Add parent to item

migrations/2024-07-03-122248_item_add_parent/down.sql

@@ -0,0 +1,10 @@
+-- SPDX-FileCopyrightText: 2024 Simon Bruder <simon@sbruder.de>
+--
+-- SPDX-License-Identifier: AGPL-3.0-or-later
+
+ALTER TABLE items
+  DROP parent;
+
+DROP VIEW item_tree;
+
+DROP FUNCTION check_item_cycle;

migrations/2024-07-03-122248_item_add_parent/up.sql

@@ -0,0 +1,50 @@
+-- SPDX-FileCopyrightText: 2024 Simon Bruder <simon@sbruder.de>
+--
+-- SPDX-License-Identifier: AGPL-3.0-or-later
+
+ALTER TABLE items
+  ADD parent UUID REFERENCES items(id);
+
+CREATE RECURSIVE VIEW item_tree (id, parents) AS (
+  SELECT id, ARRAY[]::UUID[] AS parents FROM items WHERE parent IS NULL
+  UNION
+  SELECT items.id, item_tree.parents || items.parent FROM items, item_tree WHERE items.parent = item_tree.id
+);
+
+CREATE FUNCTION check_item_cycle()
+RETURNS TRIGGER AS $$
+BEGIN
+  IF NEW.parent IS NULL THEN
+    RETURN NEW;
+  END IF;
+
+  IF NEW.id = NEW.parent THEN
+    RAISE EXCEPTION 'Cycle detected';
+  END IF;
+
+  IF (WITH RECURSIVE cte AS (
+    SELECT id, parent
+    FROM items
+    WHERE id = NEW.parent
+
+    UNION
+
+    SELECT items.id, items.parent
+    FROM items, cte
+    WHERE items.id = cte.parent
+  )
+  SELECT 1
+  FROM cte
+  WHERE parent = NEW.id
+  LIMIT 1) THEN
+    RAISE EXCEPTION 'Cycle detected';
+  END IF;
+
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER prevent_item_cycle
+BEFORE INSERT OR UPDATE ON items
+FOR EACH ROW
+EXECUTE FUNCTION check_item_cycle();

src/api/v1/item.rs

@@ -13,7 +13,8 @@ pub fn config(cfg: &mut web::ServiceConfig) {
     cfg.service(add)
         .service(list)
         .service(show)
-        .service(update);
+        .service(update)
+        .service(parents);
 }
 
 #[put("/item")]
@@ -70,3 +71,17 @@ async fn update(
 
     Ok(HttpResponse::Ok().json(item))
 }
+
+#[get("/item/{id}/parents")]
+async fn parents(
+    pool: web::Data<DbPool>,
+    path: web::Path<Uuid>,
+) -> actix_web::Result<impl Responder> {
+    let id = path.into_inner();
+
+    let parents = web::block(move || manage::item::get_parents(&mut pool.get().unwrap(), id))
+        .await?
+        .map_err(error::ErrorInternalServerError)?;
+
+    Ok(HttpResponse::Ok().json(parents))
+}

src/frontend/item.rs

@@ -113,9 +113,10 @@ async fn edit_item_post(
 ) -> actix_web::Result<impl Responder> {
     let id = path.into_inner();
 
-    let item = web::block(move || manage::item::update(&mut pool.get().unwrap(), id, data.into_inner()))
-        .await?
-        .map_err(error::ErrorInternalServerError)?;
+    let item =
+        web::block(move || manage::item::update(&mut pool.get().unwrap(), id, data.into_inner()))
+            .await?
+            .map_err(error::ErrorInternalServerError)?;
 
     Ok(web::Redirect::to("/item/".to_owned() + &item.id.to_string()).see_other())
 }

src/manage/item.rs

@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
+use std::collections::HashMap;
+
 use diesel::pg::PgConnection;
 use diesel::prelude::*;
 use uuid::Uuid;
@@ -26,9 +28,43 @@ pub fn get_all(conn: &mut PgConnection) -> Result<Vec<Item>, diesel::result::Err
     schema::items::table.select(Item::as_select()).load(conn)
 }
 
-pub fn update(conn: &mut PgConnection, id: Uuid, modified_item: NewItem) -> Result<Item, diesel::result::Error> {
+pub fn update(
+    conn: &mut PgConnection,
+    id: Uuid,
+    modified_item: NewItem,
+) -> Result<Item, diesel::result::Error> {
     diesel::update(schema::items::table.filter(schema::items::id.eq(id)))
         .set(modified_item)
         .returning(Item::as_returning())
         .get_result(conn)
 }
+
+/// Helper type for querying parents of items
+#[derive(Debug, Queryable, Selectable)]
+#[diesel(table_name = schema::item_tree)]
+#[diesel(check_for_backend(diesel::pg::Pg))]
+struct ItemTreeMapping {
+    pub id: Uuid,
+    pub parents: Vec<Uuid>,
+}
+
+pub fn get_parents(conn: &mut PgConnection, id: Uuid) -> Result<Vec<Uuid>, diesel::result::Error> {
+    schema::item_tree::table
+        .filter(schema::item_tree::id.eq(id))
+        .select(ItemTreeMapping::as_select())
+        .first(conn)
+        .map(|itm| itm.parents)
+}
+
+pub fn get_all_parents(
+    conn: &mut PgConnection,
+) -> Result<HashMap<Uuid, Vec<Uuid>>, diesel::result::Error> {
+    schema::item_tree::table
+        .select(ItemTreeMapping::as_select())
+        .load(conn)
+        .map(|itms| {
+            itms.into_iter()
+                .map(|ItemTreeMapping { id, parents }| (id, parents))
+                .collect::<HashMap<Uuid, Vec<Uuid>>>()
+        })
+}

src/models.rs

@@ -14,6 +14,7 @@ use crate::schema::*;
 pub struct Item {
     pub id: Uuid,
     pub name: String,
+    pub parent: Option<Uuid>,
 }
 
 #[derive(Debug, Insertable, Deserialize, AsChangeset)]
@@ -21,4 +22,6 @@ pub struct Item {
 #[diesel(check_for_backend(diesel::pg::Pg))]
 pub struct NewItem {
     pub name: String,
+    #[serde(default)]
+    pub parent: Option<Uuid>,
 }

src/schema.rs

@@ -8,5 +8,13 @@ diesel::table! {
     items (id) {
         id -> Uuid,
         name -> Varchar,
+        parent -> Nullable<Uuid>,
+    }
+}
+
+diesel::table! {
+    item_tree (id) {
+        id -> Uuid,
+        parents -> Array<Uuid>,
     }
 }

static/app.js

@@ -0,0 +1,14 @@
+// SPDX-FileCopyrightText: 2024 Simon Bruder <simon@sbruder.de>
+//
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+(() => {
+  // Allows a form checkbox to toggle an input element.
+  // This requires the form to have a structure like described in the bootstrap documentation:
+  // https://getbootstrap.com/docs/5.3/forms/input-group/#checkboxes-and-radios
+  Array.from(document.getElementsByClassName("input-toggle")).forEach(el => {
+    el.addEventListener("change", e => {
+      e.target.parentElement.parentElement.querySelector("input:not(.input-toggle)").disabled = !e.target.checked;
+    })
+  })
+})()

templates/base.html

@@ -55,5 +55,8 @@ SPDX-License-Identifier: AGPL-3.0-or-later
     </footer>
 
     <script src="/static/vendor/bootstrap.bundle.min.js"></script>
+    <script src="/static/app.js"></script>
+    {# TODO this is not the best way, but it works for now #}
+    {% block extra_scripts %}{% endblock %}
   </body>
 </html>

templates/item_add.html

@@ -12,6 +12,15 @@ SPDX-License-Identifier: AGPL-3.0-or-later
     <label for="name" class="form-label">Name</label>
     <input type="text" class="form-control" id="name" name="name" required{% if let Some(data) = data %} value="{{ data.name }}"{% endif %}>
   </div>
+  <div class="mb-3">
+    <label for="parent" class="form-label">Parent</label>
+    <div class="input-group">
+      <div class="input-group-text">
+        <input type="checkbox" class="form-check-input mt-0 input-toggle"{% if let Some (data) = data %}{% if data.parent.is_some() %} checked{% endif %}{% endif %}>
+      </div>
+      <input type="text" class="form-control" id="parent" name="parent"{% if let Some(data) = data %}{% if let Some(parent) = data.parent %} value="{{ parent }}"{% else %} disabled{% endif %}{% else %}disabled{% endif %}>
+    </div>
+  </div>
   <button type="submit" class="btn btn-primary">Add</button>
 </form>
 {% endblock %}

templates/item_details.html

@@ -28,6 +28,14 @@ SPDX-License-Identifier: AGPL-3.0-or-later
         {{ item.name }}
       </td>
     </tr>
+    <tr>
+      <th>
+        Parent
+      </th>
+      <td>
+        {% if let Some(parent) = item.parent %}{{ parent }}{% else %}-{% endif %}
+      </td>
+    </tr>
   </tbody>
 </table>
 {% endblock %}

templates/item_edit.html

@@ -16,6 +16,15 @@ SPDX-License-Identifier: AGPL-3.0-or-later
     <label for="name" class="form-label">Name</label>
     <input type="text" class="form-control" id="name" name="name" required value="{{ item.name }}">
   </div>
+  <div class="mb-3">
+    <label for="parent" class="form-label">Parent</label>
+    <div class="input-group">
+      <div class="input-group-text">
+        <input type="checkbox" class="form-check-input mt-0 input-toggle"{% if item.parent.is_some() %} checked{% endif %}>
+      </div>
+      <input type="text" class="form-control" id="parent" name="parent"{% if let Some(parent) = item.parent %} value="{{ parent }}"{% else %} disabled{% endif %}>
+    </div>
+  </div>
   <button type="submit" class="btn btn-primary">Edit</button>
 </form>
 {% endblock %}