From f2083ad4117a47091497b778552aad797117f00f Mon Sep 17 00:00:00 2001
From: Ian Gulliver <github@flamingcow.io>
Date: Sun, 15 Feb 2026 18:08:33 -0800
Subject: [PATCH] Add constraint kind validation per level and reorder
 constraint form

---
 main.go        | 16 ++++++++++++++++
 static/trip.js | 42 ++++++++++++++++++++++++++----------------
 2 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/main.go b/main.go
index 302a218..ea89289 100644
--- a/main.go
+++ b/main.go
@@ -638,6 +638,22 @@ func handleCreateConstraint(db *sql.DB) http.HandlerFunc {
 			http.Error(w, "students must be different", http.StatusBadRequest)
 			return
 		}
+		switch body.Level {
+		case "student":
+			if body.Kind != "prefer" && body.Kind != "prefer_not" {
+				http.Error(w, "students may only use prefer or prefer not", http.StatusBadRequest)
+				return
+			}
+		case "parent":
+			if body.Kind != "must_not" {
+				http.Error(w, "parents may only use must not", http.StatusBadRequest)
+				return
+			}
+		case "admin":
+		default:
+			http.Error(w, "invalid level", http.StatusBadRequest)
+			return
+		}
 		a, b := body.StudentAID, body.StudentBID
 		if a > b {
 			a, b = b, a
diff --git a/static/trip.js b/static/trip.js
index 54cbd49..6f83177 100644
--- a/static/trip.js
+++ b/static/trip.js
@@ -142,6 +142,30 @@ async function loadStudents() {
 
         const addRow = document.createElement('div');
         addRow.className = 'constraint-add';
+        const levelKinds = {
+            student: ['prefer', 'prefer_not'],
+            parent: ['must_not'],
+            admin: ['must', 'prefer', 'prefer_not', 'must_not']
+        };
+        const levelSelect = document.createElement('select');
+        for (const level of ['student', 'parent', 'admin']) {
+            const opt = document.createElement('option');
+            opt.value = level;
+            opt.textContent = level.charAt(0).toUpperCase() + level.slice(1);
+            levelSelect.appendChild(opt);
+        }
+        const kindSelect = document.createElement('select');
+        const updateKinds = () => {
+            kindSelect.innerHTML = '';
+            for (const kind of levelKinds[levelSelect.value]) {
+                const opt = document.createElement('option');
+                opt.value = kind;
+                opt.textContent = kindLabels[kind];
+                kindSelect.appendChild(opt);
+            }
+        };
+        updateKinds();
+        levelSelect.addEventListener('change', updateKinds);
         const studentSelect = document.createElement('select');
         const defaultOpt = document.createElement('option');
         defaultOpt.value = '';
@@ -154,20 +178,6 @@ async function loadStudents() {
             opt.textContent = other.name;
             studentSelect.appendChild(opt);
         }
-        const kindSelect = document.createElement('select');
-        for (const kind of ['must', 'prefer', 'prefer_not', 'must_not']) {
-            const opt = document.createElement('option');
-            opt.value = kind;
-            opt.textContent = kindLabels[kind];
-            kindSelect.appendChild(opt);
-        }
-        const levelSelect = document.createElement('select');
-        for (const level of ['student', 'parent', 'admin']) {
-            const opt = document.createElement('option');
-            opt.value = level;
-            opt.textContent = level.charAt(0).toUpperCase() + level.slice(1);
-            levelSelect.appendChild(opt);
-        }
         const cAddBtn = document.createElement('button');
         cAddBtn.className = 'input-action';
         cAddBtn.textContent = '+';
@@ -182,9 +192,9 @@ async function loadStudents() {
             });
             loadStudents();
         });
-        addRow.appendChild(studentSelect);
-        addRow.appendChild(kindSelect);
         addRow.appendChild(levelSelect);
+        addRow.appendChild(kindSelect);
+        addRow.appendChild(studentSelect);
         addRow.appendChild(cAddBtn);
         cDetails.appendChild(addRow);