# ui_templates.ludic — ludic.ui without a renderer: a shop written as a template, reading a view
# of the program's state and answering with its events. A press is made as a pointer would make
# it; it runs the view's event once the frame is built, and a component's own state keeps. The
# row comes from a component library, whose unexported Price no other file can use.
import "ludic.ui"
program UiTemplates {
  numbers float
  property Item {
    name: string = ""
    cost: int = 0
  }
  state UiTemplatesState {
    stock: []Item = new []Item
    purse: int = 100
    bought: []int = new []int
  }
  function add(ui_templates_st: mut UiTemplatesState, name: string, cost: int) -> void {
    let it = new Item
    it.name = name
    it.cost = cost
    push(ui_templates_st.stock, it)
  }
  view Shop (ui_templates_st: mut UiTemplatesState) {
    purse = ui_templates_st.purse
    stock = ui_templates_st.stock
    owned: int = len(ui_templates_st.bought)
    function afford(i: int) -> bool { return ui_templates_st.purse >= ui_templates_st.stock[i].cost }
    on buy(i: int) {
      ui_templates_st.purse -= ui_templates_st.stock[i].cost
      push(ui_templates_st.bought, i)
    }
  }
  const KIT: string = "<ui>\n<component name='Price'><text>${cost}</text></component>\n<component name='Line' export='true'>\n  <state picks='{0}'/>\n  <row gap='8' w='fill' align='center'>\n    <text color='{picked ? \"#ffcc00\" : \"#eeeeee\"}'>{item.name} -</text>\n    <Price cost='{item.cost}'/>\n    <spacer w='fill'/>\n    <text>{picks}</text>\n    <button enabled='{afford(i)}' on-press='buy(i); set picks = picks + 1; emit chose'>Buy</button>\n  </row>\n</component>\n</ui>\n"
  const PAGE: string = "<ui>\n<import src='kit.xml' as='kit'/>\n<screen name='shop' gap='4' pad='10'>\n  <state pick='{-1}'/>\n  <text size='24'>The purse: ${purse}</text>\n  <each in='{stock}' as='item' index='i'>\n    <kit:Line item='{item}' i='{i}' picked='{pick == i}' on-chose='set pick = i'/>\n  </each>\n  <if test='{owned == 0}'><text>Nothing bought yet</text></if>\n  <else><text>{owned} bought, the last {pick + 1}</text></else>\n</screen>\n</ui>\n"
  const PRIVATE: string = "<ui><import src='kit.xml' as='kit'/><screen name='peek'><kit:Price cost='{1}'/></screen></ui>"
  entry (ui_st: mut UiState, ui_templates_st: mut UiTemplatesState) {
    add(ui_templates_st, "Rope", 30)
    add(ui_templates_st, "Lantern", 80)
    ui_load_text(ui_st, KIT, "ui/kit.xml")
    ui_load_text(ui_st, PAGE, "ui/shop.xml")
    ui_load_text(ui_st, PRIVATE, "ui/peek.xml")
    var root: UiNode = ui_nodes(ui_st, "shop", view_shop())
    ui_place(ui_st, root, 0.0, 0.0, 600.0, 400.0)
    let press = root.children[1].children[4]
    ui_press(ui_st, ui_hit(root, press.x + 1.0, press.y + 1.0))
    root = ui_nodes(ui_st, "shop", view_shop())
    ui_place(ui_st, root, 0.0, 0.0, 600.0, 400.0)
    print(`purse {ui_templates_st.purse}, bought {len(ui_templates_st.bought)}; the lantern is enabled: {root.children[2].children[4].enabled}`)
  }
}