# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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 pyarrow._compute import (  # noqa
    Function,
    FunctionOptions,
    FunctionRegistry,
    HashAggregateFunction,
    HashAggregateKernel,
    Kernel,
    ScalarAggregateFunction,
    ScalarAggregateKernel,
    ScalarFunction,
    ScalarKernel,
    VectorFunction,
    VectorKernel,
    # Option classes
    ArraySortOptions,
    AssumeTimezoneOptions,
    CastOptions,
    CountOptions,
    CumulativeOptions,
    CumulativeSumOptions,
    DayOfWeekOptions,
    DictionaryEncodeOptions,
    RunEndEncodeOptions,
    ElementWiseAggregateOptions,
    ExtractRegexOptions,
    FilterOptions,
    IndexOptions,
    JoinOptions,
    ListSliceOptions,
    ListFlattenOptions,
    MakeStructOptions,
    MapLookupOptions,
    MatchSubstringOptions,
    ModeOptions,
    NullOptions,
    PadOptions,
    PairwiseOptions,
    PartitionNthOptions,
    QuantileOptions,
    RandomOptions,
    RankOptions,
    ReplaceSliceOptions,
    ReplaceSubstringOptions,
    RoundBinaryOptions,
    RoundOptions,
    RoundTemporalOptions,
    RoundToMultipleOptions,
    ScalarAggregateOptions,
    SelectKOptions,
    SetLookupOptions,
    SliceOptions,
    SortOptions,
    SplitOptions,
    SplitPatternOptions,
    StrftimeOptions,
    StrptimeOptions,
    StructFieldOptions,
    TakeOptions,
    TDigestOptions,
    TrimOptions,
    Utf8NormalizeOptions,
    VarianceOptions,
    WeekOptions,
    # Functions
    call_function,
    function_registry,
    get_function,
    list_functions,
    # Udf
    call_tabular_function,
    register_scalar_function,
    register_tabular_function,
    register_aggregate_function,
    register_vector_function,
    UdfContext,
    # Expressions
    Expression,
)

from collections import namedtuple
import inspect
from textwrap import dedent
import warnings

import pyarrow as pa
from pyarrow import _compute_docstrings
from pyarrow.vendored import docscrape


def _get_arg_names(func):
    return func._doc.arg_names


_OptionsClassDoc = namedtuple('_OptionsClassDoc', ('params',))


def _scrape_options_class_doc(options_class):
    if not options_class.__doc__:
        return None
    doc = docscrape.NumpyDocString(options_class.__doc__)
    return _OptionsClassDoc(doc['Parameters'])


def _decorate_compute_function(wrapper, exposed_name, func, options_class):
    # Decorate the given compute function wrapper with useful metadata
    # and documentation.
    cpp_doc = func._doc

    wrapper.__arrow_compute_function__ = dict(
        name=func.name,
        arity=func.arity,
        options_class=cpp_doc.options_class,
        options_required=cpp_doc.options_required)
    wrapper.__name__ = exposed_name
    wrapper.__qualname__ = exposed_name

    doc_pieces = []

    # 1. One-line summary
    summary = cpp_doc.summary
    if not summary:
        arg_str = "arguments" if func.arity > 1 else "argument"
        summary = ("Call compute function {!r} with the given {}"
                   .format(func.name, arg_str))

    doc_pieces.append(f"{summary}.\n\n")

    # 2. Multi-line description
    description = cpp_doc.description
    if description:
        doc_pieces.append(f"{description}\n\n")

    doc_addition = _compute_docstrings.function_doc_additions.get(func.name)

    # 3. Parameter description
    doc_pieces.append(dedent("""\
        Parameters
        ----------
        """))

    # 3a. Compute function parameters
    arg_names = _get_arg_names(func)
    for arg_name in arg_names:
        if func.kind in ('vector', 'scalar_aggregate'):
            arg_type = 'Array-like'
        else:
            arg_type = 'Array-like or scalar-like'
        doc_pieces.append(f"{arg_name} : {arg_type}\n")
        doc_pieces.append("    Argument to compute function.\n")

    # 3b. Compute function option values
    if options_class is not None:
        options_class_doc = _scrape_options_class_doc(options_class)
        if options_class_doc:
            for p in options_class_doc.params:
                doc_pieces.append(f"{p.name} : {p.type}\n")
                for s in p.desc:
                    doc_pieces.append(f"    {s}\n")
        else:
            warnings.warn(f"Options class {options_class.__name__} "
                          f"does not have a docstring", RuntimeWarning)
            options_sig = inspect.signature(options_class)
            for p in options_sig.parameters.values():
                doc_pieces.append(dedent("""\
                {0} : optional
                    Parameter for {1} constructor. Either `options`
                    or `{0}` can be passed, but not both at the same time.
                """.format(p.name, options_class.__name__)))
        doc_pieces.append(dedent(f"""\
            options : pyarrow.compute.{options_class.__name__}, optional
                Alternative way of passing options.
            """))

    doc_pieces.append(dedent("""\
        memory_pool : pyarrow.MemoryPool, optional
            If not passed, will allocate memory from the default memory pool.
        """))

    # 4. Custom addition (e.g. examples)
    if doc_addition is not None:
        doc_pieces.append("\n{}\n".format(dedent(doc_addition).strip("\n")))

    wrapper.__doc__ = "".join(doc_pieces)
    return wrapper


def _get_options_class(func):
    class_name = func._doc.options_class
    if not class_name:
        return None
    try:
        return globals()[class_name]
    except KeyError:
        warnings.warn("Python binding for {} not exposed"
                      .format(class_name), RuntimeWarning)
        return None


def _handle_options(name, options_class, options, args, kwargs):
    if args or kwargs:
        if options is not None:
            raise TypeError(
                "Function {!r} called with both an 'options' argument "
                "and additional arguments"
                .format(name))
        return options_class(*args, **kwargs)

    if options is not None:
        if isinstance(options, dict):
            return options_class(**options)
        elif isinstance(options, options_class):
            return options
        raise TypeError(
            "Function {!r} expected a {} parameter, got {}"
            .format(name, options_class, type(options)))

    return None


def _make_generic_wrapper(func_name, func, options_class, arity):
    if options_class is None:
        def wrapper(*args, memory_pool=None):
            if arity is not Ellipsis and len(args) != arity:
                raise TypeError(
                    f"{func_name} takes {arity} positional argument(s), "
                    f"but {len(args)} were given"
                )
            if args and isinstance(args[0], Expression):
                return Expression._call(func_name, list(args))
            return func.call(args, None, memory_pool)
    else:
        def wrapper(*args, memory_pool=None, options=None, **kwargs):
            if arity is not Ellipsis:
                if len(args) < arity:
                    raise TypeError(
                        f"{func_name} takes {arity} positional argument(s), "
                        f"but {len(args)} were given"
                    )
                option_args = args[arity:]
                args = args[:arity]
            else:
                option_args = ()
            options = _handle_options(func_name, options_class, options,
                                      option_args, kwargs)
            if args and isinstance(args[0], Expression):
                return Expression._call(func_name, list(args), options)
            return func.call(args, options, memory_pool)
    return wrapper


def _make_signature(arg_names, var_arg_names, options_class):
    from inspect import Parameter
    params = []
    for name in arg_names:
        params.append(Parameter(name, Parameter.POSITIONAL_ONLY))
    for name in var_arg_names:
        params.append(Parameter(name, Parameter.VAR_POSITIONAL))
    if options_class is not None:
        options_sig = inspect.signature(options_class)
        for p in options_sig.parameters.values():
            assert p.kind in (Parameter.POSITIONAL_OR_KEYWORD,
                              Parameter.KEYWORD_ONLY)
            if var_arg_names:
                # Cannot have a positional argument after a *args
                p = p.replace(kind=Parameter.KEYWORD_ONLY)
            params.append(p)
        params.append(Parameter("options", Parameter.KEYWORD_ONLY,
                                default=None))
    params.append(Parameter("memory_pool", Parameter.KEYWORD_ONLY,
                            default=None))
    return inspect.Signature(params)


def _wrap_function(name, func):
    options_class = _get_options_class(func)
    arg_names = _get_arg_names(func)
    has_vararg = arg_names and arg_names[-1].startswith('*')
    if has_vararg:
        var_arg_names = [arg_names.pop().lstrip('*')]
    else:
        var_arg_names = []

    wrapper = _make_generic_wrapper(
        name, func, options_class, arity=func.arity)
    wrapper.__signature__ = _make_signature(arg_names, var_arg_names,
                                            options_class)
    return _decorate_compute_function(wrapper, name, func, options_class)


def _make_global_functions():
    """
    Make global functions wrapping each compute function.

    Note that some of the automatically-generated wrappers may be overridden
    by custom versions below.
    """
    g = globals()
    reg = function_registry()

    # Avoid clashes with Python keywords
    rewrites = {'and': 'and_',
                'or': 'or_'}

    for cpp_name in reg.list_functions():
        name = rewrites.get(cpp_name, cpp_name)
        func = reg.get_function(cpp_name)
        if func.kind == "hash_aggregate":
            # Hash aggregate functions are not callable,
            # so let's not expose them at module level.
            continue
        if func.kind == "scalar_aggregate" and func.arity == 0:
            # Nullary scalar aggregate functions are not callable
            # directly so let's not expose them at module level.
            continue
        assert name not in g, name
        g[cpp_name] = g[name] = _wrap_function(name, func)


_make_global_functions()


def cast(arr, target_type=None, safe=None, options=None, memory_pool=None):
    """
    Cast array values to another data type. Can also be invoked as an array
    instance method.

    Parameters
    ----------