Move graph computation from server to client

webapp/path_navigator.html

@@ -578,12 +578,22 @@
             });
         }
         
-        // Load from Flask API - get ALL graphs at once
+        // Load from Flask API - get chords and compute graphs client-side
         async function loadAllGraphs() {
             try {
-                const response = await fetch("/api/all-graphs");
+                const response = await fetch("/api/chords");
                 if (!response.ok) throw new Error("API not available");
-                allGraphsData = await response.json();
+                const data = await response.json();
+                
+                // Compute graphs from raw chord data client-side
+                const graphs = data.chords.map((chord, index) => {
+                    return calculateGraph(chord, index);
+                });
+                
+                allGraphsData = {
+                    total: data.total,
+                    graphs: graphs
+                };
                 
                 totalSteps = allGraphsData.total - 1;
                 
@@ -597,10 +607,100 @@
                 updateUI();
                 
             } catch (e) {
-                console.log("Error loading graphs:", e);
+                console.log("Error loading chords:", e);
             }
         }
         
+        // Compute graph (nodes + edges) from raw chord data - client-side version
+        function calculateGraph(chord, index) {
+            if (!chord) return { nodes: [], edges: [] };
+            
+            const nodes = [];
+            const dims = [2, 3, 5, 7];
+            
+            // Calculate cents for each pitch
+            for (let i = 0; i < chord.length; i++) {
+                const pitch = chord[i];
+                const fraction = parseFraction(pitch.fraction || "1");
+                const cents = fraction > 0 ? 1200 * Math.log2(fraction) : 0;
+                
+                nodes.push({
+                    id: i,
+                    cents: Math.round(cents),
+                    fraction: pitch.fraction || "1",
+                    hs_array: pitch.hs_array || []
+                });
+            }
+            
+            // Find edges: differ by ±1 in exactly one dimension (ignoring dim 0)
+            const edges = [];
+            for (let i = 0; i < chord.length; i++) {
+                for (let j = i + 1; j < chord.length; j++) {
+                    const hs1 = chord[i].hs_array || [];
+                    const hs2 = chord[j].hs_array || [];
+                    
+                    if (!hs1.length || !hs2.length) continue;
+                    
+                    // Count differences in dims 1, 2, 3
+                    let diffCount = 0;
+                    let diffDim = -1;
+                    
+                    for (let d = 1; d < hs1.length; d++) {
+                        const diff = hs2[d] - hs1[d];
+                        if (Math.abs(diff) === 1) {
+                            diffCount++;
+                            diffDim = d;
+                        } else if (diff !== 0) {
+                            break; // diff > 1 in this dimension
+                        }
+                    }
+                    
+                    // Check if exactly one dimension differs
+                    if (diffCount === 1 && diffDim > 0) {
+                        // Calculate frequency ratio
+                        const diffHs = [];
+                        for (let d = 0; d < hs1.length; d++) {
+                            diffHs.push(hs1[d] - hs2[d]);
+                        }
+                        
+                        let numerator = 1;
+                        let denominator = 1;
+                        for (let dIdx = 0; dIdx < dims.length; dIdx++) {
+                            const exp = diffHs[dIdx];
+                            if (exp > 0) {
+                                numerator *= Math.pow(dims[dIdx], exp);
+                            } else if (exp < 0) {
+                                denominator *= Math.pow(dims[dIdx], -exp);
+                            }
+                        }
+                        
+                        const ratio = denominator > 1 ? `${numerator}/${denominator}` : `${numerator}`;
+                        
+                        edges.push({
+                            source: i,
+                            target: j,
+                            ratio: ratio,
+                            dim: diffDim
+                        });
+                    }
+                }
+            }
+            
+            return { nodes, edges, index };
+        }
+        
+        // Parse fraction string to number
+        function parseFraction(fracStr) {
+            if (typeof fracStr === 'number') return fracStr;
+            if (!fracStr) return 1;
+            
+            if (fracStr.includes('/')) {
+                const [num, den] = fracStr.split('/').map(Number);
+                return num / den;
+            }
+            return Number(fracStr);
+        }
+        
         // Update UI elements
         function updateUI() {
             hasPrev = currentIndex > 0;