feat: many2many relations check

common/finders.go

@@ -0,0 +1,100 @@
+package common
+
+import (
+	"go/ast"
+	"strings"
+)
+
+func GetModelField(model *Model, fieldName string) *Field {
+	field, fieldExists := model.Fields[fieldName]
+	if fieldExists {
+		return &field
+	} else {
+		return nil
+	}
+}
+
+func GetModelFromType(modelType ast.Expr, models map[string]Model) *Model {
+	baseType := ResolveBaseType(modelType)
+	if baseType != nil {
+		return GetRelatedModel(*baseType, models)
+	} else {
+		return nil
+	}
+}
+
+func GetRelatedModel(modelName string, models map[string]Model) *Model {
+	model, modelExists := models[modelName]
+	if modelExists {
+		return &model
+	} else {
+		return nil
+	}
+}
+
+func FindParamValue(paramName string, params []string) *string {
+	for _, rawParam := range params {
+		pair := strings.Split(rawParam, ":")
+		if len(pair) < 2 {
+			return nil
+		}
+		if strings.ToLower(pair[0]) == strings.ToLower(paramName) {
+			return &pair[1]
+		}
+	}
+	return nil
+}
+
+func FindModelParam(paramName string, model Model) *Param {
+	for _, field := range model.Fields {
+		for _, param := range field.Params {
+			pair := strings.Split(param, ":")
+			if len(pair) < 2 {
+				return nil
+			}
+			if strings.ToLower(pair[0]) == strings.ToLower(paramName) {
+				return &Param{
+					Name:  pair[0],
+					Value: pair[1],
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func FindReferencesInM2M(m2mReference Field, relatedModel Model) *Field {
+	/* Find `references` field in m2m relation */
+	referencesTagValue := FindParamValue("references", m2mReference.Params)
+	if referencesTagValue != nil {
+		return GetModelField(&relatedModel, *referencesTagValue)
+	} else {
+		for _, field := range relatedModel.Fields {
+			for _, opt := range field.Options {
+				if opt == "primaryKey" {
+					return &field
+				}
+			}
+		}
+		for _, field := range relatedModel.Fields {
+			if strings.ToLower(field.Name) == "id" {
+				return &field
+			}
+		}
+		return nil
+	}
+}
+
+func FindBackReferenceInM2M(relationName string, relatedModel Model) *Field {
+	for _, field := range relatedModel.Fields {
+		m2mRelation := field.GetParam("many2many")
+		if m2mRelation != nil {
+			if m2mRelation.Value == relationName {
+				return &field
+			}
+		}
+	}
+	return nil
+}
+
+//func findForeignKey()