Add total_count field in meta for leaderboard endpoint

docs/spec/paths/integrations@rarime-points-svc@v1@public@balances.yaml

@@ -57,6 +57,13 @@ get:
     - $ref: '#/components/parameters/pageLimit'
     - $ref: '#/components/parameters/pageNumber'
     - $ref: '#/components/parameters/pageOrder'
+    - in: query
+      name: count
+      description: Count total number of users.
+      required: false
+      schema:
+        type: boolean
+        example: true
   responses:
     200:
       description: Success
@@ -71,6 +78,15 @@ get:
                 type: array
                 items:
                   $ref: '#/components/schemas/Balance'
+              meta:
+                type: object
+                required:
+                  - total_count
+                properties:
+                  total_count:
+                    type: integer
+                    description: Appears when `count=true` is specified
+                    example: 18
     400:
       $ref: '#/components/responses/invalidParameter'
     409:

internal/data/balances.go

@@ -39,6 +39,8 @@ type BalancesQ interface {
 	GetWithRank(nullifier string) (*Balance, error)
 	SelectWithRank() ([]Balance, error)
 
+	Count() (int64, error)
+
 	// WithoutPassportEvent returns balances which already
 	// have scanned passport, but there no claimed events
 	// for this. Filters are not applied.

internal/data/pg/balances.go

@@ -17,6 +17,7 @@ type balances struct {
 	selector squirrel.SelectBuilder
 	updater  squirrel.UpdateBuilder
 	rank     squirrel.SelectBuilder
+	counter  squirrel.SelectBuilder
 }
 
 func NewBalances(db *pgdb.DB) data.BalancesQ {
@@ -25,6 +26,7 @@ func NewBalances(db *pgdb.DB) data.BalancesQ {
 		selector: squirrel.Select("*").From(balancesTable),
 		updater:  squirrel.Update(balancesTable),
 		rank:     squirrel.Select("*, ROW_NUMBER() OVER (ORDER BY amount DESC, updated_at ASC) AS rank").From(balancesTable),
+		counter:  squirrel.Select("COUNT(*) as count").From(balancesTable),
 	}
 }
 
@@ -124,6 +126,18 @@ func (q *balances) Get() (*data.Balance, error) {
 	return &res, nil
 }
 
+func (q *balances) Count() (int64, error) {
+	res := struct {
+		Count int64 `db:"count"`
+	}{}
+
+	if err := q.db.Get(&res, q.counter); err != nil {
+		return 0, fmt.Errorf("get balance: %w", err)
+	}
+
+	return res.Count, nil
+}
+
 func (q *balances) GetWithRank(nullifier string) (*data.Balance, error) {
 	var res data.Balance
 	stmt := fmt.Sprintf(`
@@ -205,5 +219,6 @@ func (q *balances) applyCondition(cond squirrel.Sqlizer) data.BalancesQ {
 	q.selector = q.selector.Where(cond)
 	q.updater = q.updater.Where(cond)
 	q.rank = q.rank.Where(cond)
+	q.counter = q.counter.Where(cond)
 	return q
 }

internal/service/handlers/leaderboard.go

@@ -26,6 +26,18 @@ func Leaderboard(w http.ResponseWriter, r *http.Request) {
 
 	resp := newLeaderboardResponse(leaders)
 	resp.Links = req.GetLinks(r)
+	if req.Count {
+		leadersCount, err := BalancesQ(r).FilterDisabled().Count()
+		if err != nil {
+			Log(r).WithError(err).Error("Failed to count balances")
+			ape.RenderErr(w, problems.InternalError())
+			return
+		}
+
+		_ = resp.PutMeta(struct {
+			EventsCount int64 `json:"events_count"`
+		}{leadersCount})
+	}
 	ape.Render(w, resp)
 }
 

internal/service/requests/leaderboard.go

@@ -9,6 +9,7 @@ import (
 
 type Leaderboard struct {
 	page.OffsetParams
+	Count bool `url:"count"`
 }
 
 func NewLeaderboard(r *http.Request) (req Leaderboard, err error) {