# ============================================================================
# ui.ludic — the retained UI engine, written in Ludic.
#
# A `ui Name { … }` block in a game is DATA: the compiler flattens the widget
# tree and emits a build function that calls rt_ui_set() for each property.
# Everything after that — measure/arrange layout, 9-slice skins, text, keyboard
# focus and activation — is this file.
#
# Widgets are parallel arrays rather than a struct per widget, because Ludic
# has components for per-entity data and raw memory for everything else, and a
# widget is not an entity.
# ============================================================================

const UI_MAX: int = 256

# widget types, matching the compiler's flattener
const WT_PANEL:  int = 0
const WT_COL:    int = 1
const WT_ROW:    int = 2
const WT_LABEL:  int = 3
const WT_BUTTON: int = 4
const WT_IMAGE:  int = 5
const WT_SPACER: int = 6

# property keys — the private protocol between ludicc and this runtime
const K_TYPE: int = 0
const K_PARENT: int = 1
const K_W: int = 2
const K_H: int = 3
const K_X: int = 4
const K_Y: int = 5
const K_HASPOS: int = 6
const K_PAD: int = 7
const K_GAP: int = 8
const K_BG: int = 9
const K_FG: int = 10
const K_BORDER: int = 11
const K_ALIGN: int = 12
const K_GROW: int = 13
const K_FONT: int = 14
const K_SIZE: int = 15
const K_SKININSET: int = 16
const K_FOCUSABLE: int = 17
const K_VISIBLE: int = 18
const K_IMG: int = 19
const K_SKIN: int = 20

var ui_type: words = null
var ui_parent: words = null
var ui_w: words = null
var ui_h: words = null
var ui_x: words = null
var ui_y: words = null
var ui_haspos: words = null
var ui_pad: words = null
var ui_gap: words = null
var ui_bg: words = null
var ui_fg: words = null
var ui_border: words = null
var ui_align: words = null
var ui_grow: words = null
var ui_font: words = null
var ui_size: words = null
var ui_skin: words = null
var ui_inset: words = null
var ui_img: words = null
var ui_focusable: words = null
var ui_rx: words = null
var ui_ry: words = null
var ui_rw: words = null
var ui_rh: words = null
var ui_visible: words = null
var ui_fired: words = null
var ui_hasdyn: words = null
var ui_dyn: ptr = null        # UI_MAX * 96 bytes
var ui_text: ptr = null       # UI_MAX static string pointers

var ui_n: int = 0
var ui_active: int = -1
var ui_focus: int = -1

fn rt_ui_init() -> void {
  ui_type = words(UI_MAX)
  ui_parent = words(UI_MAX)
  ui_w = words(UI_MAX)
  ui_h = words(UI_MAX)
  ui_x = words(UI_MAX)
  ui_y = words(UI_MAX)
  ui_haspos = words(UI_MAX)
  ui_pad = words(UI_MAX)
  ui_gap = words(UI_MAX)
  ui_bg = words(UI_MAX)
  ui_fg = words(UI_MAX)
  ui_border = words(UI_MAX)
  ui_align = words(UI_MAX)
  ui_grow = words(UI_MAX)
  ui_font = words(UI_MAX)
  ui_size = words(UI_MAX)
  ui_skin = words(UI_MAX)
  ui_inset = words(UI_MAX)
  ui_img = words(UI_MAX)
  ui_focusable = words(UI_MAX)
  ui_rx = words(UI_MAX)
  ui_ry = words(UI_MAX)
  ui_rw = words(UI_MAX)
  ui_rh = words(UI_MAX)
  ui_visible = words(UI_MAX)
  ui_fired = words(UI_MAX)
  ui_hasdyn = words(UI_MAX)
  ui_dyn = bytes(UI_MAX * 96)
  ui_text = bytes(UI_MAX * 8)
}

# ---- build-time interface (called by compiler-emitted code) ---------------
fn rt_ui_reset(n: int) -> void {
  ui_n = n
  for i in 0 .. n {
    ui_type[i] = 0
    ui_parent[i] = 0 - 1
    ui_w[i] = 0
    ui_h[i] = 0
    ui_x[i] = 0
    ui_y[i] = 0
    ui_haspos[i] = 0
    ui_pad[i] = 0
    ui_gap[i] = 0
    ui_bg[i] = 0 - 1
    ui_fg[i] = 0 - 1
    ui_border[i] = 0 - 1
    ui_align[i] = 0 - 1
    ui_grow[i] = 0
    ui_font[i] = 0 - 1
    ui_size[i] = 8
    ui_skin[i] = 0 - 1
    ui_inset[i] = 6
    ui_img[i] = 0 - 1
    ui_focusable[i] = 0
    ui_visible[i] = 1
    ui_fired[i] = 0
    ui_hasdyn[i] = 0
    pokep(ui_text, i, null)
  }
}

fn rt_ui_set(i: int, k: int, v: int) -> void {
  if i < 0 { return }
  if i >= UI_MAX { return }
  if k == K_TYPE { ui_type[i] = v }
  if k == K_PARENT { ui_parent[i] = v }
  if k == K_W { ui_w[i] = v }
  if k == K_H { ui_h[i] = v }
  if k == K_X { ui_x[i] = v }
  if k == K_Y { ui_y[i] = v }
  if k == K_HASPOS { ui_haspos[i] = v }
  if k == K_PAD { ui_pad[i] = v }
  if k == K_GAP { ui_gap[i] = v }
  if k == K_BG { ui_bg[i] = v }
  if k == K_FG { ui_fg[i] = v }
  if k == K_BORDER { ui_border[i] = v }
  if k == K_ALIGN { ui_align[i] = v }
  if k == K_GROW { ui_grow[i] = v }
  if k == K_FONT { ui_font[i] = v }
  if k == K_SIZE { ui_size[i] = v }
  if k == K_SKININSET { ui_inset[i] = v }
  if k == K_FOCUSABLE { ui_focusable[i] = v }
  if k == K_VISIBLE { ui_visible[i] = v }
  if k == K_IMG { ui_img[i] = v }
  if k == K_SKIN { ui_skin[i] = v }
}

fn rt_ui_static_text(i: int, s: str) -> void {
  if i < 0 { return }
  if i >= UI_MAX { return }
  pokep(ui_text, i, s)
}

# ---- text helpers: TrueType when a font is loaded, bitmap otherwise -------
fn ui_str(i: int) -> ptr {
  if ui_hasdyn[i] == 1 { return ptr_add(ui_dyn, i * 96) }
  let t = peekp(ui_text, i)
  if (t == null) { return ptr_add(ui_dyn, i * 96) }
  return t
}

fn ui_draw_text(font: int, x: int, y: int, s: ptr, colour: int, size: int) -> void {
  if font >= 0 {
    if font < tt_n {
      rt_text_ttf(font, x, y, s, colour, size)
      return
    }
  }
  rt_text(x, y, s, colour, max(size / 8, 1))
}

fn ui_tw(font: int, s: ptr, size: int) -> int {
  if font >= 0 {
    if font < tt_n { return rt_text_w(font, s, size) }
  }
  var n = 0
  while s[n] != 0 { n = n + 1 }
  return n * 6 * max(size / 8, 1)
}

fn ui_th(font: int, size: int) -> int {
  if font >= 0 {
    if font < tt_n { return rt_text_h(font, size) }
  }
  return 7 * max(size / 8, 1)
}

fn ui_is_container(t: int) -> bool {
  if t == WT_PANEL { return true }
  if t == WT_COL { return true }
  if t == WT_ROW { return true }
  return false
}
fn ui_dir(t: int) -> int {
  if t == WT_ROW { return 0 }
  return 1
}
fn ui_under(i: int, root: int) -> bool {
  var k = i
  while k >= 0 {
    if k == root { return true }
    k = ui_parent[k]
  }
  return false
}

# ---- measure: content sizes, children before parents ----------------------
fn ui_measure() -> void {
  var i = ui_n - 1
  while i >= 0 {
    if ui_visible[i] == 0 {
      ui_rw[i] = 0
      ui_rh[i] = 0
    } else {
      let t = ui_type[i]
      let pad = ui_pad[i]
      var cw = 0
      var ch = 0
      if t == WT_LABEL { cw = 0 - 1 }
      if t == WT_BUTTON { cw = 0 - 1 }
      if cw == 0 - 1 {
        let s = ui_str(i)
        cw = ui_tw(ui_font[i], s, ui_size[i]) + 2 * pad
        ch = ui_th(ui_font[i], ui_size[i]) + 2 * pad
        if t == WT_BUTTON {
          cw = cw + 10
          ch = ch + 6
        }
      } else {
        if t == WT_IMAGE {
          let im = ui_img[i]
          if im >= 0 {
            cw = img_w[im]
            ch = img_h[im]
          }
        } else {
          if t == WT_SPACER {
            cw = ui_w[i]
            ch = ui_h[i]
          } else {
            let dir = ui_dir(t)
            var mainsz = 0
            var cross = 0
            var nc = 0
            for c in 0 .. ui_n {
              if ui_parent[c] == i {
                if ui_visible[c] == 1 {
                  if dir == 1 {
                    mainsz = mainsz + ui_rh[c]
                    cross = max(cross, ui_rw[c])
                  } else {
                    mainsz = mainsz + ui_rw[c]
                    cross = max(cross, ui_rh[c])
                  }
                  nc = nc + 1
                }
              }
            }
            if nc > 1 { mainsz = mainsz + ui_gap[i] * (nc - 1) }
            mainsz = mainsz + 2 * pad
            cross = cross + 2 * pad
            if dir == 1 {
              cw = cross
              ch = mainsz
            } else {
              cw = mainsz
              ch = cross
            }
          }
        }
      }
      var rw = ui_w[i]
      var rh = ui_h[i]
      if rw == 0 { rw = cw }
      if rh == 0 { rh = ch }
      ui_rw[i] = rw
      ui_rh[i] = rh
    }
    i = i - 1
  }
}

fn ui_eff_align(child: int, parent: int) -> int {
  if ui_align[child] >= 0 { return ui_align[child] }
  if ui_align[parent] >= 0 { return ui_align[parent] }
  return 0
}

import "ui_draw.ludic"