import sys
import asyncio

if sys.version_info >= (3, 7):
    from asyncio import get_running_loop
else:
    from asyncio import get_event_loop as get_running_loop
import concurrent
import copy
import functools
import inspect
import logging
import os
import os.path
import re
import tempfile
import threading
from importlib import import_module
from importlib import reload  # requires >= py 3.4
from random import random

import pythoncom
import pywintypes
from win32com.client import Dispatch

import xlwings
from . import conversion, Range, apps, Book, PRO, LicenseError
from .utils import VBAWriter, exception, get_cached_user_config

if PRO:
    from .pro.embedded_code import dump_embedded_code, get_udf_temp_dir
    from .pro import verify_execute_permission

logger = logging.getLogger(__name__)
cache = {}

if sys.version_info >= (3, 7):
    com_executor = concurrent.futures.ThreadPoolExecutor(
        initializer=pythoncom.CoInitialize
    )

    def backcompat_check_com_initialized():
        pass

else:
    com_executor = concurrent.futures.ThreadPoolExecutor()
    com_is_initialized = threading.local()

    def backcompat_check_com_initialized():
        try:
            com_is_initialized.done
        except AttributeError:
            pythoncom.CoInitialize()
            com_is_initialized.done = True


async def async_thread(base, my_has_dynamic_array, func, args, cache_key, expand):
    backcompat_check_com_initialized()

    try:
        if expand:
            stashme = await base.get_formula_array()
        elif my_has_dynamic_array:
            stashme = await base.get_formula2()
        else:
            stashme = await base.get_formula()

        loop = get_running_loop()
        cache[cache_key] = await loop.run_in_executor(
            com_executor, functools.partial(func, *args)
        )

        if expand:
            await base.set_formula_array(stashme)
        elif my_has_dynamic_array:
            await base.set_formula2(stashme)
        else:
            await base.set_formula(stashme)
    except:
        exception(logger, "async_thread failed")


def func_sig(f):
    s = inspect.signature(f)
    vararg = None
    args = []
    defaults = []
    for p in s.parameters.values():
        if p.kind is inspect.Parameter.POSITIONAL_OR_KEYWORD:
            args.append(p.name)
            if p.default is not inspect.Signature.empty:
                defaults.append(p.default)
        elif p.kind is inspect.Parameter.VAR_POSITIONAL:
            args.append(p.name)
            vararg = p.name
        else:
            raise Exception("xlwings does not support UDFs with keyword arguments")
    return {"args": args, "defaults": defaults, "vararg": vararg}


def get_category(**func_kwargs):
    if "category" in func_kwargs:
        category = func_kwargs.pop("category")
        if isinstance(category, int):
            if 1 <= category <= 14:
                return category
            raise Exception(
                "There is only 14 build-in categories available in Excel. "
                "Please use a string value to specify a custom category."
            )
        if isinstance(category, str):
            return category[:255]
        raise Exception(
            "Category {0} should either be a predefined Excel category (int value) "
            "or a custom one (str value).".format(category)
        )
    return "xlwings"  # Default category


def get_async_mode(**func_kwargs):
    if "async_mode" in func_kwargs:
        value = func_kwargs.pop("async_mode")
        if value in ["threading"]:
            return value
        raise Exception('The only supported async_mode mode is currently "threading".')
    else:
        return None


def check_bool(kw, default, **func_kwargs):
    if kw in func_kwargs:
        check = func_kwargs.pop(kw)
        if isinstance(check, bool):
            return check
        raise Exception(
            '{0} only takes boolean values. ("{1}" provided).'.format(kw, check)
        )
    return default


def xlfunc(f=None, **kwargs):
    def inner(f):
        if not hasattr(f, "__xlfunc__"):
            xlf = f.__xlfunc__ = {}
            xlf["name"] = f.__name__
            xlf["sub"] = False
            xlargs = xlf["args"] = []
            xlargmap = xlf["argmap"] = {}
            sig = func_sig(f)
            nArgs = len(sig["args"])
            nDefaults = len(sig["defaults"])
            nRequiredArgs = nArgs - nDefaults
            if sig["vararg"] and nDefaults > 0:
                raise Exception(
                    "xlwings does not support UDFs "
                    "with both optional and variable length arguments"
                )
            for vpos, vname in enumerate(sig["args"]):
                arg_info = {
                    "name": vname,
                    "pos": vpos,
                    "vba": None,
                    "doc": "Positional argument " + str(vpos + 1),
                    "vararg": vname == sig["vararg"],
                    "options": {},
                }
                if vpos >= nRequiredArgs:
                    arg_info["optional"] = sig["defaults"][vpos - nRequiredArgs]
                xlargs.append(arg_info)
                xlargmap[vname] = xlargs[-1]
            xlf["ret"] = {
                "doc": f.__doc__
                if f.__doc__ is not None
                else "Python function '"
                + f.__name__
                + "' defined in '"
                + str(f.__code__.co_filename)
                + "'.",
                "options": {},
            }
        f.__xlfunc__["category"] = get_category(**kwargs)
        f.__xlfunc__["call_in_wizard"] = check_bool(
            "call_in_wizard", default=True, **kwargs
        )
        f.__xlfunc__["volatile"] = check_bool("volatile", default=False, **kwargs)
        f.__xlfunc__["async_mode"] = get_async_mode(**kwargs)
        return f

    if f is None:
        return inner
    else:
        return inner(f)


def xlsub(f=None, **kwargs):
    def inner(f):
        f = xlfunc(**kwargs)(f)
        f.__xlfunc__["sub"] = True
        return f

    if f is None:
        return inner
    else:
        return inner(f)


def xlret(convert=None, **kwargs):
    if convert is not None:
        kwargs["convert"] = convert

    def inner(f):
        xlf = xlfunc(f).__xlfunc__
        xlr = xlf["ret"]
        xlr["options"].update(kwargs)
        return f

    return inner


def xlarg(arg, convert=None, **kwargs):
    if convert is not None:
        kwargs["convert"] = convert

    def inner(f):
        xlf = xlfunc(f).__xlfunc__
        if arg not in xlf["argmap"]:
            raise Exception("Invalid argument name '" + arg + "'.")
        xla = xlf["argmap"][arg]
        for special in ("vba", "doc"):
            if special in kwargs:
                xla[special] = kwargs.pop(special)
        xla["options"].update(kwargs)
        return f

    return inner


udf_modules = {}

RPC_E_SERVERCALL_RETRYLATER = {-2147418111, -2146777998}
MAX_BACKOFF_MS = 512


class ComRange(Range):
    """
    A Range subclass that stores the impl as
    a serialized COM object so it can be passed between
    threads easily

    https://devblogs.microsoft.com/oldnewthing/20151021-00/?p=91311
    """

    def __init__(self, rng):
        super().__init__(impl=rng.impl)

        self._ser_thread = threading.get_ident()
        self._ser = pythoncom.CoMarshalInterThreadInterfaceInStream(
            pythoncom.IID_IDispatch, rng.api
        )
        self._ser_resultCLSID = self._impl.api.CLSID

        self._deser_thread = None
        self._deser = None

    @property
    def impl(self):
        if threading.get_ident() == self._ser_thread:
            return self._impl
        elif threading.get_ident() == self._deser_thread:
            return self._deser

        assert self._deser is None, f"already deserialized on {self._deser_thread}"
        self._deser_thread = threading.get_ident()

        deser = pythoncom.CoGetInterfaceAndReleaseStream(
            self._ser, pythoncom.IID_IDispatch
        )
        dispatch = Dispatch(deser, resultCLSID=self._ser_resultCLSID)

        self._ser = None  # single-use
        self._deser = xlwings._xlwindows.Range(xl=dispatch)

        return self._deser

    def __copy__(self):
        """
        We need to re-serialize the COM object as they're
        single-use
        """
        return ComRange(self)

    async def _com(self, fn, *args, backoff=1):
        """
        :param backoff: if the call fails, time to wait in ms
          before the next one. Random exponential backoff to
          a cap.
        """

        loop = get_running_loop()

        if sys.version_info[:2] <= (3, 6):

            def _fn(fn, *args):
                backcompat_check_com_initialized()
                return fn(*args)

            fn = functools.partial(_fn, fn)

        try:
            return await loop.run_in_executor(
                com_executor, functools.partial(fn, copy.copy(self), *args)
            )
        except AttributeError:
            # the Dispatch object that the `com_executor` thread
            # didn't deserialize properly, as Excel was too busy
            # to handle the TypeInfo call when requested
            pass
        except Exception as e:
            if getattr(e, "hresult", 0) not in RPC_E_SERVERCALL_RETRYLATER:
                raise

        await asyncio.sleep(backoff / 1e3)
        return await self._com(
            fn, *args, backoff=min(backoff * round(1 + random()), MAX_BACKOFF_MS)
        )

    async def clear_contents(self):
        await self._com(lambda rng: rng.impl.clear_contents())

    async def set_formula_array(self, f):
        await self._com(lambda rng: setattr(rng.impl, "formula_array", f))

    async def set_formula(self, f):
        await self._com(lambda rng: setattr(rng.impl, "formula", f))

    async def set_formula2(self, f):
        await self._com(lambda rng: setattr(rng.impl, "formula2", f))

    async def get_shape(self):
        return await self._com(lambda rng: rng.impl.shape)

    async def get_formula_array(self):
        return await self._com(lambda rng: rng.impl.formula_array)

    async def get_formula(self):
        return await self._com(lambda rng: rng.impl.formula)

    async def get_formula2(self):
        return await self._com(lambda rng: rng.impl.formula2)

    async def get_address(self):
        return await self._com(lambda rng: rng.impl.address)


async def delayed_resize_dynamic_array_formula(target_range, caller):
    try:
        await asyncio.sleep(0.1)

        stashme = await caller.get_formula_array()
        if not stashme:
            stashme = await caller.get_formula()

        c_y, c_x = await caller.get_shape()
        t_y, t_x = await target_range.get_shape()
        if c_x > t_x or c_y > t_y:
            await caller.clear_contents()

        # this will call the UDF again (hitting the cache),
        # but you'll have the right size output this time
        # (`caller` will be `target_range`). We'll have to
        # be careful not to block the async loop!
        await target_range.set_formula_array(stashme)

    except:
        exception(logger, "couldn't resize")


# Setup temp dir for embedded code
if PRO:
    tempdir = get_udf_temp_dir()
    sys.path[0:0] = [tempdir.name]  # required for permissioning


def get_udf_module(module_name, xl_workbook):
    module_info = udf_modules.get(module_name, None)
    if module_info is not None:
        module = module_info["module"]
        # If filetime is None, it's not reloadable
        if module_info["filetime"] is not None:
            mtime = os.path.getmtime(module_info["filename"])
            if mtime != module_info["filetime"]:
                module = reload(module)
                module_info["filetime"] = mtime
                module_info["module"] = module
    else:
        # Handle embedded code (Excel only)
        if xl_workbook:
            wb = Book(impl=xlwings._xlwindows.Book(Dispatch(xl_workbook)))
            for sheet in wb.sheets:
                if sheet.name.endswith(".py") and not PRO:
                    raise LicenseError("Embedded code requires a valid LICENSE_KEY.")
                elif PRO:
                    dump_embedded_code(wb, tempdir.name)

        # Permission check
        if (
            get_cached_user_config("permission_check_enabled")
            and get_cached_user_config("permission_check_enabled").lower()
        ) == "true":
            if not PRO:
                raise LicenseError("Permission checks require xlwings PRO.")
            verify_execute_permission(module_names=(module_name,))

        module = import_module(module_name)
        filename = os.path.normcase(module.__file__.lower())

        try:  # getmtime fails for zip imports and frozen modules
            mtime = os.path.getmtime(filename)
        except OSError:
            mtime = None

        udf_modules[module_name] = {
            "filename": filename,
            "filetime": mtime,
            "module": module,
        }

    return module


def get_cache_key(func, args, caller):
    """only use this if function is called from cells, not VBA"""
    xw_caller = Range(impl=xlwings._xlwindows.Range(xl=caller))
    return (
        func.__name__
        + str(args)
        + str(xw_caller.sheet.book.app.pid)
        + xw_caller.sheet.book.name
        + xw_caller.sheet.name
        + xw_caller.address.split(":")[0]
    )


def call_udf(module_name, func_name, args, this_workbook=None, caller=None):
    """
    This method executes the UDF synchronously from the COM server thread
    """
    if (
        get_cached_user_config("permission_check_enabled")
        and get_cached_user_config("permission_check_enabled").lower() == "true"
    ):
        if not PRO:
            raise LicenseError("Permission checks require xlwings PRO.")
        verify_execute_permission(module_names=(module_name,))
    module = get_udf_module(module_name, this_workbook)
    func = getattr(module, func_name)
    func_info = func.__xlfunc__
    args_info = func_info["args"]
    ret_info = func_info["ret"]
    is_dynamic_array = ret_info["options"].get("expand")
    xw_caller = Range(impl=xlwings._xlwindows.Range(xl=caller))

    # If there is the 'reserved' argument "caller", assign the caller object
    for info in args_info:
        if info["name"] == "caller":
            args = list(args)
            args[info["pos"]] = ComRange(xw_caller)
            args = tuple(args)

    writing = func_info.get("writing", None)
    if writing and writing == xw_caller.address:
        return func_info["rval"]

    output_param_indices = []

    args = list(args)
    for i, arg in enumerate(args):
        arg_info = args_info[min(i, len(args_info) - 1)]
        if type(arg) is int and arg == -2147352572:  # missing
            args[i] = arg_info.get("optional", None)
        elif xlwings._xlwindows.is_range_instance(arg):
            if arg_info.get("output", False):
                output_param_indices.append(i)
                args[i] = OutputParameter(
                    Range(impl=xlwings._xlwindows.Range(xl=arg)),
                    arg_info["options"],
                    func,
                    caller,
                )
            else:
                args[i] = conversion.read(
                    Range(impl=xlwings._xlwindows.Range(xl=arg)),
                    None,
                    arg_info["options"],
                )
        else:
            args[i] = conversion.read(None, arg, arg_info["options"])
    if this_workbook:
        xlwings._xlwindows.BOOK_CALLER = Dispatch(this_workbook)

    from .server import loop

    if func_info["async_mode"] and func_info["async_mode"] == "threading":
        cache_key = get_cache_key(func, args, caller)
        cached_value = cache.get(cache_key)
        if (
            cached_value is not None
        ):  # test against None as np arrays don't have a truth value
            if not is_dynamic_array:  # for dynamic arrays, the cache is cleared below
                del cache[cache_key]
            ret = cached_value
        else:
            ret = [["#N/A waiting..." * xw_caller.columns.count] * xw_caller.rows.count]

            # this does a lot of nested COM calls, so do this all
            # synchronously on the COM thread until there is async
            # support for Sheet, Book & App.
            my_has_dynamic_array = has_dynamic_array(xw_caller.sheet.book.app.pid)

            asyncio.run_coroutine_threadsafe(
                async_thread(
                    ComRange(xw_caller),
                    my_has_dynamic_array,
                    func,
                    args,
                    cache_key,
                    is_dynamic_array,
                ),
                loop,
            )
            return ret
    else:

        if is_dynamic_array:
            cache_key = get_cache_key(func, args, caller)
            cached_value = cache.get(cache_key)
            if cached_value is not None:
                ret = cached_value
            else:
                if inspect.iscoroutinefunction(func):
                    ret = asyncio.run_coroutine_threadsafe(func(*args), loop).result()
                else:
                    ret = func(*args)
                cache[cache_key] = ret
        elif inspect.iscoroutinefunction(func):
            ret = asyncio.run_coroutine_threadsafe(func(*args), loop).result()
        else:
            ret = func(*args)

    xl_result = conversion.write(ret, None, ret_info["options"])

    if is_dynamic_array:
        current_size = (len(xw_caller.rows), len(xw_caller.columns))
        result_size = (1, 1)
        if type(xl_result) is list:
            result_height = len(xl_result)
            result_width = result_height and len(xl_result[0])
            result_size = (max(1, result_height), max(1, result_width))
        if current_size != result_size:
            target_range = xw_caller.resize(*result_size)

            asyncio.run_coroutine_threadsafe(
                delayed_resize_dynamic_array_formula(
                    target_range=ComRange(target_range), caller=ComRange(xw_caller)
                ),
                loop,
            )
        else:
            del cache[cache_key]

    return xl_result


def generate_vba_wrapper(module_name, module, f, xl_workbook):

    vba = VBAWriter(f)

    for svar in map(lambda attr: getattr(module, attr), dir(module)):
        if hasattr(svar, "__xlfunc__"):
            xlfunc = svar.__xlfunc__
            xlret = xlfunc["ret"]
            fname = xlfunc["name"]
            call_in_wizard = xlfunc["call_in_wizard"]
            volatile = xlfunc["volatile"]

            ftype = "Sub" if xlfunc["sub"] else "Function"

            func_sig = ftype + " " + fname + "("

            first = True
            vararg = ""
            n_args = len(xlfunc["args"])
            for arg in xlfunc["args"]:
                if arg["name"] == "caller":
                    arg[
                        "vba"
                    ] = "Nothing"  # will be replaced with caller under call_udf
                if not arg["vba"]:
                    argname = arg["name"]
                    if not first:
                        func_sig += ", "
                    if "optional" in arg:
                        func_sig += "Optional "
                    elif arg["vararg"]:
                        func_sig += "ParamArray "
                        vararg = argname
                    func_sig += argname
                    if arg["vararg"]:
                        func_sig += "()"
                    first = False
            func_sig += ")"

            with vba.block(func_sig):

                if ftype == "Function":
                    if not call_in_wizard:
                        vba.writeln(
                            'If (Not Application.CommandBars("Standard")'
                            ".Controls(1).Enabled) Then Exit Function"
                        )
                    if volatile:
                        vba.writeln("Application.Volatile")

                if vararg != "":
                    vba.writeln("Dim argsArray() As Variant")
                    non_varargs = [
                        arg["vba"] or arg["name"]
                        for arg in xlfunc["args"]
                        if not arg["vararg"]
                    ]
                    vba.writeln(
                        "argsArray = Array(%s)" % tuple({", ".join(non_varargs)})
                    )

                    vba.writeln(
                        "ReDim Preserve argsArray(0 to UBound("
                        + vararg
                        + ") - LBound("
                        + vararg
                        + ") + "
                        + str(len(non_varargs))
                        + ")"
                    )
                    vba.writeln(
                        "For k = LBound(" + vararg + ") To UBound(" + vararg + ")"
                    )
                    vba.writeln(
                        "argsArray("
                        + str(len(non_varargs))
                        + " + k - LBound("
                        + vararg
                        + ")) = "
                        + argname
                        + "(k)"
                    )
                    vba.writeln("Next k")

                    args_vba = "argsArray"
                else:
                    args_vba = (
                        "Array("
                        + ", ".join(arg["vba"] or arg["name"] for arg in xlfunc["args"])
                        + ")"
                    )

                # Add-ins work with ActiveWorkbook instead of ThisWorkbook
                vba_workbook = (
                    "ActiveWorkbook"
                    if xl_workbook.Name.endswith(".xlam")
                    else "ThisWorkbook"
                )

                if ftype == "Sub":
                    with vba.block('#If App = "Microsoft Excel" Then'):
                        vba.writeln(
                            'Py.CallUDF "{module_name}", "{fname}", '
                            "{args_vba}, {vba_workbook}, Application.Caller",
                            module_name=module_name,
                            fname=fname,
                            args_vba=args_vba,
                            vba_workbook=vba_workbook,
                        )
                    with vba.block("#Else"):
                        vba.writeln(
                            'Py.CallUDF "{module_name}", "{fname}", {args_vba}',
                            module_name=module_name,
                            fname=fname,
                            args_vba=args_vba,
                        )
                    vba.writeln("#End If")
                else:
                    with vba.block('#If App = "Microsoft Excel" Then'):
                        vba.writeln(
                            "If TypeOf Application.Caller Is Range Then "
                            "On Error GoTo failed"
                        )
                        vba.writeln(
                            '{fname} = Py.CallUDF("{module_name}", "{fname}", '
                            "{args_vba}, {vba_workbook}, Application.Caller)",
                            module_name=module_name,
                            fname=fname,
                            args_vba=args_vba,
                            vba_workbook=vba_workbook,
                        )
                        vba.writeln("Exit " + ftype)
                    with vba.block("#Else"):
                        vba.writeln(
                            '{fname} = Py.CallUDF("{module_name}", '
                            '"{fname}", {args_vba})',
                            module_name=module_name,
                            fname=fname,
                            args_vba=args_vba,
                        )
                        vba.writeln("Exit " + ftype)
                    vba.writeln("#End If")

                    vba.write_label("failed")
                    vba.writeln(fname + " = Err.Description")

            vba.writeln("End " + ftype)
            vba.writeln("")


def import_udfs(module_names, xl_workbook):
    module_names = module_names.split(";")

    tf = tempfile.NamedTemporaryFile(mode="w", delete=False)

    vba = VBAWriter(tf.file)

    vba.writeln('Attribute VB_Name = "xlwings_udfs"')

    vba.writeln(
        "'Autogenerated code by xlwings - changes will be lost with next import!"
    )
    vba.writeln(
        """#Const App = "Microsoft Excel" 'Adjust when using outside of Excel"""
    )

    for module_name in module_names:
        module = get_udf_module(module_name, xl_workbook)
        generate_vba_wrapper(module_name, module, tf.file, xl_workbook)

    tf.close()

    try:
        xl_workbook.VBProject.VBComponents.Remove(
            xl_workbook.VBProject.VBComponents("xlwings_udfs")
        )
    except pywintypes.com_error:
        pass

    try:
        xl_workbook.VBProject.VBComponents.Import(tf.name)
    except pywintypes.com_error:
        # Fallback. Some users get in Excel "Automation error 440" with this traceback
        # in Python: pywintypes.com_error: (-2147352567, 'Exception occurred.',
        #                                  (0, None, None, None, 0, -2146827284), None)
        xl_workbook.Application.Run("ImportXlwingsUdfsModule", tf.name)

    for module_name in module_names:
        module = get_udf_module(module_name, xl_workbook)
        for mvar in map(lambda attr: getattr(module, attr), dir(module)):
            if hasattr(mvar, "__xlfunc__"):
                xlfunc = mvar.__xlfunc__
                xlret = xlfunc["ret"]
                xlargs = xlfunc["args"]
                fname = xlfunc["name"]
                fdoc = xlret["doc"][:255]
                fcategory = xlfunc["category"]

                excel_version = [
                    int(x) for x in re.split("[,\\.]", xl_workbook.Application.Version)
                ]
                if excel_version[0] >= 14:
                    argdocs = [arg["doc"][:255] for arg in xlargs if not arg["vba"]]
                    xl_workbook.Application.MacroOptions(
                        "'" + xl_workbook.Name + "'!" + fname,
                        Description=fdoc,
                        HasMenu=False,
                        MenuText=None,
                        HasShortcutKey=False,
                        ShortcutKey=None,
                        Category=fcategory,
                        StatusBar=None,
                        HelpContextID=None,
                        HelpFile=None,
                        ArgumentDescriptions=argdocs if argdocs else None,
                    )
                else:
                    xl_workbook.Application.MacroOptions(
                        "'" + xl_workbook.Name + "'!" + fname, Description=fdoc
                    )

    # try to delete the temp file - doesn't matter too much if it fails
    try:
        os.unlink(tf.name)
    except:
        pass
    msg = f'Imported functions from the following modules: {", ".join(module_names)}'
    logger.info(msg) if logger.hasHandlers() else print(msg)


@functools.lru_cache(None)
def has_dynamic_array(pid):
    """This check in this form doesn't work on macOS,
    that's why it's here and not in utils
    """
    try:
        apps[pid].api.WorksheetFunction.Unique("dummy")
        return True
    except (AttributeError, pywintypes.com_error) as e:
        return False
