import mimetypes
import os
import uuid

from django.db import models
from django.urls import reverse
from easy_thumbnails.alias import aliases

if not aliases.get('small'):
    aliases.set('small', {'size': (150, 80), 'crop': True})


class ServedDirectory(models.Model):
    """
    A reference to a specific directory on the host machine for hosting files.

    A regex pattern is stored for filtering files in the directory down to what is intended.
    A recursive option is also stored, in case the user wishes to serve files in directories below the one specified.
    The regex pattern can be turned on or off using the boolean field.
    The regex pattern can be matched against the file path (False), or just the filename (True).
    """

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False, unique=True)
    path = models.CharField('Directory Path', max_length=260)
    recursive = models.BooleanField('Files Are Matched Recursively', default=False)
    regex_pattern = models.CharField('RegEx Matching Pattern', max_length=100, default='')
    regex = models.BooleanField('Directory RegEx Option', default=False)
    match_filename = models.BooleanField('RegEx Matches Against Filename', default=True)

    def refresh(self):
        """Refresh the directory listing to see if any new files have appeared and add them to the list."""
        for file in os.listdir(self.path):
            # Check if the file has been entered before
            entry = self.files.filter(filename__exact=file).first()
            if entry is None:
                # create the file entry
                entry = File.create(full_path=os.path.join(self.path, file))
                entry.save()

    def __str__(self):
        return self.path


class File(models.Model):
    path = models.CharField('Full Filepath', max_length=300)
    filename = models.CharField('Filename', max_length=160)
    mediatype = models.CharField('Mediatype', max_length=30)
    directory = models.ForeignKey(ServedDirectory, on_delete=models.CASCADE, related_name='files')

    @classmethod
    def create(cls, full_path: str) -> 'File':
        """Simple shortcut for creating a File database entry with just the path."""
        return File(
            path=full_path,
            filename=os.path.basename(full_path),
            mediatype=File.get_mediatype(full_path),
            directory=os.path.dirname(full_path)
        )

    def get_url(self, directory: ServedDirectory) -> str:
        """Retrieve the direct URL for a given file."""
        return reverse('file', args=(directory.id, self.filename))

    @staticmethod
    def get_mediatype(path) -> str:
        """Simple media type categorization based on the given path."""
        if os.path.exists(path):
            if os.path.isdir(path):
                return 'folder'
            mimetype = mimetypes.guess_type(path)[0]
            if mimetype is not None:
                if mimetype.startswith('image'):
                    return 'image'
                elif mimetype.startswith('video'):
                    return 'video'
            return 'file'
        return 'unknown'

    def __str__(self) -> str:
        return self.filename