"""
Brian 2
"""

import logging
import signal


def _check_dependencies():
    """Check basic dependencies"""
    import sys

    missing = []
    try:
        import numpy
    except ImportError as ex:
        sys.stderr.write(f"Importing numpy failed: '{ex}'\n")
        missing.append("numpy")
    try:
        import sympy
    except ImportError as ex:
        sys.stderr.write(f"Importing sympy failed: '{ex}'\n")
        missing.append("sympy")
    try:
        import pyparsing
    except ImportError as ex:
        sys.stderr.write(f"Importing pyparsing failed: '{ex}'\n")
        missing.append("pyparsing")
    try:
        import jinja2
    except ImportError as ex:
        sys.stderr.write(f"Importing Jinja2 failed: '{ex}'\n")
        missing.append("jinja2")

    if len(missing):
        raise ImportError(
            f"Some required dependencies are missing:\n{', '.join(missing)}"
        )


_check_dependencies()

try:
    from pylab import *
except ImportError:
    # Do the non-matplotlib pylab imports manually
    # don't let numpy's datetime hide stdlib
    import datetime

    import numpy.ma as ma
    from numpy import *
    from numpy.fft import *
    from numpy.linalg import *
    from numpy.random import *

# Make sure that Brian's unit-aware functions are used, even when directly
# using names prefixed with numpy or np
import brian2.numpy_ as np
import brian2.numpy_ as numpy

try:
    from ._version import __version__, __version_tuple__
except ImportError:
    try:
        from setuptools_scm import get_version

        __version__ = get_version(
            root="..",
            relative_to=__file__,
            version_scheme="post-release",
            local_scheme="no-local-version",
        )
        __version_tuple__ = tuple(int(x) for x in __version__.split(".")[:3])
    except ImportError:
        logging.getLogger("brian2").warning(
            "Cannot determine Brian version, running from source and "
            "setuptools_scm is not installed."
        )
        __version__ = "unknown"
        __version_tuple__ = (0, 0, 0)

# delete some annoying names from the namespace
if "x" in globals():
    del x
if "f" in globals():
    del f
if "rate" in globals():
    del rate

__docformat__ = "restructuredtext en"

from brian2.only import *
from brian2.only import test

# Initialize the logging system
BrianLogger.initialize()
logger = get_logger(__name__)


# Check the caches
def _get_size_recursively(dirname):
    import os

    total_size = 0
    for dirpath, _, filenames in os.walk(dirname):
        for fname in filenames:
            # When other simulations are running, files may disappear while
            # we walk through the directory (in particular with Cython, where
            # we delete the source files after compilation by default)
            try:
                size = os.path.getsize(os.path.join(dirpath, fname))
                total_size += size
            except OSError:
                pass  # ignore the file
    return total_size


#: Stores the cache directory for code generation targets
_cache_dirs_and_extensions = {}


def check_cache(target):
    cache_dir, _ = _cache_dirs_and_extensions.get(target, (None, None))
    if cache_dir is None:
        return
    size = _get_size_recursively(cache_dir)
    size_in_mb = int(round(size / 1024.0 / 1024.0))
    if size_in_mb > prefs.codegen.max_cache_dir_size:
        logger.info(
            f"Cache size for target '{target}': {size_in_mb} MB.\n"
            f"You can call clear_cache('{target}') to delete all "
            "files from the cache or manually delete files in the "
            f"'{cache_dir}' directory."
        )
    else:
        logger.debug(f"Cache size for target '{target}': {size_in_mb} MB")


def clear_cache(target):
    """
    Clears the on-disk cache with the compiled files for a given code generation
    target.

    Parameters
    ----------
    target : str
        The code generation target (e.g. ``'cython'``)

    Raises
    ------
    ValueError
        If the given code generation target does not have an on-disk cache
    IOError
        If the cache directory contains unexpected files, suggesting that
        deleting it would also delete files unrelated to the cache.
    """
    import os
    import shutil

    cache_dir, extensions = _cache_dirs_and_extensions.get(target, (None, None))
    if cache_dir is None:
        raise ValueError(f'No cache directory registered for target "{target}".')
    cache_dir = os.path.abspath(cache_dir)  # just to make sure...
    for folder, _, files in os.walk(cache_dir):
        for f in files:
            for ext in extensions:
                if f.endswith(ext):
                    break
            else:
                raise OSError(
                    f"The cache directory for target '{target}' contains "
                    f"the file '{os.path.join(folder, f)}' of an unexpected type and "
                    "will therefore not be removed. Delete files in "
                    f"'{cache_dir}' manually"
                )
    if os.path.exists(cache_dir):
        logger.debug(f"Clearing cache for target '{target}' (directory '{cache_dir}').")
        shutil.rmtree(cache_dir)
    else:
        logger.debug(
            f"Cache for target '{target}' (directory '{cache_dir}') does not exist, nothing to clear."
        )


def _check_caches():
    from brian2.codegen.runtime.cython_rt.extension_manager import (
        get_cython_cache_dir,
        get_cython_extensions,
    )

    for target, (dirname, extensions) in [
        ("cython", (get_cython_cache_dir(), get_cython_extensions()))
    ]:
        _cache_dirs_and_extensions[target] = (dirname, extensions)
        if prefs.codegen.max_cache_dir_size > 0:
            check_cache(target)


_check_caches()


class _InterruptHandler:
    """
    Class to turn a Ctrl+C interruption (SIGINT signal) into a `stop` signal for
    a running simulation (i.e., finish simulating the current time step and then
    stop). This handler is activated by default, but can be switched off by
    setting the `core.stop_on_keyboard_interrupt` preference to ``False``.
    Note that this will only handle interruptions during a `Network.run`,
    interrupting at any other time will raise a `KeyboardInterrupt` in the
    usual way. In case that finishing the current time step takes a long time
    (or hangs for some reason), interrupting with Ctrl+C a second time will
    force the usual interrupt, regardless of the preference setting.
    """

    def __init__(self, previous_handler):
        self.previous_handler = previous_handler

    def __call__(self, signalnum, stack_frame):
        if (
            not prefs.core.stop_on_keyboard_interrupt
            or not Network._globally_running
            or Network._globally_stopped
        ):
            self.previous_handler(signalnum, stack_frame)
        else:
            logging.getLogger("brian2").warning(
                "Simulation stop requested. Press Ctrl+C again to interrupt."
            )
            Network._globally_stopped = True


_int_handler = _InterruptHandler(signal.getsignal(signal.SIGINT))
signal.signal(signal.SIGINT, _int_handler)
