# Copyright 2015 The Meson development team

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import os, types
from pathlib import PurePath

from .. import build
from .. import dependencies
from ..dependencies.misc import ThreadDependency
from .. import mesonlib
from .. import mlog
from . import ModuleReturnValue
from . import ExtensionModule
from ..interpreterbase import permittedKwargs, FeatureNew, FeatureNewKwargs

already_warned_objs = set()

class DependenciesHelper:
    def __init__(self, state, name):
        self.state = state
        self.name = name
        self.pub_libs = []
        self.pub_reqs = []
        self.priv_libs = []
        self.priv_reqs = []
        self.cflags = []
        self.version_reqs = {}
        self.link_whole_targets = []

    def add_pub_libs(self, libs):
        libs, reqs, cflags = self._process_libs(libs, True)
        self.pub_libs = libs + self.pub_libs # prepend to preserve dependencies
        self.pub_reqs += reqs
        self.cflags += cflags

    def add_priv_libs(self, libs):
        libs, reqs, _ = self._process_libs(libs, False)
        self.priv_libs = libs + self.priv_libs
        self.priv_reqs += reqs

    def add_pub_reqs(self, reqs):
        self.pub_reqs += self._process_reqs(reqs)

    def add_priv_reqs(self, reqs):
        self.priv_reqs += self._process_reqs(reqs)

    def _check_generated_pc_deprecation(self, obj):
        if not hasattr(obj, 'generated_pc_warn'):
            return
        name = obj.generated_pc_warn[0]
        if (name, obj.name) in already_warned_objs:
            return
        mlog.deprecation('Library', mlog.bold(obj.name), 'was passed to the '
                         '"libraries" keyword argument of a previous call '
                         'to generate() method instead of first positional '
                         'argument.', 'Adding', mlog.bold(obj.generated_pc),
                         'to "Requires" field, but this is a deprecated '
                         'behaviour that will change in a future version '
                         'of Meson. Please report the issue if this '
                         'warning cannot be avoided in your case.',
                         location=obj.generated_pc_warn[1])
        already_warned_objs.add((name, obj.name))

    def _process_reqs(self, reqs):
        '''Returns string names of requirements'''
        processed_reqs = []
        for obj in mesonlib.unholder(mesonlib.listify(reqs)):
            if not isinstance(obj, str):
                FeatureNew.single_use('pkgconfig.generate requirement from non-string object', '0.46.0', self.state.subproject)
            if hasattr(obj, 'generated_pc'):
                self._check_generated_pc_deprecation(obj)
                processed_reqs.append(obj.generated_pc)
            elif hasattr(obj, 'pcdep'):
                pcdeps = mesonlib.listify(obj.pcdep)
                for d in pcdeps:
                    processed_reqs.append(d.name)
                    self.add_version_reqs(d.name, obj.version_reqs)
            elif isinstance(obj, dependencies.PkgConfigDependency):
                if obj.found():
                    processed_reqs.append(obj.name)
                    self.add_version_reqs(obj.name, obj.version_reqs)
            elif isinstance(obj, str):
                name, version_req = self.split_version_req(obj)
                processed_reqs.append(name)
                self.add_version_reqs(name, version_req)
            elif isinstance(obj, dependencies.Dependency) and not obj.found():
                pass
            elif isinstance(obj, ThreadDependency):
                pass
            else:
                raise mesonlib.MesonException('requires argument not a string, '
                                              'library with pkgconfig-generated file '
                                              'or pkgconfig-dependency object, '
                                              'got {!r}'.format(obj))
        return processed_reqs

    def add_cflags(self, cflags):
        self.cflags += mesonlib.stringlistify(cflags)

    def _process_libs(self, libs, public):
        libs = mesonlib.unholder(mesonlib.listify(libs))
        processed_libs = []
        processed_reqs = []
        processed_cflags = []
        for obj in libs:
            shared_library_only = getattr(obj, 'shared_library_only', False)
            if hasattr(obj, 'pcdep'):
                pcdeps = mesonlib.listify(obj.pcdep)
                for d in pcdeps:
                    processed_reqs.append(d.name)
                    self.add_version_reqs(d.name, obj.version_reqs)
            elif hasattr(obj, 'generated_pc'):
                self._check_generated_pc_deprecation(obj)
                processed_reqs.append(obj.generated_pc)
            elif isinstance(obj, dependencies.PkgConfigDependency):
                if obj.found():
                    processed_reqs.append(obj.name)
                    self.add_version_reqs(obj.name, obj.version_reqs)
            elif isinstance(obj, dependencies.InternalDependency):
                if obj.found():
                    processed_libs += obj.get_link_args()
                    processed_cflags += obj.get_compile_args()
                    self._add_lib_dependencies(obj.libraries, obj.whole_libraries, obj.ext_deps, public, private_external_deps=True)
            elif isinstance(obj, dependencies.Dependency):
                if obj.found():
                    processed_libs += obj.get_link_args()
                    processed_cflags += obj.get_compile_args()
            elif isinstance(obj, build.SharedLibrary) and shared_library_only:
                # Do not pull dependencies for shared libraries because they are
                # only required for static linking. Adding private requires has
                # the side effect of exposing their cflags, which is the
                # intended behaviour of pkg-config but force Debian to add more
                # than needed build deps.
                # See https://bugs.freedesktop.org/show_bug.cgi?id=105572
                processed_libs.append(obj)
            elif isinstance(obj, (build.SharedLibrary, build.StaticLibrary)):
                processed_libs.append(obj)
                # If there is a static library in `Libs:` all its deps must be
                # public too, otherwise the generated pc file will never be
                # usable without --static.
                self._add_lib_dependencies(obj.link_targets,
                                           obj.link_whole_targets,
                                           obj.external_deps,
                                           isinstance(obj, build.StaticLibrary) and public)
            elif isinstance(obj, (build.CustomTarget, build.CustomTargetIndex)):
                if not obj.is_linkable_target():
                    raise mesonlib.MesonException('library argument contains a not linkable custom_target.')
                FeatureNew.single_use('custom_target in pkgconfig.generate libraries', '0.58.0', self.state.subproject)
                processed_libs.append(obj)
            elif isinstance(obj, str):
                processed_libs.append(obj)
            else:
                raise mesonlib.MesonException('library argument not a string, library or dependency object.')

        return processed_libs, processed_reqs, processed_cflags

    def _add_lib_dependencies(self, link_targets, link_whole_targets, external_deps, public, private_external_deps=False):
        add_libs = self.add_pub_libs if public else self.add_priv_libs
        # Recursively add all linked libraries
        for t in link_targets:
            # Internal libraries (uninstalled static library) will be promoted
            # to link_whole, treat them as such here.
            if t.is_internal():
                self._add_link_whole(t, public)
            else:
                add_libs([t])
        for t in link_whole_targets:
            self._add_link_whole(t, public)
        # And finally its external dependencies
        if private_external_deps:
            self.add_priv_libs(external_deps)
        else:
            add_libs(external_deps)

    def _add_link_whole(self, t, public):
        # Don't include static libraries that we link_whole. But we still need to
        # include their dependencies: a static library we link_whole
        # could itself link to a shared library or an installed static library.
        # Keep track of link_whole_targets so we can remove them from our
        # lists in case a library is link_with and link_whole at the same time.
        # See remove_dups() below.
        self.link_whole_targets.append(t)
        self._add_lib_dependencies(t.link_targets, t.link_whole_targets, t.external_deps, public)

    def add_version_reqs(self, name, version_reqs):
        if version_reqs:
            if name not in self.version_reqs:
                self.version_reqs[name] = set()
            # Note that pkg-config is picky about whitespace.
            # 'foo > 1.2' is ok but 'foo>1.2' is not.
            # foo, bar' is ok, but 'foo,bar' is not.
            new_vreqs = [s for s in mesonlib.stringlistify(version_reqs)]
            self.version_reqs[name].update(new_vreqs)

    def split_version_req(self, s):
        for op in ['>=', '<=', '!=', '==', '=', '>', '<']:
            pos = s.find(op)
            if pos > 0:
                return s[0:pos].strip(), s[pos:].strip()
        return s, None

    def format_vreq(self, vreq):
        # vreq are '>=1.0' and pkgconfig wants '>= 1.0'
        for op in ['>=', '<=', '!=', '==', '=', '>', '<']:
            if vreq.startswith(op):
                return op + ' ' + vreq[len(op):]
        return vreq

    def format_reqs(self, reqs):
        result = []
        for name in reqs:
            vreqs = self.version_reqs.get(name, None)
            if vreqs:
                result += [name + ' ' + self.format_vreq(vreq) for vreq in vreqs]
            else:
                result += [name]
        return ', '.join(result)

    def remove_dups(self):
        # Set of ids that have already been handled and should not be added any more
        exclude = set()

        # We can't just check if 'x' is excluded because we could have copies of
        # the same SharedLibrary object for example.
        def _ids(x):
            if hasattr(x, 'generated_pc'):
                yield x.generated_pc
            if isinstance(x, build.Target):
                yield x.get_id()
            yield x

        # Exclude 'x' in all its forms and return if it was already excluded
        def _add_exclude(x):
            was_excluded = False
            for i in _ids(x):
                if i in exclude:
                    was_excluded = True
                else:
                    exclude.add(i)
            return was_excluded

        # link_whole targets are already part of other targets, exclude them all.
        for t in self.link_whole_targets:
            _add_exclude(t)

        def _fn(xs, libs=False):
            # Remove duplicates whilst preserving original order
            result = []
            for x in xs:
                # Don't de-dup unknown strings to avoid messing up arguments like:
                # ['-framework', 'CoreAudio', '-framework', 'CoreMedia']
                known_flags = ['-pthread']
                cannot_dedup = libs and isinstance(x, str) and \
                    not x.startswith(('-l', '-L')) and \
                    x not in known_flags
                if not cannot_dedup and _add_exclude(x):
                    continue
                result.append(x)
            return result

        # Handle lists in priority order: public items can be excluded from
        # private and Requires can excluded from Libs.
        self.pub_reqs = _fn(self.pub_reqs)
        self.pub_libs = _fn(self.pub_libs, True)
        self.priv_reqs = _fn(self.priv_reqs)
        self.priv_libs = _fn(self.priv_libs, True)
        # Reset exclude list just in case some values can be both cflags and libs.
        exclude = set()
        self.cflags = _fn(self.cflags)

class PkgConfigModule(ExtensionModule):

    def _get_lname(self, l, msg, pcfile, is_custom_target):
        if is_custom_target:
            basename = os.path.basename(l.get_filename())
            name = os.path.splitext(basename)[0]
            if name.startswith('lib'):
                name = name[3:]
            return name
        # Nothing special
        if not l.name_prefix_set:
            return l.name
        # Sometimes people want the library to start with 'lib' everywhere,
        # which is achieved by setting name_prefix to '' and the target name to
        # 'libfoo'. In that case, try to get the pkg-config '-lfoo' arg correct.
        if l.prefix == '' and l.name.startswith('lib'):
            return l.name[3:]
        # If the library is imported via an import library which is always
        # named after the target name, '-lfoo' is correct.
        if isinstance(l, build.SharedLibrary) and l.import_filename:
            return l.name
        # In other cases, we can't guarantee that the compiler will be able to
        # find the library via '-lfoo', so tell the user that.
        mlog.warning(msg.format(l.name, 'name_prefix', l.name, pcfile))
        return l.name

    def _escape(self, value):
        '''
        We cannot use quote_arg because it quotes with ' and " which does not
        work with pkg-config and pkgconf at all.
        '''
        # We should always write out paths with / because pkg-config requires
        # spaces to be quoted with \ and that messes up on Windows:
        # https://bugs.freedesktop.org/show_bug.cgi?id=103203
        if isinstance(value, PurePath):
            value = value.as_posix()
        return value.replace(' ', r'\ ')

    def _make_relative(self, prefix, subdir):
        prefix = PurePath(prefix)
        subdir = PurePath(subdir)
        try:
            return subdir.relative_to(prefix).as_posix()
        except ValueError:
            return subdir.as_posix()

    def generate_pkgconfig_file(self, state, deps, subdirs, name, description,
                                url, version, pcfile, conflicts, variables,
                                uninstalled=False, dataonly=False):
        coredata = state.environment.get_coredata()
        if uninstalled:
            outdir = os.path.join(state.environment.build_dir, 'meson-uninstalled')
            if not os.path.exists(outdir):
                os.mkdir(outdir)
            prefix = PurePath(state.environment.get_build_dir())
            srcdir = PurePath(state.environment.get_source_dir())
        else:
            outdir = state.environment.scratch_dir
            prefix = PurePath(coredata.get_option(mesonlib.OptionKey('prefix')))
        # These always return paths relative to prefix
        libdir = PurePath(coredata.get_option(mesonlib.OptionKey('libdir')))
        incdir = PurePath(coredata.get_option(mesonlib.OptionKey('includedir')))
        fname = os.path.join(outdir, pcfile)
        with open(fname, 'w', encoding='utf-8') as ofile:
            if not dataonly:
                ofile.write('prefix={}\n'.format(self._escape(prefix)))
                if uninstalled:
                    ofile.write('srcdir={}\n'.format(self._escape(srcdir)))
                ofile.write('libdir={}\n'.format(self._escape('${prefix}' / libdir)))
                ofile.write('includedir={}\n'.format(self._escape('${prefix}' / incdir)))
            if variables:
                ofile.write('\n')
            for k, v in variables:
                ofile.write('{}={}\n'.format(k, self._escape(v)))
            ofile.write('\n')
            ofile.write('Name: %s\n' % name)
            if len(description) > 0:
                ofile.write('Description: %s\n' % description)
            if len(url) > 0:
                ofile.write('URL: %s\n' % url)
            ofile.write('Version: %s\n' % version)
            reqs_str = deps.format_reqs(deps.pub_reqs)
            if len(reqs_str) > 0:
                ofile.write(f'Requires: {reqs_str}\n')
            reqs_str = deps.format_reqs(deps.priv_reqs)
            if len(reqs_str) > 0:
                ofile.write(f'Requires.private: {reqs_str}\n')
            if len(conflicts) > 0:
                ofile.write('Conflicts: {}\n'.format(' '.join(conflicts)))

            def generate_libs_flags(libs):
                msg = 'Library target {0!r} has {1!r} set. Compilers ' \
                      'may not find it from its \'-l{2}\' linker flag in the ' \
                      '{3!r} pkg-config file.'
                Lflags = []
                for l in libs:
                    if isinstance(l, str):
                        yield l
                    else:
                        if uninstalled:
                            install_dir = os.path.dirname(state.backend.get_target_filename_abs(l))
                        else:
                            install_dir = l.get_custom_install_dir()[0]
                        if install_dir is False:
                            continue
                        is_custom_target = isinstance(l, (build.CustomTarget, build.CustomTargetIndex))
                        if not is_custom_target and 'cs' in l.compilers:
                            if isinstance(install_dir, str):
                                Lflag = '-r${{prefix}}/{}/{}'.format(self._escape(self._make_relative(prefix, install_dir)), l.filename)
                            else:  # install_dir is True
                                Lflag = '-r${libdir}/%s' % l.filename
                        else:
                            if isinstance(install_dir, str):
                                Lflag = '-L${prefix}/%s' % self._escape(self._make_relative(prefix, install_dir))
                            else:  # install_dir is True
                                Lflag = '-L${libdir}'
                        if Lflag not in Lflags:
                            Lflags.append(Lflag)
                            yield Lflag
                        lname = self._get_lname(l, msg, pcfile, is_custom_target)
                        # If using a custom suffix, the compiler may not be able to
                        # find the library
                        if not is_custom_target and l.name_suffix_set:
                            mlog.warning(msg.format(l.name, 'name_suffix', lname, pcfile))
                        if is_custom_target or 'cs' not in l.compilers:
                            yield '-l%s' % lname

            def get_uninstalled_include_dirs(libs):
                result = []
                for l in libs:
                    if isinstance(l, (str, build.CustomTarget, build.CustomTargetIndex)):
                        continue
                    if l.get_subdir() not in result:
                        result.append(l.get_subdir())
                    for i in l.get_include_dirs():
                        curdir = i.get_curdir()
                        for d in i.get_incdirs():
                            path = os.path.join(curdir, d)
                            if path not in result:
                                result.append(path)
                return result

            def generate_uninstalled_cflags(libs):
                for d in get_uninstalled_include_dirs(libs):
                    for basedir in ['${prefix}', '${srcdir}']:
                        path = PurePath(basedir, d)
                        yield '-I%s' % self._escape(path.as_posix())

            if len(deps.pub_libs) > 0:
                ofile.write('Libs: {}\n'.format(' '.join(generate_libs_flags(deps.pub_libs))))
            if len(deps.priv_libs) > 0:
                ofile.write('Libs.private: {}\n'.format(' '.join(generate_libs_flags(deps.priv_libs))))

            cflags = []
            if uninstalled:
                cflags += generate_uninstalled_cflags(deps.pub_libs + deps.priv_libs)
            else:
                for d in subdirs:
                    if d == '.':
                        cflags.append('-I${includedir}')
                    else:
                        cflags.append(self._escape(PurePath('-I${includedir}') / d))
            cflags += [self._escape(f) for f in deps.cflags]
            if cflags and not dataonly:
                ofile.write('Cflags: {}\n'.format(' '.join(cflags)))

    @FeatureNewKwargs('pkgconfig.generate', '0.54.0', ['uninstalled_variables'])
    @FeatureNewKwargs('pkgconfig.generate', '0.42.0', ['extra_cflags'])
    @FeatureNewKwargs('pkgconfig.generate', '0.41.0', ['variables'])
    @FeatureNewKwargs('pkgconfig.generate', '0.54.0', ['dataonly'])
    @permittedKwargs({'libraries', 'version', 'name', 'description', 'filebase',
                      'subdirs', 'requires', 'requires_private', 'libraries_private',
                      'install_dir', 'extra_cflags', 'variables', 'url', 'd_module_versions',
                      'dataonly', 'conflicts', 'uninstalled_variables'})
    def generate(self, state, args, kwargs):
        default_version = state.project_version['version']
        default_install_dir = None
        default_description = None
        default_name = None
        mainlib = None
        default_subdirs = ['.']
        if not args and 'version' not in kwargs:
            FeatureNew.single_use('pkgconfig.generate implicit version keyword', '0.46.0', state.subproject)
        elif len(args) == 1:
            FeatureNew.single_use('pkgconfig.generate optional positional argument', '0.46.0', state.subproject)
            mainlib = getattr(args[0], 'held_object', args[0])
            if not isinstance(mainlib, (build.StaticLibrary, build.SharedLibrary)):
                raise mesonlib.MesonException('Pkgconfig_gen first positional argument must be a library object')
            default_name = mainlib.name
            default_description = state.project_name + ': ' + mainlib.name
            install_dir = mainlib.get_custom_install_dir()[0]
            if isinstance(install_dir, str):
                default_install_dir = os.path.join(install_dir, 'pkgconfig')
        elif len(args) > 1:
            raise mesonlib.MesonException('Too many positional arguments passed to Pkgconfig_gen.')

        dataonly = kwargs.get('dataonly', False)
        if not isinstance(dataonly, bool):
            raise mesonlib.MesonException('dataonly must be boolean.')
        if dataonly:
            default_subdirs = []
            blocked_vars = ['libraries', 'libraries_private', 'require_private', 'extra_cflags', 'subdirs']
            if any(k in kwargs for k in blocked_vars):
                raise mesonlib.MesonException(f'Cannot combine dataonly with any of {blocked_vars}')

        subdirs = mesonlib.stringlistify(kwargs.get('subdirs', default_subdirs))
        version = kwargs.get('version', default_version)
        if not isinstance(version, str):
            raise mesonlib.MesonException('Version must be specified.')
        name = kwargs.get('name', default_name)
        if not isinstance(name, str):
            raise mesonlib.MesonException('Name not specified.')
        filebase = kwargs.get('filebase', name)
        if not isinstance(filebase, str):
            raise mesonlib.MesonException('Filebase must be a string.')
        description = kwargs.get('description', default_description)
        if not isinstance(description, str):
            raise mesonlib.MesonException('Description is not a string.')
        url = kwargs.get('url', '')
        if not isinstance(url, str):
            raise mesonlib.MesonException('URL is not a string.')
        conflicts = mesonlib.stringlistify(kwargs.get('conflicts', []))

        # Prepend the main library to public libraries list. This is required
        # so dep.add_pub_libs() can handle dependency ordering correctly and put
        # extra libraries after the main library.
        libraries = mesonlib.extract_as_list(kwargs, 'libraries')
        if mainlib:
            libraries = [mainlib] + libraries

        deps = DependenciesHelper(state, filebase)
        deps.add_pub_libs(libraries)
        deps.add_priv_libs(kwargs.get('libraries_private', []))
        deps.add_pub_reqs(kwargs.get('requires', []))
        deps.add_priv_reqs(kwargs.get('requires_private', []))
        deps.add_cflags(kwargs.get('extra_cflags', []))

        dversions = kwargs.get('d_module_versions', None)
        if dversions:
            compiler = state.environment.coredata.compilers.host.get('d')
            if compiler:
                deps.add_cflags(compiler.get_feature_args({'versions': dversions}, None))

        deps.remove_dups()

        def parse_variable_list(vardict):
            reserved = ['prefix', 'libdir', 'includedir']
            variables = []
            for name, value in vardict.items():
                if not dataonly and name in reserved:
                    raise mesonlib.MesonException(f'Variable "{name}" is reserved')
                variables.append((name, value))
            return variables

        variables = self.interpreter.extract_variables(kwargs, dict_new=True)
        variables = parse_variable_list(variables)

        pcfile = filebase + '.pc'
        pkgroot = kwargs.get('install_dir', default_install_dir)
        if pkgroot is None:
            pkgroot = os.path.join(state.environment.coredata.get_option(mesonlib.OptionKey('libdir')), 'pkgconfig')
        if not isinstance(pkgroot, str):
            raise mesonlib.MesonException('Install_dir must be a string.')
        self.generate_pkgconfig_file(state, deps, subdirs, name, description, url,
                                     version, pcfile, conflicts, variables,
                                     False, dataonly)
        res = build.Data([mesonlib.File(True, state.environment.get_scratch_dir(), pcfile)], pkgroot, None, state.subproject)
        variables = self.interpreter.extract_variables(kwargs, argname='uninstalled_variables', dict_new=True)
        variables = parse_variable_list(variables)

        pcfile = filebase + '-uninstalled.pc'
        self.generate_pkgconfig_file(state, deps, subdirs, name, description, url,
                                     version, pcfile, conflicts, variables,
                                     uninstalled=True, dataonly=dataonly)
        # Associate the main library with this generated pc file. If the library
        # is used in any subsequent call to the generated, it will generate a
        # 'Requires:' or 'Requires.private:'.
        # Backward compatibility: We used to set 'generated_pc' on all public
        # libraries instead of just the main one. Keep doing that but warn if
        # anyone is relying on that deprecated behaviour.
        if mainlib:
            if not hasattr(mainlib, 'generated_pc'):
                mainlib.generated_pc = filebase
            else:
                mlog.warning('Already generated a pkg-config file for', mlog.bold(mainlib.name))
        else:
            for lib in deps.pub_libs:
                if not isinstance(lib, str) and not hasattr(lib, 'generated_pc'):
                    lib.generated_pc = filebase
                    location = state.current_node
                    lib.generated_pc_warn = [name, location]
        return ModuleReturnValue(res, [res])

def initialize(*args, **kwargs):
    return PkgConfigModule(*args, **kwargs)
