from datetime import datetime, timezone
import logging
import os
from typing import TYPE_CHECKING

from flask import current_app, g, url_for
import humanize
from werkzeug.datastructures import FileStorage
from werkzeug.utils import secure_filename

from .exceptions import ErrorException
if TYPE_CHECKING:
    from .set import BrickSet

logger = logging.getLogger(__name__)


class BrickInstructions(object):
    allowed: bool
    brickset: 'BrickSet | None'
    extension: str
    filename: str
    mtime: datetime
    number: 'str | None'
    name: str
    size: int

    def __init__(self, file: os.DirEntry | str, /):
        if isinstance(file, str):
            self.filename = file
        else:
            self.filename = file.name

            # Store the file stats
            stat = file.stat()
            self.size = stat.st_size
            self.mtime = datetime.fromtimestamp(stat.st_mtime, tz=timezone.utc)

        # Store the name and extension, check if extension is allowed
        self.name, self.extension = os.path.splitext(self.filename)
        self.extension = self.extension.lower()
        self.allowed = self.extension in current_app.config['INSTRUCTIONS_ALLOWED_EXTENSIONS'].value  # noqa: E501

        # Placeholder
        self.brickset = None
        self.number = None

        # Extract the set number
        if self.allowed:
            # Normalize special chars to improve set detection
            normalized = self.name.replace('_', '-')
            normalized = normalized.replace(' ', '-')

            splits = normalized.split('-', 2)

            if len(splits) >= 2:
                self.number = '-'.join(splits[:2])

    # Delete an instruction file
    def delete(self, /) -> None:
        os.remove(self.path())

    # Display the size in a human format
    def human_size(self) -> str:
        return humanize.naturalsize(self.size)

    # Display the time in a human format
    def human_time(self) -> str:
        return self.mtime.astimezone(g.timezone).strftime(
            current_app.config['FILE_DATETIME_FORMAT'].value
        )

    # Compute the path of an instruction file
    def path(self, /, filename=None) -> str:
        if filename is None:
            filename = self.filename

        return os.path.join(
            current_app.static_folder,  # type: ignore
            current_app.config['INSTRUCTIONS_FOLDER'].value,
            filename
        )

    # Rename an instructions file
    def rename(self, filename: str, /) -> None:
        # Add the extension
        filename = '{name}{ext}'.format(name=filename, ext=self.extension)

        if filename != self.filename:
            # Check if it already exists
            target = self.path(filename=filename)
            if os.path.isfile(target):
                raise ErrorException('Cannot rename {source} to {target} as it already exists'.format(  # noqa: E501
                    source=self.filename,
                    target=filename
                ))

            os.rename(self.path(), target)

    # Upload a new instructions file
    def upload(self, file: FileStorage, /) -> None:
        target = self.path(secure_filename(self.filename))

        if os.path.isfile(target):
            raise ErrorException('Cannot upload {target} as it already exists'.format(  # noqa: E501
                target=self.filename
            ))

        file.save(target)

        # Info
        logger.info('The instruction file {file} has been imported'.format(
            file=self.filename
        ))

    # Compute the url for a set instructions file
    def url(self, /) -> str:
        if not self.allowed:
            return ''

        folder: str = current_app.config['INSTRUCTIONS_FOLDER'].value

        # Compute the path
        path = os.path.join(folder, self.filename)

        return url_for('static', filename=path)

    # Return the icon depending on the extension
    def icon(self, /) -> str:
        if self.extension == '.pdf':
            return 'file-pdf-2-line'
        elif self.extension in ['.doc', '.docx']:
            return 'file-word-line'
        elif self.extension in ['.png', '.jpg', '.jpeg']:
            return 'file-image-line'
        else:
            return 'file-line'