# Code shared by distutils and scons builds
import sys
from os.path import join
import warnings

#-------------------
# Versioning support
#-------------------
# How to change C_API_VERSION ?
#   - increase C_API_VERSION value
#   - record the hash for the new C API with the script cversions.py
#   and add the hash to cversions.txt
# The hash values are used to remind developers when the C API number was not
# updated - generates a MismatchCAPIWarning warning which is turned into an
# exception for released version.

# Binary compatibility version number. This number is increased whenever the
# C-API is changed such that binary compatibility is broken, i.e. whenever a
# recompile of extension modules is needed.
C_ABI_VERSION = 0x01000009

# Minor API version.  This number is increased whenever a change is made to the
# C-API -- whether it breaks binary compatibility or not.  Some changes, such
# as adding a function pointer to the end of the function table, can be made
# without breaking binary compatibility.  In this case, only the C_API_VERSION
# (*not* C_ABI_VERSION) would be increased.  Whenever binary compatibility is
# broken, both C_API_VERSION and C_ABI_VERSION should be increased.
C_API_VERSION = 0x00000003

class MismatchCAPIWarning(Warning):
    pass

def is_released(config):
    """Return True if a released version of numpy is detected."""
    from distutils.version import LooseVersion

    v = config.get_version('../version.py')
    if v is None:
        raise ValueError("Could not get version")
    pv = LooseVersion(vstring=v).version
    if len(pv) > 3:
        return False
    return True

def get_api_versions(apiversion, codegen_dir):
    """Return current C API checksum and the recorded checksum for the given
    version of the C API version."""
    api_files = [join(codegen_dir, 'numpy_api_order.txt'),
                 join(codegen_dir, 'ufunc_api_order.txt')]

    # Compute the hash of the current API as defined in the .txt files in
    # code_generators
    sys.path.insert(0, codegen_dir)
    try:
        m = __import__('genapi')
        curapi_hash = m.fullapi_hash(api_files)
        apis_hash = m.get_versions_hash()
    finally:
        del sys.path[0]

    return curapi_hash, apis_hash[apiversion]

def check_api_version(apiversion, codegen_dir):
    """Emits a MismacthCAPIWarning if the C API version needs updating."""
    curapi_hash, api_hash = get_api_versions(apiversion, codegen_dir)

    # If different hash, it means that the api .txt files in
    # codegen_dir have been updated without the API version being
    # updated. Any modification in those .txt files should be reflected
    # in the api and eventually abi versions.
    # To compute the checksum of the current API, use
    # code_generators/cversions.py script
    if not curapi_hash == api_hash:
        msg = "API mismatch detected, the C API version " \
              "numbers have to be updated. Current C api version is %d, " \
              "with checksum %s, but recorded checksum for C API version %d in " \
              "codegen_dir/cversions.txt is %s. If functions were added in the " \
              "C API, you have to update C_API_VERSION  in %s."
        warnings.warn(msg % (apiversion, curapi_hash, apiversion, api_hash,
                             __file__),
                      MismatchCAPIWarning)
# Mandatory functions: if not found, fail the build
MANDATORY_FUNCS = ["sin", "cos", "tan", "sinh", "cosh", "tanh", "fabs",
        "floor", "ceil", "sqrt", "log10", "log", "exp", "asin",
        "acos", "atan", "fmod", 'modf', 'frexp', 'ldexp']

# Standard functions which may not be available and for which we have a
# replacement implementation. Note that some of these are C99 functions.
OPTIONAL_STDFUNCS = ["expm1", "log1p", "acosh", "asinh", "atanh",
        "rint", "trunc", "exp2", "log2", "hypot", "atan2", "pow",
        "copysign"]

# Subset of OPTIONAL_STDFUNCS which may alreay have HAVE_* defined by Python.h
OPTIONAL_STDFUNCS_MAYBE = ["expm1", "log1p", "acosh", "atanh", "asinh", "hypot",
        "copysign"]

# C99 functions: float and long double versions
C99_FUNCS = ["sin", "cos", "tan", "sinh", "cosh", "tanh", "fabs", "floor",
        "ceil", "rint", "trunc", "sqrt", "log10", "log", "log1p", "exp",
        "expm1", "asin", "acos", "atan", "asinh", "acosh", "atanh",
        "hypot", "atan2", "pow", "fmod", "modf", 'frexp', 'ldexp',
        "exp2", "log2", "copysign"]

C99_FUNCS_SINGLE = [f + 'f' for f in C99_FUNCS]
C99_FUNCS_EXTENDED = [f + 'l' for f in C99_FUNCS]

def fname2def(name):
    return "HAVE_%s" % name.upper()