import base64
import filetype
import os
import re

from .file import generate_breadcrumbs, sanitize_file_name, tree_join
from .page import Page
from .tree import safe_join

def bytes_to_content(file_bytes):
    if not file_bytes:
        return (None, 'empty')
    try:
        text = file_bytes.decode('utf-8')
        return (text, 'text')
    except UnicodeError:
        if filetype.is_image(file_bytes):
            # TODO: Refer to the static file once that's implemented.
            img = base64.b64encode(file_bytes)
            return (img.decode('utf-8'), 'image')

    return (None, None)

class FilePage(Page):
    def __init__(self, out_dir, name, commit, file_name, file_path, content_subdir):
        tree = safe_join(commit.tree, file_path)
        super(FilePage, self).__init__('file.md', out_dir, os.path.join(tree_join(commit, file_path), sanitize_file_name(file_name, tree.blobs) + '.md'), name, content_subdir)
        self.commit = commit
        self.file_name = file_name
        self.file_path = file_path
        self.tree = tree

    def read_file(self):
        return self.tree.join(self.file_name).data_stream.read()

    def context(self):
        file_bytes = self.read_file()
        content, file_type = bytes_to_content(file_bytes)
        backtick_max = 2
        if file_type == 'text':
            if self.file_name.lower().endswith('.md'):
                backtick_max = -1
                content = re.sub(r'(`{3,}\W)', r'\\\1', content)
            else:
                matches = re.findall('`+', content)
                backtick_max = max(max(len(match) for match in matches) if matches else 0, backtick_max)

        return {
            'backtick_max': backtick_max + 1,
            'breadcrumbs': generate_breadcrumbs(self.content_subdir, self.commit, os.path.join(self.file_path, self.file_name), self.tree.blobs),
            'content': content,
            'content_subdir': self.content_subdir,
            'file_extension': os.path.splitext(self.file_name)[1].lstrip('.'),
            'title': self.name + ': ' + self.file_name,
            'this_commit': self.commit,
            'type': file_type
        }