# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import absolute_import

import collections
import struct
from datetime import datetime


class LogMessage(collections.namedtuple('LogMessage',
                 'log_level task timestamp file_name line_number message')):

    __slots__ = ()
    response_struct = struct.Struct('<c16sccQH')

    def __str__(self):
        msec_timestamp = self.timestamp.strftime("%H:%M:%S.%f")[:-3]
        template = ('{self.log_level} {self.task} {msec_timestamp} '
                    '{self.file_name}:{self.line_number}> {self.message}')

        return template.format(self=self, msec_timestamp=msec_timestamp)

    @classmethod
    def parse(cls, packet):
        result = cls.response_struct.unpack(packet[:cls.response_struct.size])
        msg = packet[cls.response_struct.size:].decode("utf8")

        log_level = result[2].decode("utf8")
        task = result[3].decode("utf8")
        timestamp = datetime.fromtimestamp(result[4] / 1000.0)
        file_name = result[1].split(b'\x00', 1)[0].decode("utf8")  # NUL terminated
        line_number = result[5]

        return cls(log_level, task, timestamp, file_name, line_number, msg)


class StreamingLogs(object):
    '''App for receiving log messages streamed by the firmware.
    '''

    PORT_NUMBER = 0x0003

    def __init__(self, interface):
        try:
            self.socket = interface.simplex_transport.open_socket(
                    self.PORT_NUMBER)
        except AttributeError:
            raise TypeError('LoggingApp must be bound directly '
                            'to an Interface, not a Link')

    def receive(self, block=True, timeout=None):
        return LogMessage.parse(self.socket.receive(block, timeout))

    def close(self):
        self.socket.close()