"""
Simple RC Circuit Example

This example demonstrates using the pyngspice Python extension
to simulate a basic RC low-pass filter.
"""

# Note: This example requires the ngspice extension to be built and installed
# Run: pip install -e . from the ngspice root directory

try:
    from pyngspice import SimRunner, RawRead
except ImportError:
    print("pyngspice extension not installed. Run: pip install -e .")
    print("This example shows the intended API usage.")
    exit(1)

import numpy as np
import os

# Create a simple RC netlist
netlist_content = """
* Simple RC Low-Pass Filter
* Cutoff frequency: ~1.59 kHz

V1 in 0 AC 1 SIN(0 1 1k)
R1 in out 1k
C1 out 0 100n

.tran 10u 10m
.end
"""

def main():
    # Create output directory
    output_dir = "./output"
    os.makedirs(output_dir, exist_ok=True)

    # Write netlist to file
    netlist_file = os.path.join(output_dir, "simple_rc.net")
    with open(netlist_file, "w") as f:
        f.write(netlist_content)

    print(f"Created netlist: {netlist_file}")

    # Create SimRunner and run simulation
    print("Running simulation...")
    runner = SimRunner(output_folder=output_dir)
    raw_file, log_file = runner.run_now(netlist_file)

    print(f"Raw file: {raw_file}")
    print(f"Log file: {log_file}")

    # Read results
    raw = RawRead(raw_file)
    print(f"\nAnalysis type: {raw.analysis_type}")
    print(f"Number of traces: {raw.num_variables}")
    print(f"Number of points: {raw.num_points}")
    print(f"\nAvailable traces:")
    for name in raw.get_trace_names():
        print(f"  - {name}")

    # Get time and voltage data
    time = raw.get_trace("time").get_wave(0)
    v_in = raw.get_trace("V(in)").get_wave(0)
    v_out = raw.get_trace("V(out)").get_wave(0)

    print(f"\nTime range: {time[0]*1e3:.3f} ms to {time[-1]*1e3:.3f} ms")
    print(f"V(in) range: {min(v_in):.3f} V to {max(v_in):.3f} V")
    print(f"V(out) range: {min(v_out):.3f} V to {max(v_out):.3f} V")

    # Optional: Plot results if matplotlib is available
    try:
        import matplotlib.pyplot as plt

        fig, ax = plt.subplots(figsize=(10, 6))
        ax.plot(time * 1e3, v_in, label='V(in)', alpha=0.7)
        ax.plot(time * 1e3, v_out, label='V(out)', linewidth=2)
        ax.set_xlabel('Time (ms)')
        ax.set_ylabel('Voltage (V)')
        ax.set_title('RC Low-Pass Filter Response')
        ax.legend()
        ax.grid(True, alpha=0.3)

        plot_file = os.path.join(output_dir, "simple_rc.png")
        plt.savefig(plot_file, dpi=150)
        print(f"\nPlot saved to: {plot_file}")
        plt.show()

    except ImportError:
        print("\nNote: Install matplotlib to generate plots")

if __name__ == "__main__":
    main()