instrument usecases & repository methods

internal/repository/postgresql/instrument.go

@@ -1 +1,54 @@
 package postgresql
+
+import (
+	"context"
+	"fmt"
+
+	"gitea.computernetthings.ru/yash/crypto_alert_bot/internal/entities"
+)
+
+const instrumentListQuery = `
+select i.id, c_base.symbol, c_quote.symbol
+from instrument i
+join currency c_base on c_base.id = i.base_currency_id
+join currency c_quote on c_quote.id = i.quoted_currency_id
+order by i.id
+offset $1 limit $2`
+
+func (p *Postgresql) InstrumentList(ctx context.Context, offset, limit int) ([]entities.Instrument, error) {
+	rows, err := p.db.Query(ctx, instrumentListQuery, offset, limit)
+	if err != nil {
+		return nil, fmt.Errorf("failed to exec instrumentListQuery: %w", err)
+	}
+	defer rows.Close()
+
+	var instruments []entities.Instrument
+	for rows.Next() {
+		var inst entities.Instrument
+		if err := rows.Scan(&inst.ID, &inst.BaseCurrency, &inst.QuoteCurrency); err != nil {
+			return nil, fmt.Errorf("failed to scan instrument row: %w", err)
+		}
+		instruments = append(instruments, inst)
+	}
+
+	return instruments, nil
+}
+
+const createInstrumentQuery = `
+insert into instrument(base_currency_id, quoted_currency_id)
+values (
+  (select id from currency where symbol = $1),
+  (select id from currency where symbol = $2)
+)
+returning id`
+
+func (p *Postgresql) CreateInstrument(ctx context.Context, instrument *entities.Instrument) (entities.InstrumentID, error) {
+	var id entities.InstrumentID
+
+	err := p.db.QueryRow(ctx, createInstrumentQuery, instrument.BaseCurrency, instrument.QuoteCurrency).Scan(&id)
+	if err != nil {
+		return "", fmt.Errorf("failed to exec createInstrumentQuery: %w", err)
+	}
+
+	return id, nil
+}