#!/usr/bin/env python3

import codecs
import fnmatch
import locale
import os
import socketserver
from collections import namedtuple
from dataclasses import dataclass
from datetime import date, datetime
from html import escape
from http.server import SimpleHTTPRequestHandler
from operator import attrgetter
from pathlib import Path
from time import perf_counter

import markdown
from jinja2 import Environment as Env
from jinja2 import FileSystemLoader
from minicli import cli, run, wrap

# Useful for dates rendering within Jinja2.
locale.setlocale(locale.LC_ALL, "fr_FR.UTF-8")

HERE = Path(".")
DAVID = HERE / "david"
DOMAIN = "https://larlet.fr"
# Hardcoding publication at 12 in Paris timezone.
NORMALIZED_STRFTIME = "%Y-%m-%dT12:00:00+01:00"

environment = Env(loader=FileSystemLoader(str(DAVID / "templates")))


def neighborhood(iterable, first=None, last=None):
    """
    Yield the (previous, current, next) items given an iterable.

    You can specify a `first` and/or `last` item for bounds.
    """
    iterator = iter(iterable)
    previous = first
    current = next(iterator)  # Throws StopIteration if empty.
    for next_ in iterator:
        yield (previous, current, next_)
        previous = current
        current = next_
    yield (previous, current, last)


def parse_markdown(file_path):
    """Extract title, (HTML) content and metadata from a markdown file."""
    parser = markdown.Markdown(extensions=["meta"])
    with codecs.open(file_path, "r") as source:
        content = parser.convert(source.read())
        metadata = parser.Meta if hasattr(parser, "Meta") else None
        title = metadata["title"][0] if metadata is not None else ""
        return title, content, metadata


def each_markdown_from(source_dir, file_name="index.md"):
    """Walk across the `source_dir` and return the md file paths."""
    for root, dirnames, filenames in os.walk(source_dir):
        for filename in fnmatch.filter(filenames, file_name):
            yield os.path.join(root, filename)


@dataclass
class Item:
    title: str
    content: str
    file_path: str

    def __post_init__(self):
        self.full_url = f"{DOMAIN}{self.url}"
        self.normalized_date = self.date.strftime(NORMALIZED_STRFTIME)
        self.escaped_title = escape(self.title)
        self.escaped_content = escape(
            self.content.replace('href="/', f'href="{DOMAIN}/').replace(
                'src="/', f'src="{DOMAIN}/'
            )
        )

    @property
    def is_draft(self):
        return self.date > date.today()


@dataclass
class Note(Item):
    def __post_init__(self):
        suffix = len("/index.md")
        prefix = len("YYYY/MM/DD") + suffix
        date_str = self.file_path[-prefix:-suffix]
        self.url = f"/david/stream/{date_str}/"
        self.date = datetime.strptime(date_str, "%Y/%m/%d").date()
        super().__post_init__()
        self.extract = self.content.split("</p>", 1)[0] + "</p>"

    @staticmethod
    def all(source, only_published=True):
        """Retrieve all (published) notes sorted by date desc."""
        note_list = []
        for file_path in each_markdown_from(source):
            title, content, _ = parse_markdown(file_path)
            note = Note(title, content, file_path)
            if only_published and note.is_draft:
                continue
            note_list.append(note)
        return sorted(note_list, key=attrgetter("date"), reverse=True)


@dataclass
class Post(Item):
    date: str
    slug: str
    chapo: str
    lang: str

    def __post_init__(self):
        self.url = f"/david/blog/{self.date.year}/{self.slug}/"
        super().__post_init__()
        self.url_image = f"/static/david/blog/{self.date.year}/{self.slug}.jpg"
        self.url_image_thumbnail = (
            f"/static/david/blog/{self.date.year}/thumbnails/{self.slug}.jpg"
        )
        self.full_img_url = f"{DOMAIN}{self.url_image}"
        self.full_img_url_thumbnail = f"{DOMAIN}{self.url_image_thumbnail}"
        self.escaped_content = self.escaped_content + escape(
            f'<img src="{self.full_img_url_thumbnail}" width="500px" height="500px" />'
        )
        self.escaped_chapo = escape(self.chapo)

    @staticmethod
    def all(source, only_published=True):
        """Retrieve all (published) posts sorted by date desc."""
        post_list = []
        for file_path in each_markdown_from(source):
            title, content, metadata = parse_markdown(file_path)
            date = datetime.strptime(metadata["date"][0], "%Y-%m-%d").date()
            slug = metadata["slug"][0]
            chapo = metadata["chapo"][0]
            lang = metadata.get("lang", ["fr"])[0]
            post = Post(title, content, file_path, date, slug, chapo, lang)
            if only_published and post.is_draft:
                continue
            post_list.append(post)
        return sorted(post_list, key=attrgetter("date"), reverse=True)


@cli
def note(when=None):
    """Create a new note and open it in iA Writer.

    :when: Optional date in ISO format (YYYY-MM-DD)
    """
    when = datetime.strptime(when, "%Y-%m-%d") if when else date.today()
    note_path = DAVID / "stream" / str(when.year) / str(when.month) / str(when.day)
    os.makedirs(note_path)
    filename = note_path / "index.md"
    open(filename, "w+").write("title: ")
    os.popen(f'open -a "iA Writer" "{filename}"')


@cli
def stream():
    """Generate articles and archives for the stream."""
    template_article = environment.get_template("stream_2019_article.html")
    template_archives = environment.get_template("stream_2019_archives.html")
    # Default when you reach the last item.
    FakeNote = namedtuple("FakeNote", ["url", "title"])
    notes_2018 = FakeNote(url="/david/stream/2018/", title="Anciennes notes (2018)")
    note_base = DAVID / "stream" / "2019"
    unpublished = Note.all(source=note_base, only_published=False)
    published = [note for note in unpublished if not note.is_draft]
    for previous, note, next_ in neighborhood(unpublished, last=notes_2018):
        if note.is_draft:
            print(f"Soon: http://larlet.test:8001/{note.url} ({note.title})")
        # Detect if there is code for syntax highlighting + monospaced font.
        has_code = "<code>" in note.content
        # Do not link to unpublished notes.
        previous = previous and not previous.is_draft and previous or None
        page_article = template_article.render(
            note=note,
            next=previous,
            prev=next_,
            has_code=has_code,
            note_list=published,
        )
        open(
            note_base / f"{note.date.month:02}" / f"{note.date.day:02}" / "index.html",
            "w",
        ).write(page_article)

    page_archive = template_archives.render(note_list=published)
    open(note_base / "index.html", "w").write(page_archive)
    print(f"Done: http://larlet.test:8001/{note_base}/")


@cli
def blog():
    """Generate articles and archives for the blog."""
    template_article = environment.get_template("blog_article.html")
    template_archives = environment.get_template("blog_archives.html")
    # Default when you reach the last item.
    FakePost = namedtuple("FakePost", ["url", "title"])
    posts_2012 = FakePost(
        url="/david/thoughts/", title="Pensées précédentes (en anglais)"
    )
    post_base = DAVID / "blog"
    unpublished = Post.all(source=post_base, only_published=False)
    published = [post for post in unpublished if not post.is_draft]
    published_en = [post for post in published if post.lang == "en"]
    note_list = Note.all(source=DAVID / "stream" / "2019")
    for previous, post, next_ in neighborhood(unpublished, last=posts_2012):
        if post.is_draft:
            print(f"Soon: http://larlet.test:8001{post.url} ({post.title})")
        # Detect if there is code for syntax highlighting + monospaced font.
        has_code = "<code>" in post.content
        # Do not link to unpublished posts.
        previous = previous and not previous.is_draft and previous or None
        page_article = template_article.render(
            post=post,
            next=previous,
            prev=next_,
            has_code=has_code,
            post_list=published,
            published_posts_en=published_en,
            note_list=note_list,
        )
        open(post_base / str(post.date.year) / post.slug / "index.html", "w",).write(
            page_article
        )

    page_archive = template_archives.render(posts=published)
    open(post_base / "index.html", "w").write(page_archive)
    print(f"Done: http://larlet.test:8001/{post_base}/")


@cli
def feed():
    """Generate a feed from last published items in stream."""
    template = environment.get_template("feed.xml")
    content = template.render(
        note_list=Note.all(source=DAVID / "stream" / "2019")[:15],
        post_list=Post.all(source=DAVID / "blog")[:5],
        current_dt=datetime.now().strftime(NORMALIZED_STRFTIME),
        BASE_URL=f"{DOMAIN}/david/",
    )
    open(DAVID / "log" / "index.xml", "w").write(content)


@cli
def serve():
    httpd = socketserver.TCPServer(("larlet.test", 8001), SimpleHTTPRequestHandler)
    print("Serving at http://larlet.test:8001/david/")
    httpd.serve_forever()


@wrap
def perf_wrapper():
    start = perf_counter()
    yield
    elapsed = perf_counter() - start
    print(f"Done in {elapsed:.5f} seconds.")


if __name__ == "__main__":
    run()