import asyncio
import sys

from bleak import BleakClient, BleakScanner
from bleak.exc import BleakError

DEVICE_NAME = "BJ_LED"
WRITE_UUID = "0000ee01-0000-1000-8000-00805f9b34fb"
HEADER = bytes.fromhex("6996")
SCAN_SECONDS = 15
CONNECT_SECONDS = 20
CONNECT_TRIES = 3
EFFECT_MAX = 0x15


def frame(body_hex):
    return HEADER + bytes.fromhex(body_hex)


def command(action, name, speed):
    if action == "on":
        return frame("02 01 01")
    if action == "off":
        return frame("02 01 00")
    if action == "color":
        return frame("05 02 " + name)
    if action == "effect":
        mode = int(name)
        if not 0 <= mode <= EFFECT_MAX:
            sys.exit("effect must be 0-%d" % EFFECT_MAX)
        return frame("03 03 %02x %02x" % (mode, int(speed)))
    if action == "send":
        return bytes.fromhex(name)
    sys.exit("unknown action " + action)


async def find_strips():
    found = await BleakScanner.discover(timeout=SCAN_SECONDS, return_adv=True)
    return [(d, adv) for d, adv in found.values()
            if (d.name or "").startswith(DEVICE_NAME)]


async def scan():
    for device, adv in await find_strips():
        print("%s|%s|%s" % (device.name, device.address, adv.rssi))


async def write_once(address, payload, verbose):
    async with BleakClient(address, timeout=CONNECT_SECONDS) as client:
        if verbose:
            for service in client.services:
                for char in service.characteristics:
                    print("%s %s" % (char.uuid, ",".join(char.properties)), file=sys.stderr)
        await client.write_gatt_char(WRITE_UUID, payload, response=False)


## Strips at the edge of range often miss a connection attempt or two.
async def write(address, payload, verbose):
    for attempt in range(CONNECT_TRIES):
        try:
            return await write_once(address, payload, verbose)
        except (TimeoutError, BleakError) as e:
            if verbose:
                print("attempt %d: %r" % (attempt + 1, e), file=sys.stderr)
    sys.exit("could not connect to %s" % address)


def main():
    sys.stdout.reconfigure(newline="\n")
    action, address, name, speed, verbose = sys.argv[1:6]
    if action == "scan":
        asyncio.run(scan())
    else:
        asyncio.run(write(address, command(action, name, speed), verbose))


if __name__ == "__main__":
    main()