.VirtualMachine.GetVirtualMachineByID(d.Id())
	if err != nil {
		if count == 0 {
			log.Printf("[DEBUG] Instance %s does no longer exist", d.Get("name").(string))
			// Clear out all details so it's obvious the instance is gone
			d.SetId("")
			return nil
		}

		return err
	}

	// Update the config
	d.Set("name", vm.Name)
	d.Set("display_name", vm.Displayname)
	d.Set("service_offering", vm.Serviceofferingname)
	d.Set("network", vm.Nic[0].Networkname)
	d.Set("ipaddress", vm.Nic[0].Ipaddress)
	d.Set("template", vm.Templatename)
	d.Set("zone", vm.Zonename)

	return nil
}

func resourceCloudStackInstanceUpdate(d *schema.ResourceData, meta interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)
	d.Partial(true)

	name := d.Get("name").(string)

	// Check if the display name is changed and if so, update the virtual machine
	if d.HasChange("display_name") {
		log.Printf("[DEBUG] Display name changed for %s, starting update", name)

		// Create a new parameter struct
		p := cs.VirtualMachine.NewUpdateVirtualMachineParams(d.Id())

		// Set the new display name
		p.SetDisplayname(d.Get("display_name").(string))

		// Update the display name
		_, err := cs.VirtualMachine.UpdateVirtualMachine(p)
		if err != nil {
			return fmt.Errorf(
				"Error updating the display name for instance %s: %s", name, err)
		}

		d.SetPartial("display_name")
	}

	// Check if the service offering is changed and if so, update the offering
	if d.HasChange("service_offering") {
		log.Printf("[DEBUG] Service offering changed for %s, starting update", name)

		// Retrieve the service_offering UUID
		serviceofferingid, e := retrieveUUID(cs, "service_offering", d.Get("service_offering").(string))
		if e != nil {
			return e.Error()
		}

		// Create a new parameter struct
		p := cs.VirtualMachine.NewChangeServiceForVirtualMachineParams(d.Id(), serviceofferingid)

		// Before we can actually change the service offering, the virtual machine must be stopped
		_, err := cs.VirtualMachine.StopVirtualMachine(cs.VirtualMachine.NewStopVirtualMachineParams(d.Id()))
		if err != nil {
			return fmt.Errorf(
				"Error stopping instance %s before changing service offering: %s", name, err)
		}
		// Change the service offering
		_, err = cs.VirtualMachine.ChangeServiceForVirtualMachine(p)
		if err != nil {
			return fmt.Errorf(
				"Error changing the service offering for instance %s: %s", name, err)
		}
		// Start the virtual machine again
		_, err = cs.VirtualMachine.StartVirtualMachine(cs.VirtualMachine.NewStartVirtualMachineParams(d.Id()))
		if err != nil {
			return fmt.Errorf(
				"Error starting instance %s after changing service offering: %s", name, err)
		}

		d.SetPartial("service_offering")
	}

	d.Partial(false)
	return resourceCloudStackInstanceRead(d, meta)
}

func resourceCloudStackInstanceDelete(d *schema.ResourceData, meta interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)

	// Create a new parameter struct
	p := cs.VirtualMachine.NewDestroyVirtualMachineParams(d.Id())

	if d.Get("expunge").(bool) {
		p.SetExpunge(true)
	}

	log.Printf("[INFO] Destroying instance: %s", d.Get("name").(string))
	if _, err := cs.VirtualMachine.DestroyVirtualMachine(p); err != nil {
		// This is a very poor way to be told the UUID does no longer exist :(
		if strings.Contains(err.Error(), fmt.Sprintf(
			"Invalid parameter id value=%s due to incorrect long value format, "+
				"or entity does not exist", d.Id())) {
			return nil
		}

		return fmt.Errorf("Error destroying instance: %s", err)
	}

	return nil
}