import gleam/int
import lustre
import lustre/attribute
import lustre/element.{type Element, element}
import lustre/element/html
import lustre/event
// These examples are written with `lustre/ui` in mind. They'll work regardless,
// but to see what `lustre/ui` can do make sure to run each of these examples with
// the `--use-example-styles` flag:
//
//   $ gleam run -m lustre/dev start --use-example-styles
//
// In your own apps, make sure to add the `lustre/ui` dependency and include the
// stylesheet somewhere.
import lustre/ui

// MAIN ------------------------------------------------------------------------

pub fn main() {
  let app = lustre.simple(init, update, view)
  let assert Ok(_) = lustre.start(app, "#app", Nil)
}

// MODEL -----------------------------------------------------------------------

type Model =
  String

fn init(_flags) -> Model {
  "div"
}

// UPDATE ----------------------------------------------------------------------

pub opaque type Msg {
  Swap
}

fn update(model: Model, msg: Msg) -> Model {
  case msg {
    Swap if model == "div" -> "p"
    Swap if model == "p" -> "div"
    _ -> model
  }
}

// VIEW ------------------------------------------------------------------------

fn view(model: Model) -> Element(Msg) {
  let styles = [#("width", "100vw"), #("height", "100vh"), #("padding", "1rem")]

  ui.centre(
    [attribute.style(styles)],
    ui.stack([], [
      ui.button([event.on_click(Swap)], [element.text("change tag")]),
      element(model, [], case model {
        "div" -> [
          html.p([], [html.text("this is a ")]),
          html.p([], [html.text(model)]),
        ]
        "p" -> [html.span([], [html.text("but this is a " <> model)])]
        _ -> []
      }),
    ]),
  )
}