-- Editor UI controller. Loaded once at startup; owns the mode label
-- (always present) and the color picker (created/destroyed with the mode),
-- both driven by the editor.mode property. z controls stacking within an
-- overlay; equal z means don't overlap.

-- ============================== mode label ==============================

local label_overlay = ui.create_overlay{anchor = ANCHOR_TOP_LEFT, size = {160, 40}}
local label = ui.text{
  pos = {0, 32},
  size = 32,
  color = {1, 1, 1, 1},
  font = 0,
  max_length = 8,
  z = 0,
}
label:set_text(app.get("editor.mode") or "None")

-- ============================== color picker =============================
-- Elements/state are outer locals, assigned (not re-declared) each time
-- open_picker() runs, so the shared on_button etc. below always see
-- whichever picker is currently open.

local picker_overlay = nil
local bg, sv_square, hue_bar, sv_outline, sv_select
local hex_area, hue_select, hex_text, slots, slot_index, drag
local state

local function clamp01(x) return math.max(0, math.min(1, x)) end

local function update_hex_string()
  state.hex_string = string.format("#%02X%02X%02X%02X",
      math.floor(state.rgb[1]*255 + 0.5),
      math.floor(state.rgb[2]*255 + 0.5),
      math.floor(state.rgb[3]*255 + 0.5),
      math.floor(state.rgb[4]*255 + 0.5))
  hex_text:set_text(state.hex_string)
  -- Publish for C and other overlays; only ever called with a complete
  -- color, so editor.color never holds a half-typed hex string
  app.set("editor.color", state.hex_string)
end

local function sync_rgb_from_hsv()
  state.rgb[1], state.rgb[2], state.rgb[3] =
      ui.hsv_to_rgb(state.hsv[1], state.hsv[2], state.hsv[3])
  update_hex_string()
end

local function sv_pick(s, v)
  s = clamp01(s)
  v = clamp01(v)
  state.hsv[2] = s
  state.hsv[3] = v

  sv_select:set_pos(s*130 - 2, 130 - v*130 - 2)
  for corner = 0, 3 do
    sv_select:set_corner_color(corner, state.hsv[1], s, v, 1)
  end
  sv_outline:set_pos(s*130 - 3, 130 - v*130 - 3)

  sync_rgb_from_hsv()
end

local function hue_set(h)
  h = clamp01(h)
  state.hsv[1] = h

  for _, element in ipairs({sv_square, sv_select}) do
    for corner = 0, 3 do
      local _, s, v, a = element:corner_color(corner)
      element:set_corner_color(corner, h, s, v, a)
    end
  end
  hue_select:set_pos(134, 2 + h*130)

  sync_rgb_from_hsv()
end

local function hex_string_highlight(value)
  for corner = 0, 3 do
    local r, g, _, _ = hex_area:corner_color(corner)
    hex_area:set_corner_color(corner, r, g, value, value)
  end
end

local function set_saved(index, color)
  state.saved[index] = {color[1], color[2], color[3], color[4]}
  local slot = slots[index]
  for corner = 0, 3 do
    local _, _, _, a = slot:corner_color(corner)
    slot:set_corner_color(corner, color[1], color[2], color[3], a)
  end
end

-- Sync HSV+visuals from state.rgb; used after setting state.rgb directly.
local function apply_state_rgb()
  state.hsv[1], state.hsv[2], state.hsv[3] =
      ui.rgb_to_hsv(state.rgb[1], state.rgb[2], state.rgb[3])
  hue_set(state.hsv[1])
  sv_pick(state.hsv[2], state.hsv[3])
end

local function open_picker()
  if picker_overlay then return end
  picker_overlay = ui.create_overlay{anchor = ANCHOR_BOTTOM_LEFT, size = {190, 150}}

  bg = ui.rect{
    pos = {0, 0},
    size = {190, 150},
    color = {0.4, 0.4, 0.4, 0.8},
    z = 0,
  }

  sv_square = ui.rect{
    type = RECT_HSV,
    pos = {2, 2},
    size = {130, 130},
    colors = {{0, 0, 1, 1}, {0, 1, 1, 1}, {0, 0, 0, 1}, {0, 1, 0, 1}},
    events = EVENT_BUTTON,
    z = 1,
  }

  hue_bar = ui.rect{
    type = RECT_HSV,
    pos = {134, 2},
    size = {10, 130},
    colors = {{0, 1, 1, 1}, {0, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}},
    events = EVENT_BUTTON + EVENT_SCROLL,
    z = 1,
  }

  sv_outline = ui.rect{
    pos = {130-4, 130-4},
    size = {7, 7},
    color = {0, 0, 0, 1},
    z = 2,
  }

  sv_select = ui.rect{
    type = RECT_HSV,
    pos = {130-3, 130-3},
    size = {5, 5},
    color = {1, 0, 0, 1},
    z = 3,
  }

  hex_area = ui.rect{
    pos = {20, 134},
    size = {95, 15},
    events = EVENT_BUTTON + EVENT_CURSOR,
    z = 1,
  }

  hue_select = ui.rect{
    pos = {134, 2},
    size = {10, 1},
    color = {0, 0, 0, 1},
    z = 2,
  }

  hex_text = ui.text{
    pos = {2, 150},
    size = 16,
    color = {1, 1, 1, 1},
    font = 0,
    max_length = 16,
    z = 2,
  }

  -- 12 saved color slots in a 2-wide grid
  slots = {}
  slot_index = {}
  for i = 1, 12 do
    local slot = ui.rect{
      pos = {146 + ((i-1) % 2)*22, 2 + math.floor((i-1)/2)*22},
      size = {20, 20},
      color = {0, 0, 0, 1},
      events = EVENT_BUTTON,
      z = 1,
    }
    slots[i] = slot
    slot_index[slot] = i
  end

  state = {
    hsv = {0, 0, 0},
    rgb = {0, 0, 0, 1},
    saved = {},
    hex_string = "#000000FF",
  }
  for i = 1, 12 do state.saved[i] = {0, 0, 0, 0} end

  drag = {
    [sv_square] = function(x, y) sv_pick(x, 1 - y) end,
    [hue_bar] = function(x, y) hue_set(y) end,
  }

  -- adopt the current published color so reopening the picker doesn't
  -- reset the selection
  local published = app.get("editor.color")
  if published then
    for i = 1, 4 do
      state.rgb[i] = (tonumber(published:sub(2*i, 2*i + 1), 16) or 0) / 255
    end
  end
  apply_state_rgb()
end

local function close_picker()
  if not picker_overlay then return end
  picker_overlay:destroy()
  picker_overlay = nil
  bg, sv_square, hue_bar, sv_outline, sv_select = nil, nil, nil, nil, nil
  hex_area, hue_select, hex_text, slots, slot_index, drag = nil, nil, nil, nil, nil, nil
  state = nil
end

-- ============================== dispatch ================================
-- label_overlay has no handlers; every handler below only ever fires for
-- picker_overlay, but still checks since a shared script_env would call the
-- same on_button etc. for any future overlay this script owns.

function on_button(overlay, element, x, y, button, action, mods)
  if overlay ~= picker_overlay then return false end

  if drag[element] then
    if action == PRESS and button == MOUSE_LEFT then
      element:focus()
      drag[element](x, y)
    elseif action == RELEASE and button == MOUSE_LEFT then
      ui.blur()
    end
    return true

  elseif element == hex_area then
    if action == PRESS and button == MOUSE_LEFT then
      element:focus()
      hex_string_highlight(1)
    end
    return true

  elseif slot_index[element] then
    local index = slot_index[element]
    if action == PRESS then
      if button == MOUSE_LEFT then
        local saved = state.saved[index]
        state.rgb = {saved[1], saved[2], saved[3], saved[4]}
        apply_state_rgb()
      elseif button == MOUSE_RIGHT then
        set_saved(index, state.rgb)
      elseif button == MOUSE_MIDDLE then
        set_saved(index, {0, 0, 0, 0})
      end
    end
    return true
  end

  return false
end

function on_cursor(overlay, element, x, y)
  if overlay ~= picker_overlay then return false end

  for el, fn in pairs(drag) do
    if el:is_focused() then
      fn(x, y)
      return true
    end
  end
  return false
end

function on_scroll(overlay, element, x, y)
  if overlay ~= picker_overlay then return false end

  if element == hue_bar then
    hue_set(state.hsv[1] + y*0.01)
    return true
  end
  return false
end

function on_key(overlay, element, key, action, mods)
  if overlay ~= picker_overlay or element ~= hex_area then return false end

  if action == PRESS then
    if key == KEY_ESCAPE then
      sync_rgb_from_hsv()
      ui.blur()
    elseif key == KEY_ENTER then
      local s = state.hex_string
      for i = 1, 4 do
        state.rgb[i] = (tonumber(s:sub(2*i, 2*i + 1), 16) or 0) / 255
      end
      apply_state_rgb()
      ui.blur()
    elseif key == KEY_BACKSPACE then
      if #state.hex_string > 1 then
        state.hex_string = state.hex_string:sub(1, -2)
        hex_text:set_text(state.hex_string)
      end
    end
  end

  return true
end

function on_text(overlay, element, codepoint)
  if overlay ~= picker_overlay or element ~= hex_area then return false end

  if codepoint < 128 then
    local ch = string.char(codepoint):upper()
    if ch:match("[0-9A-F]") and #state.hex_string < 9 then
      state.hex_string = state.hex_string .. ch
      hex_text:set_text(state.hex_string)
    end
  end
  return true
end

function on_deselect(overlay, element)
  if overlay ~= picker_overlay then return end
  if element == hex_area then
    hex_string_highlight(0)
  end
end

-- ============================== mode tracking ============================

app.subscribe("engine.changed.editor.mode", function(source, mode)
  label:set_text(mode)
  if mode == "Vertex" or mode == "Neighbor" or mode == "Hex" then
    open_picker()
  else
    close_picker()
  end
end)