package platform

import (
	"bytes"
	"context"
	"errors"
	"regexp"
)

// DBRPMappingService provides a mapping of cluster, database and retention policy to an organization ID and bucket ID.
type DBRPMappingService interface {
	// FindBy returns the dbrp mapping the for cluster, db and rp.
	FindBy(ctx context.Context, cluster, db, rp string) (*DBRPMapping, error)
	// Find returns the first dbrp mapping the matches the filter.
	Find(ctx context.Context, filter DBRPMappingFilter) (*DBRPMapping, error)
	// FindMany returns a list of dbrp mappings that match filter and the total count of matching dbrp mappings.
	FindMany(ctx context.Context, filter DBRPMappingFilter, opt ...FindOptions) ([]*DBRPMapping, int, error)
	// Create creates a new dbrp mapping, if a different mapping exists an error is returned.
	Create(ctx context.Context, dbrpMap *DBRPMapping) error
	// Delete removes a dbrp mapping.
	// Deleting a mapping that does not exists is not an error.
	Delete(ctx context.Context, cluster, db, rp string) error
}

// DBRPMapping represents a mapping of a cluster, database and retention policy to an organization ID and bucket ID.
type DBRPMapping struct {
	Cluster         string `json:"cluster"`
	Database        string `json:"database"`
	RetentionPolicy string `json:"retention_policy"`

	// Default indicates if this mapping is the default for the cluster and database.
	Default bool `json:"default"`

	OrganizationID ID `json:"organization_id"`
	BucketID       ID `json:"bucket_id"`
}

var validPattern = regexp.MustCompile(`^[\.\w]+$`)

// Validate reports any validation errors for the mapping.
func (m DBRPMapping) Validate() error {
	if m.Cluster == "" {
		return errors.New("Cluster is required")
	}
	if !validPattern.MatchString(m.Cluster) {
		return errors.New("Cluster must contain only letters, numbers,  '_' and '.'")
	}
	if m.Database == "" {
		return errors.New("Database is required")
	}
	if !validPattern.MatchString(m.Database) {
		return errors.New("Database must contain only letters, numbers,  '_' and '.'")
	}
	if m.RetentionPolicy == "" {
		return errors.New("RetentionPolicy is required")
	}
	if !validPattern.MatchString(m.RetentionPolicy) {
		return errors.New("RetentionPolicy must contain only letters, numbers,  '_' and '.'")
	}
	if len(m.OrganizationID) == 0 {
		return errors.New("OrganizationID is required")
	}
	if len(m.BucketID) == 0 {
		return errors.New("BucketID is required")
	}
	return nil
}

func (m *DBRPMapping) Equal(o *DBRPMapping) bool {
	if m == o {
		return true
	}
	if m == nil || o == nil {
		return false
	}
	return m.Cluster == o.Cluster &&
		m.Database == o.Database &&
		m.RetentionPolicy == o.RetentionPolicy &&
		m.Default == o.Default &&
		bytes.Equal(m.OrganizationID, o.OrganizationID) &&
		bytes.Equal(m.BucketID, o.BucketID)
}

// DBRPMappingFilter represents a set of filters that restrict the returned results by cluster, database and retention policy.
type DBRPMappingFilter struct {
	Cluster         *string
	Database        *string
	RetentionPolicy *string
	Default         *bool
}