from waflib import Logs, Options, Utils

class CompilerTraits(object):

	def get_warnings_flags(self, level):

		"""get_warnings_flags(level) -> list of cflags"""

		raise NotImplementedError

	def get_optimization_flags(self, level):

		"""get_optimization_flags(level) -> list of cflags"""

		raise NotImplementedError

	def get_debug_flags(self, level):

		"""get_debug_flags(level) -> (list of cflags, list of cppdefines)"""

		raise NotImplementedError

class GccTraits(CompilerTraits):

	def __init__(self):

		super(GccTraits, self).__init__()

		# cumulative list of warnings per level

		self.warnings_flags = [['-Wall'], ['-Werror'], ['-Wextra']]

	def get_warnings_flags(self, level):

		warnings = []

		for l in range(level):

			if l < len(self.warnings_flags):

				warnings.extend(self.warnings_flags[l])

			else:

				break

		return warnings

	def get_optimization_flags(self, level):

		if level == 0:

			return ['-O0']

		elif level == 1:

			return ['-O']

		elif level == 2:

			return ['-O2']

		elif level == 3:

			return ['-O3']

	def get_debug_flags(self, level):

		if level == 0:

			return (['-g0'], ['NDEBUG'])

		elif level == 1:

			return (['-g'], [])

		elif level >= 2:

			return (['-ggdb', '-g3'], ['_DEBUG'])

class IccTraits(CompilerTraits):

	def __init__(self):

		super(IccTraits, self).__init__()

		# cumulative list of warnings per level

		# icc is _very_ verbose with -Wall, -Werror is barely achievable

		self.warnings_flags = [[], [], ['-Wall']]

	def get_warnings_flags(self, level):

		warnings = []

		for l in range(level):

			if l < len(self.warnings_flags):

				warnings.extend(self.warnings_flags[l])

			else:

				break

		return warnings

	def get_optimization_flags(self, level):

		if level == 0:

			return ['-O0']

		elif level == 1:

			return ['-O']

		elif level == 2:

			return ['-O2']

		elif level == 3:

			return ['-O3']

	def get_debug_flags(self, level):

		if level == 0:

			return (['-g0'], ['NDEBUG'])

		elif level == 1:

			return (['-g'], [])

		elif level >= 2:

			return (['-ggdb', '-g3'], ['_DEBUG'])

class MsvcTraits(CompilerTraits):

	def __init__(self):

		super(MsvcTraits, self).__init__()

		# cumulative list of warnings per level

		self.warnings_flags = [['/W2'], ['/WX'], ['/Wall']]

	def get_warnings_flags(self, level):

		warnings = []

		for l in range(level):

			if l < len(self.warnings_flags):

				warnings.extend(self.warnings_flags[l])

			else:

				break

		return warnings

	def get_optimization_flags(self, level):

		if level == 0:

			return ['/Od']

		elif level == 1:

			return []

		elif level == 2:

			return ['/O2']

		elif level == 3:

			return ['/Ox']

	def get_debug_flags(self, level):

		if level == 0:

			return ([], ['NDEBUG'])

		elif level == 1:

			return (['/ZI', '/RTC1'], [])

		elif level >= 2:

			return (['/ZI', '/RTC1'], ['_DEBUG'])

gcc = GccTraits()

icc = IccTraits()

msvc = MsvcTraits()

# how to map env['COMPILER_CC'] or env['COMPILER_CXX'] into a traits object

compiler_mapping = {

	'gcc': gcc,

	'g++': gcc,

	'msvc': msvc,

	'icc': icc,

	'icpc': icc,

	'clang': gcc,

	'clang++': gcc,

}

profiles = {

	# profile name: [optimization_level, warnings_level, debug_level]

	'default': [2, 1, 1],

	'debug': [0, 2, 3],

	'release': [3, 1, 0],

	}

default_profile = 'default'

def options(opt):

	assert default_profile in profiles

	opt.add_option('-d', '--build-profile',

		       action='store',

		       default=default_profile,

		       help=("Specify the build profile.  "

			     "Build profiles control the default compilation flags"

			     " used for C/C++ programs, if CCFLAGS/CXXFLAGS are not"

			     " set set in the environment. [Allowed Values: %s]"

			     % ", ".join([repr(p) for p in list(profiles.keys())])),

		       choices=list(profiles.keys()),

		       dest='build_profile')

def configure(conf):

	cc = conf.env['COMPILER_CC'] or None

	cxx = conf.env['COMPILER_CXX'] or None

	if not (cc or cxx):

		raise Utils.WafError("neither COMPILER_CC nor COMPILER_CXX are defined; "

				     "maybe the compiler_cc or compiler_cxx tool has not been configured yet?")

	try:

		compiler = compiler_mapping[cc]

	except KeyError:

		try:

			compiler = compiler_mapping[cxx]

		except KeyError:

			Logs.warn("No compiler flags support for compiler %r or %r"

				  % (cc, cxx))

			return

	opt_level, warn_level, dbg_level = profiles[Options.options.build_profile]

	optimizations = compiler.get_optimization_flags(opt_level)

	debug, debug_defs = compiler.get_debug_flags(dbg_level)

	warnings = compiler.get_warnings_flags(warn_level)

	if cc and not conf.env['CCFLAGS']:

		conf.env.append_value('CCFLAGS', optimizations)

		conf.env.append_value('CCFLAGS', debug)

		conf.env.append_value('CCFLAGS', warnings)

		conf.env.append_value('CCDEFINES', debug_defs)

	if cxx and not conf.env['CXXFLAGS']:

		conf.env.append_value('CXXFLAGS', optimizations)

		conf.env.append_value('CXXFLAGS', debug)

		conf.env.append_value('CXXFLAGS', warnings)

		conf.env.append_value('CXXDEFINES', debug_defs)