# -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-

from waflib import Logs, Configure, Utils

def options(opt):
    opt.add_option('--debug', '--with-debug', action='store_true', default=False, dest='debug',
                   help='''Compile in debugging mode with minimal optimizations (-O0 or -Og)''')

def configure(conf):
    cxx = conf.env['CXX_NAME'] # CXX_NAME represents generic name of the compiler
    ccver = tuple(int(i) for i in conf.env['CC_VERSION'])
    if cxx == 'gcc':
        if ccver < (4, 8, 2):
            conf.fatal('The version of gcc you are using (%s) is too old.\n'
                       'The minimum supported gcc version is 4.8.2.' %
                       '.'.join(conf.env['CC_VERSION']))
        flags = GccFlags()
    elif cxx == 'clang':
        if ccver < (3, 4, 0):
            conf.fatal('The version of clang you are using (%s) is too old.\n'
                       'The minimum supported clang version is 3.4.0.' %
                       '.'.join(conf.env['CC_VERSION']))
        flags = ClangFlags()
    else:
        flags = CompilerFlags()
        Logs.warn('The code has not yet been tested with %s compiler' % cxx)

    areCustomCxxflagsPresent = (len(conf.env.CXXFLAGS) > 0)

    # General flags are always applied (e.g., selecting C++11 mode)
    generalFlags = flags.getGeneralFlags(conf)
    conf.add_supported_cxxflags(generalFlags['CXXFLAGS'])
    conf.add_supported_linkflags(generalFlags['LINKFLAGS'])
    conf.env.DEFINES += generalFlags['DEFINES']

    # Debug or optimized CXXFLAGS and LINKFLAGS are applied only if the
    # corresponding environment variables are not set.
    # DEFINES are always applied.
    if conf.options.debug:
        extraFlags = flags.getDebugFlags(conf)
        if areCustomCxxflagsPresent:
            missingFlags = [x for x in extraFlags['CXXFLAGS'] if x not in conf.env.CXXFLAGS]
            if len(missingFlags) > 0:
                Logs.warn("Selected debug mode, but CXXFLAGS is set to a custom value '%s'"
                          % " ".join(conf.env.CXXFLAGS))
                Logs.warn("Default flags '%s' are not activated" % " ".join(missingFlags))
    else:
        extraFlags = flags.getOptimizedFlags(conf)

    if not areCustomCxxflagsPresent:
        conf.add_supported_cxxflags(extraFlags['CXXFLAGS'])
        conf.add_supported_linkflags(extraFlags['LINKFLAGS'])

    conf.env.DEFINES += extraFlags['DEFINES']

@Configure.conf
def add_supported_cxxflags(self, cxxflags):
    """
    Check which cxxflags are supported by compiler and add them to env.CXXFLAGS variable
    """
    if len(cxxflags) == 0:
        return

    self.start_msg('Checking supported CXXFLAGS')

    supportedFlags = []
    for flag in cxxflags:
        if self.check_cxx(cxxflags=['-Werror', flag], mandatory=False):
            supportedFlags += [flag]

    self.end_msg(' '.join(supportedFlags))
    self.env.prepend_value('CXXFLAGS', supportedFlags)

@Configure.conf
def add_supported_linkflags(self, linkflags):
    """
    Check which linkflags are supported by compiler and add them to env.LINKFLAGS variable
    """
    if len(linkflags) == 0:
        return

    self.start_msg('Checking supported LINKFLAGS')

    supportedFlags = []
    for flag in linkflags:
        if self.check_cxx(linkflags=['-Werror', flag], mandatory=False):
            supportedFlags += [flag]

    self.end_msg(' '.join(supportedFlags))
    self.env.prepend_value('LINKFLAGS', supportedFlags)


class CompilerFlags(object):
    def getGeneralFlags(self, conf):
        """Get dict of CXXFLAGS, LINKFLAGS, and DEFINES that are always needed"""
        return {'CXXFLAGS': [], 'LINKFLAGS': [], 'DEFINES': []}

    def getDebugFlags(self, conf):
        """Get dict of CXXFLAGS, LINKFLAGS, and DEFINES that are needed only in debug mode"""
        return {'CXXFLAGS': [], 'LINKFLAGS': [], 'DEFINES': ['_DEBUG']}

    def getOptimizedFlags(self, conf):
        """Get dict of CXXFLAGS, LINKFLAGS, and DEFINES that are needed only in optimized mode"""
        return {'CXXFLAGS': [], 'LINKFLAGS': [], 'DEFINES': ['NDEBUG']}

class GccBasicFlags(CompilerFlags):
    """
    This class defines basic flags that work for both gcc and clang compilers
    """
    def getGeneralFlags(self, conf):
        flags = super(GccBasicFlags, self).getGeneralFlags(conf)
        flags['CXXFLAGS'] += ['-std=c++11']
        return flags

    def getDebugFlags(self, conf):
        flags = super(GccBasicFlags, self).getDebugFlags(conf)
        flags['CXXFLAGS'] += ['-O0',
                              '-Og', # gcc >= 4.8, clang >= 4.0
                              '-g3',
                              '-pedantic',
                              '-Wall',
                              '-Wextra',
                              '-Werror',
                              '-Wno-unused-parameter',
                              '-Wno-error=maybe-uninitialized', # Bug #1615
                              '-Wno-error=deprecated-declarations', # Bug #3795
                              ]
        flags['LINKFLAGS'] += ['-fuse-ld=gold', '-Wl,-O1']
        return flags

    def getOptimizedFlags(self, conf):
        flags = super(GccBasicFlags, self).getOptimizedFlags(conf)
        flags['CXXFLAGS'] += ['-O2',
                              '-g',
                              '-pedantic',
                              '-Wall',
                              '-Wextra',
                              '-Wno-unused-parameter',
                              ]
        flags['LINKFLAGS'] += ['-fuse-ld=gold', '-Wl,-O1']
        return flags

class GccFlags(GccBasicFlags):
    def getDebugFlags(self, conf):
        flags = super(GccFlags, self).getDebugFlags(conf)
        version = tuple(int(i) for i in conf.env['CC_VERSION'])
        if version < (5, 1, 0):
            flags['CXXFLAGS'] += ['-Wno-missing-field-initializers']
        flags['CXXFLAGS'] += ['-fdiagnostics-color'] # gcc >= 4.9
        return flags

    def getOptimizedFlags(self, conf):
        flags = super(GccFlags, self).getOptimizedFlags(conf)
        version = tuple(int(i) for i in conf.env['CC_VERSION'])
        if version < (5, 1, 0):
            flags['CXXFLAGS'] += ['-Wno-missing-field-initializers']
        flags['CXXFLAGS'] += ['-fdiagnostics-color'] # gcc >= 4.9
        return flags

class ClangFlags(GccBasicFlags):
    def getGeneralFlags(self, conf):
        flags = super(ClangFlags, self).getGeneralFlags(conf)
        if Utils.unversioned_sys_platform() == 'darwin':
            flags['CXXFLAGS'] += ['-stdlib=libc++']
            flags['LINKFLAGS'] += ['-stdlib=libc++']
        return flags

    def getDebugFlags(self, conf):
        flags = super(ClangFlags, self).getDebugFlags(conf)
        flags['CXXFLAGS'] += ['-fcolor-diagnostics',
                              '-Wno-unused-local-typedef', # Bugs #2657 and #3209
                              '-Wno-error=unneeded-internal-declaration', # Bug #1588
                              '-Wno-error=deprecated-register',
                              '-Wno-error=keyword-macro', # Bug #3235
                              '-Wno-error=infinite-recursion', # Bug #3358
                              ]
        return flags

    def getOptimizedFlags(self, conf):
        flags = super(ClangFlags, self).getOptimizedFlags(conf)
        flags['CXXFLAGS'] += ['-fcolor-diagnostics',
                              '-Wno-unused-local-typedef', # Bugs #2657 and #3209
                              ]
        return flags