#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
#
# 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.

from __future__ import print_function
import argparse
import sys
import types
import os
import contextlib
import paddle.fluid as fluid
import paddle.tensor as tensor
import paddle.nn as nn
import paddle.complex as complex
import paddle.distributed as distributed
#import paddle.framework as framework

def parse_arg():
    parser = argparse.ArgumentParser()
    parser.add_argument('--submodules', nargs="*")
    parser.add_argument(
        '--module_name', type=str, help='Generate the documentation of which module')
    parser.add_argument(
        '--module_prefix', type=str, help='Generate the prefix of module')
    parser.add_argument(
        '--output', type=str, help='Output file or output directory for output rst')
    parser.add_argument(
        '--output_name', type=str, help='Output file or output directory for output rst')
    parser.add_argument(
        '--output_dir', type=str, help='Output file or output directory for output rst')
    parser.add_argument(
        '--to_multiple_files', type=bool, default=False, help='Whether to separate to multiple files')

    return parser.parse_args()

    def print_item(self, name):
        item = getattr(self.module, name, None)
        if item is None:
            return
        if isinstance(item, types.TypeType):
            self.print_class(name)
        elif isinstance(item, types.FunctionType):
            self.print_method(name)
        else:
            pass

class DocGenerator(object):
    def __init__(self, module_name=None, module_prefix=None): 
        self.module_name = module_name
        self.module_prefix = module_prefix
        self.stream = None

    @contextlib.contextmanager
    def guard(self, filename):
        assert self.stream is None, "stream must be None"
        self.stream = open(filename, 'w') 
        yield
        self.stream.close()
        self.stream = None

    def print_submodule(self, submodule_name):
        submodule = getattr(self.module, submodule_name)
        if submodule is None:
            raise ValueError("Cannot find submodule {0}".format(submodule_name))
        self.print_section(submodule_name)

        for item in sorted(submodule.__all__,key=str.lower):
            self.print_item(item)

    def print_current_module(self):
        for item in sorted(self.module.__all__,key=str.lower):
            self.print_item(item)

    def print_section(self, name):
        self._print_header_(name, dot='=', is_title=False)

    def print_item(self, name, output_name):
        item = getattr(self.module, name, None)
        if isinstance(item, types.TypeType):
            self.print_class(name)
        elif isinstance(item, types.FunctionType):
            self.print_method(name)
        else:
            self.stream.close()
            path = os.getcwd()+"/"+output_name+"/"+name+".rst"
            if name != "PipeReader":
                os.remove(path)

    def print_class(self, name):
        self._print_ref_(name)
        self._print_header_(name, dot='-', is_title=False)
        if "fluid.dygraph" in self.module_prefix:
            self.stream.write('''..  autoclass:: paddle.{0}.{1}
    :members:
    :noindex:

'''.format(self.module_prefix, name))
        elif "fluid.optimizer" in self.module_prefix:
            self.stream.write('''..  autoclass:: paddle.{0}.{1}
    :members:
    :inherited-members:
    :exclude-members: apply_gradients, apply_optimize, backward, load
    :noindex:

'''.format(self.module_prefix, name))
        else:
            self.stream.write('''..  autoclass:: paddle.{0}.{1}
    :members:
    :inherited-members:
    :noindex:

'''.format(self.module_prefix, name))

    def print_method(self, name):
        self._print_ref_(name)
        self._print_header_(name, dot='-', is_title=False)
        self.stream.write('''..  autofunction:: paddle.{0}.{1}
    :noindex:

'''.format(self.module_prefix, name))

    def print_header_reminder(self):
        self.stream.write('''..  THIS FILE IS GENERATED BY `gen_doc.{py|sh}`
    !DO NOT EDIT THIS FILE MANUALLY!

''')

    def _print_header_(self, name, dot, is_title):
        dot_line = dot * len(name)
        if is_title:
            self.stream.write(dot_line)
            self.stream.write('\n')
        self.stream.write(name)
        self.stream.write('\n')
        self.stream.write(dot_line)
        self.stream.write('\n')
        self.stream.write('\n')

    def _print_ref_(self, name):
        self.stream.write(".. _api_{0}_{1}:\n\n".format("_".join(
            self.module_prefix.split(".")), name))

def generate_doc(module_name, module_prefix, output, output_name, to_multiple_files, output_dir):
    if module_name == "":
        module_name = None

    if module_prefix == "":
        module_prefix = None

    gen = DocGenerator()

    if module_name is None:
        gen.module = eval(output_name)
        gen.module_name = str(output_name)
    else:
        gen.module = eval(output_name)
        for each_module_name in module_name.split('.'):
            if not hasattr(gen.module, each_module_name):
                raise ValueError("Cannot find fluid.{0}".format(module_name))
            else:
                gen.module = getattr(gen.module, each_module_name)

        gen.module_name = output_name + "." + module_name

    if module_prefix is None:
        gen.module_prefix = gen.module_name
    else:
        gen.module_prefix = output_name + "." + module_prefix

    dirname = output if to_multiple_files else os.path.dirname(output) 

    if output_dir != None:
        dirname = output_dir + "/" + dirname
        output = output_dir + "/" + output

    if len(dirname) > 0 and (not os.path.exists(dirname) or not os.path.isdir(dirname)): 
        os.makedirs(dirname)

    if not to_multiple_files:
        header_name = gen.module_name
        if module_prefix is not None:
            prefix_len = len(gen.module_prefix)
            assert gen.module_prefix == gen.module_name[0:prefix_len],    \
                "module_prefix must be prefix of module_name"
            diff_name = gen.module_name[prefix_len+1:]
            if diff_name != "":
                header_name = diff_name
    else:
        header_name = None

    if not to_multiple_files:
        with gen.guard(output):
            gen.print_header_reminder()
            gen._print_header_(header_name, dot='=', is_title=True)
            gen.print_current_module()
    else:
        apis = sorted(gen.module.__all__,key=str.lower)
        for api in apis:
            header_name = api
            with gen.guard(os.path.join(output, api + '.rst')):
                gen.print_header_reminder()
                gen.print_item(api, output_name)


def main():
    args = parse_arg()
    generate_doc(args.module_name, args.module_prefix, args.output, args.output_name, args.to_multiple_files, args.output_dir)


if __name__ == '__main__':
    main()