refactor(backend): migrate to modular repository pattern with separated concerns

- Extract database layer into model and repo packages
- Split repository into focused modules (control, federation, flow, groups, mutations)
- Remove monolithic db.go and sqlite/repository.go
- Update handlers to use new repository structure
- Migrate contract tests to new patterns
- Add migration plan documentation

go-backend/internal/http/handler/jobs.go

@@ -2,12 +2,11 @@ package handler
 
 import (
 	"context"
-	"database/sql"
 	"time"
 )
 
 func (h *Handler) StartBackgroundJobs() {
-	if h == nil || h.repo == nil || h.repo.DB() == nil {
+	if h == nil || h.repo == nil {
 		return
 	}
 
@@ -97,47 +96,28 @@ func durationUntilNextDailyMaintenance(now time.Time) time.Duration {
 }
 
 func (h *Handler) runStatisticsFlowJob(now time.Time) {
-	if h == nil || h.repo == nil || h.repo.DB() == nil {
+	if h == nil || h.repo == nil {
 		return
 	}
 
-	db := h.repo.DB()
 	nowMs := now.UnixMilli()
 	cutoffMs := nowMs - int64((48*time.Hour)/time.Millisecond)
-	_, _ = db.Exec(`DELETE FROM statistics_flow WHERE created_time < ?`, cutoffMs)
+	_ = h.repo.PurgeOldStatisticsFlows(cutoffMs)
 
 	hourMark := now.Truncate(time.Hour)
 	hourText := hourMark.Format("15:04")
 	createdTime := hourMark.UnixMilli()
 
-	rows, err := db.Query(`SELECT id, in_flow, out_flow FROM user ORDER BY id ASC`)
+	users, err := h.repo.ListAllUserFlowSnapshots()
 	if err != nil {
 		return
 	}
-	type userFlowSnapshot struct {
-		userID  int64
-		inFlow  int64
-		outFlow int64
-	}
-	users := make([]userFlowSnapshot, 0)
-
-	for rows.Next() {
-		var userID int64
-		var inFlow int64
-		var outFlow int64
-		if err := rows.Scan(&userID, &inFlow, &outFlow); err != nil {
-			continue
-		}
-		users = append(users, userFlowSnapshot{userID: userID, inFlow: inFlow, outFlow: outFlow})
-	}
-	_ = rows.Close()
 
 	for _, user := range users {
-		currentTotal := user.inFlow + user.outFlow
+		currentTotal := user.InFlow + user.OutFlow
 		increment := currentTotal
 
-		var lastTotal sql.NullInt64
-		err := db.QueryRow(`SELECT total_flow FROM statistics_flow WHERE user_id = ? ORDER BY id DESC LIMIT 1`, user.userID).Scan(&lastTotal)
+		lastTotal, err := h.repo.GetLastStatisticsFlowTotal(user.UserID)
 		if err == nil && lastTotal.Valid {
 			increment = currentTotal - lastTotal.Int64
 			if increment < 0 {
@@ -145,15 +125,12 @@ func (h *Handler) runStatisticsFlowJob(now time.Time) {
 			}
 		}
 
-		_, _ = db.Exec(`
-			INSERT INTO statistics_flow(user_id, flow, total_flow, time, created_time)
-			VALUES(?, ?, ?, ?, ?)
-		`, user.userID, increment, currentTotal, hourText, createdTime)
+		_ = h.repo.CreateStatisticsFlow(user.UserID, increment, currentTotal, hourText, createdTime)
 	}
 }
 
 func (h *Handler) runResetAndExpiryJob(now time.Time) {
-	if h == nil || h.repo == nil || h.repo.DB() == nil {
+	if h == nil || h.repo == nil {
 		return
 	}
 
@@ -163,108 +140,39 @@ func (h *Handler) runResetAndExpiryJob(now time.Time) {
 }
 
 func (h *Handler) resetMonthlyFlow(now time.Time) {
-	db := h.repo.DB()
 	currentDay := now.Day()
 	lastDay := time.Date(now.Year(), now.Month()+1, 0, 0, 0, 0, 0, now.Location()).Day()
 
-	if currentDay == lastDay {
-		_, _ = db.Exec(`
-			UPDATE user
-			SET in_flow = 0, out_flow = 0
-			WHERE flow_reset_time != 0
-			  AND (flow_reset_time = ? OR flow_reset_time > ?)
-		`, currentDay, lastDay)
-		_, _ = db.Exec(`
-			UPDATE user_tunnel
-			SET in_flow = 0, out_flow = 0
-			WHERE flow_reset_time != 0
-			  AND (flow_reset_time = ? OR flow_reset_time > ?)
-		`, currentDay, lastDay)
-		return
-	}
-
-	_, _ = db.Exec(`
-		UPDATE user
-		SET in_flow = 0, out_flow = 0
-		WHERE flow_reset_time != 0
-		  AND flow_reset_time = ?
-	`, currentDay)
-	_, _ = db.Exec(`
-		UPDATE user_tunnel
-		SET in_flow = 0, out_flow = 0
-		WHERE flow_reset_time != 0
-		  AND flow_reset_time = ?
-	`, currentDay)
+	_ = h.repo.ResetUserMonthlyFlow(currentDay, lastDay)
+	_ = h.repo.ResetUserTunnelMonthlyFlow(currentDay, lastDay)
 }
 
 func (h *Handler) disableExpiredUsers(nowMs int64) {
-	db := h.repo.DB()
-	rows, err := db.Query(`
-		SELECT id
-		FROM user
-		WHERE role_id != 0
-		  AND status = 1
-		  AND exp_time IS NOT NULL
-		  AND exp_time < ?
-	`, nowMs)
+	userIDs, err := h.repo.ListExpiredActiveUserIDs(nowMs)
 	if err != nil {
 		return
 	}
-	userIDs := make([]int64, 0)
-
-	for rows.Next() {
-		var userID int64
-		if err := rows.Scan(&userID); err != nil {
-			continue
-		}
-		userIDs = append(userIDs, userID)
-	}
-	_ = rows.Close()
 
 	for _, userID := range userIDs {
 		forwards, err := h.listActiveForwardsByUser(userID)
 		if err == nil {
 			h.pauseForwardRecords(forwards, nowMs)
 		}
-		_, _ = db.Exec(`UPDATE user SET status = 0 WHERE id = ?`, userID)
+		_ = h.repo.DisableUser(userID)
 	}
 }
 
 func (h *Handler) disableExpiredUserTunnels(nowMs int64) {
-	db := h.repo.DB()
-	rows, err := db.Query(`
-		SELECT id, user_id, tunnel_id
-		FROM user_tunnel
-		WHERE status = 1
-		  AND exp_time IS NOT NULL
-		  AND exp_time < ?
-	`, nowMs)
+	items, err := h.repo.ListExpiredActiveUserTunnels(nowMs)
 	if err != nil {
 		return
 	}
-	type expiredUserTunnel struct {
-		userTunnelID int64
-		userID       int64
-		tunnelID     int64
-	}
-	items := make([]expiredUserTunnel, 0)
-
-	for rows.Next() {
-		var userTunnelID int64
-		var userID int64
-		var tunnelID int64
-		if err := rows.Scan(&userTunnelID, &userID, &tunnelID); err != nil {
-			continue
-		}
-		items = append(items, expiredUserTunnel{userTunnelID: userTunnelID, userID: userID, tunnelID: tunnelID})
-	}
-	_ = rows.Close()
 
 	for _, item := range items {
-		forwards, err := h.listActiveForwardsByUserTunnel(item.userID, item.tunnelID)
+		forwards, err := h.listActiveForwardsByUserTunnel(item.UserID, item.TunnelID)
 		if err == nil {
 			h.pauseForwardRecords(forwards, nowMs)
 		}
-		_, _ = db.Exec(`UPDATE user_tunnel SET status = 0 WHERE id = ?`, item.userTunnelID)
+		_ = h.repo.DisableUserTunnel(item.ID)
 	}
 }