import time
import uuid
from sx1262 import SX1262

import uasyncio as asyncio
from queue import Queue


class FixedDeque:
    def __init__(self, maxlen):
        self.maxlen = maxlen
        self.data = []

    def append(self, x):
        if len(self.data) >= self.maxlen:
            self.data.pop(0)
        self.data.append(x)

    def __iter__(self):
        return iter(self.data)

class LoRaMessage:
    def __init__(self, sender_id: str, recipient_id: str, payload: bytes):
        self.sender_id = sender_id
        self.recipient_id = recipient_id
        self.payload = payload
        self.message_id = str(uuid.uuid4())
        self.lifetime = 7
        
    def encode(self) -> bytes:
        encoded = bytearray()
        
        encoded.append(len(self.sender_id))
        encoded.extend(self.sender_id.encode("utf-8"))
        
        encoded.append(len(self.recipient_id))
        encoded.extend(self.recipient_id.encode("utf-8"))
        
        encoded.extend(self.payload)
        
        return bytes(encoded)

    @staticmethod
    def decode(data: bytes):
        sender_id_len = data[0]
        sender_id = data[1:1+sender_id_len].decode("utf-8")
        
        recipient_id_len = data[1+sender_id_len]
        recipient_id = data[2+sender_id_len:2+sender_id_len+recipient_id_len].decode("utf-8")
        
        payload = data[2+sender_id_len+recipient_id_len:]
        
        return LoRaMessage(sender_id=sender_id, recipient_id=recipient_id, payload=payload)

class LoRaHandler:
    def __init__(self):
        print("Initializing LoRa...")
        
        self.my_id = str(uuid.uuid4())
        
        # initialize our radio, im using the HAT SX1262 hat for the pico
        self.radio = SX1262(spi_bus=1, clk=10, mosi=11, miso=12, cs=3, irq=20, rst=15, gpio=2)
        self.radio.begin(freq=915, bw=125, power=22)
        self.radio.setBlockingCallback(False, self.irq)
        
        self.recent_messages = FixedDeque(32)
        self.neighbours = set()
        self.message_queue = Queue()
            
    def send(self, data: bytes, recipient_id: str):
        msg_bytes = LoRaMessage(sender_id=self.my_id, recipient_id=recipient_id, payload=data).encode()
        self.radio.send(msg_bytes)
        
    def has_seen_message(self, msg: LoRaMessage) -> bool:
        if msg.message_id in self.recent_messages:
            return True
        self.recent_messages.append(msg.message_id)
        return False
        
    def forward(self, msg: LoRaMessage):
        # ensure we don't process a message twice
        if self.has_seen_message(msg):
            return
        
        msg_bytes = msg.encode()
        self.radio.send(msg_bytes)
        
    def advertise(self):
        # send an advertisement message to let neighbors know we're here
        self.send(b"ADVERTISE", recipient_id="BROADCAST")
        
    def on_receive(self, msg: LoRaMessage):
        # ensure we don't process a message twice
        if self.has_seen_message(msg):
            return
        
        # messages has a lifetime to prevent infinite loops.
        # if we receive a message with lifetime <= 0 we just drop it,
        # otherwise we decrement the lifetime and forward it to all
        # neighbors except the sender
        msg.lifetime -= 1
        if msg.lifetime <= 0:
            return
        
        # forward messages if they aren't meant for us
        
        if (msg.recipient_id != self.my_id) and msg.recipient_id != "BROADCAST":
            print("Forwarding message...")
            self.forward(msg)
            return
        
        if msg.payload == b"ADVERTISE":
            if not msg.sender_id in self.neighbours:
                print(f"Neighbour discovered: {msg.sender_id}")
                self.neighbours.add(msg.sender_id)
                
            # tell the sender we heard them by sending a ping back
            self.send(b"Ping!", msg.sender_id)
            self.forward(msg)
            return
        
        asyncio.create_task(self.message_queue.put(msg))
        
        
        
    def irq(self, events):
        #print(f"LORA EVENT: {events}")
        if events & SX1262.RX_DONE:
            msg, err = self.radio.recv()
            error = SX1262.STATUS[err]
            
            if error != "ERR_NONE":
                print(f"Error receiving message: {error}")
                return
            
            self.on_receive(LoRaMessage.decode(msg))
        elif events & SX1262.TX_DONE:
            pass
            #print('TX done.')