package google

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

	"github.com/hashicorp/terraform/helper/resource"
	"github.com/hashicorp/terraform/helper/schema"
	"google.golang.org/api/container/v1"
)

func resourceContainerCluster() *schema.Resource {
	return &schema.Resource{
		Create: resourceContainerClusterCreate,
		Read:   resourceContainerClusterRead,
		Update: resourceContainerClusterUpdate,
		Delete: resourceContainerClusterDelete,

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

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

			"cluster_ipv4_cidr": &schema.Schema{
				Type:     schema.TypeString,
				Optional: true,
				Computed: true,
				ForceNew: true,
				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
					value := v.(string)
					_, ipnet, err := net.ParseCIDR(value)

					if err != nil || ipnet == nil || value != ipnet.String() {
						errors = append(errors, fmt.Errorf(
							"%q must contain a valid CIDR", k))
					}
					return
				},
			},

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

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

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

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

			"master_auth": &schema.Schema{
				Type:     schema.TypeList,
				Required: true,
				ForceNew: true,
				Elem: &schema.Resource{
					Schema: map[string]*schema.Schema{
						"client_certificate": &schema.Schema{
							Type:     schema.TypeString,
							Computed: true,
						},
						"client_key": &schema.Schema{
							Type:     schema.TypeString,
							Computed: true,
						},
						"cluster_ca_certificate": &schema.Schema{
							Type:     schema.TypeString,
							Computed: true,
						},

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

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

			"name": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
					value := v.(string)

					if len(value) > 40 {
						errors = append(errors, fmt.Errorf(
							"%q cannot be longer than 40 characters", k))
					}
					if !regexp.MustCompile("^[a-z0-9-]+$").MatchString(value) {
						errors = append(errors, fmt.Errorf(
							"%q can only contain lowercase letters, numbers and hyphens", k))
					}
					if !regexp.MustCompile("^[a-z]").MatchString(value) {
						errors = append(errors, fmt.Errorf(
							"%q must start with a letter", k))
					}
					if !regexp.MustCompile("[a-z0-9]$").MatchString(value) {
						errors = append(errors, fmt.Errorf(
							"%q must end with a number or a letter", k))
					}
					return
				},
			},

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

			"node_config": &schema.Schema{
				Type:     schema.TypeList,
				Optional: true,
				Computed: true,
				ForceNew: true,
				Elem: &schema.Resource{
					Schema: map[string]*schema.Schema{
						"machine_type": &schema.Schema{
							Type:     schema.TypeString,
							Optional: true,
							Computed: true,
							ForceNew: true,
						},

						"disk_size_gb": &schema.Schema{
							Type:     schema.TypeInt,
							Optional: true,
							Computed: true,
							ForceNew: true,
							ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
								value := v.(int)

								if value < 10 {
									errors = append(errors, fmt.Errorf(
										"%q cannot be less than 10", k))
								}
								return
							},
						},

						"oauth_scopes": &schema.Schema{
							Type:     schema.TypeList,
							Elem:     &schema.Schema{Type: schema.TypeString},
							Optional: true,
							Computed: true,
							ForceNew: true,
						},
					},
				},
			},

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

			"instance_group_urls": &schema.Schema{
				Type:     schema.TypeList,
				Computed: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
		},
	}
}

func resourceContainerClusterCreate(d *schema.ResourceData, meta interface{}) error {
	config := meta.(*Config)

	zoneName := d.Get("zone").(string)
	clusterName := d.Get("name").(string)

	masterAuths := d.Get("master_auth").([]interface{})
	if len(masterAuths) > 1 {
		return fmt.Errorf("Cannot specify more than one master_auth.")
	}
	masterAuth := masterAuths[0].(map[string]interface{})

	cluster := &container.Cluster{
		MasterAuth: &container.MasterAuth{
			Password: masterAuth["password"].(string),
			Username: masterAuth["username"].(string),
		},
		Name:             clusterName,
		InitialNodeCount: int64(d.Get("initial_node_count").(int)),
	}

	if v, ok := d.GetOk("cluster_ipv4_cidr"); ok {
		cluster.ClusterIpv4Cidr = v.(string)
	}

	if v, ok := d.GetOk("description"); ok {
		cluster.Description = v.(string)
	}

	if v, ok := d.GetOk("logging_service"); ok {
		cluster.LoggingService = v.(string)
	}

	if v, ok := d.GetOk("monitoring_service"); ok {
		cluster.MonitoringService = v.(string)
	}

	if v, ok := d.GetOk("network"); ok {
		cluster.Network = v.(string)
	}

	if v, ok := d.GetOk("node_config"); ok {
		nodeConfigs := v.([]interface{})
		if len(nodeConfigs) > 1 {
			return fmt.Errorf("Cannot specify more than one node_config.")
		}
		nodeConfig := nodeConfigs[0].(map[string]interface{})

		cluster.NodeConfig = &container.NodeConfig{}

		if v, ok = nodeConfig["machine_type"]; ok {
			cluster.NodeConfig.MachineType = v.(string)
		}

		if v, ok = nodeConfig["disk_size_gb"]; ok {
			cluster.NodeConfig.DiskSizeGb = v.(int64)
		}

		if v, ok := nodeConfig["oauth_scopes"]; ok {
			scopesList := v.([]interface{})
			scopes := []string{}
			for _, v := range scopesList {
				scopes = append(scopes, v.(string))
			}

			cluster.NodeConfig.OauthScopes = scopes
		}
	}

	req := &container.CreateClusterRequest{
		Cluster: cluster,
	}

	op, err := config.clientContainer.Projects.Zones.Clusters.Create(
		config.Project, zoneName, req).Do()
	if err != nil {
		return err
	}

	// Wait until it's created
	wait := resource.StateChangeConf{
		Pending:    []string{"PENDING", "RUNNING"},
		Target:     "DONE",
		Timeout:    30 * time.Minute,
		MinTimeout: 3 * time.Second,
		Refresh: func() (interface{}, string, error) {
			resp, err := config.clientContainer.Projects.Zones.Operations.Get(
				config.Project, zoneName, op.Name).Do()
			log.Printf("[DEBUG] Progress of creating GKE cluster %s: %s",
				clusterName, resp.Status)
			return resp, resp.Status, err
		},
	}

	_, err = wait.WaitForState()
	if err != nil {
		return err
	}

	log.Printf("[INFO] GKE cluster %s has been created", clusterName)

	d.SetId(clusterName)

	return resourceContainerClusterRead(d, meta)
}

func resourceContainerClusterRead(d *schema.ResourceData, meta interface{}) error {
	config := meta.(*Config)

	zoneName := d.Get("zone").(string)

	cluster, err := config.clientContainer.Projects.Zones.Clusters.Get(
		config.Project, zoneName, d.Get("name").(string)).Do()
	if err != nil {
		return err
	}

	d.Set("name", cluster.Name)
	d.Set("zone", cluster.Zone)
	d.Set("endpoint", cluster.Endpoint)

	masterAuth := []map[string]interface{}{
		map[string]interface{}{
			"username":               cluster.MasterAuth.Username,
			"password":               cluster.MasterAuth.Password,
			"client_certificate":     cluster.MasterAuth.ClientCertificate,
			"client_key":             cluster.MasterAuth.ClientKey,
			"cluster_ca_certificate": cluster.MasterAuth.ClusterCaCertificate,
		},
	}
	d.Set("master_auth", masterAuth)

	d.Set("initial_node_count", cluster.InitialNodeCount)
	d.Set("node_version", cluster.CurrentNodeVersion)
	d.Set("cluster_ipv4_cidr", cluster.ClusterIpv4Cidr)
	d.Set("description", cluster.Description)
	d.Set("logging_service", cluster.LoggingService)
	d.Set("monitoring_service", cluster.MonitoringService)
	d.Set("network", cluster.Network)
	d.Set("node_config", flattenClusterNodeConfig(cluster.NodeConfig))
	d.Set("instance_group_urls", cluster.InstanceGroupUrls)

	return nil
}

func resourceContainerClusterUpdate(d *schema.ResourceData, meta interface{}) error {
	config := meta.(*Config)

	zoneName := d.Get("zone").(string)
	clusterName := d.Get("name").(string)
	desiredNodeVersion := d.Get("node_version").(string)

	req := &container.UpdateClusterRequest{
		Update: &container.ClusterUpdate{
			DesiredNodeVersion: desiredNodeVersion,
		},
	}
	op, err := config.clientContainer.Projects.Zones.Clusters.Update(
		config.Project, zoneName, clusterName, req).Do()
	if err != nil {
		return err
	}

	// Wait until it's updated
	wait := resource.StateChangeConf{
		Pending:    []string{"PENDING", "RUNNING"},
		Target:     "DONE",
		Timeout:    10 * time.Minute,
		MinTimeout: 2 * time.Second,
		Refresh: func() (interface{}, string, error) {
			log.Printf("[DEBUG] Checking if GKE cluster %s is updated", clusterName)
			resp, err := config.clientContainer.Projects.Zones.Operations.Get(
				config.Project, zoneName, op.Name).Do()
			log.Printf("[DEBUG] Progress of updating GKE cluster %s: %s",
				clusterName, resp.Status)
			return resp, resp.Status, err
		},
	}

	_, err = wait.WaitForState()
	if err != nil {
		return err
	}

	log.Printf("[INFO] GKE cluster %s has been updated to %s", d.Id(),
		desiredNodeVersion)

	return resourceContainerClusterRead(d, meta)
}

func resourceContainerClusterDelete(d *schema.ResourceData, meta interface{}) error {
	config := meta.(*Config)

	zoneName := d.Get("zone").(string)
	clusterName := d.Get("name").(string)

	log.Printf("[DEBUG] Deleting GKE cluster %s", d.Get("name").(string))
	op, err := config.clientContainer.Projects.Zones.Clusters.Delete(
		config.Project, zoneName, clusterName).Do()
	if err != nil {
		return err
	}

	// Wait until it's deleted
	wait := resource.StateChangeConf{
		Pending:    []string{"PENDING", "RUNNING"},
		Target:     "DONE",
		Timeout:    10 * time.Minute,
		MinTimeout: 3 * time.Second,
		Refresh: func() (interface{}, string, error) {
			log.Printf("[DEBUG] Checking if GKE cluster %s is deleted", clusterName)
			resp, err := config.clientContainer.Projects.Zones.Operations.Get(
				config.Project, zoneName, op.Name).Do()
			log.Printf("[DEBUG] Progress of deleting GKE cluster %s: %s",
				clusterName, resp.Status)
			return resp, resp.Status, err
		},
	}

	_, err = wait.WaitForState()
	if err != nil {
		return err
	}

	log.Printf("[INFO] GKE cluster %s has been deleted", d.Id())

	d.SetId("")

	return nil
}

func flattenClusterNodeConfig(c *container.NodeConfig) []map[string]interface{} {
	config := []map[string]interface{}{
		map[string]interface{}{
			"machine_type": c.MachineType,
			"disk_size_gb": c.DiskSizeGb,
		},
	}

	if len(c.OauthScopes) > 0 {
		config[0]["oauth_scopes"] = c.OauthScopes
	}

	return config
}