import datetime
import json
import os
import os.path
import re
import shutil
import uuid

from jinja2 import Environment, FileSystemLoader

from markdown import markdown

from yird.post import NewPostForm, Post

from yird.settings import Settings


class PostsService:
    settings = Settings()

    @classmethod
    def get_post(cls, post_id):
        bare_post_path = os.path.join(cls.settings.POSTS_PATH, post_id)
        with open(bare_post_path + '.json') as f:
            metadata = json.loads(f.read())
        with open(bare_post_path + '.md') as f:
            content = f.read()
        return Post(
            post_id,
            metadata['title'],
            metadata['slug'],
            datetime.date.fromisoformat(metadata['date']),
            content,
            metadata['changed']
        )

    @classmethod
    def get_posts(cls):
        posts_path = cls.settings.POSTS_PATH
        posts = []
        paths = os.listdir(posts_path)
        paths = [p for p in paths if re.search('.*(\\.json)', p)]
        for path in paths:
            post_id, extension = os.path.splitext(path)
            post = cls.get_post(post_id)
            posts.append(post)
        return sorted(posts, key=lambda post: post.date, reverse=True)

    @classmethod
    def generate_posts(cls):
        cls.__reset_public_dir()
        posts = cls.get_posts()
        template = cls.__get_post_template()
        for post in posts:
            cls.__generate_post(template, post)

    @classmethod
    def create_post(cls, post_data):
        id = str(uuid.uuid4())
        post = Post(
            id,
            post_data['title'],
            post_data['slug'],
            datetime.date.fromisoformat(post_data['date']),
            post_data['content'],
        )
        post.write()
        return post

    @classmethod
    def update_post(cls, post_id, post_data):
        post = Post(
            post_id,
            post_data['title'],
            post_data['slug'],
            datetime.date.fromisoformat(post_data['date']),
            post_data['content'],
        )
        post.write()

    @classmethod
    def get_post_form(cls, post=None):
        if post is None:
            return NewPostForm(date=datetime.date.today())
        return NewPostForm(
            title=post.title,
            slug=post.slug,
            date=post.date,
            content=post.content
        )

    @classmethod
    def __generate_post(cls, template, post):
        settings = cls.settings
        output_post_dir = os.path.join(settings.PUBLIC_PATH, post.id)
        metadata_path = os.path.join(settings.POSTS_PATH, post.id + '.json')
        os.mkdir(output_post_dir)
        post.content = markdown(post.content)
        with open(metadata_path) as f:
            metadata = json.loads(f.read())
        metadata['changed'] = False
        with open(metadata_path, "w") as f:
            f.write(json.dumps(metadata))
        with open(os.path.join(output_post_dir, "index.html"), "w") as f:
            f.write(template.render(post=post))

    @classmethod
    def __reset_public_dir(cls):
        shutil.rmtree(cls.settings.PUBLIC_PATH)
        os.mkdir(cls.settings.PUBLIC_PATH)

    @classmethod
    def __get_post_template(cls):
        loader = FileSystemLoader(cls.settings.TEMPLATES_PATH)
        env = Environment(loader=loader)
        return env.get_template('post.html')