feat: Safety plan version history with diff view (#96)

- Store up to 20 plan versions in localStorage
- Migrate legacy single-plan format automatically
- History button in plan modal footer
- Diff view: additions (green) / deletions (red) between versions
- Restore any previous version with one click
- No PII leaves the device

index.html

@@ -739,11 +739,25 @@ html, body {
     </div>
     <div class="modal-footer">
       <button class="btn btn-secondary" id="cancel-safety-plan">Cancel</button>
+      <button class="btn btn-secondary" id="show-version-history" title="View previous versions">History</button>
       <button class="btn btn-primary" id="save-safety-plan">Save Plan</button>
     </div>
   </div>
 </div>
 
+<!-- Safety Plan Version History Modal -->
+<div id="version-history-modal" class="modal-overlay" role="dialog" aria-modal="true" aria-labelledby="vh-title">
+  <div class="modal-content" style="max-width: 640px;">
+    <div class="modal-header">
+      <h2 id="vh-title">Safety Plan History</h2>
+      <button class="close-modal" id="close-version-history" aria-label="Close history">&times;</button>
+    </div>
+    <div class="modal-body" id="vh-body" style="max-height: 400px; overflow-y: auto;">
+      <p id="vh-empty" style="color: #8b949e;">No previous versions saved.</p>
+    </div>
+  </div>
+</div>
+
 <script>
 (function() {
   'use strict';
@@ -1169,17 +1183,40 @@ Sovereignty and service always.`;
   });
 
   // ===== SAFETY PLAN LOGIC =====
+  // Safety plan version storage key
+  var SP_STORAGE_KEY = 'timmy_safety_plan_versions';
+
+  function _getPlanVersions() {
+    try {
+      var raw = localStorage.getItem(SP_STORAGE_KEY);
+      if (raw) return JSON.parse(raw);
+      // Migrate legacy single-plan format
+      var legacy = localStorage.getItem('timmy_safety_plan');
+      if (legacy) {
+        var plan = JSON.parse(legacy);
+        var versions = [{ plan: plan, timestamp: new Date().toISOString(), label: 'Migrated' }];
+        localStorage.setItem(SP_STORAGE_KEY, JSON.stringify(versions));
+        localStorage.removeItem('timmy_safety_plan');
+        return versions;
+      }
+    } catch (e) {}
+    return [];
+  }
+
+  function _setPlanVersions(versions) {
+    localStorage.setItem(SP_STORAGE_KEY, JSON.stringify(versions));
+  }
+
   function loadSafetyPlan() {
     try {
-      var saved = localStorage.getItem('timmy_safety_plan');
-      if (saved) {
-        var plan = JSON.parse(saved);
-        document.getElementById('sp-warning-signs').value = plan.warningSigns || '';
-        document.getElementById('sp-coping').value = plan.coping || '';
-        document.getElementById('sp-distraction').value = plan.distraction || '';
-        document.getElementById('sp-help').value = plan.help || '';
-        document.getElementById('sp-environment').value = plan.environment || '';
-      }
+      var versions = _getPlanVersions();
+      if (versions.length === 0) return;
+      var plan = versions[versions.length - 1].plan;
+      document.getElementById('sp-warning-signs').value = plan.warningSigns || '';
+      document.getElementById('sp-coping').value = plan.coping || '';
+      document.getElementById('sp-distraction').value = plan.distraction || '';
+      document.getElementById('sp-help').value = plan.help || '';
+      document.getElementById('sp-environment').value = plan.environment || '';
     } catch (e) {}
   }
 
@@ -1202,10 +1239,13 @@ Sovereignty and service always.`;
       environment: document.getElementById('sp-environment').value
     };
     try {
-      localStorage.setItem('timmy_safety_plan', JSON.stringify(plan));
+      var versions = _getPlanVersions();
+      versions.push({ plan: plan, timestamp: new Date().toISOString(), label: 'Saved' });
+      if (versions.length > 20) versions = versions.slice(-20);
+      _setPlanVersions(versions);
       safetyPlanModal.classList.remove('active');
       _restoreSafetyPlanFocus();
-      alert('Safety plan saved locally.');
+      alert('Safety plan saved. Version ' + versions.length + ' of 20.');
     } catch (e) {
       alert('Error saving plan.');
     }
@@ -1299,6 +1339,119 @@ Sovereignty and service always.`;
     });
   }
 
+  // ===== SAFETY PLAN VERSION HISTORY =====
+  var versionHistoryModal = document.getElementById('version-history-modal');
+  var showVersionHistoryBtn = document.getElementById('show-version-history');
+  var closeVersionHistoryBtn = document.getElementById('close-version-history');
+  var vhBody = document.getElementById('vh-body');
+
+  var SP_FIELDS = [
+    { key: 'warningSigns', label: 'Warning signs' },
+    { key: 'coping', label: 'Coping strategies' },
+    { key: 'distraction', label: 'People/Places for distraction' },
+    { key: 'help', label: 'People I can ask for help' },
+    { key: 'environment', label: 'Making my environment safe' }
+  ];
+
+  function _diffPlans(oldPlan, newPlan) {
+    var changes = [];
+    for (var i = 0; i < SP_FIELDS.length; i++) {
+      var f = SP_FIELDS[i];
+      var ov = (oldPlan[f.key] || '').trim();
+      var nv = (newPlan[f.key] || '').trim();
+      if (ov !== nv) changes.push({ label: f.label, old: ov, new: nv });
+    }
+    return changes;
+  }
+
+  function _renderVersionHistory() {
+    var versions = _getPlanVersions();
+    vhBody.innerHTML = '';
+    if (versions.length === 0) {
+      vhBody.innerHTML = '<p style="color:#8b949e;">No previous versions saved.</p>';
+      return;
+    }
+    for (var i = versions.length - 1; i >= 0; i--) {
+      var v = versions[i];
+      var ts = new Date(v.timestamp).toLocaleString();
+      var card = document.createElement('div');
+      card.style.cssText = 'border:1px solid #30363d;border-radius:8px;padding:12px;margin-bottom:8px;';
+      var header = document.createElement('div');
+      header.style.cssText = 'display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;';
+      var label = document.createElement('strong');
+      label.textContent = 'v' + (i + 1) + ' — ' + ts;
+      header.appendChild(label);
+      var restoreBtn = document.createElement('button');
+      restoreBtn.textContent = 'Restore';
+      restoreBtn.className = 'btn btn-secondary';
+      restoreBtn.style.cssText = 'padding:2px 10px;font-size:0.8rem;';
+      restoreBtn.setAttribute('data-version', i);
+      restoreBtn.addEventListener('click', function() {
+        var idx = parseInt(this.getAttribute('data-version'));
+        var v2 = _getPlanVersions()[idx];
+        if (!v2) return;
+        var fields = ['sp-warning-signs', 'sp-coping', 'sp-distraction', 'sp-help', 'sp-environment'];
+        var keys = ['warningSigns', 'coping', 'distraction', 'help', 'environment'];
+        for (var j = 0; j < fields.length; j++) {
+          document.getElementById(fields[j]).value = v2.plan[keys[j]] || '';
+        }
+        versionHistoryModal.classList.remove('active');
+        safetyPlanModal.classList.add('active');
+      });
+      header.appendChild(restoreBtn);
+      card.appendChild(header);
+      if (i > 0) {
+        var changes = _diffPlans(versions[i - 1].plan, v.plan);
+        if (changes.length === 0) {
+          var noChange = document.createElement('div');
+          noChange.style.cssText = 'color:#8b949e;font-size:0.85rem;';
+          noChange.textContent = 'No changes from previous version.';
+          card.appendChild(noChange);
+        } else {
+          for (var c = 0; c < changes.length; c++) {
+            var ch = changes[c];
+            var diffDiv = document.createElement('div');
+            diffDiv.style.cssText = 'margin-bottom:4px;font-size:0.85rem;';
+            var lbl = document.createElement('div');
+            lbl.style.color = '#58a6ff';
+            lbl.textContent = ch.label;
+            diffDiv.appendChild(lbl);
+            if (ch.old) {
+              var del = document.createElement('div');
+              del.style.cssText = 'color:#f85149;text-decoration:line-through;padding:2px 4px;';
+              del.textContent = '- ' + ch.old.substring(0, 100);
+              diffDiv.appendChild(del);
+            }
+            if (ch.new) {
+              var add = document.createElement('div');
+              add.style.cssText = 'color:#3fb950;padding:2px 4px;';
+              add.textContent = '+ ' + ch.new.substring(0, 100);
+              diffDiv.appendChild(add);
+            }
+            card.appendChild(diffDiv);
+          }
+        }
+      } else {
+        var initial = document.createElement('div');
+        initial.style.cssText = 'color:#8b949e;font-size:0.85rem;';
+        initial.textContent = 'Initial version.';
+        card.appendChild(initial);
+      }
+      vhBody.appendChild(card);
+    }
+  }
+
+  showVersionHistoryBtn.addEventListener('click', function() {
+    safetyPlanModal.classList.remove('active');
+    _renderVersionHistory();
+    versionHistoryModal.classList.add('active');
+  });
+
+  closeVersionHistoryBtn.addEventListener('click', function() {
+    versionHistoryModal.classList.remove('active');
+    safetyPlanModal.classList.add('active');
+  });
+
   // ===== TEXTAREA AUTO-RESIZE =====
   msgInput.addEventListener('input', function() {
     this.style.height = 'auto';