import argparse
import config
import getpass
import logging
import mqtt
import re
import report
import time

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

from mytui import MultiSelect

try:
    from config import APP_NAME as ROOT_LOGGER_NAME
except ImportError:
    ROOT_LOGGER_NAME = 'root'
logger = logging.getLogger(ROOT_LOGGER_NAME)


class MqttHandler(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 __get_logger__(self, prefix, topic):
        return logging.getLogger(ROOT_LOGGER_NAME).getChild(prefix + '.' + topic.replace('/', '.'))

    def __rx__(self, client, userdata, message):
        logger = self.__get_logger__('rx', message.topic)
        logger.debug("Received message: topic=%s, payload=%s type=%s", message.topic, repr(message.payload), repr(type(message.payload)))
        self.app.call_from_thread(self.app.add_log, message)

    def send(self, topic, payload):
        logger = self.__get_logger__('tx', topic)
        logger.debug("Sending message: topic=%s, payload=%s type=%s", topic, repr(payload), repr(type(payload)))
        self.mqtt_client.send(topic, payload)


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

    CSS_PATH = "style.tcss"
    BINDINGS = [
        ("q", "quit", "Quit"),
        ("c", "clear_screen", "Clear")
    ]
    MAX_LOGS = 1000

    def __init__(self, args, password):
        super().__init__()
        self.args = args
        self.password = password
        #
        self.mqtt = None
        self.all_logs = []
        self.__topic_selection__ = MultiSelect((), prompt="Full", id="topic_filter")
        self.send_topic = ""
        self.send_payload = ""
        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="filter-bar"):
            yield self.__topic_selection__
            yield Input(placeholder="Filter", id="select_filter")
        with Vertical(id="send-bar"):
            yield Input(placeholder="topic...", id="send_topic")
            yield Input(placeholder="payload...", id="send_payload")
            yield Button("Send", variant="success", id="send_button")
        yield Footer()

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

    def add_log(self, record) -> None:
        """Add new mqt messages and update the tui."""
        asctime = time.asctime()
        self.__topic_selection__.AddEntry(record.topic)
        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

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

            self.log_display.write(message)

    def action_clear_screen(self):
        self.all_logs = []
        self._update_display()

    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 tui inputs and execute task, if requireed."""
        if message.input.id == "select_filter":
            self.__topic_selection__.SetSelectionRegEx(message.value)
        elif message.input.id == "send_topic":
            self.send_topic = message.value
        elif message.input.id == "send_payload":
            self.send_payload = message.value

    def on_select_changed(self, message: Select.Changed) -> None:
        if message.select.id in ('topic_filter', ):
            self._update_display()

    def on_button_pressed(self, event: Button.Pressed) -> None:
        """Event handler called when a button is pressed."""
        if event.button.id == "send_button":
            if self.mqtt is not None:
                if len(self.send_topic) > 0:
                    self.mqtt.send(self.send_topic, self.send_payload)
                else:
                    logger.warning("Can't send mqtt message with empty topic. topic=%s; payload=%s", repr(self.send_topic), repr(self.send_payload))


if __name__ == "__main__":
    #
    # Logging
    #
    if config.DEBUG:
        report.add_handler_socket(logger)

    #
    # 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()