use egui_file::FileDialog;

/// We derive Deserialize/Serialize so we can persist app state on shutdown.
#[derive(serde::Deserialize, serde::Serialize)]
#[serde(default)] // if we add new fields, give them default values when deserializing old state
pub struct TemplateApp {
  // Example stuff:
  label: String,

  #[serde(skip)] // This how you opt-out of serialization of a field
  value: f32,
  #[serde(skip)]
  file_dialog: Option<FileDialog>,
}

impl Default for TemplateApp {
  fn default() -> Self {
    Self {
      // Example stuff:
      label: "Hello World!".to_owned(),
      value: 2.7,
      file_dialog: None,
    }
  }
}

impl TemplateApp {
  /// Called once before the first frame.
  pub fn new(cc: &eframe::CreationContext<'_>) -> Self {
    // This is also where you can customize the look and feel of egui using
    // `cc.egui_ctx.set_visuals` and `cc.egui_ctx.set_fonts`.

    // Load previous app state (if any).
    // Note that you must enable the `persistence` feature for this to work.
    if let Some(storage) = cc.storage {
      eframe::get_value(storage, eframe::APP_KEY).unwrap_or_default()
    } else {
      Default::default()
    }
  }
}

impl eframe::App for TemplateApp {
  /// Called by the framework to save state before shutdown.
  fn save(&mut self, storage: &mut dyn eframe::Storage) {
    eframe::set_value(storage, eframe::APP_KEY, self);
  }

  /// Called each time the UI needs repainting, which may be many times per second.
  fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
    // Put your widgets into a `SidePanel`, `TopBottomPanel`, `CentralPanel`, `Window` or `Area`.
    // For inspiration and more examples, go to https://emilk.github.io/egui

    egui::TopBottomPanel::top("top_panel").show(ctx, |ui| {
      // The top panel is often a good place for a menu bar:

      egui::MenuBar::new().ui(ui, |ui| {
        // NOTE: no File->Quit on web pages!
        let is_web = cfg!(target_arch = "wasm32");
        if !is_web {
          ui.menu_button("File", |ui| {
            if ui.button("Quit").clicked() {
              ctx.send_viewport_cmd(egui::ViewportCommand::Close);
            }
          });
          ui.add_space(16.0);
        }

        egui::widgets::global_theme_preference_buttons(ui);
      });
    });

    egui::CentralPanel::default().show(ctx, |ui| {
      // The central panel the region left after adding TopPanel's and SidePanel's
      ui.heading("eframe template");

      ui.horizontal(|ui| {
        ui.label("Write something: ");
        ui.text_edit_singleline(&mut self.label);
      });


      if ui.button("Open File").clicked() {
        let mut dialog = FileDialog::open_file(None);
        dialog.open();
        self.file_dialog = Some(dialog);
      }

      ui.add(egui::Slider::new(&mut self.value, 0.0..=10.0).text("value"));
      if ui.button("Increment").clicked() {
        self.value += 1.0;
      }

      ui.separator();

      if let Some(dialog) = &mut self.file_dialog {
        dialog.pick_file()
      }

      ui.add(egui::github_link_file!(
        "https://github.com/emilk/eframe_template/blob/main/",
        "Source code."
      ));

      ui.with_layout(egui::Layout::bottom_up(egui::Align::LEFT), |ui| {
        powered_by_egui_and_eframe(ui);
        egui::warn_if_debug_build(ui);
      });
    });
  }
}

fn powered_by_egui_and_eframe(ui: &mut egui::Ui) {
  ui.horizontal(|ui| {
    ui.spacing_mut().item_spacing.x = 0.0;
    ui.label("Powered by ");
    ui.hyperlink_to("egui", "https://github.com/emilk/egui");
    ui.label(" and ");
    ui.hyperlink_to(
      "eframe",
      "https://github.com/emilk/egui/tree/master/crates/eframe",
    );
    ui.label(".");
  });
}