// image_view.rs
//
// Copyright 2020 Christopher Davis <christopherdavis@gnome.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: GPL-3.0-or-later

use gdk::prelude::*;
use glib::clone;
use glib::subclass::prelude::*;
use gtk::prelude::*;
use gtk::subclass::prelude::*;
use gtk::subclass::widget::WidgetImplExt;
use gtk::CompositeTemplate;

use anyhow::Context;
use ashpd::desktop::wallpaper::{SetOn, WallpaperOptions, WallpaperProxy};
use ashpd::{BasicResponse as Basic, RequestProxy, Response, WindowIdentifier};
use std::cell::{Cell, RefCell};

mod imp {
    use super::*;
    use glib::subclass;

    static PROPERTIES: [subclass::Property; 3] = [
        subclass::Property("header-visible", |header_visible| {
            glib::ParamSpec::boolean(
                header_visible,
                "Header visible",
                "Whether or not the headerbar is visible",
                false,
                glib::ParamFlags::READWRITE,
            )
        }),
        subclass::Property("primary-menu-model", |primary_menu_model| {
            glib::ParamSpec::object(
                primary_menu_model,
                "Primary Menu Model",
                "The menu model for the menu button",
                gio::MenuModel::static_type(),
                glib::ParamFlags::READWRITE,
            )
        }),
        subclass::Property("popover-menu-model", |popover_menu_model| {
            glib::ParamSpec::object(
                popover_menu_model,
                "Popover Menu Model",
                "The menu model for the menu button",
                gio::MenuModel::static_type(),
                glib::ParamFlags::READWRITE,
            )
        }),
    ];

    #[derive(Debug, CompositeTemplate)]
    pub struct IvImageView {
        #[template_child]
        pub headerbar: TemplateChild<gtk::HeaderBar>,
        #[template_child]
        pub menu_button: TemplateChild<gtk::MenuButton>,
        #[template_child]
        pub picture: TemplateChild<gtk::Picture>,
        #[template_child]
        pub popover: TemplateChild<gtk::PopoverMenu>,
        #[template_child]
        pub click_gesture: TemplateChild<gtk::GestureClick>,
        #[template_child]
        pub press_gesture: TemplateChild<gtk::GestureLongPress>,

        pub connection: zbus::Connection,
        // Cell<T> allows for interior mutability of primitive types.
        pub header_visible: Cell<bool>,
        // RefCell<T> does the same for non-primitive types.
        pub menu_model: RefCell<Option<gio::MenuModel>>,
        pub popover_menu_model: RefCell<Option<gio::MenuModel>>,
    }

    impl ObjectSubclass for IvImageView {
        const NAME: &'static str = "IvImageView";
        type Type = super::IvImageView;
        type ParentType = gtk::Widget;
        type Instance = subclass::simple::InstanceStruct<Self>;
        type Class = subclass::simple::ClassStruct<Self>;

        glib::object_subclass!();

        fn new() -> Self {
            let connection =
                zbus::Connection::new_session().expect("Could not create zbus session");

            Self {
                headerbar: TemplateChild::default(),
                menu_button: TemplateChild::default(),
                picture: TemplateChild::default(),
                popover: TemplateChild::default(),
                click_gesture: TemplateChild::default(),
                press_gesture: TemplateChild::default(),
                connection,
                header_visible: Cell::new(false),
                menu_model: RefCell::default(),
                popover_menu_model: RefCell::default(),
            }
        }

        fn class_init(klass: &mut Self::Class) {
            klass.install_properties(&PROPERTIES);
            klass.set_template_from_resource("/org/gnome/ImageViewer/gtk/image_view.ui");
            Self::bind_template_children(klass);
        }

        fn instance_init(obj: &glib::subclass::InitializingObject<Self::Type>) {
            obj.init_template();
        }
    }

    impl ObjectImpl for IvImageView {
        fn constructed(&self, obj: &Self::Type) {
            self.parent_constructed(obj);

            obj.bind_property("header-visible", &*self.headerbar, "visible")
                .flags(glib::BindingFlags::BIDIRECTIONAL)
                .flags(glib::BindingFlags::SYNC_CREATE)
                .build()
                .unwrap();

            self.click_gesture
                .connect_pressed(clone!(@weak obj => move |_, _, x, y| {
                    obj.show_popover_at(x, y);
                }));

            self.press_gesture
                .connect_pressed(clone!(@weak obj => move |_, x, y| {
                    obj.show_popover_at(x, y);
                }));
        }

        fn get_property(&self, _obj: &Self::Type, id: usize) -> glib::Value {
            let prop = &PROPERTIES[id];

            match *prop {
                subclass::Property("header-visible", ..) => self.header_visible.get().to_value(),
                subclass::Property("primary-menu-model", ..) => self.menu_model.borrow().to_value(),
                subclass::Property("popover-menu-model", ..) => {
                    self.popover_menu_model.borrow().to_value()
                }
                _ => unimplemented!(),
            }
        }

        fn set_property(&self, _obj: &Self::Type, id: usize, value: &glib::Value) {
            let prop = &PROPERTIES[id];

            match *prop {
                subclass::Property("header-visible", ..) => {
                    self.header_visible
                        .set(value.get().unwrap().unwrap_or_default());
                }
                subclass::Property("primary-menu-model", ..) => {
                    let model: Option<gio::MenuModel> = value.get().unwrap();
                    self.menu_button.set_menu_model(model.as_ref());
                    *self.menu_model.borrow_mut() = model;
                }
                subclass::Property("popover-menu-model", ..) => {
                    let model: Option<gio::MenuModel> = value.get().unwrap();
                    self.popover.set_menu_model(model.as_ref());
                    *self.popover_menu_model.borrow_mut() = model;
                }
                _ => unimplemented!(),
            }
        }

        fn dispose(&self, obj: &Self::Type) {
            log::debug!("Disposing {}", Self::NAME);
            if let Some(child) = obj.get_first_child() {
                while let Some(sibling) = child.get_next_sibling() {
                    sibling.unparent();
                }
                child.unparent();
            }
        }
    }

    impl WidgetImpl for IvImageView {
        fn size_allocate(&self, widget: &Self::Type, width: i32, height: i32, baseline: i32) {
            self.parent_size_allocate(widget, width, height, baseline);
            self.popover.present();
        }
    }
}

glib::wrapper! {
    pub struct IvImageView(ObjectSubclass<imp::IvImageView>)
        @extends gtk::Widget,
        @implements gtk::Buildable, gtk::ConstraintTarget, gtk::Orientable;
}

impl IvImageView {
    pub fn set_image_from_file(&self, file: &gio::File) {
        let imp = imp::IvImageView::from_instance(&self);

        imp.picture.set_file(Some(file));
    }

    pub fn set_wallpaper(&self) -> anyhow::Result<()> {
        let imp = imp::IvImageView::from_instance(&self);

        let wallpaper = self.uri().context("No URI for current file")?;
        let wallpaper_proxy = WallpaperProxy::new(&imp.connection)?;

        let request_handle = wallpaper_proxy.set_wallpaper_uri(
            WindowIdentifier::default(),
            &wallpaper,
            WallpaperOptions::default().set_on(SetOn::Background),
        )?;

        let request = RequestProxy::new(&imp.connection, &request_handle)?;
        request.on_response(|response: Response<Basic>| {
            log::debug!("Response is OK: {}", response.is_ok());
        })?;

        Ok(())
    }

    pub fn print(&self) -> anyhow::Result<()> {
        let imp = imp::IvImageView::from_instance(&self);

        let file = imp.picture.get_file().context("No file to print")?;
        let operation = gtk::PrintOperation::new();
        let path = file.get_path().context("No path for current file")?;
        let pb = gdk_pixbuf::Pixbuf::from_file(path)?;

        let setup = gtk::PageSetup::default();
        let page_size = gtk::PaperSize::new(Some(&gtk::PAPER_NAME_A4));
        setup.set_paper_size(&page_size);
        operation.set_default_page_setup(Some(&setup));

        let settings = gtk::PrintSettings::default();
        operation.set_print_settings(Some(&settings));

        operation.connect_begin_print(move |op, _| {
            op.set_n_pages(1);
        });

        operation.connect_draw_page(clone!(@weak pb => move |op, ctx, _| {
            let cr = ctx.get_cairo_context().expect("No cairo context for print context");
            cr.set_source_pixbuf(&pb, 0.0, 0.0);
            cr.paint();
        }));

        log::debug!("Running print operation...");
        let root = self.get_root().context("Could not get root for widget")?;
        let window = root
            .downcast_ref::<gtk::Window>()
            .context("Could not downcast to GtkWindow")?;
        operation.run(gtk::PrintOperationAction::PrintDialog, Some(window))?;

        Ok(())
    }

    pub fn uri(&self) -> Option<String> {
        let imp = imp::IvImageView::from_instance(&self);
        let file = imp.picture.get_file()?;
        Some(file.get_uri().to_string())
    }

    pub fn show_popover_at(&self, x: f64, y: f64) {
        let imp = imp::IvImageView::from_instance(&self);

        let rect = gdk::Rectangle {
            x: x as i32,
            y: y as i32,
            width: 0,
            height: 0,
        };

        imp.popover.set_pointing_to(&rect);
        imp.popover.popup();
    }
}