import imp
import os
import sys
import subprocess

from SCons.Script import BoolVariable, Dir, Environment, PathVariable, Variables
from distutils.version import LooseVersion
from SCons.Script import BoolVariable, Dir, Environment, File, PathVariable, SCons, Variables


monoreg = imp.load_source('mono_reg_utils', 'modules/mono/mono_reg_utils.py')


def find_file_in_dir(directory, files, prefix='', extension=''):
    if not extension.startswith('.'):
        extension = '.' + extension
    for curfile in files:
        if os.path.isfile(os.path.join(directory, prefix + curfile + extension)):
            return curfile
    return ''


def can_build(platform):
    if platform in ['javascript']:
        return False # Not yet supported
    return True


def is_enabled():
    # The module is disabled by default. Use module_mono_enabled=yes to enable it.
    return False


def get_doc_classes():
    return [
        '@C#',
        'CSharpScript',
        'GodotSharp',
    ]


def get_doc_path():
    return 'doc_classes'


def find_file_in_dir(directory, files, prefix='', extension=''):
    if not extension.startswith('.'):
        extension = '.' + extension
    for curfile in files:
        if os.path.isfile(os.path.join(directory, prefix + curfile + extension)):
            return curfile
    return ''


def copy_file(src_dir, dst_dir, name):
    from shutil import copyfile

    src_path = os.path.join(src_dir, name)
    dst_path = os.path.join(dst_dir, name)

    if not os.path.isdir(dst_dir):
        os.mkdir(dst_dir)

    copyfile(src_path, dst_path)


def configure(env):
    env.use_ptrcall = True
    env.add_module_version_string('mono')

    envvars = Variables()
    envvars.Add(BoolVariable('mono_static', 'Statically link mono', False))
    envvars.Add(PathVariable('mono_assemblies_output_dir', 'Path to the assemblies output directory', '#bin', PathVariable.PathIsDirCreate))
    envvars.Update(env)

    bits = env['bits']

    mono_static = env['mono_static']
    assemblies_output_dir = Dir(env['mono_assemblies_output_dir']).abspath

    mono_lib_names = ['mono-2.0-sgen', 'monosgen-2.0']

    if env['platform'] == 'windows':
        if bits == '32':
            if os.getenv('MONO32_PREFIX'):
                mono_root = os.getenv('MONO32_PREFIX')
            elif os.name == 'nt':
                mono_root = monoreg.find_mono_root_dir(bits)
        else:
            if os.getenv('MONO64_PREFIX'):
                mono_root = os.getenv('MONO64_PREFIX')
            elif os.name == 'nt':
                mono_root = monoreg.find_mono_root_dir(bits)

        if not mono_root:
            raise RuntimeError('Mono installation directory not found')

        mono_version = mono_root_try_find_mono_version(mono_root)
        configure_for_mono_version(env, mono_version)

        mono_lib_path = os.path.join(mono_root, 'lib')

        env.Append(LIBPATH=mono_lib_path)
        env.Append(CPPPATH=os.path.join(mono_root, 'include', 'mono-2.0'))

        if mono_static:
            lib_suffix = Environment()['LIBSUFFIX']

            if env.msvc:
                mono_static_lib_name = 'libmono-static-sgen'
            else:
                mono_static_lib_name = 'libmonosgen-2.0'

            if not os.path.isfile(os.path.join(mono_lib_path, mono_static_lib_name + lib_suffix)):
                raise RuntimeError('Could not find static mono library in: ' + mono_lib_path)

            if env.msvc:
                env.Append(LINKFLAGS=mono_static_lib_name + lib_suffix)

                env.Append(LINKFLAGS='Mincore' + lib_suffix)
                env.Append(LINKFLAGS='msvcrt' + lib_suffix)
                env.Append(LINKFLAGS='LIBCMT' + lib_suffix)
                env.Append(LINKFLAGS='Psapi' + lib_suffix)
            else:
                env.Append(LINKFLAGS=os.path.join(mono_lib_path, mono_static_lib_name + lib_suffix))

                env.Append(LIBS='psapi')
                env.Append(LIBS='version')
        else:
            mono_lib_name = find_file_in_dir(mono_lib_path, mono_lib_names, extension='.lib')

            if not mono_lib_name:
                raise RuntimeError('Could not find mono library in: ' + mono_lib_path)

            if env.msvc:
                env.Append(LINKFLAGS=mono_lib_name + Environment()['LIBSUFFIX'])
            else:
                env.Append(LIBS=mono_lib_name)

            mono_bin_path = os.path.join(mono_root, 'bin')

            mono_dll_name = find_file_in_dir(mono_bin_path, mono_lib_names, extension='.dll')

            if not mono_dll_name:
                raise RuntimeError('Could not find mono shared library in: ' + mono_bin_path)

            copy_file(mono_bin_path, 'bin', mono_dll_name + '.dll')

        copy_file(os.path.join(mono_lib_path, 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')
    else:
        sharedlib_ext = '.dylib' if sys.platform == 'darwin' else '.so'

        mono_root = ''
        mono_lib_path = ''

        if bits == '32':
            if os.getenv('MONO32_PREFIX'):
                mono_root = os.getenv('MONO32_PREFIX')
        else:
            if os.getenv('MONO64_PREFIX'):
                mono_root = os.getenv('MONO64_PREFIX')

        # We can't use pkg-config to link mono statically,
        # but we can still use it to find the mono root directory
        if not mono_root and mono_static:
            mono_root = pkgconfig_try_find_mono_root(mono_lib_names, sharedlib_ext)
            if not mono_root:
                raise RuntimeError('Building with mono_static=yes, but failed to find the mono prefix with pkg-config. Specify one manually')

        if mono_root:
            mono_version = mono_root_try_find_mono_version(mono_root)
            configure_for_mono_version(env, mono_version)

            mono_lib_path = os.path.join(mono_root, 'lib')

            env.Append(LIBPATH=mono_lib_path)
            env.Append(CPPPATH=os.path.join(mono_root, 'include', 'mono-2.0'))

            mono_lib = find_file_in_dir(mono_lib_path, mono_lib_names, prefix='lib', extension='.a')

            if not mono_lib:
                raise RuntimeError('Could not find mono library in: ' + mono_lib_path)

            env.Append(CPPFLAGS=['-D_REENTRANT'])

            if mono_static:
                mono_lib_file = os.path.join(mono_lib_path, 'lib' + mono_lib + '.a')

                if sys.platform == 'darwin':
                    env.Append(LINKFLAGS=['-Wl,-force_load,' + mono_lib_file])
                elif sys.platform == 'linux' or sys.platform == 'linux2':
                    env.Append(LINKFLAGS=['-Wl,-whole-archive', mono_lib_file, '-Wl,-no-whole-archive'])
                else:
                    raise RuntimeError('mono-static: Not supported on this platform')
            else:
                env.Append(LIBS=[mono_lib])

            if sys.platform == 'darwin':
                env.Append(LIBS=['iconv', 'pthread'])
            elif sys.platform == 'linux' or sys.platform == 'linux2':
                env.Append(LIBS=['m', 'rt', 'dl', 'pthread'])

            if not mono_static:
                mono_so_name = find_file_in_dir(mono_lib_path, mono_lib_names, prefix='lib', extension=sharedlib_ext)

                if not mono_so_name:
                    raise RuntimeError('Could not find mono shared library in: ' + mono_lib_path)

                copy_file(mono_lib_path, 'bin', 'lib' + mono_so_name + sharedlib_ext)

            copy_file(os.path.join(mono_lib_path, 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')
        else:
            if mono_static:
                raise RuntimeError('mono-static: Not supported with pkg-config. Specify a mono prefix manually')

            mono_version = pkgconfig_try_find_mono_version()
            configure_for_mono_version(env, mono_version)

            env.ParseConfig('pkg-config monosgen-2 --cflags --libs')

            mono_lib_path = ''
            mono_so_name = ''
            mono_prefix = subprocess.check_output(['pkg-config', 'mono-2', '--variable=prefix']).decode('utf8').strip()

            tmpenv = Environment()
            tmpenv.AppendENVPath('PKG_CONFIG_PATH', os.getenv('PKG_CONFIG_PATH'))
            tmpenv.ParseConfig('pkg-config monosgen-2 --libs-only-L')

            for hint_dir in tmpenv['LIBPATH']:
                name_found = find_file_in_dir(hint_dir, mono_lib_names, prefix='lib', extension=sharedlib_ext)
                if name_found:
                    mono_lib_path = hint_dir
                    mono_so_name = name_found
                    break

            if not mono_so_name:
                raise RuntimeError('Could not find mono shared library in: ' + str(tmpenv['LIBPATH']))

            copy_file(mono_lib_path, 'bin', 'lib' + mono_so_name + sharedlib_ext)
            copy_file(os.path.join(mono_prefix, 'lib', 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')

        env.Append(LINKFLAGS='-rdynamic')


def configure_for_mono_version(env, mono_version):
    if mono_version is None:
        raise RuntimeError('Mono JIT compiler version not found')
    print('Mono JIT compiler version: ' + str(mono_version))
    if mono_version >= LooseVersion("5.12.0"):
        env.Append(CPPFLAGS=['-DHAS_PENDING_EXCEPTIONS'])


def pkgconfig_try_find_mono_root(mono_lib_names, sharedlib_ext):
    tmpenv = Environment()
    tmpenv.AppendENVPath('PKG_CONFIG_PATH', os.getenv('PKG_CONFIG_PATH'))
    tmpenv.ParseConfig('pkg-config monosgen-2 --libs-only-L')
    for hint_dir in tmpenv['LIBPATH']:
        name_found = find_file_in_dir(hint_dir, mono_lib_names, prefix='lib', extension=sharedlib_ext)
        if name_found and os.path.isdir(os.path.join(hint_dir, '..', 'include', 'mono-2.0')):
            return os.path.join(hint_dir, '..')
    return ''


def pkgconfig_try_find_mono_version():
    lines = subprocess.check_output(['pkg-config', 'monosgen-2', '--modversion']).splitlines()
    greater_version = None
    for line in lines:
        try:
            version = LooseVersion(line)
            if greater_version is None or version > greater_version:
                greater_version = version
        except ValueError:
            pass
    return greater_version


def mono_root_try_find_mono_version(mono_root):
    first_line = subprocess.check_output([os.path.join(mono_root, 'bin', 'mono'), '--version']).splitlines()[0]
    try:
        return LooseVersion(first_line.split()[len('Mono JIT compiler version'.split())])
    except (ValueError, IndexError):
        return None