first commit of restructured project

trahn-trade-backend/internal/repository/sr.go

@@ -0,0 +1,139 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"math"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/kjannette/trahn-backend/internal/models"
+)
+
+type SRRepo struct {
+	pool *pgxpool.Pool
+}
+
+func NewSRRepo(pool *pgxpool.Pool) *SRRepo {
+	return &SRRepo{pool: pool}
+}
+
+func (r *SRRepo) Record(ctx context.Context, sr *models.SupportResistance) (*models.SupportResistance, error) {
+	ts := sr.Timestamp
+	if ts.IsZero() {
+		ts = time.Now()
+	}
+	row := r.pool.QueryRow(ctx,
+		`INSERT INTO support_resistance_history
+		 (timestamp, method, lookback_days, support, resistance, midpoint, avg_price, grid_recalculated)
+		 VALUES ($1,$2,$3,$4,$5,$6,$7,$8)
+		 RETURNING *`,
+		ts, sr.Method, sr.LookbackDays, sr.Support, sr.Resistance,
+		sr.Midpoint, sr.AvgPrice, sr.GridRecalculated,
+	)
+	return scanSR(row)
+}
+
+func (r *SRRepo) GetLatest(ctx context.Context) (*models.SupportResistance, error) {
+	row := r.pool.QueryRow(ctx,
+		`SELECT * FROM support_resistance_history ORDER BY timestamp DESC LIMIT 1`,
+	)
+	sr, err := scanSR(row)
+	if err != nil {
+		if err.Error() == "no rows in result set" {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return sr, nil
+}
+
+func (r *SRRepo) GetHistory(ctx context.Context, limit int) ([]models.SupportResistance, error) {
+	rows, err := r.pool.Query(ctx,
+		`SELECT * FROM support_resistance_history ORDER BY timestamp DESC LIMIT $1`,
+		limit,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	return collectSRs(rows)
+}
+
+func (r *SRRepo) NeedsRefresh(ctx context.Context, refreshHours int) (bool, error) {
+	latest, err := r.GetLatest(ctx)
+	if err != nil {
+		return false, err
+	}
+	if latest == nil {
+		return true, nil
+	}
+	age := time.Since(latest.Timestamp)
+	return age >= time.Duration(refreshHours)*time.Hour, nil
+}
+
+type ChangeAnalysis struct {
+	HasChanged    bool                       `json:"hasChanged"`
+	ChangePercent *float64                   `json:"changePercent"`
+	Previous      *models.SupportResistance  `json:"previous"`
+	Reason        string                     `json:"reason"`
+}
+
+func (r *SRRepo) CheckSignificantChange(ctx context.Context, newSR *models.SupportResistance, thresholdPercent float64) (*ChangeAnalysis, error) {
+	previous, err := r.GetLatest(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if previous == nil {
+		return &ChangeAnalysis{
+			HasChanged: true,
+			Reason:     "First S/R fetch",
+		}, nil
+	}
+
+	pct := math.Abs((newSR.Midpoint - previous.Midpoint) / previous.Midpoint * 100)
+	changed := pct >= thresholdPercent
+
+	reason := "S/R stable"
+	if changed {
+		reason = fmt.Sprintf("Midpoint changed %.2f%%", pct)
+	}
+
+	return &ChangeAnalysis{
+		HasChanged:    changed,
+		ChangePercent: &pct,
+		Previous:      previous,
+		Reason:        reason,
+	}, nil
+}
+
+// --- scan helpers ---
+
+func scanSR(row scannable) (*models.SupportResistance, error) {
+	var sr models.SupportResistance
+	err := row.Scan(
+		&sr.ID, &sr.Timestamp, &sr.Method, &sr.LookbackDays,
+		&sr.Support, &sr.Resistance, &sr.Midpoint, &sr.AvgPrice,
+		&sr.GridRecalculated, &sr.CreatedAt,
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &sr, nil
+}
+
+func collectSRs(rows rowsIter) ([]models.SupportResistance, error) {
+	var out []models.SupportResistance
+	for rows.Next() {
+		var sr models.SupportResistance
+		if err := rows.Scan(
+			&sr.ID, &sr.Timestamp, &sr.Method, &sr.LookbackDays,
+			&sr.Support, &sr.Resistance, &sr.Midpoint, &sr.AvgPrice,
+			&sr.GridRecalculated, &sr.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		out = append(out, sr)
+	}
+	return out, rows.Err()
+}