// Package sql defines reusable database SQL statements.
package sql

const (
	// MeasurementCountSelect selects the number of measurements matching a
	// token hierarchy and is used during token existence validation.
	MeasurementCountSelect = "SELECT COUNT(*)"

	// MeasurementRowsSelect selects complete measurement rows after a token has
	// been parsed into its hierarchy conditions.
	MeasurementRowsSelect = "SELECT m.*"

	// MeasurementLimitTwo limits token resolution to two rows so callers can
	// distinguish a unique match from an ambiguous token without loading all matches.
	MeasurementLimitTwo = "LIMIT 2"

	// MeasurementIDWhere is the GORM condition used to query a measurement by
	// its database primary key.
	MeasurementIDWhere = "id = ?"

	// MeasurementTokenValidationQueryBase contains the common hierarchy joins
	// used by all supported measurement token formats.
	MeasurementTokenValidationQueryBase = MeasurementCountSelect + `
		FROM measurement AS m
		INNER JOIN component AS c ON c.global_uuid = m.component_uuid
		INNER JOIN bay AS b ON b.bay_uuid = m.bay_uuid
		INNER JOIN station AS s ON s.id = c.station_id
		INNER JOIN zone AS z ON z.id = s.zone_id
		INNER JOIN grid AS g ON g.id = z.grid_id`

	// MeasurementSevenPartTokenWhere matches a complete token in the form
	// token1.token2.token3.token4.token5.token6.token7. Token6 is validated as
	// "bay" before this condition is used.
	MeasurementSevenPartTokenWhere = `WHERE g.tagname = ?
  		AND z.tagname = ? AND s.tagname = ?
  		AND c.nspath = ? AND c.tag = ?
  		AND m.tag = ?`

	// MeasurementFourPartTokenWhere matches a local measurement token in the
	// form token4.token5.token6.token7. Token6 is validated as "bay" before use.
	MeasurementFourPartTokenWhere = `WHERE c.nspath = ? AND c.tag = ?
  		AND m.tag = ?`

	// MeasurementTwoPartTokenWhere matches the short measurement token format
	// token4.token7 using component namespace path and measurement tag.
	MeasurementTwoPartTokenWhere = `WHERE c.nspath = ? AND m.tag = ?`

	// MeasurementComponentByUUID returns the component hierarchy fields needed
	// to construct a measurement's canonical name and seven-part ID.
	MeasurementComponentByUUID = `SELECT global_uuid, nspath, 
		tag, grid, zone, station FROM component
		WHERE global_uuid = ? LIMIT 1`

	// MeasurementGridTags returns every grid tag used to construct the first
	// level of the measurement recommendation hierarchy.
	MeasurementGridTags = `SELECT tagname FROM grid`

	// MeasurementZoneHierarchy returns zones together with their parent grid
	// tags for building the grid-to-zone recommendation mapping.
	MeasurementZoneHierarchy = `SELECT zone.*, 
		grid.tagname AS grid_tag FROM zone
		LEFT JOIN grid ON zone.grid_id = grid.id`

	// MeasurementStationHierarchy returns stations together with their parent
	// zone tags for building the zone-to-station recommendation mapping.
	MeasurementStationHierarchy = `SELECT station.*, zone.tagname AS zone_tag
		FROM station
		LEFT JOIN zone ON station.zone_id = zone.id`

	// MeasurementComponentHierarchy returns components together with their
	// parent station tags for building station, namespace, and component mappings.
	MeasurementComponentHierarchy = `SELECT component.*, 
		station.tagname AS station_tag 
		FROM component LEFT JOIN station 
		ON component.station_id = station.id`

	// MeasurementTagHierarchy returns measurements together with their owning
	// component tags for building the component-to-measurement mapping.
	MeasurementTagHierarchy = `
    SELECT measurement.*,
        component.tag AS comp_tag,
        component.nspath AS comp_nspath,
        bay.tag AS bay_tag
    FROM measurement
    LEFT JOIN component
        ON measurement.component_uuid = component.global_uuid
    LEFT JOIN bay
        ON measurement.bay_uuid = bay.bay_uuid`
)