provenance-cli 0.2.3

use super::{local_markdown_path, resolve_markdown_link, DocPage, DocsSite, MARKDOWN_OPTIONS};
use axum::{
    extract::State,
    http::{header, StatusCode, Uri},
    response::{Html, IntoResponse},
    routing::get,
    Router,
};
use pulldown_cmark::{html, CowStr, Event, Parser, Tag};
use std::{fmt::Write as _, sync::Arc};

const DOCS_CSS: &str = r#"
:root {
  color-scheme: light dark;
  --pv-canvas-bg: #faf8f5;
  --pv-canvas-dots: #e0dbd4;
  --pv-card-bg: #fffdf9;
  --pv-card-border: #e4ddd3;
  --pv-card-shadow: rgba(120, 100, 70, 0.08);
  --pv-ink: #201b14;
  --pv-muted: #6f6659;
  --pv-source: #d4a574;
  --pv-requirement: #6b9e7a;
  --pv-resolution: #8b7bb5;
  --pv-rule: #5a8f9e;
  --pv-status-discovery: #b89e5a;
  --pv-font-display: "Source Serif 4", Georgia, "Times New Roman", serif;
  --pv-font-body: "DM Sans", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --pv-font-mono: "DM Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --pv-canvas-bg: #17140f;
    --pv-canvas-dots: #332b21;
    --pv-card-bg: #242119;
    --pv-card-border: #40382d;
    --pv-card-shadow: rgba(0, 0, 0, 0.3);
    --pv-ink: #f4ead9;
    --pv-muted: #b8a995;
    --pv-source: #d9ad78;
    --pv-requirement: #84bf91;
    --pv-resolution: #a898cf;
    --pv-rule: #77adba;
    --pv-status-discovery: #d1b16b;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--pv-ink);
  background:
    radial-gradient(circle at 12% 8%, color-mix(in srgb, var(--pv-resolution) 12%, transparent), transparent 26rem),
    radial-gradient(circle at 92% 18%, color-mix(in srgb, var(--pv-source) 14%, transparent), transparent 22rem),
    linear-gradient(180deg, var(--pv-canvas-bg), color-mix(in srgb, var(--pv-canvas-bg) 94%, var(--pv-card-border)));
  font-family: var(--pv-font-body);
  line-height: 1.65;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: radial-gradient(var(--pv-canvas-dots) 0.75px, transparent 0.75px);
  background-size: 18px 18px;
  opacity: 0.35;
}

body > header {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.8rem clamp(1rem, 3vw, 2rem);
  border-bottom: 1px solid var(--pv-card-border);
  background: color-mix(in srgb, var(--pv-canvas-bg) 88%, transparent);
  backdrop-filter: blur(16px) saturate(1.1);
}

body > header p { margin: 0; color: var(--pv-muted); font-size: 0.88rem; }
body > header strong { color: var(--pv-ink); font-family: var(--pv-font-display); font-size: 1.15rem; }

body > div {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(14rem, 18rem) minmax(0, 1fr);
  min-height: calc(100vh - 3.2rem);
}

aside {
  border-right: 1px solid var(--pv-card-border);
  padding: 1.25rem;
  background: color-mix(in srgb, var(--pv-card-bg) 76%, transparent);
}

aside nav { position: sticky; top: 5rem; }
nav h2 { margin: 0 0 0.75rem; color: var(--pv-muted); font-size: 0.72rem; letter-spacing: 0.12em; text-transform: uppercase; }
nav ol { list-style: none; margin: 0; padding: 0; }
nav li { margin: 0.12rem 0; }
nav li[data-depth="1"] { margin-left: 0.85rem; }
nav li[data-depth="2"] { margin-left: 1.7rem; }
nav li[data-depth="3"] { margin-left: 2.55rem; }
nav a {
  display: block;
  border-radius: 0.65rem;
  padding: 0.42rem 0.55rem;
  color: var(--pv-ink);
  text-decoration: none;
  font-size: 0.92rem;
}
nav a:hover { background: color-mix(in srgb, var(--pv-card-border) 50%, transparent); }
nav a[aria-current="page"] { color: var(--pv-resolution); background: color-mix(in srgb, var(--pv-resolution) 12%, transparent); font-weight: 700; }

main {
  width: min(100%, 78rem);
  padding: clamp(1.25rem, 4vw, 4rem) clamp(1rem, 5vw, 5rem) 5rem;
}

article {
  max-width: 52rem;
  border: 1px solid var(--pv-card-border);
  border-radius: 1.1rem;
  padding: clamp(1.2rem, 4vw, 3rem);
  background: color-mix(in srgb, var(--pv-card-bg) 93%, transparent);
  box-shadow: 0 1.4rem 4rem var(--pv-card-shadow);
}

article > p:first-child {
  display: inline-flex;
  width: auto;
  margin: 0 0 1rem;
  border: 1px solid color-mix(in srgb, var(--pv-status-discovery) 40%, transparent);
  border-radius: 999px;
  padding: 0.24rem 0.62rem;
  color: var(--pv-muted);
  background: color-mix(in srgb, var(--pv-status-discovery) 12%, transparent);
  font-size: 0.78rem;
  font-weight: 650;
}

h1, h2, h3 { font-family: var(--pv-font-display); line-height: 1.08; letter-spacing: -0.025em; }
h1 { margin: 0 0 1.15rem; max-width: 15ch; font-size: clamp(2.2rem, 7vw, 4.8rem); letter-spacing: -0.055em; }
h2 { margin-top: 2.1rem; font-size: 1.65rem; }
h3 { margin-top: 1.6rem; font-size: 1.25rem; }
p, li { color: color-mix(in srgb, var(--pv-ink) 86%, var(--pv-muted)); }
a { color: var(--pv-resolution); text-decoration-thickness: 0.08em; text-underline-offset: 0.18em; }
code, pre { font-family: var(--pv-font-mono); }
code { border-radius: 0.35rem; padding: 0.1rem 0.28rem; background: color-mix(in srgb, var(--pv-rule) 13%, transparent); }
pre { overflow: auto; border-radius: 0.85rem; padding: 1rem; background: color-mix(in srgb, var(--pv-card-border) 48%, transparent); }
blockquote { margin-left: 0; border-left: 0.28rem solid var(--pv-source); padding: 0.5rem 0 0.5rem 1rem; color: var(--pv-muted); }
table { width: 100%; border-collapse: collapse; }
th, td { border-bottom: 1px solid var(--pv-card-border); padding: 0.6rem 0.5rem; text-align: left; vertical-align: top; }
th { color: var(--pv-muted); font-size: 0.8rem; letter-spacing: 0.06em; text-transform: uppercase; }

@media (max-width: 820px) {
  body > header { align-items: flex-start; flex-direction: column; }
  body > div { grid-template-columns: 1fr; }
  aside { border-right: 0; border-bottom: 1px solid var(--pv-card-border); }
  aside nav { position: static; }
  main { padding-top: 1.25rem; }
}
"#;

pub(super) fn router(site: DocsSite) -> Router {
    Router::new()
        .route("/assets/provenance-docs.css", get(stylesheet))
        .fallback(get(render_docs_page))
        .with_state(Arc::new(site))
}

async fn stylesheet() -> impl IntoResponse {
    (
        [(header::CONTENT_TYPE, "text/css; charset=utf-8")],
        DOCS_CSS,
    )
}

async fn render_docs_page(State(site): State<Arc<DocsSite>>, uri: Uri) -> impl IntoResponse {
    let path = uri.path().to_string();
    site.page_for_request_path(&path).map_or_else(
        || (StatusCode::NOT_FOUND, Html(site.render_not_found(&path))).into_response(),
        |page| Html(site.render_page(page)).into_response(),
    )
}

impl DocsSite {
    fn page_for_request_path(&self, path: &str) -> Option<&DocPage> {
        let route = normalize_request_route(path);
        self.page_by_route
            .get(&route)
            .and_then(|index| self.pages.get(*index))
    }

    fn render_page(&self, page: &DocPage) -> String {
        let nav = self.render_nav(&page.route);
        let body = self.render_markdown(page);
        format!(
            "<!doctype html>\n<html lang=\"en\">\n<head>\n<meta charset=\"utf-8\">\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">\n<title>{} - Provenance Docs</title>\n<link rel=\"stylesheet\" href=\"/assets/provenance-docs.css\">\n</head>\n<body>\n<header><p><strong>Provenance Docs</strong></p><p>plain Markdown, inferred routes, checked links</p></header>\n<div>\n<aside>{nav}</aside>\n<main><article><p><code>{}</code></p>{body}</article></main>\n</div>\n</body>\n</html>\n",
            escape_html(&page.title),
            escape_html(&page.source_path),
        )
    }

    fn render_not_found(&self, path: &str) -> String {
        let escaped_path = escape_html(path);
        let nav = self.render_nav("");
        format!(
            "<!doctype html>\n<html lang=\"en\">\n<head>\n<meta charset=\"utf-8\">\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">\n<title>Not Found - Provenance Docs</title>\n<link rel=\"stylesheet\" href=\"/assets/provenance-docs.css\">\n</head>\n<body>\n<header><p><strong>Provenance Docs</strong></p><p>plain Markdown, inferred routes, checked links</p></header>\n<div>\n<aside>{nav}</aside>\n<main><article><h1>Page not found</h1><p>No docs page is served at <code>{escaped_path}</code>.</p></article></main>\n</div>\n</body>\n</html>\n",
        )
    }

    fn render_nav(&self, current_route: &str) -> String {
        let mut nav = String::from("<nav aria-label=\"Docs navigation\"><h2>Docs</h2><ol>");
        for page in &self.pages {
            let current = if page.route == current_route {
                " aria-current=\"page\""
            } else {
                ""
            };
            let depth = page.depth.min(3);
            write!(
                nav,
                "<li data-depth=\"{depth}\"><a href=\"{}\"{current}>{}</a></li>",
                escape_attr(&page.route),
                escape_html(&page.title)
            )
            .expect("writing to a String should not fail");
        }
        nav.push_str("</ol></nav>");
        nav
    }

    fn render_markdown(&self, page: &DocPage) -> String {
        let events = Parser::new_ext(&page.markdown, MARKDOWN_OPTIONS).map(|event| match event {
            Event::Start(Tag::Link {
                link_type,
                dest_url,
                title,
                id,
            }) => {
                let rewritten = self
                    .rewrite_markdown_link(page, &dest_url)
                    .unwrap_or_else(|| dest_url.to_string());
                Event::Start(Tag::Link {
                    link_type,
                    dest_url: CowStr::Boxed(rewritten.into_boxed_str()),
                    title,
                    id,
                })
            }
            other => other,
        });
        let mut rendered = String::new();
        html::push_html(&mut rendered, events);
        rendered
    }

    /// Turns a link that names a local document into the route the site
    /// serves for it, keeping any fragment.
    ///
    /// Scope and resolution come from the same two functions the docs link
    /// decision is built from (`rule_docs_links_resolve`), so the server
    /// rewrites exactly the links `docs check` resolved and leaves the rest
    /// - anchors, absolute paths, web addresses - as the author wrote them.
    fn rewrite_markdown_link(&self, page: &DocPage, destination: &str) -> Option<String> {
        let (_path_part, suffix) = local_markdown_path(destination)?;
        let target_path = resolve_markdown_link(page, destination)?;
        let route = self.route_by_path.get(&target_path)?;
        Some(format!("{route}{suffix}"))
    }
}

fn normalize_request_route(path: &str) -> String {
    if path == "/" || path.is_empty() {
        return "/".to_string();
    }

    let mut route = path.to_string();
    if !route.starts_with('/') {
        route.insert(0, '/');
    }
    if !route.ends_with('/') {
        route.push('/');
    }
    route
}

fn escape_html(value: &str) -> String {
    value
        .replace('&', "&amp;")
        .replace('<', "&lt;")
        .replace('>', "&gt;")
}

fn escape_attr(value: &str) -> String {
    escape_html(value).replace('"', "&quot;")
}