6 files changed, 542 insertions, 0 deletions
diff --git a/item/controller.go b/item/controller.go
new file mode 100644
index 0000000..b4e27c1
--- /dev/null
+++ b/item/controller.go
@@ -0,0 +1,156 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	e "vidhukant.com/openbills/errors"
+	"github.com/gin-gonic/gin"
+	"net/http"
+	"strconv"
+)
+
+func handleGetBrandItems (ctx *gin.Context) {
+	id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+	if err != nil {
+		ctx.Error(e.ErrInvalidID)
+		return
+	}
+
+	var items []SavedItem
+	err = getBrandItems(&items, uint(id))
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+		"data": items,
+	})
+}
+
+func handleGetBrands (ctx *gin.Context) {
+	var brands []Brand
+
+	err := getBrands(&brands)
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+		"data": brands,
+	})
+}
+
+func handleSaveBrand (ctx *gin.Context) {
+	var brand Brand
+	ctx.Bind(&brand)
+
+	err := brand.upsert()
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+		"data": brand,
+	})
+}
+
+func handleDelBrand (ctx *gin.Context) {
+	id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+	if err != nil {
+		ctx.Error(e.ErrInvalidID)
+		return
+	}
+
+	var brand Brand
+	brand.ID = uint(id)
+
+	err = brand.del()
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+	})
+}
+
+func handleGetItems (ctx *gin.Context) {
+	var items []SavedItem
+
+	err := getItems(&items)
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+		"data": items,
+	})
+}
+
+func handleSaveItem (ctx *gin.Context) {
+	var item SavedItem
+	ctx.Bind(&item)
+
+	err := item.upsert()
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+		"data": item,
+	})
+}
+
+func handleDelItem (ctx *gin.Context) {
+	id, err := strconv.ParseUint(ctx.Param("id"), 10, 64)
+	if err != nil {
+		ctx.Error(e.ErrInvalidID)
+		return
+	}
+
+	var item SavedItem
+	item.ID = uint(id)
+
+	err = item.del()
+	if err != nil {
+		ctx.Error(err)
+		ctx.Abort()
+		return
+	}
+
+	ctx.JSON(http.StatusOK, gin.H{
+		"message": "success",
+	})
+}
diff --git a/item/hooks.go b/item/hooks.go
new file mode 100644
index 0000000..ddb9a44
--- /dev/null
+++ b/item/hooks.go
@@ -0,0 +1,57 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	"gorm.io/gorm"
+	"vidhukant.com/openbills/errors"
+)
+
+func (i *SavedItem) BeforeSave(tx *gorm.DB) error {
+	var err error
+
+	err = checkIfBrandExists(i.BrandID)
+	if err != nil {
+		return err
+	}
+
+	err = i.validate()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (b *Brand) BeforeSave(tx *gorm.DB) error {
+	err := b.validate()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (b *Brand) BeforeDelete(tx *gorm.DB) error {
+  // if ID is 0, brand won't be deleted
+	if b.ID == 0 {
+		return errors.ErrNoWhereCondition
+	}
+
+	return nil
+}
diff --git a/item/item.go b/item/item.go
new file mode 100644
index 0000000..4da9c78
--- /dev/null
+++ b/item/item.go
@@ -0,0 +1,52 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	"gorm.io/gorm"
+	d "vidhukant.com/openbills/db"
+)
+
+var db *gorm.DB
+func init() {
+	db = d.DB
+
+	db.AutoMigrate(&SavedItem{}, &Brand{})
+}
+
+type Brand struct {
+	gorm.Model
+	Name  string
+}
+
+type Item struct {
+	BrandID            uint
+	Brand              Brand
+	UnitOfMeasure      string // TODO: probably has to be a custom type
+	HasDecimalQuantity bool
+	Name               string
+	Description        string
+	HSN                string
+	UnitPrice          string // float
+	GSTPercentage      string // float
+}
+
+type SavedItem struct {
+	gorm.Model
+	Item
+}
diff --git a/item/router.go b/item/router.go
new file mode 100644
index 0000000..fab973f
--- /dev/null
+++ b/item/router.go
@@ -0,0 +1,40 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+func Routes(route *gin.RouterGroup) {
+	b := route.Group("/brand")
+	{
+		b.GET("/", handleGetBrands)
+		b.GET("/:id/items", handleGetBrandItems)
+		b.POST("/", handleSaveBrand)
+		b.DELETE("/:id", handleDelBrand)
+	}
+
+	i := route.Group("/item")
+	{
+		i.GET("/", handleGetItems)
+		//i.GET("/:id", handleGetBrandItems)
+		i.POST("/", handleSaveItem)
+		i.DELETE("/:id", handleDelItem)
+	}
+}
diff --git a/item/service.go b/item/service.go
new file mode 100644
index 0000000..c8a72f6
--- /dev/null
+++ b/item/service.go
@@ -0,0 +1,126 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	"vidhukant.com/openbills/errors"
+	e "vidhukant.com/openbills/errors"
+)
+
+func getBrandItems(items *[]SavedItem, id uint) error {
+	// check if id is valid
+	var count int64
+	err := db.Model(&Brand{}).
+		Select("id").
+		Where("id = ?", id).
+		Count(&count).
+		Error
+
+	if err != nil {
+		return err
+  }
+
+	if count == 0 {
+		return errors.ErrBrandNotFound
+	}
+
+	res := db.Model(&SavedItem{}).Where("brand_id = ?", id).Find(&items)
+
+	// TODO: handle potential errors
+	if res.Error != nil {
+		return res.Error
+	}
+
+	if res.RowsAffected == 0 {
+		return e.ErrEmptyResponse
+	}
+
+	return nil
+}
+
+func getBrands(brands *[]Brand) error {
+	res := db.Find(&brands)
+
+	// TODO: handle potential errors
+	if res.Error != nil {
+		return res.Error
+	}
+
+	if res.RowsAffected == 0 {
+		return e.ErrEmptyResponse
+	}
+
+	return nil
+}
+
+func (b *Brand) upsert() error {
+	res := db.Save(b)
+	// TODO: handle potential errors
+	return res.Error
+}
+
+func (b *Brand) del() error {
+	res := db.Delete(b)
+
+	// TODO: handle potential errors
+	if res.Error != nil {
+		return res.Error
+	}
+
+	if res.RowsAffected == 0 {
+		return e.ErrNotFound
+	}
+
+	return nil
+}
+
+func getItems(items *[]SavedItem) error {
+	res := db.Preload("Brand").Find(&items)
+
+	// TODO: handle potential errors
+	if res.Error != nil {
+		return res.Error
+	}
+
+	if res.RowsAffected == 0 {
+		return e.ErrEmptyResponse
+	}
+
+	return nil
+}
+
+func (i *SavedItem) upsert() error {
+	res := db.Save(i)
+	// TODO: handle potential errors
+	return res.Error
+}
+
+func (i *SavedItem) del() error {
+	res := db.Delete(i)
+
+	// TODO: handle potential errors
+	if res.Error != nil {
+		return res.Error
+	}
+
+	if res.RowsAffected == 0 {
+		return e.ErrNotFound
+	}
+
+	return nil
+}
diff --git a/item/validators.go b/item/validators.go
new file mode 100644
index 0000000..09162ab
--- /dev/null
+++ b/item/validators.go
@@ -0,0 +1,111 @@
+/* openbills - Server for web based Libre Billing Software
+ * Copyright (C) 2023  Vidhu Kant Sharma <vidhukant@vidhukant.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package item
+
+import (
+	"strconv"
+	"strings"
+
+	"vidhukant.com/openbills/errors"
+)
+
+func (b *Brand) validate() error {
+	// trim whitespaces
+	b.Name = strings.TrimSpace(b.Name)
+
+	if b.Name == "" {
+		return errors.ErrEmptyBrandName
+	}
+
+	// make sure GSTIN is unique
+	var count int64
+	err := db.Model(&Brand{}).
+		Select("name").
+		Where("name = ?", b.Name).
+		Count(&count).
+		Error
+
+	if err != nil {
+		return err
+	}
+
+	if count > 0 {
+		return errors.ErrNonUniqueBrandName
+	}
+
+	return nil
+}
+
+func checkIfBrandExists(id uint) error {
+	// check if brand id is valid
+	var count int64
+	err := db.Model(&Brand{}).
+		Select("id").
+		Where("id = ?", id).
+		Count(&count).
+		Error
+
+	if err != nil {
+		return err
+  }
+
+	if count == 0 {
+		return errors.ErrBrandNotFound
+	}
+
+	return nil
+}
+
+func (i *SavedItem) validate() error {
+	// trim whitespaces
+	i.Name = strings.TrimSpace(i.Name)
+	i.Description = strings.TrimSpace(i.Description)
+	i.HSN = strings.TrimSpace(i.HSN)
+
+	var err error
+
+	// check if UnitPrice is float
+	_, err = strconv.ParseFloat(i.UnitPrice, 64)
+	if err != nil && strings.TrimSpace(i.UnitPrice) != "" {
+		return errors.ErrInvalidUnitPrice
+	}
+
+	// check if GSTPercentage is float
+	_, err = strconv.ParseFloat(i.GSTPercentage, 64)
+	if err != nil && strings.TrimSpace(i.GSTPercentage) != "" {
+		return errors.ErrInvalidGSTPercentage
+	}
+
+	// check if item with same name and brand already exists
+	var count int64
+	err = db.Model(&SavedItem{}).
+		Select("name, brand_id").
+		Where("brand_id = ? and name = ?", i.BrandID, i.Name).
+		Count(&count).
+		Error
+
+	if err != nil {
+		return err
+  }
+
+	if count != 0 {
+		return errors.ErrNonUniqueBrandItem
+	}
+
+	return nil
+}