"""Text parser plugin for iOS sysdiag log files."""

import pyparsing

from dfdatetime import time_elements as dfdatetime_time_elements

from plaso.containers import events
from plaso.lib import errors
from plaso.parsers import text_parser
from plaso.parsers.text_plugins import interface


class IOSSysdiagLogEventData(events.EventData):
    """iOS sysdiagnose log event data.

    Attributes:
      message_body (str): message body.
      originating_call (str): call that created the entry.
      process_identifier (str): process_identifier.
      severity (str): severity of the message.
      written_time (dfdatetime.DateTimeValues): date and time the log entry was
          written.
    """

    DATA_TYPE = "ios:sysdiag_log:entry"

    def __init__(self):
        """Initializes event data."""
        super().__init__(data_type=self.DATA_TYPE)
        self.message_body = None
        self.originating_call = None
        self.process_identifier = None
        self.severity = None
        self.written_time = None


class IOSSysdiagLogTextPlugin(interface.TextPluginWithLineContinuation):
    """Text parser plugin for iOS mobile installation log files."""

    NAME = "ios_sysdiag_log"
    DATA_FORMAT = "iOS sysdiag log"

    _MONTH_DICT = {
        "jan": 1,
        "feb": 2,
        "mar": 3,
        "apr": 4,
        "may": 5,
        "jun": 6,
        "jul": 7,
        "aug": 8,
        "sep": 9,
        "oct": 10,
        "nov": 11,
        "dec": 12,
    }

    _INTEGER = pyparsing.Word(pyparsing.nums).set_parse_action(
        lambda tokens: int(tokens[0], 10)
    )

    _ONE_OR_TWO_DIGITS = pyparsing.Word(pyparsing.nums, max=2).set_parse_action(
        lambda tokens: int(tokens[0], 10)
    )

    _TWO_DIGITS = pyparsing.Word(pyparsing.nums, exact=2).set_parse_action(
        lambda tokens: int(tokens[0], 10)
    )

    _FOUR_DIGITS = pyparsing.Word(pyparsing.nums, exact=4).set_parse_action(
        lambda tokens: int(tokens[0], 10)
    )

    _THREE_LETTERS = pyparsing.Word(pyparsing.alphas, exact=3)

    # Date and time values are formatted as: Wed Aug 11 05:51:02 2021
    _DATE_TIME = (
        _THREE_LETTERS.suppress()
        + _THREE_LETTERS
        + _ONE_OR_TWO_DIGITS
        + _TWO_DIGITS
        + pyparsing.Suppress(":")
        + _TWO_DIGITS
        + pyparsing.Suppress(":")
        + _TWO_DIGITS
        + _FOUR_DIGITS
    )

    _ORIGINATING_CALL = pyparsing.Combine(
        pyparsing.Optional(
            pyparsing.Word("+-", exact=1)
            + pyparsing.Literal("[")
            + pyparsing.CharsNotIn("]")
            + pyparsing.Literal("]")
        )
        + pyparsing.Optional(pyparsing.CharsNotIn(":"))
    )

    _END_OF_LINE = pyparsing.Suppress(pyparsing.LineEnd())

    _LOG_LINE_START = (
        _DATE_TIME.set_results_name("date_time")
        + pyparsing.Suppress("[")
        + _INTEGER.set_results_name("process_identifier")
        + pyparsing.Suppress("]")
        + pyparsing.Suppress("<")
        + pyparsing.Word(pyparsing.alphanums).set_results_name("severity")
        + pyparsing.Suppress(">")
        + pyparsing.Suppress("(")
        + pyparsing.Word(pyparsing.alphanums).set_results_name("id")
        + pyparsing.Suppress(")")
        + _ORIGINATING_CALL.set_results_name("originating_call")
        + pyparsing.Suppress(": ")
    )

    _LOG_LINE = (
        _LOG_LINE_START
        + pyparsing.restOfLine().set_results_name("message_body")
        + _END_OF_LINE
    )

    _LINE_STRUCTURES = [("log_line", _LOG_LINE)]

    VERIFICATION_GRAMMAR = _LOG_LINE

    def __init__(self):
        """Initializes a text parser plugin."""
        super().__init__()
        self._body_lines = None
        self._event_data = None

    def _ParseFinalize(self, parser_mediator):
        """Finalizes parsing.

        Args:
          parser_mediator (ParserMediator): mediates interactions between parsers
              and other components, such as storage and dfVFS.
        """
        if self._event_data:
            self._event_data.message_body = " ".join(self._body_lines)
            self._body_lines = None

            parser_mediator.ProduceEventData(self._event_data)
            self._event_data = None

    def _ParseLogline(self, structure):
        """Parses a log line.

        Args:
          structure (pyparsing.ParseResults): structure of tokens derived from
              a line of a text file.
        """
        time_elements_structure = self._GetValueFromStructure(structure, "date_time")

        message_body = self._GetValueFromStructure(structure, "message_body")

        event_data = IOSSysdiagLogEventData()
        event_data.originating_call = self._GetValueFromStructure(
            structure, "originating_call"
        )
        event_data.process_identifier = self._GetValueFromStructure(
            structure, "process_identifier"
        )
        event_data.severity = self._GetValueFromStructure(structure, "severity")
        event_data.written_time = self._ParseTimeElements(time_elements_structure)

        self._event_data = event_data
        self._body_lines = [message_body]

    def _ParseRecord(self, parser_mediator, key, structure):
        """Parses a pyparsing structure.

        Args:
          parser_mediator (ParserMediator): mediates interactions between parsers
              and other components, such as storage and dfVFS.
          key (str): name of the parsed structure.
          structure (pyparsing.ParseResults): tokens from a parsed log line.

        Raises:
          ParseError: if the structure cannot be parsed.
        """
        if key == "_line_continuation":
            message_body = structure.replace("\n", " ").strip()
            self._body_lines.append(message_body)

        else:
            if self._event_data:
                self._event_data.message_body = " ".join(self._body_lines)

                parser_mediator.ProduceEventData(self._event_data)

            self._ParseLogline(structure)

    def _ParseTimeElements(self, time_elements_structure):
        """Parses date and time elements of a log line.

        Args:
          time_elements_structure (pyparsing.ParseResults): date and time elements
              of a log line.

        Returns:
          dfdatetime.TimeElements: date and time value.

        Raises:
          ParseError: if a valid date and time value cannot be derived from
              the time elements.
        """
        try:
            month_string, day_of_month, hours, minutes, seconds, year = (
                time_elements_structure
            )

            month = self._MONTH_DICT.get(month_string.lower(), 0)

            time_elements_tuple = (year, month, day_of_month, hours, minutes, seconds)

            return dfdatetime_time_elements.TimeElements(
                time_elements_tuple=time_elements_tuple
            )

        except (IndexError, TypeError, ValueError) as exception:
            raise errors.ParseError(
                f"Unable to parse time elements with error: {exception!s}"
            )

    def _ResetState(self):
        """Resets stored values."""
        self._body_lines = None
        self._event_data = None

    def CheckRequiredFormat(self, parser_mediator, text_reader):
        """Check if the log record has the minimal structure required by the parser.

        Args:
          parser_mediator (ParserMediator): mediates interactions between parsers
              and other components, such as storage and dfVFS.
          text_reader (EncodedTextReader): text reader.

        Returns:
          bool: True if this is the correct plugin, False otherwise.
        """
        try:
            structure = self._VerifyString(text_reader.lines)
        except errors.ParseError:
            return False

        time_elements_structure = self._GetValueFromStructure(structure, "date_time")

        try:
            self._ParseTimeElements(time_elements_structure)
        except errors.ParseError:
            return False

        self._ResetState()

        return True


text_parser.TextLogParser.RegisterPlugin(IOSSysdiagLogTextPlugin)
