# Copyright 2018 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.

'''This module provides helper functions for generating documentation using hotdoc'''

import os
from collections import OrderedDict

from mesonbuild import mesonlib
from mesonbuild import mlog, build
from mesonbuild.coredata import MesonException
from . import ModuleReturnValue
from . import ExtensionModule
from ..dependencies import Dependency, InternalDependency
from ..interpreterbase import FeatureNew, InvalidArguments, noPosargs, noKwargs
from ..interpreter import CustomTargetHolder
from ..programs import ExternalProgram


def ensure_list(value):
    if not isinstance(value, list):
        return [value]
    return value


MIN_HOTDOC_VERSION = '0.8.100'


class HotdocTargetBuilder:
    def __init__(self, name, state, hotdoc, interpreter, kwargs):
        self.hotdoc = hotdoc
        self.build_by_default = kwargs.pop('build_by_default', False)
        self.kwargs = kwargs
        self.name = name
        self.state = state
        self.interpreter = interpreter
        self.include_paths = OrderedDict()

        self.builddir = state.environment.get_build_dir()
        self.sourcedir = state.environment.get_source_dir()
        self.subdir = state.subdir
        self.build_command = state.environment.get_build_command()

        self.cmd = ['conf', '--project-name', name, "--disable-incremental-build",
                    '--output', os.path.join(self.builddir, self.subdir, self.name + '-doc')]

        self._extra_extension_paths = set()
        self.extra_assets = set()
        self._dependencies = []
        self._subprojects = []

    def process_known_arg(self, option, types, argname=None,
                          value_processor=None, mandatory=False,
                          force_list=False):
        if not argname:
            argname = option.strip("-").replace("-", "_")

        value, _ = self.get_value(
            types, argname, None, value_processor, mandatory, force_list)

        self.set_arg_value(option, value)

    def set_arg_value(self, option, value):
        if value is None:
            return

        if isinstance(value, bool):
            if value:
                self.cmd.append(option)
        elif isinstance(value, list):
            # Do not do anything on empty lists
            if value:
                # https://bugs.python.org/issue9334 (from 2010 :( )
                # The syntax with nargs=+ is inherently ambiguous
                # A workaround for this case is to simply prefix with a space
                # every value starting with a dash
                escaped_value = []
                for e in value:
                    if isinstance(e, str) and e.startswith('-'):
                        escaped_value += [' %s' % e]
                    else:
                        escaped_value += [e]
                if option:
                    self.cmd.extend([option] + escaped_value)
                else:
                    self.cmd.extend(escaped_value)
        else:
            # argparse gets confused if value(s) start with a dash.
            # When an option expects a single value, the unambiguous way
            # to specify it is with =
            if isinstance(value, str):
                self.cmd.extend([f'{option}={value}'])
            else:
                self.cmd.extend([option, value])

    def check_extra_arg_type(self, arg, value):
        value = getattr(value, 'held_object', value)
        if isinstance(value, list):
            for v in value:
                self.check_extra_arg_type(arg, v)
            return

        valid_types = (str, bool, mesonlib.File, build.IncludeDirs, build.CustomTarget, build.BuildTarget)
        if not isinstance(value, valid_types):
            raise InvalidArguments('Argument "{}={}" should be of type: {}.'.format(
                arg, value, [t.__name__ for t in valid_types]))

    def process_extra_args(self):
        for arg, value in self.kwargs.items():
            option = "--" + arg.replace("_", "-")
            self.check_extra_arg_type(arg, value)
            self.set_arg_value(option, value)

    def get_value(self, types, argname, default=None, value_processor=None,
                  mandatory=False, force_list=False):
        if not isinstance(types, list):
            types = [types]
        try:
            uvalue = value = self.kwargs.pop(argname)
            if value_processor:
                value = value_processor(value)

            for t in types:
                if isinstance(value, t):
                    if force_list and not isinstance(value, list):
                        return [value], uvalue
                    return value, uvalue
            raise MesonException("%s field value %s is not valid,"
                                 " valid types are %s" % (argname, value,
                                                          types))
        except KeyError:
            if mandatory:
                raise MesonException("%s mandatory field not found" % argname)

            if default is not None:
                return default, default

        return None, None

    def setup_extension_paths(self, paths):
        if not isinstance(paths, list):
            paths = [paths]

        for path in paths:
            self.add_extension_paths([path])

        return []

    def add_extension_paths(self, paths):
        for path in paths:
            if path in self._extra_extension_paths:
                continue

            self._extra_extension_paths.add(path)
            self.cmd.extend(["--extra-extension-path", path])

    def process_extra_extension_paths(self):
        self.get_value([list, str], 'extra_extensions_paths',
                       default="", value_processor=self.setup_extension_paths)

    def replace_dirs_in_string(self, string):
        return string.replace("@SOURCE_ROOT@", self.sourcedir).replace("@BUILD_ROOT@", self.builddir)

    def process_gi_c_source_roots(self):
        if self.hotdoc.run_hotdoc(['--has-extension=gi-extension']) != 0:
            return

        value, _ = self.get_value([list, str], 'gi_c_source_roots', default=[], force_list=True)
        value.extend([
            os.path.join(self.state.environment.get_source_dir(),
                         self.interpreter.subproject_dir, self.state.subproject),
            os.path.join(self.state.environment.get_build_dir(), self.interpreter.subproject_dir, self.state.subproject)
        ])

        self.cmd += ['--gi-c-source-roots'] + value

    def process_dependencies(self, deps):
        cflags = set()
        for dep in mesonlib.listify(ensure_list(deps)):
            dep = getattr(dep, "held_object", dep)
            if isinstance(dep, InternalDependency):
                inc_args = self.state.get_include_args(dep.include_directories)
                cflags.update([self.replace_dirs_in_string(x)
                               for x in inc_args])
                cflags.update(self.process_dependencies(dep.libraries))
                cflags.update(self.process_dependencies(dep.sources))
                cflags.update(self.process_dependencies(dep.ext_deps))
            elif isinstance(dep, Dependency):
                cflags.update(dep.get_compile_args())
            elif isinstance(dep, (build.StaticLibrary, build.SharedLibrary)):
                self._dependencies.append(dep)
                for incd in dep.get_include_dirs():
                    cflags.update(incd.get_incdirs())
            elif isinstance(dep, HotdocTarget):
                # Recurse in hotdoc target dependencies
                self.process_dependencies(dep.get_target_dependencies())
                self._subprojects.extend(dep.subprojects)
                self.process_dependencies(dep.subprojects)
                self.add_include_path(os.path.join(self.builddir, dep.hotdoc_conf.subdir))
                self.cmd += ['--extra-assets=' + p for p in dep.extra_assets]
                self.add_extension_paths(dep.extra_extension_paths)
            elif isinstance(dep, build.CustomTarget) or isinstance(dep, build.BuildTarget):
                self._dependencies.append(dep)

        return [f.strip('-I') for f in cflags]

    def process_extra_assets(self):
        self._extra_assets, _ = self.get_value("--extra-assets", (str, list), default=[],
                                               force_list=True)
        for assets_path in self._extra_assets:
            self.cmd.extend(["--extra-assets", assets_path])

    def process_subprojects(self):
        _, value = self.get_value([
            list, HotdocTarget], argname="subprojects",
            force_list=True, value_processor=self.process_dependencies)

        if value is not None:
            self._subprojects.extend(value)

    def flatten_config_command(self):
        cmd = []
        for arg in mesonlib.listify(self.cmd, flatten=True):
            arg = getattr(arg, 'held_object', arg)
            if isinstance(arg, mesonlib.File):
                arg = arg.absolute_path(self.state.environment.get_source_dir(),
                                        self.state.environment.get_build_dir())
            elif isinstance(arg, build.IncludeDirs):
                for inc_dir in arg.get_incdirs():
                    cmd.append(os.path.join(self.sourcedir, arg.get_curdir(), inc_dir))
                    cmd.append(os.path.join(self.builddir, arg.get_curdir(), inc_dir))

                continue
            elif isinstance(arg, build.CustomTarget) or isinstance(arg, build.BuildTarget):
                self._dependencies.append(arg)
                arg = self.interpreter.backend.get_target_filename_abs(arg)

            cmd.append(arg)

        return cmd

    def generate_hotdoc_config(self):
        cwd = os.path.abspath(os.curdir)
        ncwd = os.path.join(self.sourcedir, self.subdir)
        mlog.log('Generating Hotdoc configuration for: ', mlog.bold(self.name))
        os.chdir(ncwd)
        self.hotdoc.run_hotdoc(self.flatten_config_command())
        os.chdir(cwd)

    def ensure_file(self, value):
        if isinstance(value, list):
            res = []
            for val in value:
                res.append(self.ensure_file(val))
            return res

        if not isinstance(value, mesonlib.File):
            return mesonlib.File.from_source_file(self.sourcedir, self.subdir, value)

        return value

    def ensure_dir(self, value):
        if os.path.isabs(value):
            _dir = value
        else:
            _dir = os.path.join(self.sourcedir, self.subdir, value)

        if not os.path.isdir(_dir):
            raise InvalidArguments('"%s" is not a directory.' % _dir)

        return os.path.relpath(_dir, os.path.join(self.builddir, self.subdir))

    def check_forbidden_args(self):
        for arg in ['conf_file']:
            if arg in self.kwargs:
                raise InvalidArguments('Argument "%s" is forbidden.' % arg)

    def add_include_path(self, path):
        self.include_paths[path] = path

    def make_targets(self):
        self.check_forbidden_args()
        file_types = (str, mesonlib.File)
        self.process_known_arg("--index", file_types, mandatory=True, value_processor=self.ensure_file)
        self.process_known_arg("--project-version", str, mandatory=True)
        self.process_known_arg("--sitemap", file_types, mandatory=True, value_processor=self.ensure_file)
        self.process_known_arg("--html-extra-theme", str, value_processor=self.ensure_dir)
        self.process_known_arg(None, list, "include_paths", force_list=True,
                               value_processor=lambda x: [self.add_include_path(self.ensure_dir(v)) for v in ensure_list(x)])
        self.process_known_arg('--c-include-directories',
                               [Dependency, build.StaticLibrary, build.SharedLibrary, list], argname="dependencies",
                               force_list=True, value_processor=self.process_dependencies)
        self.process_gi_c_source_roots()
        self.process_extra_assets()
        self.process_extra_extension_paths()
        self.process_subprojects()

        install, install = self.get_value(bool, "install", mandatory=False)
        self.process_extra_args()

        fullname = self.name + '-doc'
        hotdoc_config_name = fullname + '.json'
        hotdoc_config_path = os.path.join(
            self.builddir, self.subdir, hotdoc_config_name)
        with open(hotdoc_config_path, 'w', encoding='utf-8') as f:
            f.write('{}')

        self.cmd += ['--conf-file', hotdoc_config_path]
        self.add_include_path(os.path.join(self.builddir, self.subdir))
        self.add_include_path(os.path.join(self.sourcedir, self.subdir))

        depfile = os.path.join(self.builddir, self.subdir, self.name + '.deps')
        self.cmd += ['--deps-file-dest', depfile]

        for path in self.include_paths.keys():
            self.cmd.extend(['--include-path', path])

        if self.state.environment.coredata.get_option(mesonlib.OptionKey('werror', subproject=self.state.subproject)):
            self.cmd.append('--fatal-warning')
        self.generate_hotdoc_config()

        target_cmd = self.build_command + ["--internal", "hotdoc"] + \
            self.hotdoc.get_command() + ['run', '--conf-file', hotdoc_config_name] + \
            ['--builddir', os.path.join(self.builddir, self.subdir)]

        target = HotdocTarget(fullname,
                              subdir=self.subdir,
                              subproject=self.state.subproject,
                              hotdoc_conf=mesonlib.File.from_built_file(
                                  self.subdir, hotdoc_config_name),
                              extra_extension_paths=self._extra_extension_paths,
                              extra_assets=self._extra_assets,
                              subprojects=self._subprojects,
                              command=target_cmd,
                              depends=self._dependencies,
                              output=fullname,
                              depfile=os.path.basename(depfile),
                              build_by_default=self.build_by_default)

        install_script = None
        if install is True:
            install_script = self.state.backend.get_executable_serialisation(self.build_command + [
                "--internal", "hotdoc",
                "--install", os.path.join(fullname, 'html'),
                '--name', self.name,
                '--builddir', os.path.join(self.builddir, self.subdir)] +
                self.hotdoc.get_command() +
                ['run', '--conf-file', hotdoc_config_name])

        return (target, install_script)


class HotdocTargetHolder(CustomTargetHolder):
    def __init__(self, target, interp):
        super().__init__(target, interp)
        self.methods.update({'config_path': self.config_path_method})

    @noPosargs
    @noKwargs
    def config_path_method(self, *args, **kwargs):
        conf = self.held_object.hotdoc_conf.absolute_path(self.interpreter.environment.source_dir,
                                                          self.interpreter.environment.build_dir)
        return self.interpreter.holderify(conf)


class HotdocTarget(build.CustomTarget):
    def __init__(self, name, subdir, subproject, hotdoc_conf, extra_extension_paths, extra_assets,
                 subprojects, **kwargs):
        super().__init__(name, subdir, subproject, kwargs, absolute_paths=True)
        self.hotdoc_conf = hotdoc_conf
        self.extra_extension_paths = extra_extension_paths
        self.extra_assets = extra_assets
        self.subprojects = subprojects

    def __getstate__(self):
        # Make sure we do not try to pickle subprojects
        res = self.__dict__.copy()
        res['subprojects'] = []

        return res


class HotDocModule(ExtensionModule):
    @FeatureNew('Hotdoc Module', '0.48.0')
    def __init__(self, interpreter):
        super().__init__(interpreter)
        self.hotdoc = ExternalProgram('hotdoc')
        if not self.hotdoc.found():
            raise MesonException('hotdoc executable not found')

        try:
            from hotdoc.run_hotdoc import run  # noqa: F401
            self.hotdoc.run_hotdoc = run
        except Exception as e:
            raise MesonException('hotdoc {} required but not found. ({})'.format(
                MIN_HOTDOC_VERSION, e))

    @noKwargs
    def has_extensions(self, state, args, kwargs):
        res = self.hotdoc.run_hotdoc(['--has-extension=%s' % extension for extension in args]) == 0
        return ModuleReturnValue(res, [res])

    def generate_doc(self, state, args, kwargs):
        if len(args) != 1:
            raise MesonException('One positional argument is'
                                 ' required for the project name.')

        project_name = args[0]
        builder = HotdocTargetBuilder(project_name, state, self.hotdoc, self.interpreter, kwargs)
        target, install_script = builder.make_targets()
        targets = [HotdocTargetHolder(target, self.interpreter)]
        if install_script:
            targets.append(install_script)

        return ModuleReturnValue(targets[0], targets)


def initialize(interpreter):
    return HotDocModule(interpreter)
