// ============================================================================
// template.typ — technical, minimal presentation template
//
// Usage:
//   #import "template.typ": *
//   #show: presentation.with(title: "...", subtitle: "...", author: "...")
//
//   #slide(title: "Title")[ ... ]   // two-part slide: title part | content part
//   #slide[ ... ]                   // single-part, full-width slide
//   #img("assets/fig.svg")          // centered image, optional caption
// ============================================================================

// Palette: warm paper, petrol accent, terracotta counterpoint.
// All text/background pairs keep >= 4.5:1 contrast; decorative
// elements (bars, markers, watermarks) never carry information.
#let paper = rgb("#faf8f3")
#let ink = rgb("#2d2a26")
#let accent = rgb("#22617f")
#let accent-soft = rgb("#4c8fad")
#let ember = rgb("#a85430")
#let wash = rgb("#edf2f5")
#let mono = "DejaVu Sans Mono"

// Short vertical accent rule (petrol -> terracotta).
#let hairline-v = 3.5pt + gradient.linear(accent, ember, angle: 90deg)
// Horizontal hairline for title/section slides.
#let hairline-h = 1pt + gradient.linear(accent, ember, angle: 0deg)

#let slide-counter = counter("slide")
#let deck-title = state("deck-title", none)

// Footer: deck title bottom-left, slide counter bottom-right.
#let slide-footer() = context {
  let n = slide-counter.get().first()
  let total = slide-counter.final().first()
  set text(font: mono, size: 0.55em, fill: luma(150))
  place(bottom + left, dy: -1em, deck-title.get())
  place(bottom + right, dy: -1em, {
    text(fill: accent, weight: "bold", str(n))
    text(fill: luma(165), " / " + str(total))
  })
}

// Tinted content panel with a colored spine — used for paired columns
// (Grok = ember, Mistral = petrol). The spine is decorative reinforcement;
// the column headers carry the information.
#let panel(body, c: accent) = block(
  width: 100%,
  fill: c.lighten(95%),
  stroke: (left: 2.5pt + c),
  inset: (x: 0.55em, y: 0.45em),
  radius: (top-right: 2pt, bottom-right: 2pt),
  {
    set par(spacing: 0.85em)
    body
  },
)

// Thin gradient band across the top edge of every page.
#let top-band = place(top + left, rect(width: 100%, height: 2.5pt, fill: gradient.linear(accent, ember, angle: 0deg)))

// Import an image, centered; optional caption (never numbered).
#let img(path, width: 82%, caption: none) = {
  let im = image(path, width: width)
  if caption == none {
    align(center, im)
  } else {
    align(center, figure(im, caption: caption, numbering: none))
  }
}

// Two-part slide: a narrow title part on the left, content on the right.
// Without `title`, the body takes the full width.
#let slide(body, title: none, ..args) = {
  slide-counter.update(n => n + 1)
  page(
    footer: slide-footer(),
    ..args,
    if title == none {
      body
    } else {
      grid(
        columns: (0.3fr, 1.1fr),
        column-gutter: 2.2em,
        align(top, block(
          stroke: (left: hairline-v),
          inset: (left: 0.9em, top: 0.4em, bottom: 0.1em),
          text(font: mono, weight: "bold", size: 0.85em, tracking: 0.1em, fill: accent, upper(title)),
        )),
        align(top, body),
      )
    },
  )
}

// Section divider slide, with a large decorative ghost numeral.
#let section-counter = counter("section")
#let section(name, note: none) = {
  section-counter.step()
  slide[
    #align(horizon)[
      #block(width: 72%, align(left)[
        #context {
          let n = section-counter.get().first()
          place(top + right, dy: -1.1em, dx: 0.2em,
            text(font: mono, size: 4.2em, weight: "bold", fill: accent.lighten(86%))[
              0#str(n)
            ])
        }
        #text(font: mono, size: 0.65em, weight: "bold", tracking: 0.2em, fill: accent)[SECTION]
        #v(0.4em)
        #text(size: 2em, weight: "bold")[#name]
        #v(0.55em)
        #box(width: 4.5em, align(left, line(length: 100%, stroke: hairline-h)))
        #if note != none [#v(0.5em); #text(font: mono, size: 0.7em, fill: luma(110))[#note]]
      ])
    ]
  ]
}

// Title slide.
#let title-slide(title, subtitle: none, author: none, date: none) = {
  align(center + horizon)[
    #block(width: 72%, align(left)[
      #text(size: 2.1em, weight: "bold")[#title]
      #if subtitle != none [#v(0.4em); #text(size: 1.15em, fill: luma(90))[#subtitle]]
      #v(0.9em)
      #line(length: 100%, stroke: hairline-h)
      #v(0.6em)
      #let meta = if author == none { date } else if date == none { author } else { author + "  ·  " + date }
      #text(font: mono, size: 0.7em, fill: luma(110))[#meta]
    ])
  ]
  pagebreak()
}

// Main presentation wrapper. All options are named; the document content is
// bound to `doc` by the show rule.
#let presentation(
  title: "Presentation",
  subtitle: none,
  author: none,
  date: auto,
  doc,
) = {
  set page(paper: "presentation-16-9", margin: (x: 3em, y: 2.6em), fill: paper, footer: none, background: top-band)
  set text(size: 20pt, fill: ink)
  set par(justify: false, leading: 0.68em)
  show strong: set text(fill: accent)
  show list: set list(marker: (
    text(fill: accent-soft)[•],
    text(fill: accent-soft)[–],
  ))
  show raw: set text(font: mono, size: 0.85em)
  show raw.where(block: true): it => block(width: 100%, fill: wash, inset: 0.9em, radius: 0pt, it)

  deck-title.update(title)

  let d = datetime.today()
  let mm = if d.month() < 10 { "0" + str(d.month()) } else { str(d.month()) }
  let dd = if d.day() < 10 { "0" + str(d.day()) } else { str(d.day()) }
  let the-date = if date == auto {
    str(d.year()) + "-" + mm + "-" + dd
  } else {
    date
  }

  title-slide(title, subtitle: subtitle, author: author, date: the-date)
  doc
}