"""
Extract mass from NX measure expression in Bracket.prt

This script reads the mass value directly from the model's measure expression,
bypassing the need for GRDPNT output in the OP2 file.
"""

import sys
from pathlib import Path
import NXOpen

def extract_mass_from_prt(prt_file: Path) -> float:
    """
    Extract mass from NX .prt file measure expression.

    Args:
        prt_file: Path to .prt file with mass measure expression

    Returns:
        Mass in kg
    """
    theSession = NXOpen.Session.GetSession()

    # Open the part file
    print("[1/2] Opening part file: " + str(prt_file))
    try:
        basePart, partLoadStatus = theSession.Parts.OpenBaseDisplay(str(prt_file))
        partLoadStatus.Dispose()
    except Exception as e:
        raise RuntimeError("Failed to open part file: " + str(e))

    # Get all expressions
    print("[2/2] Reading expressions...")
    expressions = basePart.Expressions

    # Search for mass expression (common names: "mass", "bracket_mass", "total_mass", etc.)
    mass_value = None
    mass_expr_name = None

    for expr in expressions:
        expr_name = expr.Name.lower()
        if 'mass' in expr_name:
            # Found a mass expression
            mass_expr_name = expr.Name
            mass_value = expr.Value
            print("  Found mass expression: '" + expr.Name + "' = " + str(mass_value))
            break

    if mass_value is None:
        # List all expressions to help debug
        print("\n  Available expressions:")
        for expr in expressions:
            print("    - " + expr.Name + " = " + str(expr.Value))
        raise ValueError("No mass expression found in part file")

    # Close the part
    theSession.Parts.CloseAll(NXOpen.BasePart.CloseWholeTree.False, None)

    print("\n[OK] Mass extracted: {:.6f} kg".format(mass_value))
    return mass_value


if __name__ == "__main__":
    if len(sys.argv) > 1:
        prt_file = Path(sys.argv[1])
    else:
        # Default to Bracket.prt in same directory
        prt_file = Path(__file__).parent / "Bracket.prt"

    if not prt_file.exists():
        print(f"ERROR: Part file not found: {prt_file}")
        sys.exit(1)

    try:
        mass_kg = extract_mass_from_prt(prt_file)
        print(f"\nMass: {mass_kg:.6f} kg ({mass_kg * 1000:.2f} g)")
    except Exception as e:
        print(f"\nERROR: {e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)