import pycatima as catima
import numpy as np, sys
import matplotlib.pyplot as plt

# --- 1. Constants ---
P_TORR = 250
P_CO2 = 0
if(len(sys.argv)==3):
    P_TORR=int(sys.argv[1])
    P_CO2 = int(sys.argv[2])

TEMP_K = 293.15
R = 8.3144
MEV2U = 1.0 / 931.494

# Gas Density Calculations
p_pa = P_TORR * 133.322
molar_density = p_pa / (R * TEMP_K)
m_he, m_c, m_o= 4.0026, 12.0000, 15.9949
m_mix_avg = ((1 - P_CO2 / 100) * m_he) + (P_CO2 / 100 * (m_c + 2*m_o))
rho_g_cm3 = (molar_density * m_mix_avg) / 1e6
print(f"Gas density at {P_TORR} Torr: {rho_g_cm3:.6e} g/cm^3")

# --- 2. Material & Step Setup ---
material_def = [(m_he, 2, (1 - P_CO2 / 100)), (m_c, 6, P_CO2 / 100), (m_o, 8, 2*P_CO2 / 100)]
gas_mix = catima.Material(material_def)
gas_mix.density(rho_g_cm3)

# Thickness step settings
step_mg_cm2 = 0.001
step_g_cm2 = step_mg_cm2 / 1000.0
max_steps = 1000000000             # Adjust based on how far you want to track

coarse_step_cm = 0.2  
fine_step_cm = 0.03     
fine_zone_frac = 0.085  

# Set relative integration tolerance (lower = higher precision, slower calculation)
catima.Config.epsrel = 1e-6
# Set absolute integration tolerance
catima.Config.epsabs = 1e-9

def generate_lookup(z, mass_u, e_start_mev, label):
    filename = f"Eloss/E_vs_x_{label}.dat"
    header = (
        "Distance_cm\tEnergy_MeV\tSigma_E_MeV\tSigma_x_cm\tSigma_a_cm\t"
        "Thickness_mg_cm2\tEin_MeV\tSigma_r\tCov\tToF\tStoppingPower"
    )

    projectile = catima.Projectile(mass_u, z)
    e_u_init = e_start_mev / mass_u

    # 1. Get exact analytical range directly from CATIMA
    projectile.T(e_u_init)
    total_range_g_cm2 = catima.range(projectile, gas_mix)
    total_range_cm = total_range_g_cm2 / rho_g_cm3
    fine_zone_start_cm = total_range_cm * (1.0 - fine_zone_frac)

    output = []
    current_dist_cm = 0.0

    # 2. Step directly at checkpoint resolution
    while current_dist_cm <= total_range_cm * 1.05: # Track slightly past range
        thickness_g_cm2 = current_dist_cm * rho_g_cm3

        # Configure target thickness for this checkpoint
        gas_mix.density(rho_g_cm3).thickness(thickness_g_cm2)
        projectile.T(e_u_init)
        result = catima.calculate(projectile, gas_mix)

        # Save checkpoint row
        e_total_out = result.Eout * mass_u
        output.append([
            current_dist_cm, e_total_out, result.sigma_E, result.sigma_x,
            result.sigma_a, thickness_g_cm2 * 1000.0, result.Ein,
            result.sigma_r, result.cov, result.tof, result.sp
        ])

        if result.Eout == 0:
            break

        # Adaptive spatial step
        step = fine_step_cm if current_dist_cm >= fine_zone_start_cm else coarse_step_cm
        current_dist_cm += step

    data = np.asarray(output)
    data = data[np.argsort(data[:, 1])]
    np.savetxt(
        filename, data, fmt='%.6f', delimiter='\t', header=header, comments=""
    )
    print(f"Lookup table created: {filename} ({len(output)} rows)")

    # Plot in increasing distance order even though the saved table is energy-sorted.
    plot_data = data[::-1]
    dist_cm, energy_mev, sigma_e, tof = (
        plot_data[:, 0], plot_data[:, 1], plot_data[:, 2], plot_data[:, 9]
    )

    fig, (ax_e, ax_sig, ax_tof) = plt.subplots(3, 1, figsize=(8, 12), sharex=True)

    ax_e.plot(dist_cm, energy_mev)
    ax_e.fill_between(dist_cm, energy_mev - sigma_e, energy_mev + sigma_e, alpha=0.3)
    ax_e.set_ylabel("Energy (MeV)")
    ax_e.set_title(f"Energy Loss Curve {label.capitalize()}")
    ax_e.grid(True)

    ax_sig.plot(dist_cm, sigma_e)
    ax_sig.set_ylabel("Energy straggle $\\sigma_E$ (MeV)")
    ax_sig.grid(True)

    ax_tof.plot(dist_cm, tof)
    ax_tof.set_xlabel("Distance (cm)")
    ax_tof.set_ylabel("Time of flight (ns)")
    ax_tof.grid(True)

    plt.tight_layout()
    plt.show()
    


# --- 3. Run ---
# Format: generate_lookup(Z, mass_u, E_start_MeV, label)
generate_lookup(1, 1.0078, 30, "proton")
generate_lookup(1, 2.01355, 30, "deuteron")
generate_lookup(2, 4.0026, 50, "alpha")
generate_lookup(13,26.9815, 56.1, "aluminum")
#generate_lookup(9,17.0021, 70, "fluorine")
#generate_lookup(8,15.9949, 70, "oxygen")