#!/usr/bin/env python
# encoding: utf-8
# Thomas Nagy, 2007 (ita)
# Gustavo Carneiro (gjc), 2007

"Python support"

import os, sys
import TaskGen, Utils, Utils, Runner, Options, Build
from Logs import debug, warn, info
from TaskGen import extension, taskgen, before, after, feature
from Configure import conf

EXT_PY = ['.py']
FRAG_2 = '''
#ifdef __cplusplus
extern "C" {
#endif
	void Py_Initialize(void);
	void Py_Finalize(void);
#ifdef __cplusplus
}
#endif
int main()
{
   Py_Initialize();
   Py_Finalize();
   return 0;
}
'''

@before('apply_incpaths', 'apply_lib_vars', 'apply_type_vars')
@feature('pyext')
@before('apply_bundle')
def init_pyext(self):
	self.default_install_path = '${PYTHONDIR}'
	self.uselib = self.to_list(getattr(self, 'uselib', ''))
	if not 'PYEXT' in self.uselib:
		self.uselib.append('PYEXT')
	self.env['MACBUNDLE'] = True

@before('apply_link', 'apply_lib_vars', 'apply_type_vars')
@after('apply_bundle')
@feature('pyext')
def pyext_shlib_ext(self):
	# override shlib_PATTERN set by the osx module
	self.env['shlib_PATTERN'] = self.env['pyext_PATTERN']

@before('apply_incpaths', 'apply_lib_vars', 'apply_type_vars')
@feature('pyembed')
def init_pyembed(self):
	self.uselib = self.to_list(getattr(self, 'uselib', ''))
	if not 'PYEMBED' in self.uselib:
		self.uselib.append('PYEMBED')

@extension(EXT_PY)
def process_py(self, node):
	if not (self.bld.is_install and self.install_path):
		return
	def inst_py(ctx):
		install_pyfile(self, node)
	self.bld.add_post_fun(inst_py)

def install_pyfile(self, node):
	path = self.bld.get_install_path(self.install_path + os.sep + node.name, self.env)

	self.bld.install_files(self.install_path, [node], self.env, self.chmod, postpone=False)
	if self.bld.is_install < 0:
		info("* removing byte compiled python files")
		for x in 'co':
			try:
				os.remove(path + x)
			except OSError:
				pass

	if self.bld.is_install > 0:
		if self.env['PYC'] or self.env['PYO']:
			info("* byte compiling %r" % path)

		if self.env['PYC']:
			program = ("""
import sys, py_compile
for pyfile in sys.argv[1:]:
	py_compile.compile(pyfile, pyfile + 'c')
""")
			argv = [self.env['PYTHON'], '-c', program, path]
			ret = Utils.pproc.Popen(argv).wait()
			if ret:
				raise Utils.WafError('bytecode compilation failed %r' % path)

		if self.env['PYO']:
			program = ("""
import sys, py_compile
for pyfile in sys.argv[1:]:
	py_compile.compile(pyfile, pyfile + 'o')
""")
			argv = [self.env['PYTHON'], self.env['PYFLAGS_OPT'], '-c', program, path]
			ret = Utils.pproc.Popen(argv).wait()
			if ret:
				raise Utils.WafError('bytecode compilation failed %r' % path)

# COMPAT
class py_taskgen(TaskGen.task_gen):
	def __init__(self, *k, **kw):
		TaskGen.task_gen.__init__(self, *k, **kw)

@before('apply_core')
@after('vars_target_cprogram', 'vars_target_cstaticlib')
@feature('py')
def init_py(self):
	self.default_install_path = '${PYTHONDIR}'

def _get_python_variables(python_exe, variables, imports=['import sys']):
	"""Run a python interpreter and print some variables"""
	program = list(imports)
	program.append('')
	for v in variables:
		program.append("print(repr(%s))" % v)
	os_env = dict(os.environ)
	try:
		del os_env['MACOSX_DEPLOYMENT_TARGET'] # see comments in the OSX tool
	except KeyError:
		pass
	proc = Utils.pproc.Popen([python_exe, "-c", '\n'.join(program)], stdout=Utils.pproc.PIPE, env=os_env)
	output = proc.communicate()[0].split("\n") # do not touch, python3
	if proc.returncode:
		if Options.options.verbose:
			warn("Python program to extract python configuration variables failed:\n%s"
				       % '\n'.join(["line %03i: %s" % (lineno+1, line) for lineno, line in enumerate(program)]))
		raise RuntimeError
	return_values = []
	for s in output:
		s = s.strip()
		if not s:
			continue
		if s == 'None':
			return_values.append(None)
		elif s[0] == "'" and s[-1] == "'":
			return_values.append(s[1:-1])
		elif s[0].isdigit():
			return_values.append(int(s))
		else: break
	return return_values

@conf
def check_python_headers(conf):
	"""Check for headers and libraries necessary to extend or embed python.

	On success the environment variables xxx_PYEXT and xxx_PYEMBED are added for uselib

	PYEXT: for compiling python extensions
	PYEMBED: for embedding a python interpreter"""

	if not conf.env['CC_NAME'] and not conf.env['CXX_NAME']:
		conf.fatal('load a compiler first (gcc, g++, ..)')

	if not conf.env['PYTHON_VERSION']:
		conf.check_python_version()

	env = conf.env
	python = env['PYTHON']
	if not python:
		conf.fatal('could not find the python executable')

	## On Mac OSX we need to use mac bundles for python plugins
	if Options.platform == 'darwin':
		conf.check_tool('osx')

	try:
		# Get some python configuration variables using distutils
		v = 'prefix SO SYSLIBS LDFLAGS SHLIBS LIBDIR LIBPL INCLUDEPY Py_ENABLE_SHARED MACOSX_DEPLOYMENT_TARGET'.split()
		(python_prefix, python_SO, python_SYSLIBS, python_LDFLAGS, python_SHLIBS,
		 python_LIBDIR, python_LIBPL, INCLUDEPY, Py_ENABLE_SHARED,
		 python_MACOSX_DEPLOYMENT_TARGET) = \
			_get_python_variables(python, ["get_config_var('%s')" % x for x in v],
					      ['from distutils.sysconfig import get_config_var'])
	except RuntimeError:
		conf.fatal("Python development headers not found (-v for details).")

	conf.log.write("""Configuration returned from %r:
python_prefix = %r
python_SO = %r
python_SYSLIBS = %r
python_LDFLAGS = %r
python_SHLIBS = %r
python_LIBDIR = %r
python_LIBPL = %r
INCLUDEPY = %r
Py_ENABLE_SHARED = %r
MACOSX_DEPLOYMENT_TARGET = %r
""" % (python, python_prefix, python_SO, python_SYSLIBS, python_LDFLAGS, python_SHLIBS,
	python_LIBDIR, python_LIBPL, INCLUDEPY, Py_ENABLE_SHARED, python_MACOSX_DEPLOYMENT_TARGET))

	if python_MACOSX_DEPLOYMENT_TARGET:
		conf.env['MACOSX_DEPLOYMENT_TARGET'] = python_MACOSX_DEPLOYMENT_TARGET
		conf.environ['MACOSX_DEPLOYMENT_TARGET'] = python_MACOSX_DEPLOYMENT_TARGET

	env['pyext_PATTERN'] = '%s'+python_SO

	# Check for python libraries for embedding
	if python_SYSLIBS is not None:
		for lib in python_SYSLIBS.split():
			if lib.startswith('-l'):
				lib = lib[2:] # strip '-l'
			env.append_value('LIB_PYEMBED', lib)

	if python_SHLIBS is not None:
		for lib in python_SHLIBS.split():
			if lib.startswith('-l'):
				env.append_value('LIB_PYEMBED', lib[2:]) # strip '-l'
			else:
				env.append_value('LINKFLAGS_PYEMBED', lib)

	if Options.platform != 'darwin' and python_LDFLAGS:
		env.append_value('LINKFLAGS_PYEMBED', python_LDFLAGS.split())

	result = False
	name = 'python' + env['PYTHON_VERSION']

	if python_LIBDIR is not None:
		path = [python_LIBDIR]
		conf.log.write("\n\n# Trying LIBDIR: %r\n" % path)
		result = conf.check(lib=name, uselib='PYEMBED', libpath=path)

	if not result and python_LIBPL is not None:
		conf.log.write("\n\n# try again with -L$python_LIBPL (some systems don't install the python library in $prefix/lib)\n")
		path = [python_LIBPL]
		result = conf.check(lib=name, uselib='PYEMBED', libpath=path)

	if not result:
		conf.log.write("\n\n# try again with -L$prefix/libs, and pythonXY name rather than pythonX.Y (win32)\n")
		path = [os.path.join(python_prefix, "libs")]
		name = 'python' + env['PYTHON_VERSION'].replace('.', '')
		result = conf.check(lib=name, uselib='PYEMBED', libpath=path)

	if result:
		env['LIBPATH_PYEMBED'] = path
		env.append_value('LIB_PYEMBED', name)
	else:
		conf.log.write("\n\n### LIB NOT FOUND\n")

	# under certain conditions, python extensions must link to
	# python libraries, not just python embedding programs.
	if (sys.platform == 'win32' or sys.platform.startswith('os2')
		or sys.platform == 'darwin' or Py_ENABLE_SHARED):
		env['LIBPATH_PYEXT'] = env['LIBPATH_PYEMBED']
		env['LIB_PYEXT'] = env['LIB_PYEMBED']

	# We check that pythonX.Y-config exists, and if it exists we
	# use it to get only the includes, else fall back to distutils.
	python_config = conf.find_program(
		'python%s-config' % ('.'.join(env['PYTHON_VERSION'].split('.')[:2])),
		var='PYTHON_CONFIG')
	if not python_config:
		python_config = conf.find_program(
			'python-config-%s' % ('.'.join(env['PYTHON_VERSION'].split('.')[:2])),
			var='PYTHON_CONFIG')

	includes = []
	if python_config:
		for incstr in Utils.cmd_output("%s %s --includes" % (python, python_config)).strip().split():
			# strip the -I or /I
			if (incstr.startswith('-I')
			    or incstr.startswith('/I')):
				incstr = incstr[2:]
			# append include path, unless already given
			if incstr not in includes:
				includes.append(incstr)
		conf.log.write("Include path for Python extensions "
			       "(found via python-config --includes): %r\n" % (includes,))
		env['CPPPATH_PYEXT'] = includes
		env['CPPPATH_PYEMBED'] = includes
	else:
		conf.log.write("Include path for Python extensions "
			       "(found via distutils module): %r\n" % (INCLUDEPY,))
		env['CPPPATH_PYEXT'] = [INCLUDEPY]
		env['CPPPATH_PYEMBED'] = [INCLUDEPY]

	# Code using the Python API needs to be compiled with -fno-strict-aliasing
	if env['CC_NAME'] == 'gcc':
		env.append_value('CCFLAGS_PYEMBED', '-fno-strict-aliasing')
		env.append_value('CCFLAGS_PYEXT', '-fno-strict-aliasing')
	if env['CXX_NAME'] == 'gcc':
		env.append_value('CXXFLAGS_PYEMBED', '-fno-strict-aliasing')
		env.append_value('CXXFLAGS_PYEXT', '-fno-strict-aliasing')

	# See if it compiles
	conf.check(header_name='Python.h', define_name='HAVE_PYTHON_H',
		   uselib='PYEMBED', fragment=FRAG_2,
		   errmsg='Could not find the python development headers', mandatory=1)

@conf
def check_python_version(conf, minver=None):
	"""
	Check if the python interpreter is found matching a given minimum version.
	minver should be a tuple, eg. to check for python >= 2.4.2 pass (2,4,2) as minver.

	If successful, PYTHON_VERSION is defined as 'MAJOR.MINOR'
	(eg. '2.4') of the actual python version found, and PYTHONDIR is
	defined, pointing to the site-packages directory appropriate for
	this python version, where modules/packages/extensions should be
	installed.
	"""
	assert minver is None or isinstance(minver, tuple)
	python = conf.env['PYTHON']
	if not python:
		conf.fatal('could not find the python executable')

	# Get python version string
	cmd = [python, "-c", "import sys\nfor x in sys.version_info: print(str(x))"]
	debug('python: Running python command %r' % cmd)
	proc = Utils.pproc.Popen(cmd, stdout=Utils.pproc.PIPE)
	lines = proc.communicate()[0].split()
	assert len(lines) == 5, "found %i lines, expected 5: %r" % (len(lines), lines)
	pyver_tuple = (int(lines[0]), int(lines[1]), int(lines[2]), lines[3], int(lines[4]))

	# compare python version with the minimum required
	result = (minver is None) or (pyver_tuple >= minver)

	if result:
		# define useful environment variables
		pyver = '.'.join([str(x) for x in pyver_tuple[:2]])
		conf.env['PYTHON_VERSION'] = pyver

		if 'PYTHONDIR' in conf.environ:
			pydir = conf.environ['PYTHONDIR']
		else:
			if sys.platform == 'win32':
				(python_LIBDEST, pydir) = \
						_get_python_variables(python,
											  ["get_config_var('LIBDEST')",
											   "get_python_lib(standard_lib=0, prefix=%r)" % conf.env['PREFIX']],
											  ['from distutils.sysconfig import get_config_var, get_python_lib'])
			else:
				python_LIBDEST = None
				(pydir,) = \
						_get_python_variables(python,
											  ["get_python_lib(standard_lib=0, prefix=%r)" % conf.env['PREFIX']],
											  ['from distutils.sysconfig import get_config_var, get_python_lib'])
			if python_LIBDEST is None:
				if conf.env['LIBDIR']:
					python_LIBDEST = os.path.join(conf.env['LIBDIR'], "python" + pyver)
				else:
					python_LIBDEST = os.path.join(conf.env['PREFIX'], "lib", "python" + pyver)

		if hasattr(conf, 'define'): # conf.define is added by the C tool, so may not exist
			conf.define('PYTHONDIR', pydir)
		conf.env['PYTHONDIR'] = pydir

	# Feedback
	pyver_full = '.'.join(map(str, pyver_tuple[:3]))
	if minver is None:
		conf.check_message_custom('Python version', '', pyver_full)
	else:
		minver_str = '.'.join(map(str, minver))
		conf.check_message('Python version', ">= %s" % minver_str, result, option=pyver_full)

	if not result:
		conf.fatal('The python version is too old (%r)' % pyver_full)

@conf
def check_python_module(conf, module_name):
	"""
	Check if the selected python interpreter can import the given python module.
	"""
	result = not Utils.pproc.Popen([conf.env['PYTHON'], "-c", "import %s" % module_name],
			   stderr=Utils.pproc.PIPE, stdout=Utils.pproc.PIPE).wait()
	conf.check_message('Python module', module_name, result)
	if not result:
		conf.fatal('Could not find the python module %r' % module_name)

def detect(conf):

	if not conf.env.PYTHON:
		conf.env.PYTHON = sys.executable

	python = conf.find_program('${MODPY_BIN}', var='PYTHON')
	if not python:
		conf.fatal('Could not find the path of the python executable')

	v = conf.env

	v['PYCMD'] = '"import sys, py_compile;py_compile.compile(sys.argv[1], sys.argv[2])"'
	v['PYFLAGS'] = ''
	v['PYFLAGS_OPT'] = '-O'

	v['PYC'] = getattr(Options.options, 'pyc', 1)
	v['PYO'] = getattr(Options.options, 'pyo', 1)

def set_options(opt):
	opt.add_option('--nopyc',
			action='store_false',
			default=1,
			help = 'Do not install bytecode compiled .pyc files (configuration) [Default:install]',
			dest = 'pyc')
	opt.add_option('--nopyo',
			action='store_false',
			default=1,
			help='Do not install optimised compiled .pyo files (configuration) [Default:install]',
			dest='pyo')

