#!/usr/bin/env python3
# /// script
# requires-python = ">=3.10"
# dependencies = [
#     "pyyaml",
#     "markdown",
# ]
# ///
"""Build script for Quiet's Blog.

Reads Markdown files with YAML frontmatter from content/ and generates
static HTML in dist/ using templates from templates/.
"""

import glob
import os
import shutil

import markdown
import yaml

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
CONTENT_DIR = os.path.join(BASE_DIR, "content")
TEMPLATE_DIR = os.path.join(BASE_DIR, "templates")
STATIC_DIR = os.path.join(BASE_DIR, "static")
DIST_DIR = os.path.join(BASE_DIR, "dist")


def parse_post(filepath):
    """Parse a Markdown file with YAML frontmatter. Returns dict with
    title, date, description, content (HTML), and source path info."""
    with open(filepath, "r") as f:
        text = f.read()

    if not text.startswith("---"):
        raise ValueError(f"Missing frontmatter in {filepath}")

    _, fm_raw, body = text.split("---", 2)
    meta = yaml.safe_load(fm_raw)

    md = markdown.Markdown(extensions=["fenced_code", "tables"])
    html_content = md.convert(body.strip())

    slug = os.path.splitext(os.path.basename(filepath))[0]

    return {
        "title": meta["title"],
        "date": str(meta["date"]),
        "description": meta.get("description", ""),
        "content": html_content,
        "slug": slug,
        "source": filepath,
    }


def load_template(name):
    path = os.path.join(TEMPLATE_DIR, name)
    with open(path, "r") as f:
        return f.read()


def render(template_str, **kwargs):
    result = template_str
    for key, value in kwargs.items():
        result = result.replace("{{" + key + "}}", str(value))
    return result


def collect_posts(subdir):
    """Collect and parse all .md files in content/<subdir>/."""
    pattern = os.path.join(CONTENT_DIR, subdir, "*.md")
    posts = []
    for filepath in sorted(glob.glob(pattern)):
        post = parse_post(filepath)
        post["category"] = subdir
        posts.append(post)
    posts.sort(key=lambda p: p["date"], reverse=True)
    return posts


def build_post_page(post, template, output_dir, root_prefix):
    """Render a single post page and write it to output_dir."""
    os.makedirs(output_dir, exist_ok=True)
    html = render(
        template,
        title=post["title"],
        date=post["date"],
        content=post["content"],
        css_path=root_prefix + "styles.css",
        root=root_prefix,
    )
    out_path = os.path.join(output_dir, post["slug"] + ".html")
    with open(out_path, "w") as f:
        f.write(html)
    return out_path


def build_post_card(post, href):
    """Generate HTML for a post card on the index page."""
    return (
        f'                    <article class="post-card">\n'
        f'                        <h3>{post["title"]}</h3>\n'
        f'                        <p class="post-date">{post["date"]}</p>\n'
        f'                        <p>{post["description"]}</p>\n'
        f'                        <a href="{href}" class="read-more">Read More &rarr;</a>\n'
        f"                    </article>"
    )


def build_list_section(title, posts, url_prefix):
    """Generate HTML for a section in the posts listing page."""
    if not posts:
        return ""
    items = "\n".join(
        f'                <li><a href="{url_prefix}/{p["slug"]}.html">{p["title"]}</a> '
        f'<span class="post-date">{p["date"]}</span></li>'
        for p in posts
    )
    return (
        f"            <h3>{title}</h3>\n"
        f"            <ul>\n{items}\n"
        f"            </ul>"
    )


def main():
    # Clean dist
    if os.path.exists(DIST_DIR):
        shutil.rmtree(DIST_DIR)
    os.makedirs(DIST_DIR)

    # Load templates
    post_template = load_template("post.html")
    index_template = load_template("index.html")
    posts_template = load_template("posts.html")
    about_template = load_template("about.html")

    # Collect posts by category
    regular_posts = collect_posts("posts")
    daily_posts = collect_posts("daily")
    weekly_posts = collect_posts("weekly")

    # Build individual post pages
    for post in regular_posts:
        build_post_page(post, post_template, os.path.join(DIST_DIR, "posts"), "../")
    for post in daily_posts:
        build_post_page(post, post_template, os.path.join(DIST_DIR, "daily"), "../")
    for post in weekly_posts:
        build_post_page(post, post_template, os.path.join(DIST_DIR, "weekly"), "../")

    # Build index page with latest posts across all categories
    all_posts = regular_posts + daily_posts + weekly_posts
    all_posts.sort(key=lambda p: p["date"], reverse=True)

    def post_href(post):
        return f'{post["category"]}/{post["slug"]}.html'

    post_cards = "\n\n".join(
        build_post_card(p, post_href(p)) for p in all_posts
    )
    index_html = render(index_template, post_cards=post_cards)
    with open(os.path.join(DIST_DIR, "index.html"), "w") as f:
        f.write(index_html)

    # Build posts listing page
    daily_section = build_list_section("Daily Posts", daily_posts, "daily")
    weekly_section = build_list_section("Weekly Posts", weekly_posts, "weekly")
    posts_section = build_list_section("Posts", regular_posts, "posts")

    posts_html = render(
        posts_template,
        daily_section=daily_section,
        weekly_section=weekly_section,
        posts_section=posts_section,
    )
    with open(os.path.join(DIST_DIR, "posts.html"), "w") as f:
        f.write(posts_html)

    # Build about page
    about_post = parse_post(os.path.join(CONTENT_DIR, "about.md"))
    about_html = render(
        about_template,
        title=about_post["title"],
        date=about_post["date"],
        content=about_post["content"],
    )
    with open(os.path.join(DIST_DIR, "about.html"), "w") as f:
        f.write(about_html)

    # Copy static files
    shutil.copy2(
        os.path.join(STATIC_DIR, "styles.css"),
        os.path.join(DIST_DIR, "styles.css"),
    )

    # Summary
    total = len(regular_posts) + len(daily_posts) + len(weekly_posts)
    print(f"Built {total} posts ({len(regular_posts)} regular, "
          f"{len(daily_posts)} daily, {len(weekly_posts)} weekly)")
    print(f"Output: {DIST_DIR}/")


if __name__ == "__main__":
    main()