Show item classes as tree

.sqlx/query-689a5177bdbc4ac788579a47fe033eb6b9639a356fe7ec543691e385ffef51e7.json

@@ -0,0 +1,32 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "WITH RECURSIVE item_class_children AS (\n                SELECT\n                    item_classes.id,\n                    array_remove(array_agg(children.id), NULL) AS \"children\"\n                FROM item_classes\n                LEFT JOIN item_classes AS \"children\"\n                    ON item_classes.id = children.parent\n                GROUP BY item_classes.id\n            ),\n            cte AS (\n                SELECT\n                    item_classes.id,\n                    item_classes.name,\n                    item_class_children.children,\n                    0 AS \"reverse_level\"\n                FROM item_classes\n                JOIN item_class_children\n                    ON item_classes.id = item_class_children.id\n                WHERE item_class_children.children = '{}'\n\n                UNION\n\n                SELECT\n                    item_classes.id,\n                    item_classes.name,\n                    item_class_children.children,\n                    cte.reverse_level + 1\n                FROM item_classes\n                JOIN item_class_children\n                    ON item_classes.id = item_class_children.id\n                JOIN cte\n                    ON cte.id = ANY (item_class_children.children)\n            )\n            SELECT\n                id AS \"id!\",\n                name AS \"name!\",\n                children AS \"children!\"\n            FROM cte\n            GROUP BY id, name, children\n            ORDER BY max(reverse_level)",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "id!",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 1,
+        "name": "name!",
+        "type_info": "Varchar"
+      },
+      {
+        "ordinal": 2,
+        "name": "children!",
+        "type_info": "UuidArray"
+      }
+    ],
+    "parameters": {
+      "Left": []
+    },
+    "nullable": [
+      null,
+      null,
+      null
+    ]
+  },
+  "hash": "689a5177bdbc4ac788579a47fe033eb6b9639a356fe7ec543691e385ffef51e7"
+}

src/database/item_classes/list.rs

@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
+use std::collections::HashMap;
+
 use sqlx::query;
 use uuid::Uuid;
 
@@ -13,6 +15,12 @@ pub struct ItemClassListEntry {
     pub parent: Option<ItemClassPreview>,
 }
 
+pub struct ItemClassTreeElement {
+    pub id: Uuid,
+    pub name: String,
+    pub children: Vec<ItemClassTreeElement>,
+}
+
 impl ItemClassRepository {
     pub async fn list(&self) -> sqlx::Result<Vec<ItemClassListEntry>> {
         query!(
@@ -33,4 +41,77 @@ impl ItemClassRepository {
         .fetch_all(&self.pool)
         .await
     }
+
+    pub async fn tree(&self) -> sqlx::Result<Vec<ItemClassTreeElement>> {
+        let mut mappings: HashMap<Uuid, ItemClassTreeElement> = HashMap::new();
+
+        for row in query!(
+            r##"WITH RECURSIVE item_class_children AS (
+                SELECT
+                    item_classes.id,
+                    array_remove(array_agg(children.id), NULL) AS "children"
+                FROM item_classes
+                LEFT JOIN item_classes AS "children"
+                    ON item_classes.id = children.parent
+                GROUP BY item_classes.id
+            ),
+            cte AS (
+                SELECT
+                    item_classes.id,
+                    item_classes.name,
+                    item_class_children.children,
+                    0 AS "reverse_level"
+                FROM item_classes
+                JOIN item_class_children
+                    ON item_classes.id = item_class_children.id
+                WHERE item_class_children.children = '{}'
+
+                UNION
+
+                SELECT
+                    item_classes.id,
+                    item_classes.name,
+                    item_class_children.children,
+                    cte.reverse_level + 1
+                FROM item_classes
+                JOIN item_class_children
+                    ON item_classes.id = item_class_children.id
+                JOIN cte
+                    ON cte.id = ANY (item_class_children.children)
+            )
+            SELECT
+                id AS "id!",
+                name AS "name!",
+                children AS "children!"
+            FROM cte
+            GROUP BY id, name, children
+            ORDER BY max(reverse_level)"##
+        )
+        .fetch_all(&self.pool)
+        .await?
+        {
+            let mut children = if row.children.is_empty() {
+                Vec::new()
+            } else {
+                row.children
+                    .iter()
+                    .map(|id| mappings.remove(dbg!(id)).unwrap())
+                    .collect()
+            };
+            children.sort_by(|this, other| this.name.cmp(&other.name));
+
+            mappings.insert(
+                row.id,
+                ItemClassTreeElement {
+                    id: row.id,
+                    name: row.name,
+                    children,
+                },
+            );
+        }
+
+        let mut item_classes = mappings.into_values().collect::<Vec<_>>();
+        item_classes.sort_by(|this, other| this.name.cmp(&other.name));
+        Ok(item_classes)
+    }
 }

src/database/item_classes/mod.rs

@@ -14,6 +14,7 @@ use uuid::Uuid;
 
 pub use add::{ItemClassAddForm, ItemClassAddFormPrefilled};
 pub use edit::ItemClassEditForm;
+pub use list::ItemClassTreeElement;
 
 #[derive(Clone)]
 pub struct ItemClassRepository {

src/frontend/item_class/list.rs

@@ -6,7 +6,6 @@ use actix_identity::Identity;
 use actix_web::{error, get, web, Responder};
 use maud::html;
 
-use crate::database::item_classes::ItemClassPreview;
 use crate::database::ItemClassRepository;
 use crate::frontend::templates::{
     self,
@@ -24,7 +23,7 @@ async fn get(
     user: Identity,
 ) -> actix_web::Result<impl Responder> {
     let item_classes = item_class_repo
-        .list()
+        .tree()
         .await
         .map_err(error::ErrorInternalServerError)?;
 
@@ -47,26 +46,9 @@ async fn get(
             ..Default::default()
         },
         html! {
-            table .table {
+            ul {
-                thead {
-                    tr {
-                        th { "Name" }
-                        th { "Parents" }
-                    }
-                }
-                tbody {
                 @for item_class in item_classes {
-                        tr {
+                    (item_class)
-                            td { (ItemClassPreview::new(item_class.id, item_class.name)) }
-                            td {
-                                @if let Some(parent) = item_class.parent {
-                                    (parent)
-                                } @else {
-                                    "-"
-                                }
-                            }
-                        }
-                    }
                 }
             }
         },

src/frontend/templates/render.rs

@@ -7,7 +7,11 @@ use std::fmt::{self, Display};
 use maud::{html, Markup, Render};
 
 use crate::database::items::ItemPreview;
-use crate::database::{item_classes::ItemClassPreview, item_events::ItemEvent, items::ItemName};
+use crate::database::{
+    item_classes::{ItemClassPreview, ItemClassTreeElement},
+    item_events::ItemEvent,
+    items::ItemName,
+};
 
 impl Render for ItemClassPreview {
     fn render(&self) -> Markup {
@@ -68,3 +72,20 @@ impl Render for ItemPreview {
         }
     }
 }
+
+impl Render for ItemClassTreeElement {
+    fn render(&self) -> Markup {
+        html! {
+            li {
+                (ItemClassPreview::new(self.id, self.name.clone()))
+                @if !self.children.is_empty() {
+                    ul {
+                        @for child in &self.children {
+                            (child)
+                        }
+                    }
+                }
+            }
+        }
+    }
+}