Super basic version

app/controllers/dashboard_controller.rb

@@ -1,2 +1,31 @@
 class DashboardController < ApplicationController
+  def index
+    joint_column = 'joint'
+    # Grab distinct values for dropdown filters
+    @available_joints = Joint.distinct.pluck(joint_column)
+
+    # Fetch initial records
+    @records = filter_records
+
+    respond_to do |format|
+      format.html # Renders app/views/dashboards/index.html.erb
+      format.json { render json: @records } # Returns filtered data as JSON for JS
+    end
+  end
+
+  private
+
+  def filter_records
+    records = Joint.all
+    records = records.where(joint: params[:joint]) if params[:joint].present?
+    records
+  end
+
+  # old broken: def index
+  # old broken:   @joint = Joint.distinct.pluck(:Joint)
+  # old broken: 
+  # old broken:   @records = Joint.all
+  # old broken: 
+  # old broken:   @records = @records.where(Joint: params[joint]) if params[:joint].present?
+  # old broken: end
 end

app/models/joint.rb

@@ -1,2 +1,5 @@
 class Joint < ApplicationRecord
+  def readonly?
+    true
+  end
 end

app/models/joints_info.rb

@@ -1,2 +1,5 @@
 class JointsInfo < ApplicationRecord
+  def readonly?
+    true
+  end
 end

app/models/special_test.rb

@@ -1,2 +1,5 @@
 class SpecialTest < ApplicationRecord
+  def readonly?
+    true
+  end
 end

app/views/dashboard/index.html.erb

@@ -0,0 +1,88 @@
+<h1>Excel Replacement Dashboard</h1>
+
+<!-- Dropdown Filters (No submit button needed, JS handles it) -->
+<%= form_with url: dashboard_path, method: :get, id: "filter-form" do |f| %>
+  <div>
+    <%= f.label :joint, "Select Joint:" %>
+    <%= f.select :joint, options_for_select(@available_joints, params[:joint]), include_blank: "All joints", id: "joint" %>
+  </div>
+<% end %>
+
+<hr>
+
+<h2>Dashboard Results</h2>
+<div style="overflow-x: auto;">
+  <table border="1" id="results-table">
+    <thead>
+      <tr id="table-headers">
+        <!-- Dynamically populated headers -->
+      </tr>
+    </thead>
+    <tbody id="table-body">
+      <!-- Dynamically populated rows (supports 4 to 20+ values) -->
+    </tbody>
+  </table>
+</div>
+
+<script>
+document.addEventListener("DOMContentLoaded", () => {
+  const jointSelect = document.getElementById("joint");
+  const tableHeaders = document.getElementById("table-headers");
+  const tableBody = document.getElementById("table-body");
+
+  function fetchFilteredData() {
+    const joint = jointSelect.value;
+
+    // Build query parameters
+    const params = new URLSearchParams();
+    if (joint) params.append("joint", joint);
+
+    // Fetch data from Rails with JSON format
+    fetch(`/dashboard?${params.toString()}`, {
+      headers: { "Accept": "application/json" }
+    })
+    .then(response => response.json())
+    .then(data => {
+      renderTable(data);
+    })
+    .catch(error => console.error("Error fetching dashboard data:", error));
+  }
+
+  function renderTable(records) {
+    tableHeaders.innerHTML = "";
+    tableBody.innerHTML = "";
+
+    if (records.length === 0) {
+      tableBody.innerHTML = "<tr><td colspan='100'>No records found</td></tr>";
+      return;
+    }
+
+    // Extract column keys dynamically from the first record (handles variable lengths)
+    const columns = Object.keys(records[0]);
+
+    // 1. Build dynamic headers
+    columns.forEach(col => {
+      const th = document.createElement("th");
+      th.textContent = col.replace(/_/g, " ").toUpperCase();
+      tableHeaders.appendChild(th);
+    });
+
+    // 2. Build dynamic rows (whether 4 or 20 attributes long)
+    records.forEach(record => {
+      const tr = document.createElement("tr");
+      columns.forEach(col => {
+        const td = document.createElement("td");
+        td.textContent = record[col] !== null ? record[col] : "";
+        tr.appendChild(td);
+      });
+      tableBody.appendChild(tr);
+    });
+  }
+
+  // Trigger fetch when either dropdown changes
+  jointSelect.addEventListener("change", fetchFilteredData);
+
+  // Load initial data on page load
+  fetchFilteredData();
+});  
+</script>