import codecs
import os
import sys
import time
import unicodedata
from abc import ABC, abstractmethod
from contextlib import contextmanager
from queue import Empty, Queue
from typing import Any, Dict, Iterator
from xml.sax.saxutils import XMLGenerator
from xml.sax.xmlreader import AttributesImpl

from colorama import Fore, Style


class AbstractLogger(ABC):
    @abstractmethod
    def log(self, message: str, attributes: Dict[str, str] = {}) -> None:
        pass

    @abstractmethod
    @contextmanager
    def subtest(self, name: str, attributes: Dict[str, str] = {}) -> Iterator[None]:
        pass

    @abstractmethod
    @contextmanager
    def nested(self, message: str, attributes: Dict[str, str] = {}) -> Iterator[None]:
        pass

    @abstractmethod
    def info(self, *args, **kwargs) -> None:  # type: ignore
        pass

    @abstractmethod
    def warning(self, *args, **kwargs) -> None:  # type: ignore
        pass

    @abstractmethod
    def error(self, *args, **kwargs) -> None:  # type: ignore
        pass

    @abstractmethod
    def log_serial(self, message: str, machine: str) -> None:
        pass

    @abstractmethod
    def print_serial_logs(self, enable: bool) -> None:
        pass


class Logger(AbstractLogger):
    def __init__(self) -> None:
        self.logfile = os.environ.get("LOGFILE", "/dev/null")
        self.logfile_handle = codecs.open(self.logfile, "wb")
        self.xml = XMLGenerator(self.logfile_handle, encoding="utf-8")
        self.queue: "Queue[Dict[str, str]]" = Queue()

        self.xml.startDocument()
        self.xml.startElement("logfile", attrs=AttributesImpl({}))

        self._print_serial_logs = True

    def print_serial_logs(self, enable: bool) -> None:
        self._print_serial_logs = enable

    @staticmethod
    def _eprint(*args: object, **kwargs: Any) -> None:
        print(*args, file=sys.stderr, **kwargs)

    def close(self) -> None:
        self.xml.endElement("logfile")
        self.xml.endDocument()
        self.logfile_handle.close()

    def sanitise(self, message: str) -> str:
        return "".join(ch for ch in message if unicodedata.category(ch)[0] != "C")

    def maybe_prefix(self, message: str, attributes: Dict[str, str]) -> str:
        if "machine" in attributes:
            return f"{attributes['machine']}: {message}"
        return message

    def log_line(self, message: str, attributes: Dict[str, str]) -> None:
        self.xml.startElement("line", attrs=AttributesImpl(attributes))
        self.xml.characters(message)
        self.xml.endElement("line")

    def info(self, *args, **kwargs) -> None:  # type: ignore
        self.log(*args, **kwargs)

    def warning(self, *args, **kwargs) -> None:  # type: ignore
        self.log(*args, **kwargs)

    def error(self, *args, **kwargs) -> None:  # type: ignore
        self.log(*args, **kwargs)
        sys.exit(1)

    def log(self, message: str, attributes: Dict[str, str] = {}) -> None:
        self._eprint(self.maybe_prefix(message, attributes))
        self.drain_log_queue()
        self.log_line(message, attributes)

    def log_serial(self, message: str, machine: str) -> None:
        self.enqueue({"msg": message, "machine": machine, "type": "serial"})
        if self._print_serial_logs:
            self._eprint(Style.DIM + f"{machine} # {message}" + Style.RESET_ALL)

    def enqueue(self, item: Dict[str, str]) -> None:
        self.queue.put(item)

    def drain_log_queue(self) -> None:
        try:
            while True:
                item = self.queue.get_nowait()
                msg = self.sanitise(item["msg"])
                del item["msg"]
                self.log_line(msg, item)
        except Empty:
            pass

    @contextmanager
    def subtest(self, name: str, attributes: Dict[str, str] = {}) -> Iterator[None]:
        with self.nested("subtest: " + name, attributes):
            yield

    @contextmanager
    def nested(self, message: str, attributes: Dict[str, str] = {}) -> Iterator[None]:
        self._eprint(
            self.maybe_prefix(
                Style.BRIGHT + Fore.GREEN + message + Style.RESET_ALL, attributes
            )
        )

        self.xml.startElement("nest", attrs=AttributesImpl({}))
        self.xml.startElement("head", attrs=AttributesImpl(attributes))
        self.xml.characters(message)
        self.xml.endElement("head")

        tic = time.time()
        self.drain_log_queue()
        yield
        self.drain_log_queue()
        toc = time.time()
        self.log(f"(finished: {message}, in {toc - tic:.2f} seconds)")

        self.xml.endElement("nest")


rootlog: AbstractLogger = Logger()