# ui_draw.ludic — layout arrange, drawing, focus/activation and the game-facing
# accessors. Split out of ui.ludic (the storage/build/measure half).

# ---- arrange: rects, parents before children ------------------------------
fn ui_arrange(i: int, x: int, y: int) -> void {
  poke32(ui_rx, i, x)
  poke32(ui_ry, i, y)
  let t = peek32(ui_type, i)
  if ui_is_container(t) == false { return }
  let dir = ui_dir(t)
  let pad = peek32(ui_pad, i)
  let gap = peek32(ui_gap, i)
  let innerw = peek32(ui_rw, i) - 2 * pad
  let innerh = peek32(ui_rh, i) - 2 * pad
  var total = 0
  var ng = 0
  var grows = 0
  for c in 0 .. ui_n {
    if peek32(ui_parent, c) == i {
      if peek32(ui_visible, c) == 1 {
        if dir == 1 { total = total + peek32(ui_rh, c) } else { total = total + peek32(ui_rw, c) }
        ng = ng + 1
        grows = grows + peek32(ui_grow, c)
      }
    }
  }
  if ng > 1 { total = total + gap * (ng - 1) }
  var avail = innerw
  if dir == 1 { avail = innerh }
  let extra = max(avail - total, 0)
  var cx = x + pad
  var cy = y + pad
  for c in 0 .. ui_n {
    if peek32(ui_parent, c) == i {
      if peek32(ui_visible, c) == 1 {
        var kw = peek32(ui_rw, c)
        var kh = peek32(ui_rh, c)
        if peek32(ui_grow, c) != 0 {
          if grows > 0 {
            if dir == 1 { kh = kh + extra / grows } else { kw = kw + extra / grows }
          }
        }
        let al = ui_eff_align(c, i)
        poke32(ui_rw, c, kw)
        poke32(ui_rh, c, kh)
        if dir == 1 {
          var ax = x + pad
          if al == 1 { ax = x + pad + (innerw - kw) / 2 }
          if al == 2 { ax = x + pad + (innerw - kw) }
          ui_arrange(c, ax, cy)
          cy = cy + kh + gap
        } else {
          var ay = y + pad
          if al == 1 { ay = y + pad + (innerh - kh) / 2 }
          if al == 2 { ay = y + pad + (innerh - kh) }
          ui_arrange(c, cx, ay)
          cx = cx + kw + gap
        }
      }
    }
  }
}

fn ui_layout() -> void {
  if ui_active < 0 { return }
  ui_measure()
  var px = (rt_fbw - peek32(ui_rw, ui_active)) / 2
  var py = (rt_fbh - peek32(ui_rh, ui_active)) / 2
  if peek32(ui_haspos, ui_active) == 1 {
    px = peek32(ui_x, ui_active)
    py = peek32(ui_y, ui_active)
  }
  ui_arrange(ui_active, px, py)
}

# ---- drawing --------------------------------------------------------------
fn ui_lighten(c: int) -> int {
  var r = ((c >> 16) & 255)
  var g = ((c >> 8) & 255)
  var b = (c & 255)
  r = r + (255 - r) * 4 / 10
  g = g + (255 - g) * 4 / 10
  b = b + (255 - b) * 4 / 10
  return (((r << 16) | (g << 8)) | b)
}

fn ui_draw_node(i: int) -> void {
  if peek32(ui_visible, i) == 0 { return }
  let t = peek32(ui_type, i)
  let rx = peek32(ui_rx, i)
  let ry = peek32(ui_ry, i)
  let rw = peek32(ui_rw, i)
  let rh = peek32(ui_rh, i)
  let skin = peek32(ui_skin, i)
  var focused = 0
  if i == ui_focus { focused = 1 }

  if t == WT_PANEL {
    if skin >= 0 {
      rt_draw_9slice(skin, rx, ry, rw, rh, peek32(ui_inset, i))
    } else {
      if peek32(ui_bg, i) >= 0 { rt_fill_rect(rx, ry, rw, rh, peek32(ui_bg, i)) }
      if peek32(ui_border, i) >= 0 { rt_frame_rect(rx, ry, rw, rh, peek32(ui_border, i)) }
    }
  }
  if t == WT_BUTTON {
    var bg = peek32(ui_bg, i)
    if bg < 0 { bg = 0x2a2a3a }
    if focused == 1 { bg = ui_lighten(bg) }
    if skin >= 0 {
      rt_draw_9slice(skin, rx, ry, rw, rh, peek32(ui_inset, i))
    } else {
      rt_fill_rect(rx, ry, rw, rh, bg)
    }
    var bc = peek32(ui_border, i)
    if bc < 0 { bc = 0x555577 }
    if focused == 1 { bc = 0xffff00 }
    rt_frame_rect(rx, ry, rw, rh, bc)
    let s = ui_str(i)
    var fg = peek32(ui_fg, i)
    if fg < 0 { fg = 0xffffff }
    let font = peek32(ui_font, i)
    let size = peek32(ui_size, i)
    ui_draw_text(font, rx + (rw - ui_tw(font, s, size)) / 2, ry + (rh - ui_th(font, size)) / 2, s, fg, size)
  }
  if t == WT_LABEL {
    let s = ui_str(i)
    var fg = peek32(ui_fg, i)
    if fg < 0 { fg = 0xffffff }
    let font = peek32(ui_font, i)
    let size = peek32(ui_size, i)
    let pad = peek32(ui_pad, i)
    let tw = ui_tw(font, s, size)
    var tx = rx + pad
    let al = peek32(ui_align, i)
    if al == 1 { tx = rx + (rw - tw) / 2 }
    if al == 2 { tx = rx + rw - pad - tw }
    ui_draw_text(font, tx, ry + pad, s, fg, size)
  }
  if t == WT_IMAGE {
    if peek32(ui_img, i) >= 0 { rt_draw_image_scaled(peek32(ui_img, i), rx, ry, rw, rh) }
  }
  for c in 0 .. ui_n {
    if peek32(ui_parent, c) == i { ui_draw_node(c) }
  }
}

# ---- focus and activation -------------------------------------------------
var ui_fl: ptr = ptr_null()

fn ui_focusables() -> int {
  if ptr_is_null(ui_fl) { ui_fl = mem_alloc(UI_MAX * 4) }
  var n = 0
  for i in 0 .. ui_n {
    if peek32(ui_focusable, i) == 1 {
      if peek32(ui_visible, i) == 1 {
        if ui_under(i, ui_active) {
          poke32(ui_fl, n, i)
          n = n + 1
        }
      }
    }
  }
  return n
}

fn rt_ui_open(root: int) -> void {
  ui_active = root
  let n = ui_focusables()
  ui_focus = 0 - 1
  if n > 0 { ui_focus = peek32(ui_fl, 0) }
}

fn rt_ui_tick(k: int) -> void {
  if ui_active < 0 { return }
  for i in 0 .. ui_n { poke32(ui_fired, i, 0) }
  ui_layout()
  let n = ui_focusables()
  if n == 0 {
    ui_focus = 0 - 1
    return
  }
  var cur = 0 - 1
  for i in 0 .. n {
    if peek32(ui_fl, i) == ui_focus { cur = i }
  }
  if cur < 0 {
    cur = 0
    ui_focus = peek32(ui_fl, 0)
  }
  if k == 119 {                     # 'w'
    cur = (cur - 1 + n) % n
    ui_focus = peek32(ui_fl, cur)
  }
  if k == 115 {                     # 's'
    cur = (cur + 1) % n
    ui_focus = peek32(ui_fl, cur)
  }
  if k == 32 { poke32(ui_fired, ui_focus, 1) }
  if k == 10 { poke32(ui_fired, ui_focus, 1) }
  if k == 13 { poke32(ui_fired, ui_focus, 1) }
}

fn rt_ui_render() -> void {
  if ui_active < 0 { return }
  ui_layout()
  ui_draw_node(ui_active)
}

# ---- game-facing accessors ------------------------------------------------
fn rt_ui_clicked(id: int) -> bool {
  if id < 0 { return false }
  if id >= ui_n { return false }
  return peek32(ui_fired, id) == 1
}

fn rt_ui_set_text(id: int, s: str) -> void {
  if id < 0 { return }
  if id >= ui_n { return }
  let base = id * 96
  var i = 0
  var ch = peek8(s, 0)
  while ch != 0 {
    if i >= 95 { ch = 0 }
    if ch != 0 {
      poke8(ui_dyn, base + i, ch)
      i = i + 1
      ch = peek8(s, i)
    }
  }
  poke8(ui_dyn, base + i, 0)
  poke32(ui_hasdyn, id, 1)
}

fn rt_ui_set_int(id: int, n: int) -> void {
  if id < 0 { return }
  if id >= ui_n { return }
  let base = id * 96
  var at = 0
  var v = n
  if v < 0 {
    poke8(ui_dyn, base, 45)
    at = 1
    v = 0 - v
  }
  if v == 0 {
    poke8(ui_dyn, base + at, 48)
    at = at + 1
  } else {
    var digits = 0
    var t = v
    while t > 0 {
      digits = digits + 1
      t = t / 10
    }
    var p = digits
    while p > 0 {
      var div = 1
      for k in 1 .. p { div = div * 10 }
      poke8(ui_dyn, base + at, 48 + (v / div) % 10)
      at = at + 1
      p = p - 1
    }
  }
  poke8(ui_dyn, base + at, 0)
  poke32(ui_hasdyn, id, 1)
}

fn rt_ui_focus(id: int) -> void {
  if id < 0 { return }
  if id >= ui_n { return }
  ui_focus = id
}

fn rt_ui_focused() -> int {
  return ui_focus
}

fn rt_ui_visible(id: int, v: int) -> void {
  if id < 0 { return }
  if id >= ui_n { return }
  poke32(ui_visible, id, v)
}