// Copyright (c) 2023-2025 Sophie Herold
// Copyright (c) 2023 Julian Hofer
// Copyright (c) 2025 Mukul Joshi
//
// 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

//! The print layout widget that also coordinates the print process

use std::cell::{Cell, OnceCell, RefCell};
use std::rc::Rc;

use adw::prelude::*;
use adw::subclass::prelude::*;
use glib::Properties;
use gtk::CompositeTemplate;

use crate::decoder::{self};
use crate::deps::*;
use crate::util::gettext::*;
use crate::widgets::{LpImage, LpPrintPreview};

#[derive(Default, Clone, Copy)]
struct PageAlignment {
    horizontal: HAlignment,
    vertical: VAlignment,
}

#[derive(Default, Clone, Copy)]
enum HAlignment {
    Left,
    #[default]
    Center,
    Right,
}

#[derive(Default, Clone, Copy)]
enum VAlignment {
    Top,
    #[default]
    Middle,
    Bottom,
}

/// Scope guard for non user ui changes
///
/// Creates a context in which other signals know that changes are not user
/// input. This avoids things like loops between value change signals.
#[derive(Default, Clone, Debug)]
struct UiUpdates {
    disabled: Rc<Cell<u32>>,
}

impl UiUpdates {
    pub fn disable(&self) -> Self {
        self.disabled.set(self.disabled.get().saturating_add(1));
        self.clone()
    }
}

impl Drop for UiUpdates {
    fn drop(&mut self) {
        self.disabled.set(self.disabled.get().saturating_sub(1));
    }
}

impl From<&str> for PageAlignment {
    fn from(s: &str) -> Self {
        let alignment = match s {
            "top" => (HAlignment::Center, VAlignment::Top),
            "center" => (HAlignment::Center, VAlignment::Middle),
            "bottom" => (HAlignment::Center, VAlignment::Bottom),
            "left" => (HAlignment::Left, VAlignment::Middle),
            "right" => (HAlignment::Right, VAlignment::Middle),
            pos => {
                tracing::error!("Unknown alignment '{pos}'");
                (HAlignment::default(), VAlignment::default())
            }
        };

        Self::from(alignment)
    }
}

impl From<(HAlignment, VAlignment)> for PageAlignment {
    fn from((horizontal, vertical): (HAlignment, VAlignment)) -> Self {
        Self {
            horizontal,
            vertical,
        }
    }
}

impl std::fmt::Display for PageAlignment {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
        let s = match (self.horizontal, self.vertical) {
            (HAlignment::Center, VAlignment::Top) => gettext("Top"),
            (HAlignment::Center, VAlignment::Middle) => gettext("Center"),
            (HAlignment::Center, VAlignment::Bottom) => gettext("Bottom"),
            (HAlignment::Left, VAlignment::Middle) => gettext("Left"),
            (HAlignment::Right, VAlignment::Middle) => gettext("Right"),
            _ => String::from("Unsupported (Error)"),
        };

        f.write_str(&s)
    }
}

#[derive(Default, Clone, Copy)]
enum Unit {
    Centimeter,
    Inch,
    #[default]
    Pixel,
    Percent,
}

impl<T: AsRef<str>> From<T> for Unit {
    fn from(s: T) -> Self {
        match s.as_ref() {
            "cm" => Self::Centimeter,
            "in" => Self::Inch,
            "px" => Self::Pixel,
            "%" => Self::Percent,
            unit => {
                tracing::error!("Unknown unit '{unit}'");
                Self::default()
            }
        }
    }
}

impl std::fmt::Display for Unit {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
        let s = match self {
            // Translators: Shorthand for centimeter
            Self::Centimeter => gettext("cm"),
            // Translators: Shorthand for inch
            Self::Inch => gettext("in"),
            // Translators: Shorthand for pixel
            Self::Pixel => gettext("px"),
            Self::Percent => String::from("%"),
        };

        f.write_str(&s)
    }
}

impl Unit {
    fn factor(&self, dpi: f64, total_size: f64) -> f64 {
        match self {
            Self::Centimeter => 2.54 / dpi,
            Self::Inch => 1. / dpi,
            Self::Pixel => 1.,
            Self::Percent => 100. / total_size,
        }
    }

    fn digits(&self) -> u32 {
        match self {
            Self::Centimeter => 2,
            Self::Inch => 2,
            Self::Pixel => 0,
            Self::Percent => 2,
        }
    }

    fn ceil(&self, num: f64) -> f64 {
        let f = 10_f64.powi(self.digits() as i32);
        (num * f).ceil() / f
    }

    fn floor(&self, num: f64) -> f64 {
        let f = 10_f64.powi(self.digits() as i32);
        (num * f).floor() / f
    }

    fn round(&self, num: f64) -> f64 {
        let f = 10_f64.powi(self.digits() as i32);
        (num * f).round() / f
    }

    fn expression() -> gtk::ClosureExpression {
        gtk::ClosureExpression::new::<glib::GString>(
            [] as [gtk::Expression; 0],
            glib::closure!(|s: gtk::StringObject| Self::from(s.string().as_str()).to_string()),
        )
    }
}

mod imp {
    use super::*;

    #[derive(Debug, Default, CompositeTemplate, Properties)]
    #[template(file = "print.ui")]
    #[properties(wrapper_type = super::LpPrint)]
    pub struct LpPrint {
        #[template_child]
        pub(super) title: TemplateChild<adw::WindowTitle>,
        #[template_child]
        pub(super) preview: TemplateChild<LpPrintPreview>,

        // ListBox entries
        #[template_child]
        pub(super) alignment: TemplateChild<adw::ComboRow>,

        #[template_child]
        pub(super) margin_unit: TemplateChild<gtk::DropDown>,
        #[property(get, set)]
        pub(super) margin_unit_factor: Cell<f64>,
        #[template_child]
        pub(super) margin_horizontal: TemplateChild<adw::SpinRow>,
        #[template_child]
        pub(super) margin_vertical: TemplateChild<adw::SpinRow>,

        #[template_child]
        pub(super) size_unit: TemplateChild<gtk::DropDown>,
        #[property(get, set)]
        pub(super) width_unit_factor: Cell<f64>,
        #[property(get, set)]
        pub(super) height_unit_factor: Cell<f64>,
        #[template_child]
        pub(super) fill_space: TemplateChild<adw::SwitchRow>,
        #[template_child]
        pub(super) width: TemplateChild<adw::SpinRow>,
        #[template_child]
        pub(super) height: TemplateChild<adw::SpinRow>,

        #[property(get, set, construct_only)]
        pub(super) image: OnceCell<LpImage>,
        #[property(get, set, construct_only)]
        pub(super) preview_image: OnceCell<LpImage>,
        #[property(get, set, construct_only)]
        pub(super) parent_window: OnceCell<gtk::Window>,

        #[property(get, set, construct_only)]
        pub(super) print_dialog: OnceCell<gtk::PrintDialog>,
        #[property(get, set, construct_only)]
        pub(super) print_setup: OnceCell<gtk::PrintSetup>,

        #[property(get, set=Self::set_orientation)]
        pub(super) orientation: RefCell<String>,

        pub(super) ui_updates: UiUpdates,

        pub(super) previous_width: Cell<Option<f64>>,
    }

    #[glib::object_subclass]
    impl ObjectSubclass for LpPrint {
        const NAME: &'static str = "LpPrint";
        type Type = super::LpPrint;
        type ParentType = adw::Window;

        fn class_init(klass: &mut Self::Class) {
            Self::bind_template(klass);

            klass.install_action("print.print", None, |print, _, _| {
                print.print();
            });

            klass.install_action("print.back", None, |print, _, _| {
                print.back();
            });

            klass.install_property_action("print.orientation", "orientation");
        }

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

    impl ObjectImpl for LpPrint {
        fn constructed(&self) {
            self.parent_constructed();

            let obj = self.obj();

            obj.set_width_unit_factor(1.);
            obj.set_height_unit_factor(1.);
            obj.set_margin_unit_factor(1.);

            obj.set_transient_for(Some(&obj.parent_window()));
            obj.set_modal(true);

            // Page alignment (center, left, ...)
            self.alignment.connect_selected_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.draw_preview()
            ));

            self.alignment
                .set_expression(Some(gtk::ClosureExpression::new::<glib::GString>(
                    [] as [gtk::Expression; 0],
                    glib::closure!(
                        |s: gtk::StringObject| PageAlignment::from(s.string().as_str()).to_string()
                    ),
                )));

            // Margin signals
            self.margin_unit.connect_selected_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_margin_unit_changed()
            ));
            self.margin_unit.set_expression(Some(Unit::expression()));
            self.margin_horizontal.connect_value_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_margin_changed()
            ));
            self.margin_vertical.connect_value_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_margin_changed()
            ));

            // Size signals
            self.size_unit.connect_selected_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_size_unit_changed()
            ));
            self.size_unit.set_expression(Some(Unit::expression()));
            self.fill_space.connect_active_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_fill_space_changed()
            ));
            self.width.connect_value_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_width_changed()
            ));
            self.height.connect_value_notify(glib::clone!(
                #[weak]
                obj,
                move |_| obj.on_height_changed()
            ));

            let imp = self;

            let basename = obj
                .file()
                .basename()
                .map(|x| x.display().to_string())
                .unwrap_or_default();
            imp.title.set_title(&gettext_f(
                // Translators: {} is a placeholder for the filename
                "Print “{}”",
                [basename],
            ));
            if let Some(printer) = obj.print_settings().printer() {
                imp.title.set_subtitle(&printer);
            }

            imp.margin_horizontal.adjustment().set_step_increment(0.5);
            imp.margin_horizontal.adjustment().set_page_increment(2.5);
            imp.margin_vertical.adjustment().set_step_increment(0.5);
            imp.margin_vertical.adjustment().set_page_increment(2.5);

            imp.width.adjustment().set_step_increment(1.);
            imp.width.adjustment().set_page_increment(5.);
            imp.height.adjustment().set_step_increment(1.);
            imp.height.adjustment().set_page_increment(5.);

            let ui_updates_disabled = obj.disable_ui_updates();
            obj.set_ranges();
            obj.on_margin_unit_changed();
            obj.on_size_unit_changed();

            let size_unit = obj.size_unit();
            imp.width
                .set_value(size_unit.round(obj.original_size().0 * obj.width_unit_factor()));

            // Default to inch for USA and Liberia
            if let Some(unit_locale) = getlocale(gettextrs::LocaleCategory::LcMeasurement)
                && let Some(locale) = unit_locale
                    .split(|x| *x == b'_')
                    .nth(1)
                    .and_then(|x| x.get(0..2))
                && (locale == b"US" || locale == b"LR")
            {
                imp.margin_unit.set_selected(Unit::Inch as u32);
                imp.size_unit.set_selected(Unit::Inch as u32);
            }

            let orientation = match obj.page_setup().orientation() {
                gtk::PageOrientation::Portrait => "portrait",
                gtk::PageOrientation::Landscape => "landscape",
                _ => "other",
            };
            obj.set_orientation(orientation);
            drop(ui_updates_disabled);

            tracing::debug!("Showing print dialog");
            obj.present();
        }

        fn properties() -> &'static [glib::ParamSpec] {
            Self::derived_properties()
        }
        fn set_property(&self, id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
            self.derived_set_property(id, value, pspec)
        }
        fn property(&self, id: usize, pspec: &glib::ParamSpec) -> glib::Value {
            self.derived_property(id, pspec)
        }
    }

    impl WidgetImpl for LpPrint {}
    impl WindowImpl for LpPrint {}
    impl AdwWindowImpl for LpPrint {}

    impl LpPrint {
        pub fn set_orientation(&self, orientation: String) {
            let obj = self.obj();
            let _ui_updates_disabled = obj.disable_ui_updates();

            self.orientation.replace(orientation);

            let orientation = if obj.orientation() == "landscape" {
                gtk::PageOrientation::Landscape
            } else {
                gtk::PageOrientation::Portrait
            };
            obj.page_setup().set_orientation(orientation);
            obj.set_ranges();
            // If fill space is enabeld, recalculated to fill space
            obj.on_fill_space_changed();
            obj.draw_preview();
        }
    }
}
glib::wrapper! {
    pub struct LpPrint(ObjectSubclass<imp::LpPrint>)
        @extends gtk::Widget, gtk::Window, adw::Window,
        @implements gtk::Buildable, gtk::ConstraintTarget, gtk::Accessible, gtk::Native, gtk::Root, gtk::ShortcutManager;
}

impl LpPrint {
    pub fn show_print_dialog(
        image: LpImage,
        parent: gtk::Window,
        print_setup: Option<gtk::PrintSetup>,
    ) {
        let Some(file) = image.file() else {
            tracing::error!("Tried to print LpImage without GFile");
            return;
        };

        let preview_image = LpImage::new_still();
        preview_image.set_fixed_background_color(Some(gdk::RGBA::new(0.94, 0.94, 0.94, 1.)));
        glib::spawn_future_local(glib::clone!(
            #[strong]
            preview_image,
            #[strong]
            file,
            async move { preview_image.load(&file).await }
        ));

        let print_dialog = gtk::PrintDialog::builder()
            .accept_label(gettext("Continue…"))
            .title(gettext("Print Image"))
            .build();

        let print_settings = if let Some(print_setup) = print_setup {
            print_dialog.set_page_setup(&print_setup.page_setup());

            print_setup.print_settings()
        } else {
            gtk::PrintSettings::new()
        };

        print_dialog.set_print_settings(&print_settings);

        let uri = file.uri();
        print_settings.set(gtk::PRINT_SETTINGS_OUTPUT_URI, Some(&format!("{uri}.pdf")));

        glib::spawn_future_local(async move {
            let print_setup = match print_dialog.setup_future(Some(&parent)).await {
                Err(err) => {
                    // TODO: show error
                    tracing::warn!("Failed to print: {err}");
                    return;
                }
                Ok(print_setup) => print_setup,
            };

            Self::new(image, preview_image, parent, print_dialog, print_setup);
        });
    }

    pub fn new(
        image: LpImage,
        preview_image: LpImage,
        parent: gtk::Window,
        print_dialog: gtk::PrintDialog,
        print_setup: gtk::PrintSetup,
    ) -> Self {
        let obj: Self = glib::Object::builder()
            .property("image", image)
            .property("preview-image", preview_image)
            .property("parent-window", parent)
            .property("print-dialog", print_dialog)
            .property("print-setup", print_setup)
            .build();

        obj
    }

    pub fn original_size(&self) -> (f64, f64) {
        let image = self.image();
        let metadata = image.metadata();
        if let Some((w, h)) = metadata.dimensions_inch() {
            let dpi = self.dpi();

            ((w * dpi).round(), (h * dpi).round())
        } else {
            let (w, h) = self.image().image_size();

            (w as f64, h as f64)
        }
    }

    pub fn print_settings(&self) -> gtk::PrintSettings {
        self.print_setup().print_settings()
    }

    pub fn file(&self) -> gio::File {
        self.image().file().unwrap()
    }

    /// Returns `true` if the current update is caused by user input
    ///
    /// If ui input is changed via code, this is set to `false`
    /// via `disable_ui_updates` before.
    fn ui_updates(&self) -> bool {
        self.imp().ui_updates.disabled.get() == 0
    }

    /// Creates scope guard that allows ui changes via code afterwards
    fn disable_ui_updates(&self) -> UiUpdates {
        self.imp().ui_updates.disable()
    }

    fn size_unit(&self) -> Unit {
        Unit::from(
            self.imp()
                .size_unit
                .selected_item()
                .and_downcast::<gtk::StringObject>()
                .map(|x| x.string())
                .unwrap_or_default(),
        )
    }

    fn margin_unit(&self) -> Unit {
        Unit::from(
            self.imp()
                .margin_unit
                .selected_item()
                .and_downcast::<gtk::StringObject>()
                .map(|x| x.string())
                .unwrap_or_default(),
        )
    }

    pub fn dpi(&self) -> f64 {
        self.print_settings().resolution() as f64
    }

    fn indirect_disable_fill_space(&self) {
        self.imp().previous_width.set(None);
        self.imp().fill_space.set_active(false);
    }

    pub fn on_width_changed(&self) {
        if self.ui_updates() {
            let _ui_updates_disabled = self.disable_ui_updates();
            // Disable 'fill space' when manually changing size
            self.indirect_disable_fill_space();
            self.update_height();
            self.draw_preview();
        }
    }

    pub fn on_height_changed(&self) {
        if self.ui_updates() {
            let imp = self.imp();
            let _ui_updates_disabled = self.disable_ui_updates();
            // Disable 'fill space' when manually changing size
            self.indirect_disable_fill_space();

            let (orig_width, orig_height) = self.original_size();
            let width = self
                .size_unit()
                .round(imp.height.value() * orig_width / orig_height);
            imp.width.set_value(width);

            self.draw_preview();
        }
    }

    fn user_alignment(&self) -> PageAlignment {
        let s = self
            .imp()
            .alignment
            .selected_item()
            .and_then(|x| x.downcast::<gtk::StringObject>().ok())
            .map(|x| x.string())
            .unwrap_or_default();

        PageAlignment::from(s.as_str())
    }

    /// Returns user selected image width in pixels
    pub fn user_width(&self) -> f64 {
        f64::max(1., self.imp().width.value() / self.width_unit_factor())
    }

    /// Returns user selected image height in pixels
    pub fn user_height(&self) -> f64 {
        let (_, orig_height) = self.original_size();

        f64::max(1., orig_height * self.user_scale())
    }

    /// Returns scaling of the original image based on selected image size
    pub fn user_scale(&self) -> f64 {
        let (orig_width, _) = self.original_size();

        self.user_width() / orig_width
    }

    /// Returns scaling of the original image based on selected image size
    pub fn user_scale_original(&self) -> f64 {
        let (orig_width, _) = self.image().image_size();

        self.user_width() / orig_width as f64
    }

    pub fn on_margin_changed(&self) {
        if self.ui_updates() {
            let _ui_updates_disabled = self.disable_ui_updates();
            self.set_ranges();
            if self.fill_space() {
                self.update_width();
                self.update_height();
            }
            self.draw_preview();
        }
    }

    /// Returns user selected left margin in pixels
    pub fn user_margin_horizontal(&self) -> f64 {
        self.imp().margin_horizontal.value() / self.margin_unit_factor()
    }

    /// Returns left margin that positions the image according to user settings
    pub fn effective_margin_left(&self) -> f64 {
        match self.user_alignment().horizontal {
            HAlignment::Left => self.user_margin_horizontal(),
            HAlignment::Center => (self.paper_width() - self.user_width()) / 2.,
            HAlignment::Right => {
                self.paper_width() - self.user_width() - self.user_margin_horizontal()
            }
        }
    }

    /// Returns width of physical paper in pixels
    pub fn paper_width(&self) -> f64 {
        self.page_setup().paper_width(gtk::Unit::Inch) * self.dpi()
    }

    /// Returns height of physical paper in pixels
    pub fn paper_height(&self) -> f64 {
        self.page_setup().paper_height(gtk::Unit::Inch) * self.dpi()
    }

    /// Returns user selected top margin in pixels
    pub fn user_margin_vertical(&self) -> f64 {
        self.imp().margin_vertical.value() / self.margin_unit_factor()
    }

    pub fn effective_margin_top(&self) -> f64 {
        match self.user_alignment().vertical {
            VAlignment::Top => self.user_margin_vertical(),
            VAlignment::Middle => (self.paper_height() - self.user_height()) / 2.,
            VAlignment::Bottom => {
                self.paper_height() - self.user_height() - self.user_margin_vertical()
            }
        }
    }

    /// Redraws the preview widget child
    fn draw_preview(&self) {
        self.imp().preview.queue_resize();
    }

    /// Sets the allowed ranges for the spin button based on current unit
    fn set_ranges(&self) {
        let imp = self.imp();

        let margin_unit = self.margin_unit();
        let min_horizontal_margin = f64::max(
            self.page_setup().left_margin(gtk::Unit::Inch),
            self.page_setup().right_margin(gtk::Unit::Inch),
        ) * self.dpi();
        let min_vertical_margin = f64::max(
            self.page_setup().top_margin(gtk::Unit::Inch),
            self.page_setup().bottom_margin(gtk::Unit::Inch),
        ) * self.dpi();

        imp.margin_horizontal.set_range(
            margin_unit.ceil(min_horizontal_margin * self.margin_unit_factor()),
            margin_unit.floor((self.paper_width() / 2.) * self.margin_unit_factor()),
        );
        imp.margin_vertical.set_range(
            margin_unit.ceil(min_vertical_margin * self.margin_unit_factor()),
            margin_unit.floor((self.paper_height() / 2.) * self.margin_unit_factor()),
        );

        let size_unit = self.size_unit();
        let max_width = self.fill_space_width();
        let max_height = self.fill_space_height();

        imp.width.set_range(
            size_unit.ceil(self.width_unit_factor()),
            size_unit.floor(max_width * self.width_unit_factor()),
        );
        imp.height.set_range(
            size_unit.ceil(self.width_unit_factor()),
            size_unit.floor(max_height * self.height_unit_factor()),
        );
    }

    /// Returns width that makes the image fill the page
    fn fill_space_width(&self) -> f64 {
        let width1 = self.paper_width() - 2. * self.user_margin_horizontal();

        let height = self.paper_height() - 2. * self.user_margin_vertical();
        let (orig_width, orig_height) = self.original_size();
        let width2 = height * orig_width / orig_height;

        f64::min(width1, width2)
    }

    /// Returns height that makes the image fill the page
    fn fill_space_height(&self) -> f64 {
        let (orig_width, orig_height) = self.original_size();

        self.fill_space_width() * orig_height / orig_width
    }

    /// Updates width according to margins if fill space is activated
    fn update_width(&self) {
        if self.fill_space() {
            let value = self
                .size_unit()
                .floor(self.fill_space_width() * self.width_unit_factor());
            self.imp().width.set_value(value);
        }
    }

    /// Updates height according to width
    fn update_height(&self) {
        let height = if self.fill_space() {
            self.fill_space_height()
        } else {
            self.user_height()
        };

        let value = self.size_unit().round(height * self.height_unit_factor());
        self.imp().height.set_value(value);
    }

    fn on_size_unit_changed(&self) {
        let imp = self.imp();

        // Only show one size input for percentage
        if matches!(self.size_unit(), Unit::Percent) {
            imp.width.set_title(&gettext("_Scale"));
            imp.height.set_visible(false);
        } else {
            imp.width.set_title(&gettext("_Width"));
            imp.height.set_visible(true);
        }

        let _ui_updates_disabled = self.disable_ui_updates();

        let (orig_width, orig_height) = self.original_size();

        let unit = self.size_unit();
        let width_factor = unit.factor(self.dpi(), orig_width);
        let height_factor = unit.factor(self.dpi(), orig_height);

        let width = imp.width.value() * width_factor / self.width_unit_factor();
        let height = imp.height.value() * height_factor / self.height_unit_factor();

        self.set_width_unit_factor(width_factor);
        self.set_height_unit_factor(height_factor);

        let _ui_updates_disabled = self.disable_ui_updates();
        self.set_ranges();

        imp.width.set_digits(unit.digits());
        imp.width.set_value(width);

        imp.height.set_digits(unit.digits());
        imp.height.set_value(height);

        self.draw_preview();
    }

    fn on_margin_unit_changed(&self) {
        let imp = self.imp();

        let _ui_updates_disabled = self.disable_ui_updates();

        let unit = self.margin_unit();
        let unit_factor = unit.factor(self.dpi(), 1.);

        let update_factor = unit_factor / self.margin_unit_factor();
        let margin_horizontal = imp.margin_horizontal.value() * update_factor;
        let margin_vertical = imp.margin_vertical.value() * update_factor;

        self.set_margin_unit_factor(unit_factor);
        self.set_ranges();

        imp.margin_horizontal.set_digits(unit.digits());
        imp.margin_horizontal.set_value(margin_horizontal);

        imp.margin_vertical.set_digits(unit.digits());
        imp.margin_vertical.set_value(margin_vertical);

        self.draw_preview();
    }

    /// Returns if the option to fill the page with the image is activated
    pub fn fill_space(&self) -> bool {
        self.imp().fill_space.is_active()
    }

    fn on_fill_space_changed(&self) {
        let imp = self.imp();
        if self.fill_space() {
            imp.previous_width.set(Some(imp.width.value()));
            let _ui_updates_disabled = self.disable_ui_updates();
            self.update_width();
            self.update_height();
            self.draw_preview();
        } else if let Some(width) = imp.previous_width.get() {
            let _ui_updates_disabled = self.disable_ui_updates();
            imp.width.set_value(width);
            self.update_height();
            self.draw_preview();
        }
    }

    pub fn page_setup(&self) -> gtk::PageSetup {
        self.print_setup().page_setup()
    }

    /// Go back to print dialog from image layout
    fn back(&self) {
        self.close();
        Self::show_print_dialog(self.image(), self.parent_window(), Some(self.print_setup()));
    }

    /// Initialize actual print operation
    fn print(&self) {
        self.close();

        let obj = self.clone();

        glib::spawn_future_local(async move {
            let result = obj
                .print_dialog()
                .print_future(Some(&obj.parent_window()), Some(&obj.print_setup()))
                .await;

            let draw_result = match result {
                Err(err) => {
                    tracing::warn!("Print error: {err}");
                    return;
                }
                Ok(output_stream) => obj.draw_page(output_stream).await,
            };

            if let Err(err) = draw_result {
                tracing::warn!("Print error: {err}");
            }
        });
    }

    /// Draw PDF for printing
    async fn draw_page(&self, output_stream: gio::OutputStream) -> anyhow::Result<()> {
        tracing::debug!("Drawing image to print");
        let image = self.image();

        let (orig_width, orig_height) = self.original_size();

        let texture_scale = self.user_width() / orig_width;

        let texture = if image.metadata().is_svg() {
            // Render SVG to exact needed sizes
            decoder::formats::Svg::render_print(
                &image.file().unwrap(),
                (orig_width * texture_scale) as i32,
                (orig_height * texture_scale) as i32,
            )
            .await?
        } else {
            image.print_data(texture_scale).unwrap()
        };

        let image_surface = {
            let mut downloader = gdk::TextureDownloader::new(&texture);
            downloader.set_format(gdk::MemoryFormat::B8g8r8a8Premultiplied);

            let (data, stride) = downloader.download_bytes();
            let data = data.to_vec();

            let width = texture.width();
            let height = texture.height();

            cairo::ImageSurface::create_for_data(
                data,
                cairo::Format::ARgb32,
                width,
                height,
                stride as i32,
            )
            .unwrap()
        };

        let paper_width = self.page_setup().paper_width(gtk::Unit::Inch) * self.dpi();
        let paper_height = self.page_setup().paper_height(gtk::Unit::Inch) * self.dpi();

        let cairo_surface =
            cairo::PdfSurface::for_stream(paper_width, paper_height, output_stream.into_write())?;

        let cairo_context = cairo::Context::new(&cairo_surface)?;

        let margin_left = self.effective_margin_left();
        let margin_top = self.effective_margin_top();

        cairo_context.set_source_surface(image_surface, margin_left, margin_top)?;

        cairo_context.paint()?;
        cairo_surface.finish_output_stream().map_err(|x| x.error)?;

        Ok(())
    }
}

// TODO: Upstream to gettext if possible
pub fn getlocale(category: gettextrs::LocaleCategory) -> Option<Vec<u8>> {
    unsafe {
        let ret = gettext_sys::setlocale(category as i32, std::ptr::null());
        if ret.is_null() {
            None
        } else {
            Some(std::ffi::CStr::from_ptr(ret).to_bytes().to_owned())
        }
    }
}