# coding=utf-8
# Copyright 2020 The HuggingFace Inc. 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.
"""Style utils for the .rst and the docstrings."""

import argparse
import os
import re
import warnings


# Regexes
# Re pattern that catches list introduction (with potential indent)
_re_list = re.compile(r"^(\s*-\s+|\s*\*\s+|\s*\d+\.\s+)")
# Re pattern that catches code block introduction (with potentinal indent)
_re_code = re.compile(r"^(\s*)```(.*)$")
# Re pattern that catches rst args blocks of the form `Parameters:`.
_re_args = re.compile("^\s*(Args?|Arguments?|Params?|Parameters?):\s*$")
# Re pattern that catches return blocks of the form `Return:`.
_re_returns = re.compile("^\s*Returns?:\s*$")
# Matches the special tag to ignore some paragraphs.
_re_doc_ignore = re.compile(r"(\.\.|#)\s*docstyle-ignore")


DOCTEST_PROMPTS = [">>>", "..."]


def is_empty_line(line):
    return len(line) == 0 or line.isspace()


def find_indent(line):
    """
    Returns the number of spaces that start a line indent.
    """
    search = re.search("^(\s*)(?:\S|$)", line)
    if search is None:
        return 0
    return len(search.groups()[0])


def format_text(text, max_len, prefix="", min_indent=None):
    """
    Format a text in the biggest lines possible with the constraint of a maximum length and an indentation.

    Args:
        text (`str`): The text to format
        max_len (`int`): The maximum length per line to use
        prefix (`str`, *optional*, defaults to `""`): A prefix that will be added to the text.
            The prefix doesn't count toward the indent (like a - introducing a list).
        min_indent (`int`, *optional*): The minimum indent of the text.
            If not set, will default to the length of the `prefix`.

    Returns:
        `str`: The formatted text.
    """
    text = re.sub(r"\s+", " ", text)
    if min_indent is not None:
        if len(prefix) < min_indent:
            prefix = " " * (min_indent - len(prefix)) + prefix

    indent = " " * len(prefix)
    new_lines = []
    words = text.split(" ")
    current_line = f"{prefix}{words[0]}"
    for word in words[1:]:
        try_line = f"{current_line} {word}"
        if len(try_line) > max_len:
            new_lines.append(current_line)
            current_line = f"{indent}{word}"
        else:
            current_line = try_line
    new_lines.append(current_line)
    return "\n".join(new_lines)


def split_line_on_first_colon(line):
    splits = line.split(":")
    return splits[0], ":".join(splits[1:])


def style_docstring(docstring, max_len):
    """
    Style a docstring by making sure there is no useless whitespace and the maximum horizontal space is used.

    Args:
        docstring (`str`): The docstring to style.
        max_len (`int`): The maximum length of each line.

    Returns:
        `str`: The styled docstring
    """
    lines = docstring.split("\n")
    new_lines = []

    # Initialization
    current_paragraph = None
    current_indent = -1
    in_code = False
    param_indent = -1
    prefix = ""

    # Special case for docstrings that begin with continuation of Args with no Args block.
    idx = 0
    while idx < len(lines) and is_empty_line(lines[idx]):
        idx += 1
    if (
        len(lines[idx]) > 1
        and lines[idx].rstrip().endswith(":")
        and find_indent(lines[idx + 1]) > find_indent(lines[idx])
    ):
        param_indent = find_indent(lines[idx])

    for idx, line in enumerate(lines):
        # Doing all re searches once for the one we need to repeat.
        list_search = _re_list.search(line)
        code_search = _re_code.search(line)

        # Are we starting a new paragraph?
        # New indentation or new line:
        new_paragraph = find_indent(line) != current_indent or is_empty_line(line)
        # List item
        new_paragraph = new_paragraph or list_search is not None
        # Code block beginning
        new_paragraph = new_paragraph or code_search is not None

        # In this case, we treat the current paragraph
        if not in_code and new_paragraph and current_paragraph is not None and len(current_paragraph) > 0:
            paragraph = " ".join(current_paragraph)
            new_lines.append(format_text(paragraph, max_len, prefix=prefix, min_indent=current_indent))
            current_paragraph = None

        if code_search is not None:
            if not in_code:
                current_paragraph = []
                current_indent = len(code_search.groups()[0])
                current_code = code_search.groups()[1]
                prefix = ""
                if current_indent < param_indent:
                    param_indent = -1
            else:
                current_indent = -1
                code = "\n".join(current_paragraph)
                if current_code in ["py", "python"]:
                    new_lines.append(code)
                    # new_lines.append(format_code_example(code, max_len))
                else:
                    new_lines.append(code)
                current_paragraph = None
            new_lines.append(line)
            in_code = not in_code

        elif in_code:
            current_paragraph.append(line)
        elif is_empty_line(line):
            current_paragraph = None
            current_indent = -1
            prefix = ""
            new_lines.append(line)
        elif list_search is not None:
            prefix = list_search.groups()[0]
            current_indent = len(prefix)
            current_paragraph = [line[current_indent:]]
        elif _re_args.search(line):
            new_lines.append(line)
            param_indent = find_indent(lines[idx + 1])
        elif current_paragraph is None or find_indent(line) != current_indent:
            indent = find_indent(line)
            # Special behavior for parameters intros.
            if indent == param_indent:
                # Special rules for some docstring where the Returns blocks has the same indent as the parameters.
                if _re_returns.search(line) is not None:
                    param_indent = -1
                    new_lines.append(line)
                elif len(line) < max_len:
                    new_lines.append(line)
                else:
                    intro, description = split_line_on_first_colon(line)
                    new_lines.append(intro + ":")
                    if len(description) != 0:
                        if find_indent(lines[idx + 1]) > indent:
                            current_indent = find_indent(lines[idx + 1])
                        else:
                            current_indent = indent + 4
                        current_paragraph = [description.strip()]
                        prefix = ""
            else:
                # Check if we have exited the parameter block
                if indent < param_indent:
                    param_indent = -1

                current_paragraph = [line.strip()]
                current_indent = find_indent(line)
                prefix = ""
        elif current_paragraph is not None:
            current_paragraph.append(line.lstrip())

    if current_paragraph is not None and len(current_paragraph) > 0:
        paragraph = " ".join(current_paragraph)
        new_lines.append(format_text(paragraph, max_len, prefix=prefix, min_indent=current_indent))

    return "\n".join(new_lines)


def style_file_docstrings(code_file, max_len=119, check_only=False):
    """
    Style all docstrings in  a given file.

    Args:
        code_file (`str` or `os.PathLike`): The file in which we want to style the docstring.
        max_len (`int`): The maximum number of characters per line.
        check_only (`bool`, *optional*, defaults to `False`):
            Whether to restyle file or just check if they should be restyled.

    Returns:
        `bool`: Whether or not the file was or should be restyled.
    """
    with open(code_file, "r", encoding="utf-8", newline="\n") as f:
        code = f.read()
    # fmt: off
    splits = code.split('\"\"\"')
    splits = [
        (s if i % 2 == 0 or _re_doc_ignore.search(splits[i - 1]) is not None else style_docstring(s, max_len=max_len))
        for i, s in enumerate(splits)
    ]
    clean_code = '\"\"\"'.join(splits)
    # fmt: on

    diff = clean_code != code
    if not check_only and diff:
        print(f"Overwriting content of {code_file}.")
        with open(code_file, "w", encoding="utf-8", newline="\n") as f:
            f.write(clean_code)

    return diff


def style_mdx_file(mdx_file, max_len=119, check_only=False):
    """
    Style a MDX file by formatting all Python code samples.

    Args:
        mdx_file (`str` or `os.PathLike`): The file in which we want to style the examples.
        max_len (`int`): The maximum number of characters per line.
        check_only (`bool`, *optional*, defaults to `False`):
            Whether to restyle file or just check if they should be restyled.

    Returns:
        `bool`: Whether or not the file was or should be restyled.
    """
    with open(mdx_file, "r", encoding="utf-8", newline="\n") as f:
        content = f.read()

    lines = content.split("\n")
    current_code = []
    current_language = ""
    in_code = False
    new_lines = []
    for line in lines:
        if _re_code.search(line) is not None:
            in_code = not in_code
            if in_code:
                current_language = _re_code.search(line).groups()[1]
                current_code = []
            else:
                code = "\n".join(current_code)
                if current_language in ["py", "python"]:
                    pass
                    # code = format_code_example(code, max_len)
                new_lines.append(code)

            new_lines.append(line)
        elif in_code:
            current_code.append(line)
        else:
            new_lines.append(line)

    clean_content = "\n".join(new_lines)
    diff = clean_content != content
    if not check_only and diff:
        print(f"Overwriting content of {mdx_file}.")
        with open(mdx_file, "w", encoding="utf-8", newline="\n") as f:
            f.write(clean_content)

    return diff


def style_doc_files(*files, max_len=119, check_only=False):
    """
    Applies doc styling or checks everything is correct in a list of files.

    Args:
        files (several `str` or `os.PathLike`): The files to treat.
        max_len (`int`): The maximum number of characters per line.
        check_only (`bool`, *optional*, defaults to `False`):
            Whether to restyle file or just check if they should be restyled.

    Returns:
        List[`str`]: The list of files changed or that should be restyled.
    """
    changed = []
    for file in files:
        # Treat folders
        if os.path.isdir(file):
            files = [os.path.join(file, f) for f in os.listdir(file)]
            files = [f for f in files if os.path.isdir(f) or f.endswith(".rst") or f.endswith(".py")]
            changed += style_doc_files(*files, max_len=max_len, check_only=check_only)
        # Treat mdx
        elif file.endswith(".mdx"):
            if style_mdx_file(file, max_len=max_len, check_only=check_only):
                changed.append(file)
        # Treat python files
        elif file.endswith(".py"):
            try:
                if style_file_docstrings(file, max_len=max_len, check_only=check_only):
                    changed.append(file)
            except Exception:
                print(f"There is a problem in {file}.")
                raise
        else:
            warnings.warn(f"Ignoring {file} because it's not a py or an mdx file or a folder.")
    return changed


def main(*files, max_len=119, check_only=False):
    changed = style_doc_files(*files, max_len=max_len, check_only=check_only)
    if check_only and len(changed) > 0:
        raise ValueError(f"{len(changed)} files should be restyled!")
    elif len(changed) > 0:
        print(f"Cleaned {len(changed)} files!")


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("files", nargs="+", help="The file(s) or folder(s) to restyle.")
    parser.add_argument("--max_len", type=int, help="The maximum length of lines.")
    parser.add_argument("--check_only", action="store_true", help="Whether to only check and not fix styling issues.")
    args = parser.parse_args()

    main(*args.files, max_len=args.max_len, check_only=args.check_only)