# docgen_gen.ludic — `ludic-dev docs-gen`: the documentation-site generator, ported from
# tools/docgen/gen.py. Parses docs/language/** (front-matter + bodies) and
# docs/site/*, reads the asset templates in tools/docgen/assets, and emits the
# whole pages-branch payload (per-symbol pages, namespace/color/api pages, the
# landing page, ludic-highlight.js, symbols.json, .nojekyll) into --out. Output
# is byte-for-byte identical to the Python generator (gated in ludic-dev test).
#
# Shared helpers (Sb, hesc/hescattr, the JSON writer, codeify, string utils)
# live in docgen.ludic; the JSON reader (json_parse/j_get) in json.ludic.

# ---- the parsed-doc model ---------------------------------------------------
property Meta { keys: []pointer, vals: []pointer }
property Param { name: pointer = "", desc: pointer = "" }
property Split { desc: pointer = "", examples: []pointer, params: []Param }
property Doc { m: Meta, body: pointer = "" }
property Entry {
  id: pointer = "", name: pointer = "", sig: pointer = "", kind: pointer = "",
  tip: pointer = "", ns: pointer = "", order: int = 999,
  desc_html: pointer = "", examples: []pointer, params: []Param,
  tokens_list: []pointer, related_list: []pointer
}
property Section {
  id: pointer = "", title: pointer = "", order: int = 999, blurb: pointer = "",
  cat: pointer = "", ns_name: pointer = "", entries: []Entry
}
property Symbols { items: JVal, sym: JVal }

function meta_new() -> Meta {
  let m = new Meta
  m.keys = new []pointer
  m.vals = new []pointer
  return m
}
function meta_put(m: Meta, k: pointer, v: pointer) -> void {
  var i = 0
  while i < len(m.keys) { if m.keys[i] == k { m.vals[i] = v;  return };  i += 1 }
  push(m.keys, k)
  push(m.vals, v)
}
function meta_get(m: Meta, k: pointer, dflt: pointer) -> pointer {
  var i = 0
  while i < len(m.keys) { if m.keys[i] == k { return m.vals[i] };  i += 1 }
  return dflt
}

# ---- asset / snippet IO -----------------------------------------------------
function read_asset(name: pointer) -> pointer {
  let s = read_file("tools/docgen/assets/" + name)
  if s == null { return "" }
  return s
}
# read a snippet file, rstrip("\n") (trailing newlines only)
function read_snippet(rel: pointer) -> pointer {
  let s = read_file(rel)
  if s == null { return "" }
  var n = slen(s)
  while n > 0 and s[n - 1] == '\n' { n -= 1 }
  return sslice(s, 0, n)
}

# ---- front-matter + body parsing (parse_doc) --------------------------------
function parse_doc(path: pointer) -> Doc {
  let d = new Doc
  d.m = meta_new()
  let text = read_file(path)
  if text == null { d.body = "";  return d }
  d.body = text
  if not s_starts(text, "---") { return d }
  let end = s_index(text, "\n---", 3)
  if end < 0 { return d }
  let fm = sslice(text, 3, end)
  let fn2 = slen(fm)
  var j = 0
  while j < fn2 {
    let ln = line_at(fm, j)
    j = j + slen(ln) + 1
    let t = s_trim(ln)
    if slen(t) == 0 { continue }
    let c = s_index(ln, ":", 0)
    if c < 0 { continue }
    let key = s_trim(sslice(ln, 0, c))
    let val = s_trim(sslice(ln, c + 1, slen(ln)))
    meta_put(d.m, key, val)
  }
  d.body = lstrip_nl(sslice(text, end + 4, slen(text)))
  return d
}

# match ^-\s*`?(\w+)`?\s*[—-]+\s*(.*)$ against an already-trimmed line
function param_match(line: pointer, p: Param) -> bool {
  let n = slen(line)
  var i = 0
  if i < n and line[i] == '-' { i += 1 } else { return false }
  while i < n and is_ws(line[i]) { i += 1 }
  if i < n and line[i] == '`' { i += 1 }
  let ws = i
  while i < n and is_word(line[i]) { i += 1 }
  if i == ws { return false }
  let name = sslice(line, ws, i)
  if i < n and line[i] == '`' { i += 1 }
  while i < n and is_ws(line[i]) { i += 1 }
  var sep = 0
  while i < n {
    if line[i] == '-' { i += 1;  sep += 1 }
    else if (line[i] & 255) == 226 and i + 2 < n and (line[i + 1] & 255) == 128 and (line[i + 2] & 255) == 148 { i += 3;  sep += 1 }
    else { break }
  }
  if sep == 0 { return false }
  while i < n and is_ws(line[i]) { i += 1 }
  p.name = name
  p.desc = codeify(s_trim(sslice(line, i, n)))
  return true
}

# split desc on /\n\s*\n/ into trimmed, non-empty paragraphs
function split_paras(desc: pointer) -> []pointer {
  let out = new []pointer
  let n = slen(desc)
  var start = 0
  var i = 0
  while i < n {
    if desc[i] == '\n' {
      var jj = i
      var nl = 0
      while jj < n and is_space_all(desc[jj]) { if desc[jj] == '\n' { nl += 1 };  jj += 1 }
      if nl >= 2 {
        let part = s_trim(sslice(desc, start, i))
        if slen(part) > 0 { push(out, part) }
        start = jj
        i = jj
        continue
      }
      i = jj
    } else {
      i += 1
    }
  }
  let last = s_trim(sslice(desc, start, n))
  if slen(last) > 0 { push(out, last) }
  return out
}

function split_body(body: pointer) -> Split {
  let r = new Split
  r.examples = new []pointer
  r.params = new []Param
  # 1) pull ```ludic fences out, keep the rest
  let wo = sb_new()
  let n = slen(body)
  var i = 0
  while i < n {
    let p = s_index(body, "```ludic\n", i)
    if p < 0 {
      var k = i
      while k < n { sb_putc(wo, body[k]);  k += 1 }
      i = n
    } else {
      var k = i
      while k < p { sb_putc(wo, body[k]);  k += 1 }
      let cs = p + 9
      let q = s_index(body, "\n```", cs)
      if q < 0 {
        var k2 = p
        while k2 < cs { sb_putc(wo, body[k2]);  k2 += 1 }
        i = cs
      } else {
        push(r.examples, sslice(body, cs, q))
        i = q + 4
      }
    }
  }
  let body2 = sb_str(wo)
  # 2) pull a Parameters: block, keep every other line
  let m2 = slen(body2)
  let keep = sb_new()
  var firstkeep = true
  var li = 0
  while li < m2 {
    let ln = line_at(body2, li)
    let lnlen = slen(ln)
    li = li + lnlen + 1
    let low = lower_ascii(s_trim(ln))
    if s_starts(low, "parameters:") {
      while li < m2 {
        let ln2 = line_at(body2, li)
        let l2 = slen(ln2)
        let t2 = s_trim(ln2)
        if slen(t2) == 0 { break }
        li = li + l2 + 1
        let pp = new Param
        if param_match(t2, pp) { push(r.params, pp) }
      }
    } else {
      if not firstkeep { sb_putc(keep, '\n') }
      firstkeep = false
      var kk = 0
      while kk < lnlen { sb_putc(keep, ln[kk]);  kk += 1 }
    }
  }
  # 3) desc -> paragraphs joined </p><p>, each codeified
  let desc = s_trim(sb_str(keep))
  let paras = split_paras(desc)
  let ob = sb_new()
  var pi = 0
  while pi < len(paras) {
    if pi > 0 { sb_puts(ob, "</p><p>") }
    sb_puts(ob, codeify(paras[pi]))
    pi += 1
  }
  r.desc = sb_str(ob)
  return r
}

# the first sentence of a blurb, tags stripped, truncated to 160 with an ellipsis
function plain_text(s: pointer) -> pointer {
  let sb = sb_new()
  let n = slen(s)
  var i = 0
  while i < n {
    if s[i] == '<' {
      while i < n and s[i] != '>' { i += 1 }
      if i < n { i += 1 }
    } else {
      sb_putc(sb, s[i])
      i += 1
    }
  }
  let t0 = s_trim(sb_str(sb))
  let tn = slen(t0)
  var cut = -1
  var j = 0
  while j < tn {
    let c = t0[j]
    if c == '\n' { break }
    if (c == '.' or c == '!' or c == '?') and j >= 1 {
      if j + 1 >= tn { cut = j + 1;  break }
      if is_space_all(t0[j + 1]) { cut = j + 1;  break }
    }
    j += 1
  }
  var t = t0
  if cut >= 0 { t = sslice(t0, 0, cut) }
  # Python len()/slicing is by codepoint; count codepoints (a byte is a lead when
  # (b & 0xC0) != 0x80) and truncate at the 160th, not the 160th byte.
  let tl = slen(t)
  var cpc = 0
  var bi = 0
  while bi < tl { if (t[bi] & 192) != 128 { cpc += 1 };  bi += 1 }
  if cpc <= 160 { return t }
  var idx = 0
  var seen = 0
  while idx < tl and seen < 160 {
    idx += 1
    while idx < tl and (t[idx] & 192) == 128 { idx += 1 }
    seen += 1
  }
  let pre = sslice(t, 0, idx)
  var sp = slen(pre) - 1
  while sp >= 0 and pre[sp] != ' ' { sp -= 1 }
  var head = pre
  if sp >= 0 { head = sslice(pre, 0, sp) }
  return head + "…"
}

# ---- load the section/entry model -------------------------------------------
function list_sorted(dir: pointer) -> []pointer {
  let out = new []pointer
  let s = capture(`LC_ALL=C ls -1A {dir} 2>/dev/null`)
  let n = slen(s)
  var i = 0
  while i < n {
    let ln = line_at(s, i)
    i = i + slen(ln) + 1
    if slen(ln) > 0 { push(out, ln) }
  }
  return out
}
function is_dir(path: pointer) -> bool { return shq(`test -d {path}`) }

function build_entry(path: pointer) -> Entry {
  let d = parse_doc(path)
  let sp = split_body(d.body)
  let e = new Entry
  e.id = meta_get(d.m, "id", "")
  e.name = meta_get(d.m, "name", "")
  e.sig = meta_get(d.m, "sig", "")
  e.kind = meta_get(d.m, "kind", "")
  e.tip = meta_get(d.m, "tip", "")
  e.ns = meta_get(d.m, "ns", "")
  e.order = str_to_int(meta_get(d.m, "order", "999"))
  e.desc_html = sp.desc
  e.examples = sp.examples
  e.params = sp.params
  e.tokens_list = split_ws(meta_get(d.m, "tokens", ""))
  e.related_list = split_ws(meta_get(d.m, "related", ""))
  return e
}

function entry_gt(a: Entry, b: Entry) -> bool {
  if a.order != b.order { return a.order > b.order }
  return str_gt(a.name, b.name)
}
function entries_sort(es: []Entry) -> void {
  var i = 1
  while i < len(es) {
    let cur = es[i]
    var j = i - 1
    while j >= 0 and entry_gt(es[j], cur) { es[j + 1] = es[j];  j -= 1 }
    es[j + 1] = cur
    i += 1
  }
}
function section_gt(a: Section, b: Section) -> bool {
  if a.order != b.order { return a.order > b.order }
  return str_gt(a.title, b.title)
}
function sections_sort(ss: []Section) -> void {
  var i = 1
  while i < len(ss) {
    let cur = ss[i]
    var j = i - 1
    while j >= 0 and section_gt(ss[j], cur) { ss[j + 1] = ss[j];  j -= 1 }
    ss[j + 1] = cur
    i += 1
  }
}

function load_sections() -> []Section {
  let sections = new []Section
  let cats = list_sorted("docs/language")
  var ci = 0
  while ci < len(cats) {
    let cat = cats[ci]
    ci += 1
    let cdir = "docs/language/" + cat
    if not is_dir(cdir) { continue }
    var sid = cat
    var stitle = title_case(cat)
    var sorder = 999
    var sblurb = ""
    let secp = cdir + "/_section.md"
    if file_exists(secp) {
      let sd = parse_doc(secp)
      sid = meta_get(sd.m, "id", cat)
      stitle = meta_get(sd.m, "title", title_case(cat))
      sorder = str_to_int(meta_get(sd.m, "order", "999"))
      sblurb = codeify(s_trim(sd.body))
    }
    let entries = new []Entry
    let files = list_sorted(cdir)
    var fi = 0
    while fi < len(files) {
      let fn = files[fi]
      fi += 1
      if not s_ends(fn, ".md") { continue }
      if fn == "_section.md" { continue }
      push(entries, build_entry(cdir + "/" + fn))
    }
    entries_sort(entries)
    var nsname = ""
    var ei = 0
    while ei < len(entries) {
      let e = entries[ei]
      if e.kind == "namespace-method" and slen(e.ns) > 0 { nsname = e.ns;  break }
      ei += 1
    }
    let sec = new Section
    sec.id = sid
    sec.title = stitle
    sec.order = sorder
    sec.blurb = sblurb
    sec.cat = cat
    sec.entries = entries
    sec.ns_name = nsname
    push(sections, sec)
  }
  sections_sort(sections)
  return sections
}

# ---- symbol / highlighter model (build_symbols) -----------------------------
function ns_tip(nn: pointer, sections: []Section) -> pointer {
  if nn == "Color" { return "The named color palette." }
  var i = 0
  while i < len(sections) {
    if sections[i].ns_name == nn { return plain_text(sections[i].blurb) }
    i += 1
  }
  return ""
}

function build_symbols(sections: []Section) -> Symbols {
  let items = jvo()
  let sym = jvo()
  let kw = jvo()
  let types = jvo()
  let phases = jvo()
  let builtins = jvo()
  let nsm = jvo()
  let annot = jvo()
  let namespaces = jvo()
  let tips = jvo()
  let cards = jvo()
  jvput(sym, "keywords", kw)
  jvput(sym, "types", types)
  jvput(sym, "phases", phases)
  jvput(sym, "builtins", builtins)
  jvput(sym, "nsmethods", nsm)
  jvput(sym, "annotations", annot)
  jvput(sym, "namespaces", namespaces)
  jvput(sym, "tips", tips)
  jvput(sym, "cards", cards)
  jvput(sym, "colors_page", jvs("ns-color"))
  var si = 0
  while si < len(sections) {
    let s = sections[si]
    si += 1
    var ei = 0
    while ei < len(s.entries) {
      let e = s.entries[ei]
      ei += 1
      let eid = e.id
      let kind = e.kind
      let tip = e.tip
      let page = eid + ".html"
      let it = jvo()
      jvput(it, "id", jvs(eid))
      jvput(it, "name", jvs(e.name))
      jvput(it, "sig", jvs(e.sig))
      jvput(it, "kind", jvs(kind))
      jvput(it, "category", jvs(s.id))
      jvput(it, "section", jvs(s.title))
      jvput(it, "tip", jvs(tip))
      jvput(it, "page", jvs(page))
      jvput(items, eid, it)
      let cd = jvo()
      jvput(cd, "name", jvs(e.name))
      jvput(cd, "sig", jvs(e.sig))
      jvput(cd, "tip", jvs(tip))
      jvput(cd, "kind", jvs(kind))
      jvput(cd, "page", jvs(page))
      jvput(cd, "section", jvs(s.title))
      jvput(cards, eid, cd)
      var ti = 0
      while ti < len(e.tokens_list) {
        let tok = e.tokens_list[ti]
        ti += 1
        if kind == "keyword" { jvput(kw, tok, jvs(eid)) }
        else if kind == "type" { jvput(types, tok, jvs(eid)) }
        else if kind == "phase" { jvput(phases, tok, jvs(eid)) }
        else if kind == "builtin" {
          let o = jvo()
          jvput(o, "id", jvs(eid))
          let pa = jva()
          var qi = 0
          while qi < len(e.params) { jvpush(pa, jvs(e.params[qi].name));  qi += 1 }
          jvput(o, "params", pa)
          jvput(builtins, tok, o)
        }
        else if kind == "namespace-method" {
          let o = jvo()
          jvput(o, "id", jvs(eid))
          let pa = jva()
          var qi = 0
          while qi < len(e.params) { jvpush(pa, jvs(e.params[qi].name));  qi += 1 }
          jvput(o, "params", pa)
          jvput(nsm, tok, o)
        }
        else if kind == "annotation" { jvput(annot, tok, jvs(eid)) }
        if slen(tip) > 0 { jvput(tips, tok, jvs(tip)) }
      }
    }
  }
  let nsnames = new []pointer
  var ki = 0
  while ki < len(nsm.keys) {
    let tok = nsm.keys[ki]
    ki += 1
    let dot = s_index(tok, ".", 0)
    if dot >= 0 { set_add(nsnames, sslice(tok, 0, dot)) }
  }
  set_add(nsnames, "Color")
  strs_sort(nsnames)
  var ni = 0
  while ni < len(nsnames) {
    let nn = nsnames[ni]
    ni += 1
    let pg = "ns-" + lower_ascii(nn)
    jvput(namespaces, nn, jvs(pg))
    let cd = jvo()
    jvput(cd, "name", jvs(nn))
    jvput(cd, "sig", jvs(nn + ".*"))
    jvput(cd, "kind", jvs("namespace"))
    jvput(cd, "tip", jvs(ns_tip(nn, sections)))
    jvput(cd, "page", jvs(pg + ".html"))
    jvput(cd, "section", jvs("Namespaces"))
    jvput(cards, pg, cd)
  }
  let res = new Symbols
  res.items = items
  res.sym = sym
  return res
}

# ---- shared chrome ----------------------------------------------------------
function js_get(v: JVal, key: pointer) -> pointer {
  let x = j_get(v, key)
  if x.t == JV_STR { return x.s }
  return ""
}
function j_has(v: JVal, key: pointer) -> bool {
  if v.t != JV_OBJ { return false }
  var i = 0
  while i < len(v.keys) { if v.keys[i] == key { return true };  i += 1 }
  return false
}

# The stylesheets are linked, not inlined: base.css alone is ~6 KB, and there
# are 900+ pages, so inlining cost ~10 MB of duplicated bytes and meant a design
# change had to be regenerated to be seen. Linking makes the browser cache them
# once across the whole site. Fonts are the platform's own — no webfont request.
function emit_head(b: Sb, title: pointer, desc: pointer, cssfile: pointer) -> void {
  sb_puts(b, `<!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>{hesc(title)}</title>\n<meta name="description" content="{hescattr(desc)}">\n<link rel="stylesheet" href="base.css">\n<link rel="stylesheet" href="{cssfile}">\n</head>`)
}

# nav links; a link whose href equals cta_href gets the nav-cta class
function nav_html(b: Sb, links: JVal, cta_href: pointer) -> void {
  if links.t != JV_ARR { return }
  var i = 0
  while i < len(links.kids) {
    let nlk = links.kids[i]
    i += 1
    let href = js_get(nlk, "href")
    let label = js_get(nlk, "label")
    if href == cta_href { sb_puts(b, `<a class="nav-cta" href="{href}">{hesc(label)}</a>`) }
    else { sb_puts(b, `<a href="{href}">{hesc(label)}</a>`) }
  }
}

function topbar(b: Sb, cfg: JVal) -> void {
  var links = j_get(cfg, "ref_nav_links")
  if links.t != JV_ARR { links = j_get(cfg, "nav_links") }
  sb_puts(b, `<header class="nav"><div class="wrap nav-in"><a class="brand" href="index.html"><span class="logo">L</span> {hesc(js_get(cfg,"brand"))}</a><button class="nav-toggle" aria-label="Toggle menu" aria-expanded="false">☰</button><nav class="nav-links">`)
  nav_html(b, links, "")
  sb_puts(b, `<a class="nav-cta" href="{js_get(cfg,"repo_url")}">Source ↗</a></nav></div></header>`)
}

# ---- per-item page ----------------------------------------------------------
function render_params(e: Entry) -> pointer {
  if len(e.params) == 0 { return "" }
  let b = sb_new()
  sb_puts(b, `<div class="params"><h2>Parameters</h2>`)
  var i = 0
  while i < len(e.params) {
    let p = e.params[i]
    i += 1
    sb_puts(b, `<div class="param" id="param-{p.name}"><code class="pname">{hesc(p.name)}</code><span class="pdesc">{p.desc}</span></div>`)
  }
  sb_puts(b, `</div>`)
  return sb_str(b)
}
function render_examples(e: Entry) -> pointer {
  if len(e.examples) == 0 { return "" }
  let b = sb_new()
  sb_puts(b, `<div class="examples"><h2>Example</h2>`)
  var i = 0
  while i < len(e.examples) {
    sb_puts(b, `<pre data-lang="ludic">{hesc(e.examples[i])}</pre>`)
    i += 1
  }
  sb_puts(b, `</div>`)
  return sb_str(b)
}
function render_related(e: Entry, items: JVal) -> pointer {
  let b = sb_new()
  var cnt = 0
  var i = 0
  while i < len(e.related_list) {
    let r = e.related_list[i]
    i += 1
    let it = j_get(items, r)
    if it.t == JV_NULL { continue }
    if cnt == 0 { sb_puts(b, `<div class="related"><h2>Related</h2><div class="rel-row">`) }
    cnt += 1
    sb_puts(b, `<a class="rel" href="{r}.html">{hesc(js_get(it,"name"))}</a>`)
  }
  if cnt == 0 { return "" }
  sb_puts(b, `</div></div>`)
  return sb_str(b)
}

function render_item(b: Sb, e: Entry, s: Section, cfg: JVal, items: JVal) -> void {
  emit_head(b, e.name + " — Ludic", e.tip, "docs.css")
  sb_puts(b, "\n<body>\n")
  topbar(b, cfg)
  sb_putc(b, '\n')
  var sechref = "api.html#" + s.id
  if slen(s.ns_name) > 0 { sechref = "ns-" + lower_ascii(s.ns_name) + ".html" }
  var kindc = e.kind
  if e.kind == "namespace-method" { kindc = "method" }
  var kindlabel = e.kind
  if e.kind == "namespace-method" { kindlabel = "method" }
  else if e.kind == "builtin" { kindlabel = "function" }
  var descv = e.desc_html
  if slen(descv) == 0 { descv = hesc(e.tip) }
  sb_puts(b, `<main class="wrap item">\n`)
  sb_puts(b, `  <div class="crumbs"><a href="api.html">API Reference</a> <span>›</span> <a href="{sechref}">{hesc(s.title)}</a> <span>›</span> <span class="here">{hesc(e.name)}</span></div>\n`)
  sb_puts(b, `  <div class="item-head">\n`)
  sb_puts(b, `    <span class="kind-badge kind-{kindc}">{hesc(kindlabel)}</span>\n`)
  sb_puts(b, `    <h1 id="top">{hesc(e.name)}</h1>\n`)
  sb_puts(b, `  </div>\n`)
  sb_puts(b, `  <code class="sig">{hesc(e.sig)}</code>\n`)
  sb_puts(b, `  <div class="desc"><p>{descv}</p></div>\n`)
  sb_puts(b, `  {render_params(e)}\n`)
  sb_puts(b, `  {render_examples(e)}\n`)
  sb_puts(b, `  {render_related(e, items)}\n`)
  sb_puts(b, `  <a class="back" href="api.html">← All symbols</a>\n`)
  sb_puts(b, `</main>\n`)
  sb_puts(b, `<script src="ludic-highlight.js"></script>\n`)
  sb_puts(b, `<script>Ludic.highlightAll(); Ludic.installCards(); Ludic.flashTarget();</script>\n`)
  sb_puts(b, `</body></html>`)
}

# ---- namespace overview page ------------------------------------------------
function render_ns(b: Sb, nsname: pointer, s: Section, cfg: JVal) -> void {
  emit_head(b, nsname + " — Ludic", plain_text(s.blurb), "docs.css")
  sb_puts(b, "\n<body>\n")
  topbar(b, cfg)
  sb_putc(b, '\n')
  sb_puts(b, `<main class="wrap item">\n`)
  sb_puts(b, `  <div class="crumbs"><a href="api.html">API Reference</a> <span>›</span> <span class="here">{hesc(nsname)}</span></div>\n`)
  sb_puts(b, `  <div class="item-head"><span class="kind-badge kind-namespace">namespace</span><h1 id="top">{hesc(nsname)}</h1></div>\n`)
  sb_puts(b, `  <p class="ns-blurb">{s.blurb}</p>\n`)
  sb_puts(b, `  <div class="ns-methods">`)
  var i = 0
  while i < len(s.entries) {
    let e = s.entries[i]
    i += 1
    sb_puts(b, `<a class="ns-method" href="{e.id}.html"><code class="nm-sig">{hesc(e.sig)}</code><span class="nm-tip">{hesc(e.tip)}</span></a>`)
  }
  sb_puts(b, `</div>\n`)
  sb_puts(b, `  <a class="back" href="api.html">← All symbols</a>\n`)
  sb_puts(b, `</main>\n`)
  sb_puts(b, `<script src="ludic-highlight.js"></script>\n`)
  sb_puts(b, `<script>Ludic.installCards(); Ludic.flashTarget();</script>\n`)
  sb_puts(b, `</body></html>`)
}

# ---- color page (from the in-memory palette) --------------------------------
function render_color(b: Sb, cfg: JVal) -> void {
  palette_init()
  emit_head(b, "Color — Ludic", "The Ludic named-color palette.", "docs.css")
  sb_puts(b, "\n<body>\n")
  topbar(b, cfg)
  sb_putc(b, '\n')
  sb_puts(b, `<main class="wrap item">\n`)
  sb_puts(b, `  <div class="crumbs"><a href="api.html">API Reference</a> <span>›</span> <span class="here">Color</span></div>\n`)
  sb_puts(b, `  <div class="item-head"><span class="kind-badge kind-namespace">namespace</span><h1 id="top">Color</h1></div>\n`)
  sb_puts(b, `  <p class="ns-blurb">The named color palette. Every <code>Color.Name</code> lowers to a plain <code>0xRRGGBB</code> integer at compile time — no runtime cost. {string(len(pal_names))} names are built in.</p>\n`)
  sb_puts(b, `  `)
  # groups in first-appearance order
  let seen = new []pointer
  var gi = 0
  while gi < len(pal_groups) {
    let g = pal_groups[gi]
    gi += 1
    if set_has(seen, g) { continue }
    push(seen, g)
    sb_puts(b, `<div class="swatch-group"><h3>{hesc(g)}</h3><div class="swatch-row">`)
    var ci = 0
    while ci < len(pal_names) {
      if pal_groups[ci] == g {
        let nm = pal_names[ci]
        let hx = pal_hexes[ci]
        sb_puts(b, `<div class="swatch" id="{lower_ascii(nm)}"><span class="chip" style="background:#{hx}"></span><span class="cname">Color.{hesc(nm)}</span><span class="chex">#{hx}</span></div>`)
      }
      ci += 1
    }
    sb_puts(b, `</div></div>`)
  }
  sb_puts(b, `\n`)
  sb_puts(b, `  <a class="back" href="api.html">← All symbols</a>\n`)
  sb_puts(b, `</main>\n`)
  sb_puts(b, `<script src="ludic-highlight.js"></script>\n`)
  sb_puts(b, `<script>Ludic.installCards(); Ludic.flashTarget();</script>\n`)
  sb_puts(b, `</body></html>`)
}

# ---- API index --------------------------------------------------------------
function render_api(b: Sb, sections: []Section, cfg: JVal) -> void {
  emit_head(b, "Ludic — API Reference", "The complete Ludic API Reference: every keyword, type, builtin, namespace, annotation and color, each on its own page, with fuzzy search.", "docs.css")
  sb_puts(b, "\n<body>\n")
  topbar(b, cfg)
  sb_putc(b, '\n')
  sb_puts(b, `<main class="wrap ref">\n`)
  sb_puts(b, `  <div class="ref-intro">\n`)
  sb_puts(b, `    <div class="kicker">Reference</div>\n`)
  sb_puts(b, `    <h1>API Reference</h1>\n`)
  sb_puts(b, `    <p>Every keyword, type, phase, builtin, namespace method, annotation and color in Ludic — each on its own page. Search, or browse by section. In any code sample across this site, hover a token for a summary and click to jump to its page.</p>\n`)
  sb_puts(b, `    <input id="search" class="search" type="search" placeholder="Search symbols…  (e.g. handler, fill_rectangle, @Sync)" autocomplete="off" autofocus>\n`)
  sb_puts(b, `    <div id="noresults" class="noresults" hidden>No symbols match.</div>\n`)
  sb_puts(b, `  </div>\n`)
  sb_puts(b, `  `)
  var si = 0
  while si < len(sections) {
    let s = sections[si]
    si += 1
    if s.cat == "colors" {
      sb_puts(b, `<section class="idx-sec" data-sec="{s.id}"><h2 id="{s.id}">{hesc(s.title)}</h2><p class="sec-blurb">{s.blurb}</p><div class="idx-grid"><a class="idx-item" href="ns-color.html" data-name="Color" data-tip="The named color palette."><code>Color</code><span>The named color palette (221 names).</span></a></div></section>`)
      continue
    }
    sb_puts(b, `<section class="idx-sec" data-sec="{s.id}"><h2 id="{s.id}">{hesc(s.title)}</h2><p class="sec-blurb">{s.blurb}</p><div class="idx-grid">`)
    var ei = 0
    while ei < len(s.entries) {
      let e = s.entries[ei]
      ei += 1
      sb_puts(b, `<a class="idx-item" href="{e.id}.html" data-name="{hescattr(e.name)}" data-tip="{hescattr(e.tip)}"><code>{hesc(e.name)}</code><span>{hesc(e.tip)}</span></a>`)
    }
    sb_puts(b, `</div></section>`)
  }
  sb_puts(b, `\n`)
  sb_puts(b, `</main>\n`)
  sb_puts(b, `<script src="ludic-highlight.js"></script>\n`)
  sb_puts(b, `<script>Ludic.installCards(); Ludic.installSearch();</script>\n`)
  sb_puts(b, `</body></html>`)
}

# ---- landing page (index.tmpl.html via %(key)s substitution) ----------------
function put(mk: []pointer, mv: []pointer, k: pointer, v: pointer) -> void {
  push(mk, k)
  push(mv, v)
}
function pct(tmpl: pointer, mk: []pointer, mv: []pointer) -> pointer {
  let n = slen(tmpl)
  let b = sb_new()
  var i = 0
  while i < n {
    if tmpl[i] == '%' and i + 1 < n and tmpl[i + 1] == '(' {
      var j = i + 2
      while j < n and is_word(tmpl[j]) { j += 1 }
      if j > i + 2 and j + 1 < n and tmpl[j] == ')' and tmpl[j + 1] == 's' {
        let key = sslice(tmpl, i + 2, j)
        var k = 0
        var found = false
        while k < len(mk) { if mk[k] == key { sb_puts(b, mv[k]);  found = true;  break };  k += 1 }
        i = j + 2
        continue
      }
    }
    sb_putc(b, tmpl[i])
    i += 1
  }
  return sb_str(b)
}

function build_stages(hero: JVal) -> pointer {
  let b = sb_new()
  let pl = j_get(hero, "pipeline")
  if pl.t != JV_ARR { return "" }
  let m = len(pl.kids)
  var i = 0
  while i < m {
    let st = pl.kids[i].s
    var hl = ""
    if st == "ludicc" { hl = " hl" }
    sb_puts(b, `<span class="stage{hl}">{hesc(st)}</span>`)
    if i < m - 1 { sb_puts(b, `<span class="arrow">→</span>`) }
    i += 1
  }
  return sb_str(b)
}
function build_feats(feats: JVal) -> pointer {
  let b = sb_new()
  let cards = j_get(feats, "cards")
  if cards.t != JV_ARR { return "" }
  var i = 0
  while i < len(cards.kids) {
    let c = cards.kids[i]
    i += 1
    sb_puts(b, `<div class="feat"><h3>{js_get(c,"title")}</h3><p>{js_get(c,"html")}</p></div>`)
  }
  return sb_str(b)
}
function build_phil_paras(phil: JVal) -> pointer {
  let b = sb_new()
  let ps = j_get(phil, "paras")
  if ps.t != JV_ARR { return "" }
  var i = 0
  while i < len(ps.kids) { sb_puts(b, `<p>{ps.kids[i].s}</p>`);  i += 1 }
  return sb_str(b)
}
function build_phil_stats(phil: JVal) -> pointer {
  let b = sb_new()
  let ss = j_get(phil, "stats")
  if ss.t != JV_ARR { return "" }
  var i = 0
  while i < len(ss.kids) {
    let s = ss.kids[i]
    i += 1
    sb_puts(b, `<div class="stat"><div class="big">{js_get(s,"big")}</div><div class="lbl">{hesc(js_get(s,"lbl"))}</div></div>`)
  }
  return sb_str(b)
}
function build_steps(start: JVal) -> pointer {
  let b = sb_new()
  let st = j_get(start, "steps")
  if st.t != JV_ARR { return "" }
  var i = 0
  while i < len(st.kids) {
    let s = st.kids[i]
    sb_puts(b, `<div class="step"><div class="n">{string(i + 1)}</div><div><h4>{js_get(s,"title")}</h4><p>{js_get(s,"html")}</p></div></div>`)
    i += 1
  }
  return sb_str(b)
}
function build_term(start: JVal) -> pointer {
  let b = sb_new()
  let tm = j_get(start, "terminal")
  if tm.t != JV_ARR { return "" }
  var i = 0
  while i < len(tm.kids) {
    let t = tm.kids[i]
    i += 1
    let bl = j_get(t, "blank")
    if bl.t == JV_BOOL and bl.b == 1 { sb_putc(b, '\n') }
    else if j_has(t, "comment") { sb_puts(b, `<span class="t-com"># {hesc(js_get(t,"comment"))}</span>\n`) }
    else if j_has(t, "cmd") { sb_puts(b, `<span class="prompt">$</span> {hesc(js_get(t,"cmd"))}\n`) }
    else if j_has(t, "out") { sb_puts(b, `<span class="out">{hesc(js_get(t,"out"))}</span>\n`) }
  }
  return sb_str(b)
}
function build_eds(ed: JVal) -> pointer {
  let b = sb_new()
  let ls = j_get(ed, "list")
  if ls.t != JV_ARR { return "" }
  var i = 0
  while i < len(ls.kids) { sb_puts(b, `<div class="ed"><span class="k">◆</span> {hesc(ls.kids[i].s)}</div>`);  i += 1 }
  return sb_str(b)
}
function build_footlinks(cfg: JVal) -> pointer {
  let b = sb_new()
  let nl = j_get(cfg, "nav_links")
  if nl.t == JV_ARR {
    var i = 0
    while i < len(nl.kids) {
      let n = nl.kids[i]
      i += 1
      sb_puts(b, `<a href="{js_get(n,"href")}">{hesc(js_get(n,"label"))}</a>`)
    }
  }
  sb_puts(b, `<a href="{js_get(cfg,"repo_url")}">Source ↗</a>`)
  return sb_str(b)
}
function build_samples(cfg: JVal) -> pointer {
  let sc = j_get(cfg, "showcase")
  let sm = j_get(sc, "samples")
  let arr = jva()
  if sm.t == JV_ARR {
    var i = 0
    while i < len(sm.kids) {
      let s = sm.kids[i]
      i += 1
      let o = jvo()
      jvput(o, "name", jvs(js_get(s, "name")))
      jvput(o, "label", jvs(js_get(s, "label")))
      jvput(o, "note", jvs(js_get(s, "note")))
      jvput(o, "code", jvs(read_snippet(js_get(s, "file"))))
      jvpush(arr, o)
    }
  }
  return json_dumps(arr, false, true)
}

function render_index(b: Sb, cfg: JVal) -> void {
  let hero = j_get(cfg, "hero")
  let meta = j_get(cfg, "meta")
  let feats = j_get(cfg, "features")
  let sc = j_get(cfg, "showcase")
  let phil = j_get(cfg, "philosophy")
  let start = j_get(cfg, "start")
  let ed = j_get(cfg, "editors")
  let pcta = j_get(hero, "primary_cta")
  let scta = j_get(hero, "secondary_cta")
  let mk = new []pointer
  let mv = new []pointer
  put(mk, mv, "brand", hesc(js_get(cfg, "brand")))
  put(mk, mv, "tagline", hesc(js_get(cfg, "tagline")))
  put(mk, mv, "repo", js_get(cfg, "repo_url"))
  put(mk, mv, "title", hesc(js_get(meta, "title")))
  put(mk, mv, "desc", hescattr(js_get(meta, "description")))
  put(mk, mv, "ogt", hesc(js_get(meta, "og_title")))
  put(mk, mv, "ogd", hescattr(js_get(meta, "og_description")))
  let nb = sb_new()
  nav_html(nb, j_get(cfg, "nav_links"), "api.html")
  put(mk, mv, "navlinks", sb_str(nb))
  put(mk, mv, "pill", hesc(js_get(hero, "pill")))
  put(mk, mv, "title_pre", hesc(js_get(hero, "title_pre")))
  put(mk, mv, "title_accent", hesc(js_get(hero, "title_accent")))
  put(mk, mv, "lead", js_get(hero, "lead"))
  put(mk, mv, "pcta_h", js_get(pcta, "href"))
  put(mk, mv, "pcta_l", hesc(js_get(pcta, "label")))
  put(mk, mv, "scta_h", js_get(scta, "href"))
  put(mk, mv, "scta_l", hesc(js_get(scta, "label")))
  put(mk, mv, "hero_name", hesc(js_get(hero, "snippet_name")))
  put(mk, mv, "hero_code", hesc(read_snippet(js_get(hero, "snippet"))))
  put(mk, mv, "stages", build_stages(hero))
  put(mk, mv, "pipenote", js_get(hero, "pipeline_note"))
  put(mk, mv, "feat_kicker", hesc(js_get(feats, "kicker")))
  put(mk, mv, "feat_title", hesc(js_get(feats, "title")))
  put(mk, mv, "feat_intro", js_get(feats, "intro"))
  put(mk, mv, "feats", build_feats(feats))
  put(mk, mv, "sc_kicker", hesc(js_get(sc, "kicker")))
  put(mk, mv, "sc_title", hesc(js_get(sc, "title")))
  put(mk, mv, "sc_intro", js_get(sc, "intro"))
  put(mk, mv, "phil_kicker", hesc(js_get(phil, "kicker")))
  put(mk, mv, "phil_title", hesc(js_get(phil, "title")))
  put(mk, mv, "phil_paras", build_phil_paras(phil))
  put(mk, mv, "phil_stats", build_phil_stats(phil))
  put(mk, mv, "start_kicker", hesc(js_get(start, "kicker")))
  put(mk, mv, "start_title", hesc(js_get(start, "title")))
  put(mk, mv, "start_intro", hesc(js_get(start, "intro")))
  put(mk, mv, "steps", build_steps(start))
  put(mk, mv, "term_name", hesc(js_get(start, "terminal_name")))
  put(mk, mv, "term", build_term(start))
  put(mk, mv, "ed_kicker", hesc(js_get(ed, "kicker")))
  put(mk, mv, "ed_title", hesc(js_get(ed, "title")))
  put(mk, mv, "ed_intro", js_get(ed, "intro"))
  put(mk, mv, "eds", build_eds(ed))
  put(mk, mv, "ed_note", js_get(ed, "note"))
  put(mk, mv, "footlinks", build_footlinks(cfg))
  put(mk, mv, "samples", build_samples(cfg))
  sb_puts(b, pct(read_asset("index.tmpl.html"), mk, mv))
}

function render_highlighter(sym: JVal) -> pointer {
  let tmpl = read_asset("ludic-highlight.tmpl.js")
  let payload = json_dumps(sym, false, false)
  let p = s_index(tmpl, "/*__SYMBOLS__*/{}", 0)
  if p < 0 { return tmpl }
  let b = sb_new()
  var i = 0
  while i < p { sb_putc(b, tmpl[i]);  i += 1 }
  sb_puts(b, payload)
  var j = p + slen("/*__SYMBOLS__*/{}")
  let n = slen(tmpl)
  while j < n { sb_putc(b, tmpl[j]);  j += 1 }
  return sb_str(b)
}

# ---- the command ------------------------------------------------------------
function cmd_docs_gen() -> int {
  var out = "build/pages"
  var i = 2
  while i < arg_count() {
    let a = arg(i)
    if a == "--out" {
      i += 1
      if i < arg_count() { out = arg(i) }
    }
    i += 1
  }
  shell(`mkdir -p {out}`)
  palette_init()
  let sections = load_sections()
  let syms = build_symbols(sections)
  let cfgtext = read_file("docs/site/site.json")
  if cfgtext == null { err("cannot read docs/site/site.json\n");  return 1 }
  let cfg = json_parse(cfgtext)
  var npages = 0
  var si = 0
  while si < len(sections) {
    let s = sections[si]
    si += 1
    if s.cat == "colors" { continue }
    var ei = 0
    while ei < len(s.entries) {
      let e = s.entries[ei]
      ei += 1
      let pb = sb_new()
      render_item(pb, e, s, cfg, syms.items)
      write_file(`{out}/{e.id}.html`, sb_str(pb))
      npages += 1
    }
  }
  si = 0
  while si < len(sections) {
    let s = sections[si]
    si += 1
    if slen(s.ns_name) > 0 {
      let pb = sb_new()
      render_ns(pb, s.ns_name, s, cfg)
      write_file(`{out}/ns-{lower_ascii(s.ns_name)}.html`, sb_str(pb))
      npages += 1
    }
  }
  let cb = sb_new()
  render_color(cb, cfg)
  write_file(`{out}/ns-color.html`, sb_str(cb))
  npages += 1
  let ab = sb_new()
  render_api(ab, sections, cfg)
  write_file(`{out}/api.html`, sb_str(ab))
  let ib = sb_new()
  render_index(ib, cfg)
  write_file(`{out}/index.html`, sb_str(ib))
  # the stylesheets ship as files, linked from every page (see emit_head)
  write_file(`{out}/base.css`, read_asset("base.css"))
  write_file(`{out}/site.css`, read_asset("site.css"))
  write_file(`{out}/docs.css`, read_asset("docs.css"))
  write_file(`{out}/ludic-highlight.js`, render_highlighter(syms.sym))
  let root = jvo()
  jvput(root, "items", syms.items)
  jvput(root, "highlight", syms.sym)
  write_file(`{out}/symbols.json`, json_dumps(root, true, false))
  write_file(`{out}/.nojekyll`, "")
  # The install one-liner on the landing page points at this site, so the
  # installer is published with it: the page and the script that page tells you
  # to pipe into sh can then never be from different releases.
  let inst = read_file("install.sh")
  if inst == null { err("docs-gen: install.sh is missing (the landing page's one-liner serves it)\n");  return 1 }
  write_file(`{out}/install.sh`, inst)
  print(`docs generated -> {out}`)
  print(`  pages: {string(npages)}`)
  return 0
}