#!/usr/bin/env python3
"""POST-script: auto-detect upload_port by querying connected ESP32s.

Each ESP32 running SylDa firmware responds to the serial command "ID?"
with either "SylDa_Server" or "SylDa_Client". This script scans
/dev/serial/by-id/ for Espressif devices, queries each one, and sets
UPLOAD_PORT for the matching environment.

If no device responds (e.g. first flash), the user is prompted to
select a port manually.
"""
Import("env")

if env.IsIntegrationDump():
    Return()

ENV_TO_ID = {
    "s3lite-server": "SylDa_Server",
    "s3lite-client": "SylDa_Client",
}

import glob
import os
import sys
import time

try:
    import serial
except ImportError:
    print("  WARNING: pyserial not installed, skipping auto-detect")
    print("  Install: pip install pyserial")
    Return()


def find_esp32_ports():
    by_id = "/dev/serial/by-id"
    if not os.path.isdir(by_id):
        return []
    ports = []
    for entry in sorted(os.listdir(by_id)):
        if "Espressif" in entry or "espressif" in entry:
            ports.append(os.path.join(by_id, entry))
    return ports


def query_id(port, timeout=5):
    try:
        ser = serial.Serial(port, 115200, timeout=0.5)
        time.sleep(0.1)
        ser.reset_input_buffer()
        ser.write(b"ID?\n")
        deadline = time.time() + timeout
        while time.time() < deadline:
            line = ser.readline().decode("utf-8", errors="ignore").strip()
            if line:
                ser.close()
                return line
        ser.close()
    except (serial.SerialException, OSError):
        pass
    return None


def detect_port(source, target, env):
    if env.subst("$UPLOAD_PORT"):
        print(f"  Upload port already set to {env.subst('$UPLOAD_PORT')}, skipping auto-detect")
        return

    env_name = env.subst("$PIOENV")
    expected_id = ENV_TO_ID.get(env_name)

    if not expected_id:
        print(f"  Unknown environment '{env_name}', skipping auto-detect")
        return

    ports = find_esp32_ports()

    if not ports:
        print(f"  No ESP32 serial ports found in /dev/serial/by-id/")
        print(f"  Connect an ESP32 and try again")
        sys.exit(1)

    if len(ports) == 1:
        port = ports[0]
        resp = query_id(port, timeout=5)
        if resp and expected_id in resp:
            print(f"  Auto-detected {expected_id} on {port}")
        else:
            if resp:
                print(f"  Found '{resp}' on {port} (expected {expected_id})")
            print(f"  Only one ESP32 connected, using {port}")
        env["UPLOAD_PORT"] = port
        return

    for port in ports:
        resp = query_id(port, timeout=5)
        if resp and expected_id in resp:
            print(f"  Found {expected_id} on {port}")
            env["UPLOAD_PORT"] = port
            return

    print(f"\n  Cannot auto-detect {expected_id} (no ID? response matched)")
    print(f"  Available ESP32 ports:")
    for i, port in enumerate(ports, 1):
        resp = query_id(port, timeout=3)
        label = f" ({resp})" if resp else ""
        print(f"    {i}: {port}{label}")

    try:
        choice = input(f"  Select port for {env_name} [{expected_id}] (1-{len(ports)}): ")
        idx = int(choice) - 1
        if 0 <= idx < len(ports):
            env["UPLOAD_PORT"] = ports[idx]
            return
    except (ValueError, EOFError):
        pass

    print("  Invalid choice, aborting upload")
    sys.exit(1)


env.AddPreAction("upload", detect_port)