#!/usr/bin/env python3
import os
import pyudev

def generate_rules():
    context = pyudev.Context()

    # Find all TTY devices driven by usb-serial drivers (CP210x, FTDI, etc.)
    devices = []
    for device in context.list_devices(subsystem='tty'):
        if 'ID_VENDOR_ID' in device.properties and 'ID_MODEL_ID' in device.properties:
            # We filter for USB serial devices only
            parent = device.find_parent('usb', 'usb_interface')
            if parent:
                devices.append(device)

    # Sort by their physical path so they are ordered by hub port
    # The 'DEVPATH' usually looks like .../usb1/1-2/1-2.3/1-2.3.4...
    devices.sort(key=lambda x: x.properties.get('DEVPATH', ''))

    print(f"# Detected {len(devices)} devices. Generating rules...\n")

    rules = []
    hub_counter = 1
    port_counter = 1
    last_parent_path = None

    for dev in devices:
        # Get the unique physical path identifier (KERNELS)
        # We need the parent USB interface kernel name (e.g., '1-1.2:1.0')
        parent = dev.find_parent('usb', 'usb_interface')
        if not parent: continue

        kernels_path = parent.device_path.split('/')[-1]

        # Simple heuristic to detect a new hub (big jump in path length or numbering)
        # You might need to manually tweak the hub numbers in the file later.

        # Generate the rule
        # KERNELS matches the physical port.
        # SYMLINK creates the static alias.
        rule = f'SUBSYSTEM=="tty", KERNELS=="{kernels_path}", SYMLINK+="esp_port_{len(rules)+1:02d}"'
        rules.append(rule)
        print(f"Mapped {dev.device_node} ({kernels_path}) -> /dev/esp_port_{len(rules):02d}")

    # Write to file
    with open("99-esp32-static.rules", "w") as f:
        f.write("# Persistent USB Serial mapping for ESP32 Hubs\n")
        f.write("# Generated automatically. Do not edit unless topology changes.\n\n")
        for r in rules:
            f.write(r + "\n")

    print(f"\n{'-'*60}")
    print(f"SUCCESS: Generated {len(rules)} rules in '99-esp32-static.rules'.")
    print(f"To install:\n  1. Review the file to ensure order is correct.")
    print(f"  2. sudo cp 99-esp32-static.rules /etc/udev/rules.d/")
    print(f"  3. sudo udevadm control --reload-rules")
    print(f"  4. sudo udevadm trigger")
    print(f"{'-'*60}")

if __name__ == '__main__':
    # Requires 'pyudev'. Install with: sudo dnf install python3-pyudev (or pip install pyudev)
    try:
        import pyudev
        generate_rules()
    except ImportError:
        print("Error: This script requires 'pyudev'.")
        print("Install it via: pip install pyudev")