Add db seeding with default metrics for users

cmd/http-server/main.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"fmt"
+	"os"
 	"time"
 
 	"github.com/swaggo/files"
 	"github.com/swaggo/gin-swagger"
 
+	"git.qowevisa.me/Qowevisa/fin-check-api/db"
 	docs "git.qowevisa.me/Qowevisa/fin-check-api/docs"
 	"git.qowevisa.me/Qowevisa/fin-check-api/handlers"
 	"git.qowevisa.me/Qowevisa/fin-check-api/middleware"
@@ -29,6 +32,10 @@ import (
 // @host gonapi.qowevisa.click
 // @BasePath /api
 func main() {
+	if err := db.Init(); err != nil {
+		fmt.Printf("ERROR: db.Init: %v\n", err)
+		os.Exit(1)
+	}
 	r := gin.Default()
 	docs.SwaggerInfo.BasePath = "/api"
 	r.Use(cors.New(cors.Config{

db/db.go

@@ -2,6 +2,7 @@ package db
 
 import (
 	"errors"
+	"fmt"
 	"log"
 	"os"
 	"sync"
@@ -19,6 +20,15 @@ var (
 	ERROR_DB_NOT_INIT = errors.New("Database connection is not initialized")
 )
 
+func Init() error {
+	dbc := Connect()
+	// Seeds
+	if err := initStateOfDb(dbc); err != nil {
+		return fmt.Errorf("initStateOfDb: %w", err)
+	}
+	return nil
+}
+
 func Connect() *gorm.DB {
 	conMu.Lock()
 	defer conMu.Unlock()
@@ -62,3 +72,45 @@ func Connect() *gorm.DB {
 	gormDB.AutoMigrate(&Metric{})
 	return newUDB
 }
+
+var (
+	CANT_FIND_METRIC = errors.New("Can't find proper metrics in database")
+)
+
+func initMetrics(tx *gorm.DB) error {
+	var metrics []Metric
+	if err := tx.Find(&metrics).Error; err != nil {
+		return err
+	}
+	metricsThatNeeded := []*Metric{
+		&Metric{Name: "None", Short: "pcs", Value: 0},
+		&Metric{Name: "Gram", Short: "g", Value: 1},
+		&Metric{Name: "Kilogram", Short: "kg", Value: 2},
+		&Metric{Name: "Liter", Short: "l", Value: 3},
+	}
+	if len(metrics) == 0 {
+		for _, m := range metricsThatNeeded {
+			if err := tx.Create(m).Error; err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	for _, m := range metricsThatNeeded {
+		tmp := &Metric{}
+		if err := tx.Find(tmp, m).Error; err != nil {
+			return err
+		}
+		if tmp.ID == 0 {
+			return CANT_FIND_METRIC
+		}
+	}
+	return nil
+}
+
+func initStateOfDb(tx *gorm.DB) error {
+	if err := initMetrics(tx); err != nil {
+		return fmt.Errorf("initMetrics: %w", err)
+	}
+	return nil
+}