#!/usr/bin/env python3

import fnmatch
import locale
import os
from dataclasses import dataclass
from datetime import date, datetime, timedelta
from html import escape
from pathlib import Path
from time import perf_counter

import mistune
from jinja2 import Environment as Env
from jinja2 import FileSystemLoader
from minicli import cli, run, wrap
from mistune.directives import DirectiveInclude
from slugify import slugify

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

HERE = Path(".")
DAVID = HERE / "david"
DOMAIN = "https://larlet.fr"
LOCAL_DOMAIN = "http://larlet.test:3579"
# Hardcoding publication at 12 in Paris timezone.
NORMALIZED_STRFTIME = "%Y-%m-%dT12:00:00+01:00"
TODAY = datetime.today() + timedelta(hours=6)


class CustomHTMLRenderer(mistune.HTMLRenderer):
    def heading(self, text, level):
        # Set an anchor to h2 headings.
        if level == 2:
            slug = slugify(text)
            return (
                f'<h2 id="{slug}">'
                f"{text} "
                f'<a href="#{slug}" title="Ancre vers cette partie">#</a>'
                f"</h2>"
            )
        else:
            return super().heading(text, level)


markdown = mistune.create_markdown(
    renderer=CustomHTMLRenderer(escape=False), plugins=[DirectiveInclude()]
)
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 each_markdown_from(source_dir, file_name="*.md"):
    """Walk across the `source_dir` and return the md file paths."""
    for filename in fnmatch.filter(os.listdir(source_dir), file_name):
        yield os.path.join(source_dir, filename)


@dataclass
class Page:
    title: str
    content: str
    file_path: str
    lang: str = "fr"

    def __post_init__(self):
        suffix = len(".md")
        prefix = len("YYYY/MM-DD") + suffix
        date_str = self.file_path[-prefix:-suffix].replace("-", "/")
        self.url = f"/david/{date_str}/"
        self.date = datetime.strptime(date_str, "%Y/%m/%d").date()
        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}/')
            .replace('href="#', f'href="{self.full_url}#')
        )
        # Extract first paragraph.
        self.extract = self.content.split("</p>", 1)[0] + "</p>"

    def __lt__(self, other: "Page"):
        if not isinstance(other, Page):
            return NotImplemented
        return self.date < other.date

    @staticmethod
    def all(source: Path, only_published=True):
        """Retrieve all pages sorted by desc."""
        page_list = []
        for file_path in each_markdown_from(source):
            result = markdown.read(file_path)
            title, content = result.split("</h1>", 1)
            h1_opening_size = len("<h1>")
            title = title[h1_opening_size:]
            page = Page(title, content, file_path)
            if only_published and page.is_draft:
                continue
            page_list.append(page)
        return sorted(page_list, reverse=True)

    @property
    def is_draft(self):
        return (
            datetime(year=self.date.year, month=self.date.month, day=self.date.day)
            > TODAY
        )


@cli
def orphans():
    """Print out fragments not linked to any page."""
    linked_fragments = []
    for file_path in each_markdown_from(DAVID / "2020"):
        for line in open(file_path).readlines():
            if line.startswith(".. include:: fragments/"):
                linked_fragments.append(line[len(".. include:: fragments/") : -1])
    all_fragments = []
    for file_path in each_markdown_from(DAVID / "2020" / "fragments"):
        all_fragments.append(file_path[len("david/2020/fragments/") :])
    for fragment_filename in set(all_fragments) - set(linked_fragments):
        # Prepending path for easy command+click from fish.
        print(DAVID / "2020" / "fragments" / fragment_filename)


@cli
def pages():
    """Build the agregations from fragments."""
    root_path = DAVID / "2020"
    for previous, page, next_ in neighborhood(
        reversed(Page.all(source=root_path, only_published=False)),
        first={
            "url": "/david/stream/",
            "title": "Streams 2009-2019",
            "is_draft": False,
        },
    ):
        template = environment.get_template("article_2020.html")
        content = template.render(page=page, prev=previous, next=next_,)
        target_path = Path(page.url[1:])
        target_path.mkdir(parents=True, exist_ok=True)
        open(target_path / "index.html", "w").write(content)
        if page.is_draft:
            print(f"Draft: {LOCAL_DOMAIN}{page.url} ({page.title})")
    template = environment.get_template("archives_2020.html")
    content = template.render(page_list=Page.all(source=root_path))
    open(root_path / "index.html", "w").write(content)


@cli
def home():
    """Build the home page with last published items."""
    template = environment.get_template("profil.html")
    content = template.render(page_list=Page.all(source=DAVID / "2020"),)
    open(DAVID / "index.html", "w").write(content)


@cli
def feed():
    """Generate a feed from last published items."""
    template = environment.get_template("feed.xml")
    content = template.render(
        page_list=Page.all(source=DAVID / "2020"),
        current_dt=datetime.now().strftime(NORMALIZED_STRFTIME),
        BASE_URL=f"{DOMAIN}/david/",
    )
    open(DAVID / "log" / "index.xml", "w").write(content)


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


if __name__ == "__main__":
    run()