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

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

#let points_counter(h) = {
  // Find the first heading at a level equal or higher than this one
  let headings_after = query(selector(heading)
      .after(h.location())
    ).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.last().location()) } 
  stop_value.at(0) - start_value.at(0)
}

#let show_points(pts) = [#pts] + if pts < 2 { " pt" } else { " pts" }

// Rend les réponses visibles seulement si compilé avec `--input grading=true`
#let grading(content) = if sys.inputs.at("grading", default: "solution") == "solution" { set text(fill: olive); content } else { hide(content) }

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

  {
    set text(font: "Montserrat")

    let date = if date == none { datetime.today() } else { date };

    align(center, text(size:26pt, course + " - " + date.display("[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
    }

  }

  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)))]))
  doc
};

#let question(points: 1, q, a) = {
  context pctr.step()
  let pts = strong([(#show_points(points))]);

  let num = context { qctr.step(); qctr.display() }
  [#num) #q #pts]
  let answ_block = block(width: 100%, inset: 1em, grading(a));
  block(stroke: black, answ_block)
}