use std::cmp::max;
use std::rc::Rc;
use std::time::Duration;

use smithay::backend::renderer::element::solid::{SolidColorBuffer, SolidColorRenderElement};
use smithay::backend::renderer::element::utils::{Relocate, RelocateRenderElement};
use smithay::backend::renderer::element::Kind;
use smithay::backend::renderer::{ImportAll, Renderer};
use smithay::utils::{Logical, Point, Rectangle, Scale, Size};

use super::focus_ring::FocusRing;
use super::workspace::WorkspaceRenderElement;
use super::{LayoutElement, Options};

/// Toplevel window with decorations.
#[derive(Debug)]
pub struct Tile<W: LayoutElement> {
    /// The toplevel window itself.
    window: W,

    /// The border around the window.
    border: FocusRing,

    /// Whether this tile is fullscreen.
    ///
    /// This will update only when the `window` actually goes fullscreen, rather than right away,
    /// to avoid black backdrop flicker before the window has had a chance to resize.
    is_fullscreen: bool,

    /// The black backdrop for fullscreen windows.
    fullscreen_backdrop: SolidColorBuffer,

    /// The size we were requested to fullscreen into.
    fullscreen_size: Size<i32, Logical>,

    /// Configurable properties of the layout.
    options: Rc<Options>,
}

impl<W: LayoutElement> Tile<W> {
    pub fn new(window: W, options: Rc<Options>) -> Self {
        Self {
            window,
            border: FocusRing::new(options.border),
            is_fullscreen: false, // FIXME: up-to-date fullscreen right away, but we need size.
            fullscreen_backdrop: SolidColorBuffer::new((0, 0), [0., 0., 0., 1.]),
            fullscreen_size: Default::default(),
            options,
        }
    }

    pub fn update_config(&mut self, options: Rc<Options>) {
        self.border.update_config(options.border);
        self.options = options;
    }

    pub fn update_window(&mut self) {
        // FIXME: remove when we can get a fullscreen size right away.
        if self.fullscreen_size != Size::from((0, 0)) {
            self.is_fullscreen = self.window.is_fullscreen();
        }
    }

    pub fn advance_animations(&mut self, _current_time: Duration, is_active: bool) {
        let width = self.border.width();
        self.border.update(
            (width, width).into(),
            self.window.size(),
            self.window.has_ssd(),
        );
        self.border.set_active(is_active);
    }

    pub fn window(&self) -> &W {
        &self.window
    }

    pub fn into_window(self) -> W {
        self.window
    }

    /// Returns `None` if the border is hidden and `Some(width)` if it should be shown.
    fn effective_border_width(&self) -> Option<i32> {
        if self.is_fullscreen {
            return None;
        }

        if self.border.is_off() {
            return None;
        }

        Some(self.border.width())
    }

    /// Returns the location of the window's visual geometry within this Tile.
    pub fn window_loc(&self) -> Point<i32, Logical> {
        let mut loc = Point::from((0, 0));

        // In fullscreen, center the window in the given size.
        if self.is_fullscreen {
            let window_size = self.window.size();
            let target_size = self.fullscreen_size;

            // Windows aren't supposed to be larger than the fullscreen size, but in case we get
            // one, leave it at the top-left as usual.
            if window_size.w < target_size.w {
                loc.x += (target_size.w - window_size.w) / 2;
            }
            if window_size.h < target_size.h {
                loc.y += (target_size.h - window_size.h) / 2;
            }
        }

        if let Some(width) = self.effective_border_width() {
            loc += (width, width).into();
        }

        loc
    }

    pub fn tile_size(&self) -> Size<i32, Logical> {
        let mut size = self.window.size();

        if self.is_fullscreen {
            // Normally we'd just return the fullscreen size here, but this makes things a bit
            // nicer if a fullscreen window is bigger than the fullscreen size for some reason.
            size.w = max(size.w, self.fullscreen_size.w);
            size.h = max(size.h, self.fullscreen_size.h);
            return size;
        }

        if let Some(width) = self.effective_border_width() {
            size.w = size.w.saturating_add(width * 2);
            size.h = size.h.saturating_add(width * 2);
        }

        size
    }

    pub fn window_size(&self) -> Size<i32, Logical> {
        self.window.size()
    }

    pub fn buf_loc(&self) -> Point<i32, Logical> {
        let mut loc = Point::from((0, 0));
        loc += self.window_loc();
        loc += self.window.buf_loc();
        loc
    }

    pub fn is_in_input_region(&self, mut point: Point<f64, Logical>) -> bool {
        point -= self.window_loc().to_f64();
        self.window.is_in_input_region(point)
    }

    pub fn is_in_activation_region(&self, point: Point<f64, Logical>) -> bool {
        let activation_region = Rectangle::from_loc_and_size((0, 0), self.tile_size());
        activation_region.to_f64().contains(point)
    }

    pub fn request_tile_size(&mut self, mut size: Size<i32, Logical>) {
        // Can't go through effective_border_width() because we might be fullscreen.
        if !self.border.is_off() {
            let width = self.border.width();
            size.w = max(1, size.w - width * 2);
            size.h = max(1, size.h - width * 2);
        }

        self.window.request_size(size);
    }

    pub fn tile_width_for_window_width(&self, size: i32) -> i32 {
        if self.border.is_off() {
            size
        } else {
            size.saturating_add(self.border.width() * 2)
        }
    }

    pub fn tile_height_for_window_height(&self, size: i32) -> i32 {
        if self.border.is_off() {
            size
        } else {
            size.saturating_add(self.border.width() * 2)
        }
    }

    pub fn window_height_for_tile_height(&self, size: i32) -> i32 {
        if self.border.is_off() {
            size
        } else {
            size.saturating_sub(self.border.width() * 2)
        }
    }

    pub fn request_fullscreen(&mut self, size: Size<i32, Logical>) {
        self.fullscreen_backdrop.resize(size);
        self.fullscreen_size = size;
        self.window.request_fullscreen(size);
    }

    pub fn min_size(&self) -> Size<i32, Logical> {
        let mut size = self.window.min_size();

        if let Some(width) = self.effective_border_width() {
            size.w = max(1, size.w);
            size.h = max(1, size.h);

            size.w = size.w.saturating_add(width * 2);
            size.h = size.h.saturating_add(width * 2);
        }

        size
    }

    pub fn max_size(&self) -> Size<i32, Logical> {
        let mut size = self.window.max_size();

        if let Some(width) = self.effective_border_width() {
            if size.w > 0 {
                size.w = size.w.saturating_add(width * 2);
            }
            if size.h > 0 {
                size.h = size.h.saturating_add(width * 2);
            }
        }

        size
    }

    pub fn has_ssd(&self) -> bool {
        self.effective_border_width().is_some() || self.window.has_ssd()
    }

    pub fn render<R: Renderer + ImportAll>(
        &self,
        renderer: &mut R,
        location: Point<i32, Logical>,
        scale: Scale<f64>,
    ) -> Vec<WorkspaceRenderElement<R>>
    where
        <R as Renderer>::TextureId: 'static,
    {
        let mut rv = Vec::new();

        let window_pos = location + self.window_loc();
        rv.extend(self.window.render(renderer, window_pos, scale));

        if self.effective_border_width().is_some() {
            rv.extend(
                self.border
                    .render(scale)
                    .map(|elem| {
                        RelocateRenderElement::from_element(
                            elem,
                            location.to_physical_precise_round(scale),
                            Relocate::Relative,
                        )
                    })
                    .map(Into::into),
            );
        }

        if self.is_fullscreen {
            let elem = SolidColorRenderElement::from_buffer(
                &self.fullscreen_backdrop,
                location.to_physical_precise_round(scale),
                scale,
                1.,
                Kind::Unspecified,
            );
            rv.push(elem.into());
        }

        rv
    }
}