#!/usr/bin/env python3

"""Make static website/blog with Python."""

import argparse
import datetime
import json
import locale
import os
import re
import shutil
import sys
import time
import unicodedata
from email import utils
from pathlib import Path

import requests
import mistune
from pygments import highlight
from pygments.lexers import get_lexer_by_name
from pygments.formatters import html


FRENCH_WEEKDAYS = ['lun.', 'mar.', 'mer.', 'jeu.', 'ven.', 'sam.', 'dim.']
FRENCH_MONTHS = ['janv.', 'févr.', 'mars', 'avr.', 'mai', 'juin',
                 'juil.', 'août', 'sept.', 'oct.', 'nov.', 'déc.']


class HighlightRenderer(mistune.HTMLRenderer):
    def block_code(self, code, info=None):
        if info:
            lexer = get_lexer_by_name(info, stripall=True)
            formatter = html.HtmlFormatter()
            return highlight(code, lexer, formatter)
        return '<pre><code>' + mistune.escape(code) + '</code></pre>'


markdown = mistune.create_markdown(renderer=HighlightRenderer())


def fread(filename):
    """Read file and close the file."""
    with open(filename, "r") as f:
        return f.read()


def fwrite(filename, text):
    """Write content to file and close the file."""
    basedir = os.path.dirname(filename)
    if not os.path.isdir(basedir):
        os.makedirs(basedir)

    with open(filename, "w") as f:
        f.write(text)


def log(msg, *args):
    """Log message with specified arguments."""
    sys.stderr.write(msg.format(*args) + "\n")


def truncate(text, words=25):
    """Remove tags and truncate text to the specified number of words."""
    return " ".join(re.sub(r"(?s)<.*?>", " ", text).split()[:words])


def read_headers(text):
    """Parse headers in text and yield (key, value, end-index) tuples."""
    for match in re.finditer(r"\s*<!--\s*(.+?)\s*:\s*(.+?)\s*-->\s*|.+", text):
        if not match.group(1):
            break
        yield match.group(1), match.group(2), match.end()


def rfc_2822_format(date_str):
    """Convert yyyy-mm-dd date string to RFC 2822 format date string."""
    d = datetime.datetime.strptime(date_str, "%Y-%m-%d")
    return d \
        .replace(tzinfo=datetime.timezone.utc) \
        .strftime('%a, %d %b %Y %H:%M:%S %z')


def slugify(value):
    """
    Converts to lowercase, removes non-word characters (alphanumerics and
    underscores) and converts spaces to hyphens. Also strips leading and
    trailing whitespace.
    """
    value = (
        unicodedata.normalize("NFKD", value)
                   .encode("ascii", "ignore")
                   .decode("ascii")
    )
    value = re.sub(r"[^\w\s-]", "", value).strip().lower()
    return re.sub(r"[-\s]+", "-", value)


def read_content(filename, params):
    """Read content and metadata from file into a dictionary."""
    # Read file content.
    text = fread(filename)

    # Read metadata and save it in a dictionary.
    date_slug = os.path.basename(filename).split(".")[0]
    match = re.search(r"^(?:(\d\d\d\d-\d\d-\d\d)-)?(.+)$", date_slug)
    content = {"date": match.group(1) or "1970-01-01", "slug": match.group(2)}

    # Read headers.
    end = 0
    for key, val, end in read_headers(text):
        content[key] = val

    # slugify post title
    content["slug"] = slugify(content["title"])

    # Separate content from headers.
    text = text[end:]

    # Convert Markdown content to HTML.
    if filename.endswith((".md", ".mkd", ".mkdn", ".mdown", ".markdown")):
        summary_index = text.find("<!-- more")
        if summary_index > 0:
            summary = markdown(clean_html_tag(text[:summary_index]))
        else:
            summary = truncate(markdown(clean_html_tag(text)))
        clean_text = text.replace("<!-- more -->", "")
        text = markdown(clean_text)
    else:
        summary = truncate(text)

    # Update the dictionary with content and RFC 2822 date.
    content.update(
        {
            "content": text,
            "content_rss": fix_relative_links(params["site_url"], text),
            "rfc_2822_date": rfc_2822_format(content["date"]),
            "summary": summary,
        }
    )

    return content


def fix_relative_links(site_url, text):
    """Absolute links needed in RSS feed"""
    # TODO externalize links replacement configuration
    return text \
        .replace("src=\"/images/20", "src=\"" + site_url + "/images/20") \
        .replace("href=\"/20", "href=\"" + site_url + "/20")


def clean_html_tag(text):
    """Remove HTML tags."""
    while True:
        original_text = text
        text = re.sub(r"<\w+.*?>", "", text)
        text = re.sub(r"<\/\w+>", "", text)
        if original_text == text:
            break
    return text


def render(template, **params):
    """Replace placeholders in template with values from params."""
    return re.sub(
        r"{{\s*([^}\s]+)\s*}}",
        lambda match: str(params.get(match.group(1), match.group(0))),
        template,
    )


def get_header_list_value(header_name, page_params):
    header_list = []
    if header_name in page_params:
        for s in page_params[header_name].split(" "):
            if s.strip():
                header_list.append(s.strip())
    return header_list


def get_friendly_date(date_str):
    dt = datetime.datetime.strptime(date_str, "%Y-%m-%d")
    french_month = FRENCH_MONTHS[dt.month - 1]
    return f"{dt.day:02d} {french_month} {dt.year}"


def make_posts(
        src, src_pattern, dst, layout, category_layout,
        comment_layout, comment_detail_layout, **params
):
    """Generate posts from posts directory."""
    items = []

    for posix_path in Path(src).glob(src_pattern):
        src_path = str(posix_path)
        content = read_content(src_path, params)

        # render text / summary for basic fields
        content["content"] = render(content["content"], **params)
        content["summary"] = render(content["summary"], **params)

        page_params = dict(params, **content)
        page_params["header"] = ""
        page_params["footer"] = ""
        page_params["date_path"] = page_params["date"].replace("-", "/")
        page_params["friendly_date"] = get_friendly_date(page_params["date"])
        page_params["year"] = page_params["date"].split("-")[0]
        page_params["post_url"] = \
            page_params["year"] \
            + "/" \
            + page_params["slug"] + "/"

        # categories
        categories = get_header_list_value("category", page_params)
        out_cats = []
        for category in categories:
            out_cat = render(category_layout,
                             category=category,
                             url=slugify(category))
            out_cats.append(out_cat.strip())
        page_params["categories"] = categories
        page_params["category_label"] = "".join(out_cats)

        # tags
        tags = get_header_list_value("tag", page_params)
        page_params["tags"] = tags

        #  comments
        page_comment = page_params.get("comment", "yes")
        if page_comment == "no":
            is_page_comment_enabled = False
        else:
            is_page_comment_enabled = True

        page_params["comment_count"] = 0
        page_params["comments"] = ""
        page_params["comment"] = ""

        if params["stacosys_url"] and is_page_comment_enabled:
            req_url = params["stacosys_url"] + "/comments"
            query_params = dict(
                url="/" + page_params["post_url"]
            )
            resp = requests.get(url=req_url, params=query_params)
            comments = resp.json()["data"]
            out_comments = []
            for comment in comments:
                site = comment.get("site", "")
                if site:
                    site_start = '<a href="' + site + '">'
                    site_end = '</a>'
                else:
                    site_start = ''
                    site_end = ''
                out_comment = render(
                    comment_detail_layout,
                    author=comment["author"],
                    avatar=comment.get("avatar", ""),
                    site_start=site_start,
                    site_end=site_end,
                    date=comment["date"],
                    content=markdown(comment["content"]),
                )
                out_comments.append(out_comment)
            page_params["comments"] = "".join(out_comments)
            page_params["comment_count"] = len(comments)
            page_params["comment"] = render(comment_layout, **page_params)

        content["year"] = page_params["year"]
        content["post_url"] = page_params["post_url"]
        content["categories"] = page_params["categories"]
        content["category_label"] = page_params["category_label"]
        content["tags"] = page_params["tags"]
        content["friendly_date"] = page_params["friendly_date"]
        content["comment_count"] = page_params["comment_count"]
        items.append(content)

        dst_path = render(dst, **page_params)
        output = render(layout, **page_params)

        log("Rendering {} => {} ...", src_path, dst_path)
        fwrite(dst_path, output)

    return sorted(items, key=lambda x: x["date"], reverse=True)


def make_notes(
        src, src_pattern, dst, layout, **params
):
    """Generate notes from notes directory."""
    items = []

    for posix_path in Path(src).glob(src_pattern):
        src_path = str(posix_path)
        content = read_content(src_path, params)

        # render text / summary for basic fields
        content["content"] = render(content["content"], **params)
        content["summary"] = render(content["summary"], **params)

        page_params = dict(params, **content)
        page_params["header"] = ""
        page_params["footer"] = ""
        page_params["friendly_date"] = ""
        page_params["category_label"] = ""
        page_params["post_url"] = "notes/" + page_params["slug"] + "/"

        content["post_url"] = page_params["post_url"]
        content["friendly_date"] = page_params["friendly_date"]
        content["category_label"] = page_params["category_label"]
        items.append(content)

        dst_path = render(dst, **page_params)
        output = render(layout, **page_params)

        log("Rendering {} => {} ...", src_path, dst_path)
        fwrite(dst_path, output)

    return sorted(items, key=lambda x: x["date"], reverse=True)


def make_list(
        posts, dst, list_layout, item_layout,
        header_layout, footer_layout, **params
):
    """Generate list page for a blog."""

    # header
    if header_layout is None:
        params["header"] = ""
    else:
        header = render(header_layout, **params)
        params["header"] = header

    # footer
    if footer_layout is None:
        params["footer"] = ""
    else:
        footer = render(footer_layout, **params)
        params["footer"] = footer

    # content
    items = []
    for post in posts:
        item_params = dict(params, **post)
        if "comment_count" in item_params and item_params["comment_count"]:
            if item_params["comment_count"] == 1:
                item_params["comment_label"] = "1 commentaire"
            else:
                item_params["comment_label"] = (
                        str(item_params["comment_count"]) + " commentaires"
                )
        else:
            item_params["comment_label"] = ""
        item = render(item_layout, **item_params)
        items.append(item)
    params["content"] = "".join(items)
    dst_path = render(dst, **params)
    output = render(list_layout, **params)

    log("Rendering list => {} ...", dst_path)
    fwrite(dst_path, output)


def create_blog(page_layout, list_in_page_layout, params):
    banner_layout = fread("layout/banner.html")
    paging_layout = fread("layout/paging.html")
    post_layout = fread("layout/post.html")
    post_layout = render(page_layout, content=post_layout)
    comment_layout = fread("layout/comment.html")
    comment_detail_layout = fread("layout/comment-detail.html")
    category_layout = fread("layout/category.html")
    item_layout = fread("layout/item.html")

    posts = make_posts(
        "posts",
        "**/*.md",
        "_site/{{ post_url }}/index.html",
        post_layout,
        category_layout,
        comment_layout,
        comment_detail_layout,
        **params
    )

    # Create blog list pages by 10.
    page_size = 10
    chunk_posts = [
        posts[i: i + page_size]
        for i in range(0, len(posts), page_size)
    ]
    page = 1
    last_page = len(chunk_posts)
    for chunk in chunk_posts:
        params["page"] = page
        if page == last_page:
            params["next_page"] = ""
        else:
            params["next_page"] = "/page" + str(page + 1) + "/"
        if page == 1:
            params["previous_page"] = ""
            make_list(
                chunk,
                "_site/index.html",
                list_in_page_layout,
                item_layout,
                banner_layout,
                paging_layout,
                **params
            )
        else:
            params["previous_page"] = "/page" + str(page - 1) + "/"
        make_list(
            chunk,
            "_site/page" + str(page) + "/index.html",
            list_in_page_layout,
            item_layout,
            banner_layout,
            paging_layout,
            **params
        )
        page = page + 1
    return posts


def generate_categories(list_in_page_layout, item_nosummary_layout,
                        posts, params):
    category_title_layout = fread("layout/category_title.html")
    cat_post = {}
    for post in posts:
        for cat in post["categories"]:
            if cat in cat_post:
                cat_post[cat].append(post)
            else:
                cat_post[cat] = [post]
    for cat in cat_post.keys():
        params["category"] = cat
        make_list(
            cat_post[cat],
            "_site/" + slugify(cat) + "/index.html",
            list_in_page_layout,
            item_nosummary_layout,
            category_title_layout,
            None,
            **params
        )


def generate_archives(blog_posts, list_in_page_layout, item_nosummary_layout,
                      archive_title_layout, params):
    make_list(
        blog_posts,
        "_site/archives/index.html",
        list_in_page_layout,
        item_nosummary_layout,
        archive_title_layout,
        None,
        **params
    )


def generate_notes(page_layout, archive_title_layout,
                   list_in_page_layout, params):
    note_layout = fread("layout/note.html")
    item_note_layout = fread("layout/item_note.html")
    note_layout = render(page_layout, content=note_layout)

    notes = make_notes(
        "notes",
        "**/*.md",
        "_site/{{ post_url }}/index.html",
        note_layout,
        **params
    )

    make_list(
        notes,
        "_site/notes/index.html",
        list_in_page_layout,
        item_note_layout,
        archive_title_layout,
        None,
        **params
    )


def generate_rss_feeds(posts, params):
    rss_xml = fread("layout/rss.xml")
    rss_item_xml = fread("layout/rss_item.xml")

    # Create main RSS feed for 10 last entries    
    for filename in ("_site/rss.xml", "_site/index.xml"):
        make_list(
            posts[:10],
            filename,
            rss_xml,
            rss_item_xml,
            None,
            None,
            **params
        )

    # Create RSS feed by tag
    tag_post = {}
    for post in posts:
        for tag in post["tags"]:
            if tag in tag_post:
                tag_post[tag].append(post)
            else:
                tag_post[tag] = [post]
    for tag in tag_post.keys():
        params["tag"] = tag
        make_list(
            tag_post[tag],
            "_site/rss." + slugify(tag) + ".xml",
            rss_xml,
            rss_item_xml,
            None,
            None,
            **params
        )


def generate_sitemap(posts, params):
    sitemap_xml = fread("layout/sitemap.xml")
    sitemap_item_xml = fread("layout/sitemap_item.xml")
    make_list(
        posts,
        "_site/sitemap.xml",
        sitemap_xml,
        sitemap_item_xml,
        None,
        None,
        **params
    )


def get_params(param_file):
    # Default parameters.
    params = {
        "title": "Blog",
        "subtitle": "Lorem Ipsum",
        "author": "Admin",
        "site_url": "http://localhost:8000",
        "current_year": datetime.datetime.now().year,
        "stacosys_url": "",
    }

    log("use params from " + param_file)
    if os.path.isfile(param_file):
        params.update(json.loads(fread(param_file)))
    return params


def clean_site():
    if os.path.isdir("_site"):
        shutil.rmtree("_site")
    shutil.copytree("static", "_site")


def main(param_file):

    params = get_params(param_file)

    # Create a new _site directory from scratch.
    clean_site()

    # Load layouts.
    page_layout = fread("layout/page.html")
    list_layout = fread("layout/list.html")
    list_in_page_layout = render(page_layout, content=list_layout)
    archive_title_layout = fread("layout/archives.html")
    item_nosummary_layout = fread("layout/item_nosummary.html")

    blog_posts = create_blog(page_layout, list_in_page_layout, params)

    generate_categories(list_in_page_layout, item_nosummary_layout,
                        blog_posts, params)

    generate_archives(blog_posts, list_in_page_layout, item_nosummary_layout,
                      archive_title_layout, params)

    generate_notes(page_layout, archive_title_layout,
                   list_in_page_layout, params)

    generate_rss_feeds(blog_posts, params)

    generate_sitemap(blog_posts, params)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Makesite')
    parser.add_argument('--params', dest='param_file', type=str,
                        default="params.json", help='Custom param file')
    args = parser.parse_args()
    main(args.param_file)