// The semantic elements every docs/typ topic uses, and the one place they
// are defined. Content files call them ("this is a key", "this is a
// builtin"); how each looks is decided here, per output: paged outputs
// (the A4 cheatsheet, later the book) draw them, HTML export gives them
// elements and classes for a stylesheet. Page geometry and fonts belong to
// the output wrappers beside this file.

/// The `atelier` theme (src/themes/atelier.zig): pardes's acme homage,
/// butter paper and blue-green tags.
#let palette = (
  paper: rgb("#fffdeb"),
  ink: rgb("#293f35"),
  tag-bg: rgb("#e4f0ed"),
  tag-fg: rgb("#3d6055"),
  tag-name: rgb("#6e4774"),
  grip: rgb("#36826b"),
  col-grip: rgb("#955815"),
  str: rgb("#34743d"),
  num: rgb("#9a5810"),
  rule: rgb("#95baa2"),
  mouse: rgb("#8a3a00"),
)
#let mono = "DejaVu Sans Mono"

/// Topic ids for #doc: each names a chapter (an id in `chapters`) and,
/// optionally, the label of a section in it. Old ids stay so older calls
/// keep working.
#let topics = (
  guide: ("guide", none),
  setup: ("setup", none),
  cheatsheet: ("cheatsheet", none),
  scripting: ("scripting", none),
  reference: ("reference", none),
  themes: ("themes", none),
  building: ("building", none),
  tags: ("guide", none),
  fs: ("reference", none),
  config: ("guide", "config"),
  keys: ("guide", "keys"),
  detached: ("guide", "sessions"),
)

/// Set by a wrapper that holds every chapter (the book, the HTML): #doc
/// then links to the chapter or section. Alone (the A4 sheet) it names it.
#let doc-links = state("doc-links", false)

/// The book's and the HTML's reading order. `file` is the content file
/// in docs/typ, or none while the topic is not written yet (the outputs
/// then show a placeholder). Wrappers include each with heading offset 1,
/// so a file's `=` headings sit under its chapter title, labelled
/// `ch-<id>`.
#let chapters = (
  (id: "guide", title: "Guide", file: "guide.typ"),
  (id: "setup", title: "Setting up your environment", file: "setup.typ"),
  (id: "cheatsheet", title: "Cheatsheet", file: "cheatsheet.typ"),
  (id: "scripting", title: "Scripting", file: "scripting.typ"),
  (id: "reference", title: "Reference", file: "reference.typ"),
  (id: "themes", title: "Themes", file: "themes.typ"),
  (id: "building", title: "Building", file: "building.typ"),
)

/// The tutor, shown as it is in the editor (`Tutor`), from the repo root.
#let tutor-path = "/src/tutor.txt"

/// How much room tables and shell lines get: "roomy" (the book, the HTML)
/// or "tight" (the A4 sheet sets it).
#let density = state("density", "roomy")

#let html-out() = target() == "html"
#let span(class, body) = html.elem("span", attrs: (class: class), body)
#let m(s, fill: palette.ink) = text(font: mono, size: 0.92em, fill: fill, s)

/// A key: one press (`x`, `Ctrl-w`, `Shift-Esc`), or a sequence pressed one
/// after another, written space-separated (`g g`, `SPC f c`). Either is ONE
/// pill: a combination's parts joined by a muted +, a sequence's steps by a
/// muted › (`Ctrl-w h` reads Ctrl + w › h).
#let key(k) = context if html-out() {
  html.elem("kbd", k.split(" ").map(t => html.elem("kbd", t)).join(" "))
} else {
  let muted(c) = text(fill: palette.grip.transparentize(25%), size: 0.85em, c)
  let press(t) = (if t.len() > 1 and t.contains("-") { t.split("-") } else { (t,) }).join(muted[+])
  box(
    fill: palette.grip.transparentize(84%), radius: 2pt,
    inset: (x: 1.4pt, y: 0pt), outset: (y: 1.5pt),
    text(font: mono, size: 0.92em, fill: palette.ink,
      k.split(" ").map(press).join(muted[#h(1pt)›#h(1pt)])),
  )
}

/// Alternatives: separate keys listed together, each its own command.
#let keys(..ks) = context ks.pos().map(key).join(if html-out() [ ] else { h(0.25em) })

#let button-names = ("B1": "left button", "B2": "wheel", "B3": "right button")

/// A mouse, about cap height: left button, wheel, right button. The parts
/// in `pressed` ("B1", "B2", "B3") are filled.
#let mouse(pressed) = {
  let (w, h, top) = (0.84em, 1.2em, 0.56em)
  let ink = palette.mouse
  let s = 0.7pt + ink
  let on(b) = if b in pressed { ink } else { none }
  box(width: w, height: h, baseline: 0.24em, {
    place(rect(width: w / 2, height: top, radius: (top-left: w / 2), fill: on("B1"), stroke: s))
    place(dx: w / 2, rect(width: w / 2, height: top, radius: (top-right: w / 2), fill: on("B3"), stroke: s))
    place(dy: top, rect(width: w, height: h - top, radius: (bottom: w / 2), stroke: s))
    // the wheel: a narrow tall slot over the buttons' seam, on a paper
    // halo so a filled wheel stands apart from the button outlines
    let (ww, wh, halo) = (0.26em, 0.44em, 0.07em)
    let (wx, wy) = ((w - ww) / 2, 0.06em)
    place(dx: wx - halo, dy: wy - halo / 2, rect(
      width: ww + 2 * halo, height: wh + halo, radius: ww, fill: palette.paper))
    place(dx: wx, dy: wy, rect(
      width: ww, height: wh, radius: ww / 2, stroke: 0.5pt + ink,
      fill: if "B2" in pressed { ink } else { palette.paper },
    ))
  })
}

/// A mouse button; `shift: true` for the button with Shift held.
#let btn(b, shift: false) = context if html-out() {
  let label = (if shift { "shift " } else { "" }) + button-names.at(b)
  html.elem("span", attrs: (class: "btn", aria-label: label, title: label), (if shift { "⇧" } else { "" }) + b)
} else {
  if shift { text(size: 0.8em, fill: palette.col-grip)[⇧] }
  mouse((b,))
}

/// A chord: the first button held, each next one clicked while it is.
/// Drawn as the held button, then for each click the held one and that one
/// down, with arrows between.
#let chord(..bs) = context if html-out() {
  let label = bs.pos().map(b => button-names.at(b)).join(" then ")
  html.elem("span", attrs: (class: "chord", aria-label: label, title: label), bs.pos().join("-"))
} else {
  let (held, ..clicks) = bs.pos()
  let arrow = text(size: 0.75em, fill: palette.col-grip)[#h(0.5pt)›#h(0.5pt)]
  ((mouse((held,)),) + clicks.map(c => mouse((held, c)))).join(arrow)
}

/// A tag word or builtin, as it sits in a tag.
#let word(w) = context if html-out() { span("word", raw(w)) } else {
  box(fill: palette.tag-bg, inset: (x: 1.4pt, y: 0pt), outset: (y: 1.4pt), m(w, fill: palette.tag-fg))
}

/// A whole tagline: its grip, the path, then its words.
#let tag(words, path: none) = context if html-out() {
  html.elem("div", attrs: (class: "tag"), {
    if path != none { span("path", path); [ ] }
    raw(words)
  })
} else {
  block(width: 100%, fill: palette.tag-bg, inset: (x: 2pt, y: 2.4pt), spacing: 0.5em, {
    box(fill: palette.grip, width: 0.55em, height: 0.75em, baseline: 0.1em)
    h(3pt)
    if path != none { m(path, fill: palette.tag-name); h(0.6em) }
    m(words, fill: palette.tag-fg)
  })
}

/// A look address.
#let addr(a) = context if html-out() { span("addr", raw(a)) } else { m(a, fill: palette.tag-name) }

/// A 9P path.
#let file(p) = context if html-out() { span("file", raw(p)) } else { m(p, fill: palette.str) }

/// A shell line.
#let cmd(c) = context if html-out() { raw(c, block: true, lang: "sh") } else {
  let tight = density.get() == "tight"
  block(
    width: 100%, spacing: if tight { 0.4em } else { 0.9em },
    inset: if tight { (left: 3pt, y: 1.2pt) } else { (left: 6pt, y: 3pt) },
    stroke: (left: (if tight { 1pt } else { 1.5pt }) + palette.rule),
    fill: if tight { none } else { palette.tag-bg.transparentize(50%) },
    text(font: mono, size: 0.85em, fill: palette.ink, c),
  )
}

/// Where the full story is: a topic id from `topics`, and a section label
/// in it. A link where the wrapper holds the chapters, else its name.
#let doc(id, section: none) = {
  let (chapter, default) = topics.at(id)
  let section = if section != none { section } else { default }
  let title = chapters.find(c => c.id == chapter).title
  let to = label(if section != none { section } else { "ch-" + chapter })
  let named = title + if section != none { ": " + section.replace("-", " ") } else { "" }
  context {
    if doc-links.get() {
      let found = query(to)
      let shown = if found.len() > 0 and found.first().func() == heading {
        if section != none [#title: #found.first().body] else [#title]
      } else [#named]
      link(to, text(fill: palette.num)[→ #shown])
    } else {
      text(fill: palette.num)[→ #named]
    }
  }
}

/// Pairs: a thing and what it means, as a two-column table, key column
/// first, rows on alternating tints. `split: 2` sets the rows as that many
/// tables side by side (on paper; HTML gets one table).
#let pairs(split: 1, ..cells) = {
  let rows = cells.pos().chunks(2)
  context {
    let tight = density.get() == "tight"
    let one(rows) = table(
      columns: (auto, 1fr), stroke: none,
      inset: if tight { (x: 2pt, y: 1.6pt) } else { (x: 7pt, y: 4pt) },
      fill: (_, y) => if calc.even(y) { palette.tag-bg.transparentize(35%) },
      ..rows.flatten(),
    )
    if html-out() or split == 1 { one(rows) } else {
      let n = calc.ceil(rows.len() / split)
      grid(columns: (1fr,) * split, column-gutter: if tight { 2pt } else { 10pt }, ..rows.chunks(n).map(one))
    }
  }
}