initial version. downloads historical market data. creates a graph from peak to trough.

main.py

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+from pathlib import Path
+
+from marketreturns.retrieve import (
+    compute_annual_returns,
+    compute_monthly_returns,
+    download_raw_prices,
+    validate_coverage,
+)
+
+
+def main():
+    data_dir = Path(__file__).parent / "data"
+    data_dir.mkdir(parents=True, exist_ok=True)
+
+    all_data = download_raw_prices(data_dir)
+
+    if not all_data:
+        print("No data downloaded. Exiting.")
+        return
+
+    validate_coverage(all_data)
+
+    monthly_returns = compute_monthly_returns(all_data)
+    annual_returns = compute_annual_returns(all_data)
+
+    returns_dir = data_dir / "returns"
+    returns_dir.mkdir(parents=True, exist_ok=True)
+
+    monthly_path = returns_dir / "monthly_returns.csv"
+    annual_path = returns_dir / "annual_returns.csv"
+
+    monthly_returns.to_csv(monthly_path, index=False)
+    print(f"Monthly returns saved to {monthly_path} ({len(monthly_returns)} rows)")
+
+    annual_returns.to_csv(annual_path, index=False)
+    print(f"Annual returns saved to {annual_path} ({len(annual_returns)} rows)")
+
+    print("\nSample annual returns (latest 5 years):")
+    print(annual_returns.groupby("index").tail(5).to_string(index=False))
+
+
+if __name__ == "__main__":
+    main()