import json


class UartClient:
    def __init__(self, uart):
        self.uart = uart
        self.buffer = ""

    def send_message(self, message):
        payload = json.dumps(message, separators=(",", ":")) + "\n"
        self.uart.write(payload.encode("utf-8"))

    def read_available_messages(self):
        messages = []

        while self.uart.any():
            chunk = self.uart.read()

            if not chunk:
                break

            self.buffer += chunk.decode("utf-8")

            while "\n" in self.buffer:
                line, self.buffer = self.buffer.split("\n", 1)
                line = line.strip()

                if not line:
                    continue

                try:
                    messages.append(json.loads(line))
                except ValueError:
                    messages.append({
                        "type": "error",
                        "message": "invalid_json",
                        "raw": line,
                    })

        return messages