idx

type Archive struct {
	schema.MetricDefinition
	SchemaId uint16 // index in mdata.schemas (not persisted)
	AggId    uint16 // index in mdata.aggregations (not persisted)
	IrId     uint16 // index in mdata.indexrules (not persisted)
	LastSave uint32 // last time the metricDefinition was saved to a persistent index
}

type MetaRecordIdx interface {
	// MetaTagRecordUpsert inserts, updates or deletes a meta record, depending on
	// whether it already exists or is new. The identity of a record is determined
	// by its queries.
	// If the set of queries in the given record already exists in another record,
	// then the existing record will be updated, otherwise a new one gets created.
	// If an existing record is updated with one that has no meta tags
	// associated, then this operation results in the deletion of the meta record
	// because a meta record has no effect without meta tags.
	MetaTagRecordUpsert(orgId uint32, record tagquery.MetaTagRecord) error

	// MetaTagRecordList takes an org id and returns the list of all meta tag records
	// of that given org.
	MetaTagRecordList(orgId uint32) []tagquery.MetaTagRecord

	// MetaTagRecordSwap takes a set of meta tag records and completely replaces
	// the existing ones with the new ones.
	MetaTagRecordSwap(orgId uint32, records []tagquery.MetaTagRecord) error
}

type MetricIndex interface {
	// Init initializes the index at startup and
	// blocks until the index is ready for use.
	Init() error

	// Stop shuts down the index.
	Stop()

	// Update updates an existing archive, if found.
	// It returns whether it was found, and - if so - the (updated) existing archive and its old partition
	Update(point schema.MetricPoint, partition int32) (Archive, int32, bool)

	// AddOrUpdate makes sure a metric is known in the index,
	// and should be called for every received metric.
	AddOrUpdate(mkey schema.MKey, data *schema.MetricData, partition int32) (Archive, int32, bool)

	// Get returns the archive for the requested id.
	Get(key schema.MKey) (Archive, bool)

	// GetPath returns the archives under the given path.
	GetPath(orgId uint32, path string) []Archive

	// Delete deletes items from the index
	// If the pattern matches a branch node, then
	// all leaf nodes on that branch are deleted. So if the pattern is
	// "*", all items in the index are deleted.
	// It returns a copy of all of the Archives deleted.
	Delete(orgId uint32, pattern string) ([]Archive, error)

	// Find searches the index for matching nodes.
	// * orgId describes the org to search in (public data in orgIdPublic is automatically included)
	// * pattern is handled like graphite does. see https://graphite.readthedocs.io/en/latest/render_api.html#paths-and-wildcards
	// * from is a unix timestamp. series not updated since then are excluded.
	Find(orgId uint32, pattern string, from int64) ([]Node, error)

	// List returns all Archives for the passed OrgId and the public orgId
	List(orgId uint32) []Archive

	// Prune deletes all metrics that haven't been seen since the given timestamp.
	// It returns all Archives deleted and any error encountered.
	Prune(oldest time.Time) ([]Archive, error)

	// FindByTag takes a query object and executes the query on the index. The query
	// is composed of one or many query expressions, plus a "from condition" defining
	// after which time a metric must have received its last data point in order to
	// be returned in the result.
	// The returned results are not deduplicated and in certain cases it is possible
	// that duplicate entries will be returned.
	FindByTag(orgId uint32, query tagquery.Query) []Node

	// FindTerms takes a query object and executes the query on the index. The query
	// is composed of one or many query expressions. From the matching series, a count
	// is kept for each value of the requested tags.
	// The series are not deduplicated and in certain cases it is possible that some
	// entries will be double counted.
	FindTerms(orgID uint32, tags []string, query tagquery.Query) (uint32, map[string]map[string]uint32)

	// Tags returns a list of all tag keys associated with the metrics of a given
	// organization. The return values are filtered by the regex in the second parameter.
	Tags(orgId uint32, filter *regexp.Regexp) []string

	// TagDetails returns a list of all values associated with a given tag key in the
	// given org. The occurrences of each value is counted and the count is referred to by
	// the metric names in the returned map.
	// If the third parameter is not nil it will be used to filter the values before
	// accounting for them.
	TagDetails(orgId uint32, key string, filter *regexp.Regexp) map[string]uint64

	// FindTags generates a list of possible tags that could complete a
	// given prefix. It only supports simple queries by prefix and from,
	// without any further conditions. But its faster than the alternative
	// FindTagsWithQuery()
	FindTags(orgId uint32, prefix string, limit uint) []string

	// FindTagsWithQuery generates a list of possible tags that could complete
	// a given prefix. It runs a full query on the index, so it allows the
	// user to narrow down the result by specifying additional expressions,
	// but if the query isn't necessary it is recommended to use FindTags()
	// because it is faster
	FindTagsWithQuery(orgId uint32, prefix string, query tagquery.Query, limit uint) []string

	// FindTagValues generates a list of possible values that could complete
	// a given value prefix. It requires a tag to be specified and only values
	// of the given tag will be returned. The "limit" limits the result set to a
	// specified length, since the results are sorted before being sliced it
	// can be relied on that always the first "limit" entries of the result
	// set will be returned.
	FindTagValues(orgId uint32, tag, prefix string, limit uint) []string

	// FindTagValuesWithQuery does the same thing as FindTagValues, but additionally it
	// allows the caller to pass a tag query which is used to further narrow down the
	// result set. If the tag query is not necessary, it is recommended to use
	// FindTagValues() because it is faster
	FindTagValuesWithQuery(orgId uint32, tag, prefix string, query tagquery.Query, limit uint) []string

	// DeleteTagged deletes the series returned by the given query from the tag index
	// and also the DefById index.
	DeleteTagged(orgId uint32, query tagquery.Query) ([]Archive, error)
}

type Node struct {
	Path        string
	Leaf        bool
	Defs        []Archive
	HasChildren bool

	// meta tags that should be added to the ones in the MetricDefinitions in the .Defs property.
	// it is important that all MetricDefinitions in .Defs have the same .Name and .Tags values,
	// otherwise each of them would have to get their own set of MetaTags
	MetaTags tagquery.Tags
}