"""Submodule containing the factories & page objects to create Tembo pages."""

from __future__ import annotations

import pathlib
import re
from dataclasses import dataclass
from typing import Collection, Optional

import pendulum

import tembo.utils
from tembo import exceptions
from tembo.journal.abstract import Page, PageCreator


@dataclass
class PageCreatorOptions:
    """
    Options [dataclass][dataclasses.dataclass] to create a Page.

    This is passed to an implemented instance of [PageCreator][tembo.journal.pages.PageCreator]

    Attributes:
        base_path (str): The base path.
        page_path (str): The path of the page relative to the base path.
        filename (str): The filename of the page.
        extension (str): The extension of the page.
        name (str): The name of the scope.
        user_input (Collection[str] | None, optional): User input tokens.
        example (str | None, optional): User example command.
        template_path (str | None, optional): The path which contains the templates. This should
            be the full path and not relative to the base path.
        template_filename (str | None, optional): The template filename with extension relative
            to the template path.
    """

    base_path: str
    page_path: str
    filename: str
    extension: str
    name: str
    user_input: Optional[Collection[str]] = None
    example: Optional[str] = None
    template_path: Optional[str] = None
    template_filename: Optional[str] = None


class ScopedPageCreator(PageCreator):
    """
    Factory to create a scoped page.

    Attributes:
        base_path (str): base path of tembo.
        page_path (str): path of the page relative to the base path.
        filename (str): filename relative to the page path.
        extension (str): extension of file.
    """

    def __init__(self, options: PageCreatorOptions) -> None:
        """
        Initialise a `ScopedPageCreator` factory.

        Args:
            options (PageCreatorOptions): An instance of
                [PageCreatorOptions][tembo.journal.pages.PageCreatorOptions].
        """
        self._all_input_tokens: list[str] = []
        self._options = options

    @property
    def options(self) -> PageCreatorOptions:
        """
        Return the `PageCreatorOptions` instance set on the factory.

        Returns:
            PageCreatorOptions:
                An instance of [PageCreatorOptions][tembo.journal.pages.PageCreatorOptions].
        """
        return self._options

    def create_page(self) -> Page:
        """
        Create a [ScopedPage][tembo.journal.pages.ScopedPage] object.

        This method will

        - Check the `base_path` exists
        - Verify the input tokens match the number defined in the `config.yml`
        - Substitue the input tokens in the filepath
        - Load the template contents and substitue the input tokens

        Raises:
            exceptions.MismatchedTokenError: Raises
                [MismatchedTokenError][tembo.exceptions.MismatchedTokenError] if the number of
                input tokens does not match the number of unique input tokens defined.
            exceptions.BasePathDoesNotExistError: Raises
                [BasePathDoesNotExistError][tembo.exceptions.BasePathDoesNotExistError] if the
                base path does not exist.
            exceptions.TemplateFileNotFoundError: Raises
                [TemplateFileNotFoundError][tembo.exceptions.TemplateFileNotFoundError] if the
                template file is specified but not found.


        Returns:
            Page: A [ScopedPage][tembo.journal.pages.ScopedPage] object using the
                `PageCreatorOptions`.
        """
        try:
            self._check_base_path_exists()
        except exceptions.BasePathDoesNotExistError as base_path_does_not_exist_error:
            raise base_path_does_not_exist_error
        self._all_input_tokens = self._get_input_tokens()
        try:
            self._verify_input_tokens()
        except exceptions.MismatchedTokenError as mismatched_token_error:
            raise mismatched_token_error

        path = self._convert_base_path_to_path()
        path = pathlib.Path(self._substitute_tokens(str(path)))

        try:
            template_contents = self._load_template()
        except exceptions.TemplateFileNotFoundError as template_not_found_error:
            raise template_not_found_error
        if self.options.template_filename is not None:
            template_contents = self._substitute_tokens(template_contents)

        return ScopedPage(path, template_contents)

    def _get_input_tokens(self) -> list[str]:
        """Get the input tokens from the path & user template."""
        path = str(
            pathlib.Path(
                self.options.base_path,
                self.options.page_path,
                self.options.filename,
            )
            .expanduser()
            .with_suffix(f".{self.options.extension}")
        )
        template_contents = self._load_template()
        # get the input tokens from both the path and the template
        all_input_tokens = []
        for tokenified_string in (path, template_contents):
            all_input_tokens.extend(re.findall(r"(\{input\d*\})", tokenified_string))
        return sorted(list(set(all_input_tokens)))

    def _verify_input_tokens(self) -> None:
        """
        Verify the input tokens.

        The number of input tokens should match the number of unique input tokens defined in the
        path and the user's template.

        Raises:
            exceptions.MismatchedTokenError: Raises
                [MismatchedTokenError][tembo.exceptions.MismatchedTokenError] if the number of
                input tokens does not match the number of unique input tokens defined.
        """
        if len(self._all_input_tokens) > 0 and self.options.user_input is None:
            raise exceptions.MismatchedTokenError(expected=len(self._all_input_tokens), given=0)
        if self.options.user_input is None:
            return
        if len(self._all_input_tokens) != len(self.options.user_input):
            raise exceptions.MismatchedTokenError(
                expected=len(self._all_input_tokens),
                given=len(self.options.user_input),
            )

    def _substitute_tokens(self, tokenified_string: str) -> str:
        """For a tokened string, substitute input, name and date tokens."""
        tokenified_string = self.__substitute_input_tokens(tokenified_string)
        tokenified_string = self.__substitute_name_tokens(tokenified_string)
        tokenified_string = self.__substitute_date_tokens(tokenified_string)
        return tokenified_string

    def __substitute_input_tokens(self, tokenified_string: str) -> str:
        """
        Substitue the input tokens in a `str` with the user input.

        Args:
            tokenified_string (str): a string with input tokens.

        Returns:
            str: the string with the input tokens replaced by the user input.

        Examples:
            A `user_input` of `("monthly_meeting",)` with a `tokenified_string` of
            `/meetings/{input0}/` results in a string of `/meetings/monthly_meeting/`
        """
        if self.options.user_input is not None:
            for input_value, extracted_token in zip(
                self.options.user_input, self._all_input_tokens
            ):
                tokenified_string = tokenified_string.replace(
                    extracted_token, input_value.replace(" ", "_")
                )
        return tokenified_string

    def __substitute_name_tokens(self, tokenified_string: str) -> str:
        """Find any `{name}` tokens and substitute for the name value in a `str`."""
        name_extraction = re.findall(r"(\{name\})", tokenified_string)
        for extracted_input in name_extraction:
            tokenified_string = tokenified_string.replace(extracted_input, self.options.name)
        return tokenified_string

    @staticmethod
    def __substitute_date_tokens(tokenified_string: str) -> str:
        """Find any {d:%d-%M-%Y} tokens in a `str`."""
        # extract the full token string
        date_extraction_token = re.findall(r"(\{d\:[^}]*\})", tokenified_string)
        for extracted_token in date_extraction_token:
            # extract the inner %d-%M-%Y only
            strftime_value = re.match(r"\{d\:([^\}]*)\}", extracted_token)
            if strftime_value is not None:
                strftime_value = strftime_value.group(1)
                if isinstance(strftime_value, str):
                    tokenified_string = tokenified_string.replace(
                        extracted_token, pendulum.now().strftime(strftime_value)
                    )
        return tokenified_string


class ScopedPage(Page):
    """
    A page that uses substitute tokens.

    Attributes:
        page_content (str): the content of the page from the template.
    """

    def __init__(self, path: pathlib.Path, page_content: str) -> None:
        """
        Initalise a scoped page object.

        Args:
            path (pathlib.Path): a [Path][pathlib.Path] object of the page's filepath including
                the filename.
            page_content (str): the content of the page from the template.
        """
        self._path = path
        self.page_content = page_content

    def __str__(self) -> str:
        """
        Return a `str` representation of a `ScopedPage`.

        Examples:
            ```
            >>> str(ScopedPage(Path("/home/bob/tembo/meetings/my_meeting_0.md"), ""))
            ScopedPage("/home/bob/tembo/meetings/my_meeting_0.md")
            ```

        Returns:
            str: The `ScopedPage` as a `str`.
        """
        return f'ScopedPage("{self.path}")'

    @property
    def path(self) -> pathlib.Path:
        """
        Return the full path of the page.

        Returns:
            pathlib.path: The full path of the page as a [Path][pathlib.Path] object.
        """
        return self._path

    def save_to_disk(self) -> tembo.utils.Success:
        """
        Save the scoped page to disk and write the `page_content`.

        Raises:
            exceptions.ScopedPageAlreadyExists: Raises
                [ScopedPageAlreadyExists][tembo.exceptions.ScopedPageAlreadyExists] if the page already exists.

        Returns:
            tembo.utils.Success: A [Success][tembo.utils.__init__.Success] with the path of the
                ScopedPage as the message.
        """
        # create the parent directories
        scoped_page_file = pathlib.Path(self.path)
        scoped_page_file.parents[0].mkdir(parents=True, exist_ok=True)
        if scoped_page_file.exists():
            raise exceptions.ScopedPageAlreadyExists(f"{self.path} already exists")
        with scoped_page_file.open("w", encoding="utf-8") as scoped_page:
            scoped_page.write(self.page_content)
        return tembo.utils.Success(str(self.path))