import argparse
import getpass
import logging
import json
import mqtt
import time

from textual.app import App, ComposeResult
from textual.containers import Vertical
from textual.widgets import Footer, Header, Input, RichLog


# TODO: Usage of multiple regex for topic filter
# TODO: Integrate sending of message (topic + payload)

class MqttReceiver(object):
    def __init__(self, app):
        self.app = app
        args = app.args
        password = app.password

        self.mqtt_client = mqtt.mqtt_client('mqtt_sniffer', args.hostname, args.port, username=args.username, password=password)
        self.mqtt_client.add_callback("#", self.__rx__)

    def __rx__(self, client, userdata, message):
        self.app.call_from_thread(self.app.add_log, message)


class MqttSniffer(App):
    """a textual application for viewing mqtt messages."""

    CSS_PATH = "style.tcss"
    BINDINGS = [("q", "quit", "Quit")]
    MAX_LOGS = 50

    def __init__(self, args, password):
        super().__init__()
        self.args = args
        self.password = password
        #
        self.all_logs = []
        self.topic_filter = ""
        self.log_display = RichLog(highlight=True, markup=True)

    def compose(self) -> ComposeResult:
        """Create the widgets for the application."""
        yield Header(name="Python Log Viewer")
        with Vertical(id="app-grid"):
            yield self.log_display
        with Vertical(id="bottom-bar"):
            yield Input(placeholder="topic filter...", id="topic_filter")
        yield Footer()

    def on_mount(self) -> None:
        """start the mqtt receiver."""
        MqttReceiver(self)

    def add_log(self, record) -> None:
        """Add new mqt messages and update the tui."""
        asctime = time.asctime()
        self.all_logs.append((asctime, record))
        if len(self.all_logs) > self.MAX_LOGS:
            self.all_logs = self.all_logs[-self.MAX_LOGS:]
        self._apply_filters_to_log((asctime, record))

    def _apply_filters_to_log(self, data: logging.LogRecord):
        asctime, record = data
        """filter the mqtt messages."""
        topic_match = False
        for topic_filter in self.topic_filter.split(","):
            topic_match |= topic_filter.lower() in record.topic.lower()

        if topic_match:
            try:
                payload = json.loads(record.payload)
            except:
                payload = record.payload.decode('utf-8')

            message = (
                f"[[dim]{asctime}[/dim]] "
                f"[bold]{record.topic}[/bold] - "
                f"{repr(payload)}"
            )

            self.log_display.write(message)

    def _update_display(self):
        """Clean the display and render all mqtt messages based on the current filters."""
        self.log_display.clear()
        for record in self.all_logs:
            self._apply_filters_to_log(record)

    def on_input_changed(self, message: Input.Changed) -> None:
        """Update the filter and filtered messages after the user did changes."""
        if message.input.id == "topic_filter":
            self.topic_filter = message.value

        self._update_display()


if __name__ == "__main__":
    #
    # Parse Arguments
    #
    parser = argparse.ArgumentParser(description='This is a mqtt sniffer.')
    parser.add_argument('-f', dest='hostname', default='localhost', help='Hostname of the mqtt server')
    parser.add_argument('-p', dest='port', default=1883, type=int, help='Port of the mqtt server')
    parser.add_argument('-n', dest='no_credentials', action='store_true', help='Avoid asking for credentials')
    parser.add_argument('-u', dest='username', default=None, help='Set username for mqtt server')
    parser.add_argument('-t', dest='topicfilter', default="", help='Set topic filter')
    parser.add_argument('-l', dest='logtofile', action='store_true', help='Enable logging to file')

    args = parser.parse_args()

    #
    # Ask for credentials
    #
    if not args.no_credentials:
        if args.username == None:
            args.username = input("Username: ")
        password = getpass.getpass(prompt='Password: ', stream=None)
    else:
        args.username = None
        password = None

    #
    # Start Application
    #
    app = MqttSniffer(args, password)
    app.run()