package google

import (
	"fmt"
	"log"
	"regexp"

	"github.com/hashicorp/terraform/helper/schema"
	"github.com/hashicorp/terraform/helper/validation"
	"google.golang.org/api/bigquery/v2"
)

const datasetIdRegexp = `[0-9A-Za-z_]+`

func resourceBigQueryDataset() *schema.Resource {
	return &schema.Resource{
		Create: resourceBigQueryDatasetCreate,
		Read:   resourceBigQueryDatasetRead,
		Update: resourceBigQueryDatasetUpdate,
		Delete: resourceBigQueryDatasetDelete,
		Importer: &schema.ResourceImporter{
			State: schema.ImportStatePassthrough,
		},
		Schema: map[string]*schema.Schema{
			// DatasetId: [Required] A unique ID for this dataset, without the
			// project name. The ID must contain only letters (a-z, A-Z), numbers
			// (0-9), or underscores (_). The maximum length is 1,024 characters.
			"dataset_id": {
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
					value := v.(string)
					if !regexp.MustCompile(datasetIdRegexp).MatchString(value) {
						errors = append(errors, fmt.Errorf(
							"%q must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_)", k))
					}

					if len(value) > 1024 {
						errors = append(errors, fmt.Errorf(
							"%q cannot be greater than 1,024 characters", k))
					}

					return
				},
			},

			// ProjectId: [Optional] The ID of the project containing this dataset.
			"project": {
				Type:     schema.TypeString,
				Optional: true,
				Computed: true,
				ForceNew: true,
			},

			// FriendlyName: [Optional] A descriptive name for the dataset.
			"friendly_name": {
				Type:     schema.TypeString,
				Optional: true,
			},

			// Description: [Optional] A user-friendly description of the dataset.
			"description": {
				Type:     schema.TypeString,
				Optional: true,
			},

			// Location: [Experimental] The geographic location where the dataset
			// should reside.
			"location": {
				Type:     schema.TypeString,
				Optional: true,
				ForceNew: true,
				Default:  "US",
			},

			// defaultPartitionExpirationMs: [Optional] The default partition
			// expiration for all partitioned tables in the dataset, in
			// milliseconds. Once this property is set, all newly-created
			// partitioned tables in the dataset will have an expirationMs
			// property in the timePartitioning settings set to this value, and
			// changing the value will only affect new tables, not existing ones.
			// The storage in a partition will have an expiration time of its
			// partition time plus this value. Setting this property overrides the
			// use of defaultTableExpirationMs for partitioned tables: only one of
			// defaultTableExpirationMs and defaultPartitionExpirationMs will be used
			// for any new partitioned table. If you provide an explicit
			// timePartitioning.expirationMs when creating or updating a partitioned
			// table, that value takes precedence over the default partition expiration
			// time indicated by this property.
			"default_partition_expiration_ms": {
				Type:     schema.TypeInt,
				Optional: true,
			},

			// DefaultTableExpirationMs: [Optional] The default lifetime of all
			// tables in the dataset, in milliseconds. The minimum value is 3600000
			// milliseconds (one hour). Once this property is set, all newly-created
			// tables in the dataset will have an expirationTime property set to the
			// creation time plus the value in this property, and changing the value
			// will only affect new tables, not existing ones. When the
			// expirationTime for a given table is reached, that table will be
			// deleted automatically. If a table's expirationTime is modified or
			// removed before the table expires, or if you provide an explicit
			// expirationTime when creating a table, that value takes precedence
			// over the default expiration time indicated by this property.
			"default_table_expiration_ms": {
				Type:     schema.TypeInt,
				Optional: true,
				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
					value := v.(int)
					if value < 3600000 {
						errors = append(errors, fmt.Errorf("%q cannot be shorter than 3600000 milliseconds (one hour)", k))
					}

					return
				},
			},

			// Labels: [Experimental] The labels associated with this dataset. You
			// can use these to organize and group your datasets. You can set this
			// property when inserting or updating a dataset.
			"labels": {
				Type:     schema.TypeMap,
				Optional: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},

			// Access: [Optional] An array of objects that define dataset access
			// for one or more entities. You can set this property when inserting
			// or updating a dataset in order to control who is allowed to access
			// the data.
			"access": {
				Type:     schema.TypeSet,
				Optional: true,
				// Computed because if unset, BQ adds 4 entries automatically
				Computed: true,
				Elem: &schema.Resource{
					Schema: map[string]*schema.Schema{
						"role": {
							Type:         schema.TypeString,
							Optional:     true,
							ValidateFunc: validation.StringInSlice([]string{"OWNER", "WRITER", "READER"}, false),
						},
						"domain": {
							Type:     schema.TypeString,
							Optional: true,
						},
						"group_by_email": {
							Type:     schema.TypeString,
							Optional: true,
						},
						"special_group": {
							Type:     schema.TypeString,
							Optional: true,
						},
						"user_by_email": {
							Type:     schema.TypeString,
							Optional: true,
						},
						"view": {
							Type:     schema.TypeList,
							Optional: true,
							MaxItems: 1,
							Elem: &schema.Resource{
								Schema: map[string]*schema.Schema{
									"project_id": {
										Type:     schema.TypeString,
										Required: true,
									},
									"dataset_id": {
										Type:     schema.TypeString,
										Required: true,
									},
									"table_id": {
										Type:     schema.TypeString,
										Required: true,
									},
								},
							},
						},
					},
				},
			},

			// Delete Contents on Destroy: [Optional] If True, delete all the tables in the dataset.
			// If False and the dataset contains tables, the request will fail.
			// Default is False.
			"delete_contents_on_destroy": {
				Type:             schema.TypeBool,
				Optional:         true,
				Default:          false,
				DiffSuppressFunc: emptyOrDefaultStringSuppress("false"),
			},

			// SelfLink: [Output-only] A URL that can be used to access the resource
			// again. You can use this URL in Get or Update requests to the
			// resource.
			"self_link": {
				Type:     schema.TypeString,
				Computed: true,
			},

			// Etag: [Output-only] A hash of the resource.
			"etag": {
				Type:     schema.TypeString,
				Computed: true,
			},

			// CreationTime: [Output-only] The time when this dataset was created,
			// in milliseconds since the epoch.
			"creation_time": {
				Type:     schema.TypeInt,
				Computed: true,
			},

			// LastModifiedTime: [Output-only] The date when this dataset or any of
			// its tables was last modified, in milliseconds since the epoch.
			"last_modified_time": {
				Type:     schema.TypeInt,
				Computed: true,
			},
		},
	}
}

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

	project, err := getProject(d, config)
	if err != nil {
		return nil, err
	}

	dataset := &bigquery.Dataset{
		DatasetReference: &bigquery.DatasetReference{
			DatasetId: d.Get("dataset_id").(string),
			ProjectId: project,
		},
	}

	if v, ok := d.GetOk("friendly_name"); ok {
		dataset.FriendlyName = v.(string)
	}

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

	if v, ok := d.GetOk("location"); ok {
		dataset.Location = v.(string)
	}

	if v, ok := d.GetOk("default_partition_expiration_ms"); ok {
		dataset.DefaultPartitionExpirationMs = int64(v.(int))
	}

	if v, ok := d.GetOk("default_table_expiration_ms"); ok {
		dataset.DefaultTableExpirationMs = int64(v.(int))
	}

	if v, ok := d.GetOk("labels"); ok {
		labels := map[string]string{}

		for k, v := range v.(map[string]interface{}) {
			labels[k] = v.(string)
		}

		dataset.Labels = labels
	}

	if v, ok := d.GetOk("access"); ok {
		access := []*bigquery.DatasetAccess{}
		vs := v.(*schema.Set)
		for _, m := range vs.List() {
			da := bigquery.DatasetAccess{}
			accessMap := m.(map[string]interface{})
			da.Role = accessMap["role"].(string)
			if val, ok := accessMap["domain"]; ok {
				da.Domain = val.(string)
			}
			if val, ok := accessMap["group_by_email"]; ok {
				da.GroupByEmail = val.(string)
			}
			if val, ok := accessMap["special_group"]; ok {
				da.SpecialGroup = val.(string)
			}
			if val, ok := accessMap["user_by_email"]; ok {
				da.UserByEmail = val.(string)
			}
			if val, ok := accessMap["view"]; ok {
				views := val.([]interface{})
				if len(views) > 0 {
					vm := views[0].(map[string]interface{})
					if len(vm) > 0 {
						view := bigquery.TableReference{}
						if dsId, ok := vm["dataset_id"]; ok {
							view.DatasetId = dsId.(string)
						}
						if pId, ok := vm["project_id"]; ok {
							view.ProjectId = pId.(string)
						}
						if tId, ok := vm["table_id"]; ok {
							view.TableId = tId.(string)
						}
						da.View = &view
					}
				}
			}
			access = append(access, &da)
		}
		dataset.Access = access
	}

	return dataset, nil
}

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

	project, err := getProject(d, config)
	if err != nil {
		return err
	}

	dataset, err := resourceDataset(d, meta)
	if err != nil {
		return err
	}

	log.Printf("[INFO] Creating BigQuery dataset: %s", dataset.DatasetReference.DatasetId)

	res, err := config.clientBigQuery.Datasets.Insert(project, dataset).Do()
	if err != nil {
		return err
	}

	log.Printf("[INFO] BigQuery dataset %s has been created", res.Id)

	d.SetId(res.Id)

	return resourceBigQueryDatasetRead(d, meta)
}

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

	log.Printf("[INFO] Reading BigQuery dataset: %s", d.Id())

	id, err := parseBigQueryDatasetId(d.Id())
	if err != nil {
		return err
	}

	res, err := config.clientBigQuery.Datasets.Get(id.Project, id.DatasetId).Do()
	if err != nil {
		return handleNotFoundError(err, d, fmt.Sprintf("BigQuery dataset %q", id.DatasetId))
	}

	d.Set("project", id.Project)
	d.Set("etag", res.Etag)
	d.Set("labels", res.Labels)
	if err := d.Set("access", flattenAccess(res.Access)); err != nil {
		return err
	}
	d.Set("self_link", res.SelfLink)
	d.Set("description", res.Description)
	d.Set("friendly_name", res.FriendlyName)
	d.Set("creation_time", res.CreationTime)
	d.Set("last_modified_time", res.LastModifiedTime)
	d.Set("dataset_id", res.DatasetReference.DatasetId)
	d.Set("default_partition_expiration_ms", res.DefaultPartitionExpirationMs)
	d.Set("default_table_expiration_ms", res.DefaultTableExpirationMs)

	// Older Tables in BigQuery have no Location set in the API response. This may be an issue when importing
	// tables created before BigQuery was available in multiple zones. We can safely assume that these tables
	// are in the US, as this was the default at the time.
	if res.Location == "" {
		d.Set("location", "US")
	} else {
		d.Set("location", res.Location)
	}

	return nil
}

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

	dataset, err := resourceDataset(d, meta)
	if err != nil {
		return err
	}

	log.Printf("[INFO] Updating BigQuery dataset: %s", d.Id())

	id, err := parseBigQueryDatasetId(d.Id())
	if err != nil {
		return err
	}

	if _, err = config.clientBigQuery.Datasets.Update(id.Project, id.DatasetId, dataset).Do(); err != nil {
		return err
	}

	return resourceBigQueryDatasetRead(d, meta)
}

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

	log.Printf("[INFO] Deleting BigQuery dataset: %s", d.Id())

	id, err := parseBigQueryDatasetId(d.Id())
	if err != nil {
		return err
	}

	deleteContents := d.Get("delete_contents_on_destroy").(bool)
	if err := config.clientBigQuery.Datasets.Delete(id.Project, id.DatasetId).DeleteContents(deleteContents).Do(); err != nil {
		return err
	}

	d.SetId("")
	return nil
}

type bigQueryDatasetId struct {
	Project, DatasetId string
}

func parseBigQueryDatasetId(id string) (*bigQueryDatasetId, error) {
	pd := fmt.Sprintf("(%s):(%s)", ProjectRegex, datasetIdRegexp)
	re := regexp.MustCompile(pd)
	if parts := re.FindStringSubmatch(id); parts != nil {
		return &bigQueryDatasetId{
			Project:   parts[1],
			DatasetId: parts[2],
		}, nil
	}

	return nil, fmt.Errorf("Invalid BigQuery dataset specifier. Expecting {project}:{dataset-id}, got %s", id)
}

func flattenAccess(a []*bigquery.DatasetAccess) []map[string]interface{} {
	access := make([]map[string]interface{}, 0, len(a))
	for _, da := range a {
		ai := map[string]interface{}{
			"role":           da.Role,
			"domain":         da.Domain,
			"group_by_email": da.GroupByEmail,
			"special_group":  da.SpecialGroup,
			"user_by_email":  da.UserByEmail,
		}
		if da.View != nil {
			view := []map[string]interface{}{{
				"project_id": da.View.ProjectId,
				"dataset_id": da.View.DatasetId,
				"table_id":   da.View.TableId,
			},
			}
			ai["view"] = view
		}
		access = append(access, ai)
	}
	return access
}