import numpy as np

# Note: we use dtype objects instead of dtype classes. The spec does not
# require any behavior on dtypes other than equality.
int8 = np.dtype("int8")
int16 = np.dtype("int16")
int32 = np.dtype("int32")
int64 = np.dtype("int64")
uint8 = np.dtype("uint8")
uint16 = np.dtype("uint16")
uint32 = np.dtype("uint32")
uint64 = np.dtype("uint64")
float32 = np.dtype("float32")
float64 = np.dtype("float64")
# Note: This name is changed
bool = np.dtype("bool")

_all_dtypes = (
    int8,
    int16,
    int32,
    int64,
    uint8,
    uint16,
    uint32,
    uint64,
    float32,
    float64,
    bool,
)
_boolean_dtypes = (bool,)
_floating_dtypes = (float32, float64)
_integer_dtypes = (int8, int16, int32, int64, uint8, uint16, uint32, uint64)
_integer_or_boolean_dtypes = (
    bool,
    int8,
    int16,
    int32,
    int64,
    uint8,
    uint16,
    uint32,
    uint64,
)
_numeric_dtypes = (
    float32,
    float64,
    int8,
    int16,
    int32,
    int64,
    uint8,
    uint16,
    uint32,
    uint64,
)

_dtype_categories = {
    "all": _all_dtypes,
    "numeric": _numeric_dtypes,
    "integer": _integer_dtypes,
    "integer or boolean": _integer_or_boolean_dtypes,
    "boolean": _boolean_dtypes,
    "floating-point": _floating_dtypes,
}


# Note: the spec defines a restricted type promotion table compared to NumPy.
# In particular, cross-kind promotions like integer + float or boolean +
# integer are not allowed, even for functions that accept both kinds.
# Additionally, NumPy promotes signed integer + uint64 to float64, but this
# promotion is not allowed here. To be clear, Python scalar int objects are
# allowed to promote to floating-point dtypes, but only in array operators
# (see Array._promote_scalar) method in _array_object.py.
_promotion_table = {
    (int8, int8): int8,
    (int8, int16): int16,
    (int8, int32): int32,
    (int8, int64): int64,
    (int16, int8): int16,
    (int16, int16): int16,
    (int16, int32): int32,
    (int16, int64): int64,
    (int32, int8): int32,
    (int32, int16): int32,
    (int32, int32): int32,
    (int32, int64): int64,
    (int64, int8): int64,
    (int64, int16): int64,
    (int64, int32): int64,
    (int64, int64): int64,
    (uint8, uint8): uint8,
    (uint8, uint16): uint16,
    (uint8, uint32): uint32,
    (uint8, uint64): uint64,
    (uint16, uint8): uint16,
    (uint16, uint16): uint16,
    (uint16, uint32): uint32,
    (uint16, uint64): uint64,
    (uint32, uint8): uint32,
    (uint32, uint16): uint32,
    (uint32, uint32): uint32,
    (uint32, uint64): uint64,
    (uint64, uint8): uint64,
    (uint64, uint16): uint64,
    (uint64, uint32): uint64,
    (uint64, uint64): uint64,
    (int8, uint8): int16,
    (int8, uint16): int32,
    (int8, uint32): int64,
    (int16, uint8): int16,
    (int16, uint16): int32,
    (int16, uint32): int64,
    (int32, uint8): int32,
    (int32, uint16): int32,
    (int32, uint32): int64,
    (int64, uint8): int64,
    (int64, uint16): int64,
    (int64, uint32): int64,
    (uint8, int8): int16,
    (uint16, int8): int32,
    (uint32, int8): int64,
    (uint8, int16): int16,
    (uint16, int16): int32,
    (uint32, int16): int64,
    (uint8, int32): int32,
    (uint16, int32): int32,
    (uint32, int32): int64,
    (uint8, int64): int64,
    (uint16, int64): int64,
    (uint32, int64): int64,
    (float32, float32): float32,
    (float32, float64): float64,
    (float64, float32): float64,
    (float64, float64): float64,
    (bool, bool): bool,
}


def _result_type(type1, type2):
    if (type1, type2) in _promotion_table:
        return _promotion_table[type1, type2]
    raise TypeError(f"{type1} and {type2} cannot be type promoted together")
