#import "@preview/cetz:0.2.2": coordinate

#let val(value, alignment) = {
  return (
    type: "value",
    value: value,
    alignment: alignment
  )
}

#let disc(eod: false, ..args) = {
  let pargs = args.pos()
  let left = pargs.at(0, default: (none, none))
  let right = pargs.at(1, default: (none, none))
  let center = pargs.at(2, default: (none, none))

  let kwargs = args.named()
  if "left" in kwargs { left = kwargs.left }
  if "right" in kwargs { right = kwargs.right }
  if "center" in kwargs { center = kwargs.center }
  
  let (value-l, alignment-l) = left
  let (value-r, alignment-r) = right
  let (value-c, alignment-c) = center
  return (
    type: "discontinuity",
    left: (
      value: value-l,
      alignment: alignment-l,
    ),
    right: (
      value: value-r,
      alignment: alignment-r,
    ),
    center: (
      value: value-c,
      alignment: alignment-c,
    ),
    eod: eod
  )
}

#let inter(value, start, end, i: auto) = {
  return (
    type: "intermediate",
    value: value,
    start: start,
    end: end,
    i: i,
  )
}

#let get-anchor(
  ctx,
  line-i,
  i,
  alignment,
  side,
  dx: .1,
  dy: .1
) = {
  let (_, anchor) = coordinate.resolve(ctx, "anchor-" + str(i))
  let (_, header-t) = coordinate.resolve(ctx, "header-" + str(line-i) + ".north")
  let (_, header-b) = coordinate.resolve(ctx, "header-" + str(line-i) + ".south")

  let x = anchor.at(0)
  if side == "left" {
    x -= dx
  } else if side == "right" {
    x += dx
  }

  let yt = header-t.at(1)
  let yb = header-b.at(1)
  let y = (yt + yb) / 2
  if alignment == "top" {
    y = yt - dy
  } else if alignment == "bottom" {
    y = yb + dy
  }
  return (x, y)
}