wip reciprocal relation names

yopa-web/resources/templates/index.html.tera

@@ -45,7 +45,7 @@
 		<ul>
 			{% for rel in model.relations %}
 			<li>
-				<span title="{{rel.model.id}}">"{{rel.model.name}}", pointing to: <i>{{rel.related_name}}</i></span>
+				<span title="{{rel.model.id}}">"{{rel.model.name}}", pointing to: <i>{{rel.related_name}}</i> (reciprocal as "{{rel.model.reciprocal_name}}")</span>
 				{%- if rel.model.optional %}, OPTIONAL{% endif %}
 				{%- if rel.model.multiple %}, MULTIPLE{% endif %}
 				<br>

yopa-web/resources/templates/relation_create.html.tera

@@ -20,6 +20,9 @@ Define relation
 	<label for="name">Name:</label>
 	<input type="text" id="name" name="name"><br>
 
+	<label for="reciprocal_name">Reciprocal name:</label>
+	<input type="text" id="reciprocal_name" name="reciprocal_name"><br>
+
 	<label for="optional">Optional:</label>
 	<input type="checkbox" name="optional" id="optional" value="1">
 	<br>

yopa-web/src/main.rs

@@ -168,6 +168,7 @@ fn init_yopa() -> YopaStoreWrapper {
         id: Default::default(),
         object: id_recipe,
         name: "book reference".to_string(),
+        reciprocal_name: "recipes".to_string(),
         optional: true,
         multiple: true,
         related: id_book
@@ -187,6 +188,7 @@ fn init_yopa() -> YopaStoreWrapper {
         id: Default::default(),
         object: id_recipe,
         name: "related recipe".to_string(),
+        reciprocal_name: "related recipe".to_string(),
         optional: true,
         multiple: true,
         related: id_recipe

yopa-web/src/routes.rs

@@ -178,6 +178,7 @@ pub(crate) async fn relation_model_create_form(
 pub(crate) struct RelationModelCreate {
     pub object : ID,
     pub name : String,
+    pub reciprocal_name : String,
     pub optional : Option<i32>,
     pub multiple : Option<i32>,
     pub related : ID,
@@ -195,6 +196,7 @@ pub(crate) async fn relation_model_create(
         id: Default::default(),
         object: form.object,
         name: form.name.clone(),
+        reciprocal_name: form.reciprocal_name.clone(),
         optional: form.optional.unwrap_or_default() != 0,
         multiple: form.multiple.unwrap_or_default() != 0,
         related: form.related

yopa/src/lib.rs

@@ -92,12 +92,22 @@ impl Storage {
             return Err(StorageError::NotExist(format!("related object model {}", rel.related).into()));
         }
 
-        if self.rel_models.iter().find(|(_, t)| t.name == rel.name && t.object == rel.object).is_some() {
+        if let Some((_, colliding)) = self.rel_models.iter().find(|(_, other)| {
+            (other.name == rel.name && other.object == rel.object) // Exact match
+            || (other.name == rel.reciprocal_name && other.object == rel.related) // Our reciprocal name collides with related's own relation name
+            || (other.reciprocal_name == rel.name && other.related == rel.object) // Our name name collides with a reciprocal name on the other relation
+            || (other.reciprocal_name == rel.reciprocal_name && other.related == rel.related) // Reciprocal names collide for the same destination
+        }) {
             return Err(StorageError::ConstraintViolation(
-                format!("relation with the name \"{}\" and on model {} already exists", rel.name, rel.object).into()));
+                format!("name collision (\"{}\" / \"{}\") with existing relation (\"{}\" / \"{}\")",
+                        rel.name, rel.reciprocal_name,
+                        colliding.name, colliding.reciprocal_name
+                ).into()));
         }
 
-        debug!("Define relation model \"{}\" from {} to {}", rel.name, self.describe_model(rel.object), self.describe_model(rel.related));
+        debug!("Define relation model \"{}\" from {} to {}, reciprocal name \"{}\"",
+               rel.name, self.describe_model(rel.object), self.describe_model(rel.related), rel.reciprocal_name);
+
         let id = next_id();
         rel.id = id;
         self.rel_models.insert(id, rel);

yopa/src/model.rs

@@ -35,6 +35,8 @@ pub struct RelationModel {
     pub object: ID,
     /// Relation name, unique within the parent object
     pub name: String,
+    /// Relation name when viewed from the other side, unique within the related object's relations
+    pub reciprocal_name: String,
     /// Relation is optional
     pub optional: bool,
     /// Relation can be multiple