#!/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):
    """Custom Mistune renderer that adds syntax highlighting to code blocks using Pygments."""

    def block_code(self, code, info=None):
        """Render code blocks with syntax highlighting.

        Args:
            code: The code content to render
            info: Optional language identifier for syntax highlighting

        Returns:
            str: HTML with syntax-highlighted code or plain pre/code tags
        """
        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 strip_tags_and_truncate(text, words=25):
    """Remove HTML tags and truncate text to the specified number of words."""
    return " ".join(re.sub(r"(?s)<.*?>", " ", text).split()[:words])


def parse_headers(text):
    """Parse HTML comment headers 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 parse_post_file(filename, params):
    """Parse post file: read, extract metadata, convert markdown, and generate summary."""
    # 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 parse_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(strip_html_tags(text[:summary_index]))
        else:
            summary = strip_tags_and_truncate(markdown(strip_html_tags(text)))
        clean_text = text.replace("<!-- more -->", "")
        text = markdown(clean_text)
    else:
        summary = strip_tags_and_truncate(text)

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

    return content


def make_links_absolute(site_url, text):
    """Convert relative links to absolute URLs for 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 strip_html_tags(text):
    """Remove HTML tags from text."""
    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):
    """Extract and parse a space-separated list from a header value.

    Args:
        header_name: Name of the header to extract (e.g., 'category', 'tag')
        page_params: Dict containing page parameters

    Returns:
        list: List of stripped string values from the header
    """
    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 _render_comment(comment, comment_detail_layout):
    """Render a single comment using the comment detail layout.

    Args:
        comment: Dict with keys: author, content, date, and optional: site, avatar
        comment_detail_layout: Template string for rendering a comment

    Returns:
        str: Rendered HTML for the comment
    """
    site = comment.get("site", "")
    if site:
        site_start = '<a href="' + site + '">'
        site_end = '</a>'
    else:
        site_start = ''
        site_end = ''

    return 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"]),
    )


def _fetch_comments(post_url, stacosys_url):
    """Fetch comments from Stacosys API for a given post URL.

    Args:
        post_url: Relative URL of the post (e.g., "2024/my-post/")
        stacosys_url: Base URL of the Stacosys comment service

    Returns:
        list: List of comment dictionaries from API response
    """
    req_url = stacosys_url + "/comments"
    query_params = dict(url="/" + post_url)
    resp = requests.get(url=req_url, params=query_params)
    return resp.json()["data"]


def _process_comments(page_params, stacosys_url, comment_layout,
                     comment_detail_layout):
    """Process comments for a post: fetch, render, and return comment data.

    Args:
        page_params: Dict containing page parameters (must have 'comment' and 'post_url')
        stacosys_url: Base URL of Stacosys service (empty string disables comments)
        comment_layout: Template for the overall comment section
        comment_detail_layout: Template for individual comments

    Returns:
        tuple: (comment_count, comments_html, comment_section_html)
            - comment_count: Number of comments (int)
            - comments_html: Rendered HTML of all comments (str)
            - comment_section_html: Complete comment section with form (str)
    """
    # Check if comments are enabled for this page
    page_comment = page_params.get("comment", "yes")
    is_page_comment_enabled = (page_comment != "no")

    # Default values when comments are disabled
    if not stacosys_url or not is_page_comment_enabled:
        return 0, "", ""

    # Fetch and render comments
    comments = _fetch_comments(page_params["post_url"], stacosys_url)
    out_comments = [
        _render_comment(comment, comment_detail_layout)
        for comment in comments
    ]
    comments_html = "".join(out_comments)

    # Render complete comment section
    temp_params = dict(page_params)
    temp_params["comments"] = comments_html
    temp_params["comment_count"] = len(comments)
    comment_section_html = render(comment_layout, **temp_params)

    return len(comments), comments_html, comment_section_html


def get_friendly_date(date_str):
    """Convert date string to French-formatted readable date.

    Args:
        date_str: Date string in YYYY-MM-DD format

    Returns:
        str: French-formatted date (e.g., "15 janv. 2024")
    """
    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 _process_categories(page_params, category_layout):
    """Process categories from page params and return rendered category label.

    Args:
        page_params: Dict containing page parameters (must have 'category' key)
        category_layout: Template string for rendering individual categories

    Returns:
        tuple: (list of category strings, rendered category label HTML)
    """
    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())
    category_label = "".join(out_cats)
    return categories, category_label


def _setup_page_params(content, params):
    """Set up page parameters from content and global params.

    Args:
        content: Dict containing parsed content (must have 'date' key)
        params: Global parameters dict

    Returns:
        dict: Page parameters with date_path, friendly_date, year, post_url, etc.
    """
    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"] + "/"
    )
    return page_params


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 = parse_post_file(src_path, params)

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

        # setup page parameters
        page_params = _setup_page_params(content, params)

        # process categories
        categories, category_label = _process_categories(page_params, category_layout)
        page_params["categories"] = categories
        page_params["category_label"] = category_label

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

        # comments
        comment_count, comments_html, comment_section = _process_comments(
            page_params, params.get("stacosys_url", ""),
            comment_layout, comment_detail_layout
        )
        page_params["comment_count"] = comment_count
        page_params["comments"] = comments_html
        page_params["comment"] = comment_section

        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 = parse_post_file(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.

    Args:
        posts: List of post dictionaries to include in the list
        dst: Destination path for the generated HTML file
        list_layout: Template for the overall list page
        item_layout: Template for individual list items
        header_layout: Template for page header (None to skip)
        footer_layout: Template for page footer (None to skip)
        **params: Additional parameters for template rendering
    """

    # 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):
    """Create blog posts and paginated index pages.

    Args:
        page_layout: Template for individual pages
        list_in_page_layout: Template for list pages wrapped in page layout
        params: Global site parameters

    Returns:
        list: Sorted list of all post dictionaries (newest first)
    """
    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):
    """Generate category pages grouping posts by category.

    Args:
        list_in_page_layout: Template for list pages
        item_nosummary_layout: Template for list items without summaries
        posts: List of all blog posts
        params: Global site parameters
    """
    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):
    """Generate archives page with all blog posts.

    Args:
        blog_posts: List of all blog posts
        list_in_page_layout: Template for list pages
        item_nosummary_layout: Template for list items without summaries
        archive_title_layout: Template for archive page header
        params: Global site parameters
    """
    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):
    """Generate notes pages and notes index.

    Args:
        page_layout: Template for individual pages
        archive_title_layout: Template for notes index header
        list_in_page_layout: Template for list pages
        params: Global site parameters
    """
    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):
    """Generate RSS feeds: main feed and per-tag feeds.

    Args:
        posts: List of all blog posts
        params: Global site parameters
    """
    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):
    """Generate XML sitemap for all posts.

    Args:
        posts: List of all blog posts
        params: Global site parameters
    """
    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):
    """Load site parameters from JSON file with defaults.

    Args:
        param_file: Path to JSON parameters file

    Returns:
        dict: Site parameters with defaults and loaded values
    """
    # 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 rebuild_site_directory():
    """Remove existing _site directory and recreate from static files."""
    if os.path.isdir("_site"):
        shutil.rmtree("_site")
    shutil.copytree("static", "_site")


def main(param_file):
    """Main entry point for static site generation.

    Args:
        param_file: Path to JSON parameters file
    """

    params = get_params(param_file)

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

    # 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)