#let qctr = counter("question")
#let pctr = counter("points")

#let french_month = ("janvier", "février", "mars", "avril", "mai", "juin", "juillet", "août", "septembre", "octobre", "novembre", "décembre")

#let compile_mode = sys.inputs.at("mode", default: "");

#let enable_solutions = { compile_mode in ("solution", "notes") };
#let enable_notes = { compile_mode == "notes" };



#let points_counter(h) = {
  // Find the first heading at a level equal or lower (more important) than this one
  let headings_after = query(selector(heading)
      .after(h.location(), inclusive: false)
    ).filter(nh => nh.level <= h.level);
  
  let start_value = pctr.at(h.location())
  let stop_value = if headings_after.len() == 0 { pctr.final() }
     else { pctr.at(headings_after.first().location()) }
  stop_value.at(0) - start_value.at(0)
}

#let show_points(pts) = if pts == 0 {
  none
} else if pts == 1 {
  [(1 pt)] 
} else {
  [(#pts pts)]
}

// Rend les réponses visibles seulement si compilé avec `--input mode=solution`
#let solution(content) = if enable_solutions { set text(fill: olive); content } else { hide(content) }

#let qcm(qcm_list) = {
  //let checked_box = "☑";
  //let unchecked_box = "☐";
  let checked_box = box(stroke: black, outset: 0.2em, "X") + " ";
  let unchecked_box = box(stroke: black, outset: 0.2em, hide("X")) + " ";
  set list(marker: unchecked_box, indent: 2em)
  if enable_solutions {
    show <yes>: i => { 
      show box: b => checked_box;
      set text(fill: olive);
      i
    };
    qcm_list
  } else {
    qcm_list
  }
}


#let exam(title: "Exam", course: none, date: none, class: none,
     year: none, author: none, subtitle: none, indications: none, 
     time: none, allowed: none) = doc => {

  {
    set text(font: "Montserrat")

    let date = if date == none { datetime.today() } else { date };
    let year = if year == none { date.year() } else { year }; 
    let total = context [#pctr.final().at(0)]


    let indications = if indications == none {
    [
      - Ce test doit être réalisé en maximum *#time*.

      - Aucun document n'est admis, excepté #allowed .

      - L'utilisation de tout type de matériel électronique est interdite.

      - Ne pas oublier d'inscrire votre nom et prénom à l'endroit prévu à cet effet.

      - Merci de respecter un silence absolu jusqu'à ce que le dernier étudiant
        aie rendu sa copie
]} else { indications };

    align(center, text(size:26pt, [#course  - #year]))
    align(center, text(size:26pt, title))
    align(center, text(size:15pt, fill: luma(80), subtitle))
    v(5%)
    align(center, text(size:14pt, author))
    v(3%)
    align(center, text(size:14pt, date.display("[day] ") + french_month.at(date.month() - 1)  + date.display(" [year]")))

    v(7%)
    align(left, text(size: 20pt, "Nom :"))
    align(left, text(size: 20pt, "Prénom :"))
    v(3%)

    line(length: 100%, stroke: luma(80))
    v(3%)
  
    text(size: 16pt, "Indications :")
    {
      set text(size: 12pt)
      set list(marker: "●", indent: 2em, body-indent: 1em)
      indications
    }

    v(5%)

    align(right, text(size: 12pt, [Total: #total points]))

  }

  pagebreak()

  set text(font: "Carlito", size: 12pt)
  show heading: h => pad(bottom: 0.5em, text(fill: eastern, size: 16pt, weight: "light", h.body + " " + show_points(points_counter(h))))

  let head = text(fill: gray)[#course #year - #title];

  set page(header: head, footer: align(right, text(fill: gray, "Page ") + context counter(page).display("1 | 1", both: true)))
  doc
};

// Bloc réponse caché en mode production
#let reponse(a) = {
  let answ_block = block(width: 100%, inset: 1em, solution(a));
  block(stroke: black, answ_block)
  v(2em)
}

#let notes(n) = if enable_notes { text(fill: red, n) } else { none };

// Question d'examen. Numérotée automatiquement, nombre de points optionnel
// (défaut 1), bloc de réponse automatique si 2e argument présent
#let question(points: 1, q, ..a) = {
  context pctr.update(t => t + points)
  let pts = strong(show_points(points));

  context { qctr.step() }
  let num = context { qctr.display() };
  [#num) #q #pts]
  if a.pos().len() > 0 {
    reponse(a.pos().at(0))
  }

}