package cloudstack

import (
	"bytes"
	"fmt"

	"strconv"
	"strings"

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

func resourceCloudStackPortForward() *schema.Resource {
	return &schema.Resource{
		Create: resourceCloudStackPortForwardCreate,
		Read:   resourceCloudStackPortForwardRead,
		Update: resourceCloudStackPortForwardUpdate,
		Delete: resourceCloudStackPortForwardDelete,

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

			"forward": &schema.Schema{
				Type:     schema.TypeSet,
				Required: true,
				Elem: &schema.Resource{
					Schema: map[string]*schema.Schema{
						"protocol": &schema.Schema{
							Type:     schema.TypeString,
							Required: true,
						},

						"private_port": &schema.Schema{
							Type:     schema.TypeInt,
							Required: true,
						},

						"public_port": &schema.Schema{
							Type:     schema.TypeInt,
							Required: true,
						},

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

						"uuid": &schema.Schema{
							Type:     schema.TypeString,
							Computed: true,
						},
					},
				},
				Set: resourceCloudStackPortForwardHash,
			},
		},
	}
}

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

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

	// We need to set this upfront in order to be able to save a partial state
	d.SetId(d.Get("ipaddress").(string))

	// Create all forwards that are configured
	if rs := d.Get("forward").(*schema.Set); rs.Len() > 0 {

		// Create an empty schema.Set to hold all forwards
		forwards := &schema.Set{
			F: resourceCloudStackPortForwardHash,
		}

		for _, forward := range rs.List() {
			// Create a single forward
			err := resourceCloudStackPortForwardCreateForward(d, meta, ipaddressid, forward.(map[string]interface{}))

			// We need to update this first to preserve the correct state
			forwards.Add(forward)
			d.Set("forward", forwards)

			if err != nil {
				return err
			}
		}
	}

	return resourceCloudStackPortForwardRead(d, meta)
}

func resourceCloudStackPortForwardCreateForward(
	d *schema.ResourceData, meta interface{}, ipaddressid string, forward map[string]interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)

	// Make sure all required parameters are there
	if err := verifyPortForwardParams(d, forward); err != nil {
		return err
	}

	// Retrieve the virtual_machine UUID
	virtualmachineid, e := retrieveUUID(cs, "virtual_machine", forward["virtual_machine"].(string))
	if e != nil {
		return e.Error()
	}

	// Create a new parameter struct
	p := cs.Firewall.NewCreatePortForwardingRuleParams(ipaddressid, forward["private_port"].(int),
		forward["protocol"].(string), forward["public_port"].(int), virtualmachineid)

	// Do not open the firewall automatically in any case
	p.SetOpenfirewall(false)

	r, err := cs.Firewall.CreatePortForwardingRule(p)
	if err != nil {
		return err
	}

	forward["uuid"] = r.Id

	return nil
}

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

	// Create an empty schema.Set to hold all forwards
	forwards := &schema.Set{
		F: resourceCloudStackPortForwardHash,
	}

	// Read all forwards that are configured
	if rs := d.Get("forward").(*schema.Set); rs.Len() > 0 {
		for _, forward := range rs.List() {
			forward := forward.(map[string]interface{})

			id, ok := forward["uuid"]
			if !ok || id.(string) == "" {
				continue
			}

			// Get the forward
			r, count, err := cs.Firewall.GetPortForwardingRuleByID(id.(string))
			// If the count == 0, there is no object found for this UUID
			if err != nil {
				if count != 0 {
					continue
				}

				return err
			}

			privPort, err := strconv.Atoi(r.Privateport)
			if err != nil {
				return err
			}

			pubPort, err := strconv.Atoi(r.Publicport)
			if err != nil {
				return err
			}

			// Update the values
			forward["protocol"] = r.Protocol
			forward["private_port"] = privPort
			forward["public_port"] = pubPort
			forward["virtual_machine"] = r.Virtualmachinename
			forwards.Add(forward)
		}
	}

	if forwards.Len() > 0 {
		d.Set("forward", forwards)
	} else {
		d.SetId("")
	}

	return nil
}

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

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

	// Check if the forward set as a whole has changed
	if d.HasChange("forward") {
		o, n := d.GetChange("forward")
		ors := o.(*schema.Set).Difference(n.(*schema.Set))
		nrs := n.(*schema.Set).Difference(o.(*schema.Set))

		// Now first loop through all the old forwards and delete any obsolete ones
		for _, forward := range ors.List() {
			// Delete the forward as it no longer exists in the config
			err := resourceCloudStackPortForwardDeleteForward(d, meta, forward.(map[string]interface{}))
			if err != nil {
				return err
			}
		}

		// Make sure we save the state of the currently configured forwards
		forwards := o.(*schema.Set).Intersection(n.(*schema.Set))
		d.Set("forward", forwards)

		// Then loop through al the currently configured forwards and create the new ones
		for _, forward := range nrs.List() {
			err := resourceCloudStackPortForwardCreateForward(
				d, meta, ipaddressid, forward.(map[string]interface{}))

			// We need to update this first to preserve the correct state
			forwards.Add(forward)
			d.Set("forward", forwards)

			if err != nil {
				return err
			}
		}
	}

	return resourceCloudStackPortForwardRead(d, meta)
}

func resourceCloudStackPortForwardDelete(d *schema.ResourceData, meta interface{}) error {
	// Delete all forwards
	if rs := d.Get("forward").(*schema.Set); rs.Len() > 0 {
		for _, forward := range rs.List() {
			// Delete a single forward
			err := resourceCloudStackPortForwardDeleteForward(d, meta, forward.(map[string]interface{}))

			// We need to update this first to preserve the correct state
			d.Set("forward", rs)

			if err != nil {
				return err
			}
		}
	}

	return nil
}

func resourceCloudStackPortForwardDeleteForward(
	d *schema.ResourceData, meta interface{}, forward map[string]interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)

	// Create the parameter struct
	p := cs.Firewall.NewDeletePortForwardingRuleParams(forward["uuid"].(string))

	// Delete the forward
	if _, err := cs.Firewall.DeletePortForwardingRule(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", forward["uuid"].(string))) {
			return err
		}
	}

	forward["uuid"] = ""

	return nil
}

func resourceCloudStackPortForwardHash(v interface{}) int {
	var buf bytes.Buffer
	m := v.(map[string]interface{})
	buf.WriteString(fmt.Sprintf(
		"%s-%d-%d-%s",
		m["protocol"].(string),
		m["private_port"].(int),
		m["public_port"].(int),
		m["virtual_machine"].(string)))

	return hashcode.String(buf.String())
}

func verifyPortForwardParams(d *schema.ResourceData, forward map[string]interface{}) error {
	protocol := forward["protocol"].(string)
	if protocol != "tcp" && protocol != "udp" {
		return fmt.Errorf(
			"%s is not a valid protocol. Valid options are 'tcp' and 'udp'", protocol)
	}
	return nil
}