feat: add detailed performance profiling with interactive toggle

app.py

@@ -2,7 +2,8 @@ import sys
 from pathlib import Path
 from datetime import datetime
 import re
-from flask import Flask, render_template
+import time
+from flask import Flask, render_template, g
 
 # Add scripts directory to path to allow importing from it
 scripts_dir = Path(__file__).parent / "scripts"
@@ -13,6 +14,35 @@ from match_payments import reconcile, fetch_sheet_data, fetch_exceptions, normal
 
 app = Flask(__name__)
 
+@app.before_request
+def start_timer():
+    g.start_time = time.perf_counter()
+    g.steps = []
+
+def record_step(name):
+    g.steps.append((name, time.perf_counter()))
+
+@app.context_processor
+def inject_render_time():
+    def get_render_time():
+        total = time.perf_counter() - g.start_time
+        breakdown = []
+        last_time = g.start_time
+        for name, timestamp in g.steps:
+            duration = timestamp - last_time
+            breakdown.append(f"{name}:{duration:.3f}s")
+            last_time = timestamp
+        
+        # Add remaining time as 'render'
+        render_duration = time.perf_counter() - last_time
+        breakdown.append(f"render:{render_duration:.3f}s")
+        
+        return {
+            "total": f"{total:.3f}",
+            "breakdown": " | ".join(breakdown)
+        }
+    return dict(get_render_time=get_render_time)
+
 @app.route("/")
 def index():
     # Redirect root to /fees for convenience while there are no other apps
@@ -24,6 +54,7 @@ def fees():
     payments_url = f"https://docs.google.com/spreadsheets/d/{PAYMENTS_SHEET_ID}/edit"
     
     members, sorted_months = get_members_with_fees()
+    record_step("fetch_members")
     if not members:
         return "No data."
 
@@ -40,6 +71,7 @@ def fees():
     # Get exceptions for formatting
     credentials_path = ".secret/fuj-management-bot-credentials.json"
     exceptions = fetch_exceptions(PAYMENTS_SHEET_ID, credentials_path)
+    record_step("fetch_exceptions")
     
     formatted_results = []
     for name, month_fees in results:
@@ -63,6 +95,8 @@ def fees():
             row["months"].append({"cell": cell, "overridden": is_overridden})
         formatted_results.append(row)
 
+    record_step("process_data")
+
     return render_template(
         "fees.html", 
         months=[month_labels[m] for m in sorted_months], 
@@ -81,12 +115,16 @@ def reconcile_view():
     credentials_path = ".secret/fuj-management-bot-credentials.json"
     
     members, sorted_months = get_members_with_fees()
+    record_step("fetch_members")
     if not members:
         return "No data."
         
     transactions = fetch_sheet_data(PAYMENTS_SHEET_ID, credentials_path)
+    record_step("fetch_payments")
     exceptions = fetch_exceptions(PAYMENTS_SHEET_ID, credentials_path)
+    record_step("fetch_exceptions")
     result = reconcile(members, sorted_months, transactions, exceptions)
+    record_step("reconcile")
     
     # Format month labels
     month_labels = {
@@ -128,6 +166,8 @@ def reconcile_view():
     unmatched = result["unmatched"]
     import json
     
+    record_step("process_data")
+
     return render_template(
         "reconcile.html",
         months=[month_labels[m] for m in sorted_months],
@@ -148,6 +188,7 @@ def payments():
     credentials_path = ".secret/fuj-management-bot-credentials.json"
     
     transactions = fetch_sheet_data(PAYMENTS_SHEET_ID, credentials_path)
+    record_step("fetch_payments")
     
     # Group transactions by person
     grouped = {}
@@ -171,6 +212,7 @@ def payments():
         # Sort by date descending
         grouped[p].sort(key=lambda x: str(x.get("date", "")), reverse=True)
         
+    record_step("process_data")
     return render_template(
         "payments.html",
         grouped_payments=grouped,