From 0c68de36af3ddc6439ee311bbc805b3888ca34a2 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 30 Mar 2021 09:13:46 -0700
Subject: [PATCH] TYP: tslibs

---
 pandas/_libs/tslibs/conversion.pyi | 41 ++++++++++++++++++
 pandas/_libs/tslibs/dtypes.pyi     | 65 ++++++++++++++++++++++++++++
 pandas/_libs/tslibs/fields.pyi     | 69 ++++++++++++++++++++++++++++++
 pandas/core/arrays/datetimelike.py |  1 +
 4 files changed, 176 insertions(+)
 create mode 100644 pandas/_libs/tslibs/conversion.pyi
 create mode 100644 pandas/_libs/tslibs/dtypes.pyi
 create mode 100644 pandas/_libs/tslibs/fields.pyi

diff --git a/pandas/_libs/tslibs/conversion.pyi b/pandas/_libs/tslibs/conversion.pyi
new file mode 100644
index 0000000000000..6470361542597
--- /dev/null
+++ b/pandas/_libs/tslibs/conversion.pyi
@@ -0,0 +1,41 @@
+from datetime import (
+    datetime,
+    tzinfo,
+)
+
+import numpy as np
+
+DT64NS_DTYPE: np.dtype
+TD64NS_DTYPE: np.dtype
+
+class OutOfBoundsTimedelta(ValueError): ...
+
+def precision_from_unit(
+    unit: str,
+) -> tuple[
+    int,  # int64_t
+    int,
+]: ...
+
+
+def ensure_datetime64ns(
+    arr: np.ndarray,  # np.ndarray[datetime64[ANY]]
+    copy: bool = ...,
+) -> np.ndarray: ...  # np.ndarray[datetime64ns]
+
+
+def ensure_timedelta64ns(
+    arr: np.ndarray,  # np.ndarray[timedelta64[ANY]]
+    copy: bool = ...,
+) -> np.ndarray: ...  # np.ndarray[timedelta64ns]
+
+
+def datetime_to_datetime64(
+    values: np.ndarray,  # np.ndarray[object]
+) -> tuple[
+    np.ndarray,  # np.ndarray[dt64ns]
+    tzinfo | None,
+]: ...
+
+
+def localize_pydatetime(dt: datetime, tz: tzinfo | None) -> datetime: ...
diff --git a/pandas/_libs/tslibs/dtypes.pyi b/pandas/_libs/tslibs/dtypes.pyi
new file mode 100644
index 0000000000000..53752098bafe9
--- /dev/null
+++ b/pandas/_libs/tslibs/dtypes.pyi
@@ -0,0 +1,65 @@
+from enum import Enum
+
+from pandas._libs.tslibs.offsets import BaseOffset
+
+_attrname_to_abbrevs: dict[str, str]
+_period_code_map: dict[str, int]
+
+
+class PeriodDtypeBase:
+    # actually __cinit__
+    def __new__(self, code: int): ...
+
+    def freq_group_code(self) -> int: ...
+    def date_offset(self) -> BaseOffset: ...
+
+    @classmethod
+    def from_date_offset(cls, offset: BaseOffset) -> PeriodDtypeBase: ...
+
+
+class FreqGroup(Enum):
+    FR_ANN: int = ...
+    FR_QTR: int = ...
+    FR_MTH: int = ...
+    FR_WK: int = ...
+    FR_BUS: int = ...
+    FR_DAY: int = ...
+    FR_HR: int = ...
+    FR_MIN: int = ...
+    FR_SEC: int = ...
+    FR_MS: int = ...
+    FR_US: int = ...
+    FR_NS: int = ...
+    FR_UND: int = ...
+
+    @staticmethod
+    def get_freq_group(code: int) -> FreqGroup: ...
+
+
+class Resolution(Enum):
+    RESO_NS: int = ...
+    RESO_US: int = ...
+    RESO_MS: int = ...
+    RESO_SEC: int = ...
+    RESO_MIN: int = ...
+    RESO_HR: int = ...
+    RESO_DAY: int = ...
+    RESO_MTH: int = ...
+    RESO_QTR: int = ...
+    RESO_YR: int = ...
+
+    def __lt__(self, other: Resolution) -> bool: ...
+
+    def __ge__(self, other: Resolution) -> bool: ...
+
+    @property
+    def freq_group(self) -> FreqGroup: ...
+
+    @property
+    def attrname(self) -> str: ...
+
+    @classmethod
+    def from_attrname(cls, attrname: str) -> Resolution: ...
+
+    @classmethod
+    def get_reso_from_freq(cls, freq: str) -> Resolution: ...
diff --git a/pandas/_libs/tslibs/fields.pyi b/pandas/_libs/tslibs/fields.pyi
new file mode 100644
index 0000000000000..22ae156d78b7d
--- /dev/null
+++ b/pandas/_libs/tslibs/fields.pyi
@@ -0,0 +1,69 @@
+import numpy as np
+
+def build_field_sarray(
+    dtindex: np.ndarray,  # const int64_t[:]
+) -> np.ndarray: ...
+
+def month_position_check(fields, weekdays) -> str | None: ...
+
+def get_date_name_field(
+    dtindex: np.ndarray,  # const int64_t[:]
+    field: str,
+    locale=...,
+) -> np.ndarray: ...  # np.ndarray[object]
+
+def get_start_end_field(
+    dtindex: np.ndarray,  # const int64_t[:]
+    field: str,
+    freqstr: str | None = ...,
+    month_kw: int = ...
+) -> np.ndarray: ...  # np.ndarray[bool]
+
+
+def get_date_field(
+    dtindex: np.ndarray,  # const int64_t[:]
+
+    field: str,
+) -> np.ndarray: ...  # np.ndarray[in32]
+
+
+def get_timedelta_field(
+    tdindex: np.ndarray,  # const int64_t[:]
+    field: str,
+) -> np.ndarray: ...  # np.ndarray[int32]
+
+
+def isleapyear_arr(
+    years: np.ndarray,
+) -> np.ndarray: ...  # np.ndarray[bool]
+
+def build_isocalendar_sarray(
+    dtindex: np.ndarray,  # const int64_t[:]
+) -> np.ndarray: ...
+
+
+def get_locale_names(name_type: str, locale: object = None): ...
+
+
+class RoundTo:
+    @property
+    def MINUS_INFTY(self) -> int: ...
+
+    @property
+    def PLUS_INFTY(self) -> int: ...
+
+    @property
+    def NEAREST_HALF_EVEN(self) -> int: ...
+
+    @property
+    def NEAREST_HALF_PLUS_INFTY(self) -> int: ...
+
+    @property
+    def NEAREST_HALF_MINUS_INFTY(self) -> int: ...
+
+
+def round_nsint64(
+    values: np.ndarray,   # np.ndarray[np.int64]
+    mode: RoundTo,
+    nanos: int,
+) -> np.ndarray: ...  # np.ndarray[np.int64]
diff --git a/pandas/core/arrays/datetimelike.py b/pandas/core/arrays/datetimelike.py
index 67241a866ef35..cefb9bfa51280 100644
--- a/pandas/core/arrays/datetimelike.py
+++ b/pandas/core/arrays/datetimelike.py
@@ -1727,6 +1727,7 @@ def _round(self, freq, mode, ambiguous, nonexistent):
             )
 
         values = self.view("i8")
+        values = cast(np.ndarray, values)
         nanos = to_offset(freq).nanos
         result = round_nsint64(values, mode, nanos)
         result = self._maybe_mask_results(result, fill_value=iNaT)