use gpui::{BoxShadow, Hsla, Pixels, Point, Rems, Size, point, px, rems, size};

use super::{Mode, Theme};

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum Density {
    Compact,
    #[default]
    Standard,
    Comfortable,
}

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum ControlSize {
    Sm,
    #[default]
    Md,
    Lg,
}

/// How large an avatar is.
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum AvatarSize {
    Xs,
    Sm,
    #[default]
    Md,
    Lg,
    Xl,
}

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum IconSize {
    Xs,
    Sm,
    #[default]
    Md,
    Lg,
    Xl,
    Xxl,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum TextSize {
    Xs,
    Sm,
    Base,
    Md,
    Lg,
    Xl,
    Xxl,
    Display,
}

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum ContainerSize {
    Sm,
    #[default]
    Md,
    Lg,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Radius {
    Sm,
    Md,
    Lg,
    Xl,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Elevation {
    Raised,
    Floating,
    Modal,
}

pub(super) fn px_to_rems(value: f32) -> Rems {
    rems(value / 16.0)
}

impl Theme {
    pub fn control_height(&self, size: ControlSize) -> Rems {
        let base = match size {
            ControlSize::Sm => 24.0,
            ControlSize::Md => 28.0,
            ControlSize::Lg => 32.0,
        };
        let delta = match self.density {
            Density::Compact => -4.0,
            Density::Standard => 0.0,
            Density::Comfortable => 4.0,
        };
        px_to_rems(base + delta)
    }

    pub fn control_padding(&self, size: ControlSize) -> Rems {
        let base = match size {
            ControlSize::Sm => 8.0,
            ControlSize::Md => 12.0,
            ControlSize::Lg => 16.0,
        };
        let delta = match self.density {
            Density::Compact => -2.0,
            Density::Standard => 0.0,
            Density::Comfortable => 2.0,
        };
        px_to_rems(base + delta)
    }

    pub fn avatar_size(&self, size: AvatarSize) -> Rems {
        px_to_rems(match size {
            AvatarSize::Xs => 20.0,
            AvatarSize::Sm => 24.0,
            AvatarSize::Md => 32.0,
            AvatarSize::Lg => 40.0,
            AvatarSize::Xl => 56.0,
        })
    }

    pub fn icon_size(&self, size: IconSize) -> Rems {
        let base = match size {
            IconSize::Xs => 12.0,
            IconSize::Sm => 14.0,
            IconSize::Md => 16.0,
            IconSize::Lg => 20.0,
            IconSize::Xl => 24.0,
            IconSize::Xxl => 32.0,
        };
        px_to_rems(base * self.font_scale)
    }

    pub fn container_width(&self, size: ContainerSize) -> Rems {
        px_to_rems(match size {
            ContainerSize::Sm => 640.0,
            ContainerSize::Md => 960.0,
            ContainerSize::Lg => 1200.0,
        })
    }

    pub fn sidebar_width(&self, collapsed: bool) -> Rems {
        px_to_rems(if collapsed { 56.0 } else { 240.0 })
    }

    /// Width of a side sheet, height of a top or bottom one.
    pub fn sheet_size(&self) -> Rems {
        px_to_rems(380.0)
    }

    pub fn scrollbar_thickness(&self) -> Rems {
        px_to_rems(6.0)
    }

    pub fn scrollbar_min_thumb(&self) -> Rems {
        px_to_rems(24.0)
    }

    /// Smallest a split pane or dock may shrink to.
    pub fn pane_min(&self) -> Rems {
        px_to_rems(160.0)
    }

    pub fn titlebar_height(&self) -> Rems {
        px_to_rems(38.0)
    }

    /// Room kept for the macOS traffic lights.
    pub fn traffic_light_inset(&self) -> Rems {
        px_to_rems(78.0)
    }

    /// Where the system traffic lights sit in a window this crate opens.
    pub fn traffic_light_origin(&self) -> Point<Pixels> {
        point(px(14.0), px(13.0))
    }

    /// Underline under composing text.
    pub fn underline_thickness(&self) -> Pixels {
        px(1.0)
    }

    pub fn caret_width(&self) -> Rems {
        px_to_rems(1.5)
    }

    /// Diameter of a floating action button.
    pub fn fab_size(&self) -> Rems {
        px_to_rems(56.0)
    }

    pub fn progress_thickness(&self) -> Rems {
        px_to_rems(2.0)
    }

    /// A progress ring's width, room for a percent inside.
    pub fn progress_ring(&self) -> Rems {
        px_to_rems(48.0)
    }

    pub fn about_window(&self) -> Size<Pixels> {
        size(px(360.0), px(400.0))
    }

    /// Update and crash windows.
    pub fn dialog_window(&self) -> Size<Pixels> {
        size(px(400.0), px(480.0))
    }

    pub fn splash_window(&self) -> Size<Pixels> {
        size(px(480.0), px(300.0))
    }

    /// A window's rem size at 100% zoom; gpui's own default.
    pub fn base_rem(&self) -> Pixels {
        px(16.0)
    }

    /// Gap between the edge of a screen or window and what floats by it: a mini window, a toast stack.
    pub fn window_margin(&self) -> Pixels {
        px(24.0)
    }

    /// One drawn traffic light.
    pub fn traffic_light(&self) -> Rems {
        px_to_rems(12.0)
    }

    /// A Windows caption button.
    pub fn caption_button_width(&self) -> Rems {
        px_to_rems(46.0)
    }

    /// Resize margin of a client-drawn window.
    pub fn window_inset(&self) -> Rems {
        px_to_rems(10.0)
    }

    pub fn rail_width(&self) -> Rems {
        px_to_rems(48.0)
    }

    /// Narrowest and widest window tab.
    pub fn tab_width(&self) -> (Rems, Rems) {
        (px_to_rems(96.0), px_to_rems(200.0))
    }

    /// The line that marks a chosen tab.
    pub fn tab_indicator(&self) -> Rems {
        px_to_rems(2.0)
    }

    /// Width of a navigation menu's panel of links.
    pub fn nav_panel_width(&self) -> Rems {
        px_to_rems(480.0)
    }

    /// A pie menu's ring radius and the size of each slice's button.
    pub fn pie(&self) -> (Rems, Rems) {
        (px_to_rems(84.0), px_to_rems(40.0))
    }

    /// Room between a box and what floats by it: a spotlight's ring, a selection's toolbar.
    pub fn float_gap(&self) -> Rems {
        px_to_rems(6.0)
    }

    /// Width of a dialog's card.
    pub fn dialog_width(&self) -> Rems {
        px_to_rems(440.0)
    }

    /// Width of a toast stack.
    pub fn toast_width(&self) -> Rems {
        px_to_rems(360.0)
    }

    /// How far a glow's light reaches at its brightest.
    pub fn glow_reach(&self) -> Rems {
        px_to_rems(20.0)
    }

    /// A page's cover band.
    pub fn page_cover(&self) -> Rems {
        px_to_rems(208.0)
    }

    /// A page's icon, an emoji set large.
    pub fn page_icon(&self) -> Rems {
        px_to_rems(64.0)
    }

    /// A picture's height in a skeleton card.
    pub fn skeleton_media(&self) -> Rems {
        px_to_rems(128.0)
    }

    /// A grid's column, before any resize.
    pub fn grid_column(&self) -> Rems {
        px_to_rems(96.0)
    }

    /// A table row's height at each density.
    pub fn table_row(&self, density: Density) -> Rems {
        px_to_rems(match density {
            Density::Compact => 28.0,
            Density::Standard => 36.0,
            Density::Comfortable => 44.0,
        })
    }

    /// A sparkline beside text.
    pub fn spark_size(&self) -> Size<Rems> {
        size(px_to_rems(64.0), px_to_rems(18.0))
    }

    /// How far each level of a tree steps in.
    pub fn tree_indent(&self) -> Rems {
        px_to_rems(16.0)
    }

    /// How far past the viewport a long list builds rows ahead.
    pub fn list_overdraw(&self) -> Rems {
        px_to_rems(240.0)
    }

    /// One action behind a swiped row.
    pub fn swipe_action(&self) -> Rems {
        px_to_rems(72.0)
    }

    /// A QR code's tile.
    pub fn qr_code(&self) -> Rems {
        px_to_rems(160.0)
    }

    /// The narrowest bar of a barcode; the others are whole multiples.
    pub fn barcode_module(&self) -> Rems {
        px_to_rems(2.0)
    }

    pub fn barcode_height(&self) -> Rems {
        px_to_rems(56.0)
    }

    /// A gauge's dial.
    pub fn gauge(&self) -> Rems {
        px_to_rems(144.0)
    }

    /// The track of a meter or a usage bar.
    pub fn meter_track(&self) -> Rems {
        px_to_rems(6.0)
    }

    /// One repeat of a watermark's text.
    pub fn watermark_tile(&self) -> Size<Rems> {
        size(px_to_rems(200.0), px_to_rems(96.0))
    }

    /// The label column of a description list.
    pub fn label_width(&self) -> Rems {
        px_to_rems(160.0)
    }

    /// Widest a centered block of prose runs, such as an empty state's help.
    pub fn prose_width(&self) -> Rems {
        px_to_rems(320.0)
    }

    /// Narrowest a menu's panel gets.
    pub fn menu_width(&self) -> Rems {
        px_to_rems(200.0)
    }

    /// A palette's card; its list scrolls inside.
    pub fn palette_size(&self) -> Size<Rems> {
        size(px_to_rems(600.0), px_to_rems(400.0))
    }

    /// Grab bar on a drawer.
    pub fn grip(&self) -> Size<Rems> {
        size(px_to_rems(36.0), px_to_rems(4.0))
    }

    /// Hit area of a split or resize handle.
    pub fn handle_hit(&self) -> Rems {
        px_to_rems(6.0)
    }

    /// Gap between the pointer and a tooltip.
    pub fn cursor_offset(&self) -> Rems {
        px_to_rems(18.0)
    }

    /// A checkbox or radio mark.
    pub fn check_size(&self) -> Rems {
        px_to_rems(16.0)
    }

    /// The dot inside a chosen radio.
    pub fn radio_dot(&self) -> Rems {
        px_to_rems(6.0)
    }

    /// A dot that marks a state, such as unsaved changes.
    pub fn status_dot(&self) -> Rems {
        px_to_rems(6.0)
    }

    /// A switch's track; its thumb fills the height inside a small inset.
    pub fn switch_track(&self) -> Size<Rems> {
        size(px_to_rems(32.0), px_to_rems(18.0))
    }

    pub fn slider_track(&self) -> Rems {
        px_to_rems(4.0)
    }

    pub fn slider_thumb(&self) -> Rems {
        px_to_rems(16.0)
    }

    /// Diameter and arc width of a knob.
    pub fn knob(&self) -> (Rems, Rems) {
        (px_to_rems(48.0), px_to_rems(3.0))
    }

    /// Height of a color picker's saturation and value plane.
    pub fn color_plane(&self) -> Rems {
        px_to_rems(152.0)
    }

    /// A signature pad's height and its ink's width.
    pub fn signature(&self) -> (Rems, Rems) {
        (px_to_rems(160.0), px_to_rems(2.0))
    }

    /// Tallest a list grows before it scrolls.
    pub fn list_max_height(&self) -> Rems {
        px_to_rems(280.0)
    }

    pub fn tooltip_max_width(&self) -> Rems {
        px_to_rems(256.0)
    }

    pub fn text_size(&self, size: TextSize) -> Rems {
        let base = match size {
            TextSize::Xs => 11.0,
            TextSize::Sm => 12.0,
            TextSize::Base => 13.0,
            TextSize::Md => 14.0,
            TextSize::Lg => 16.0,
            TextSize::Xl => 20.0,
            TextSize::Xxl => 24.0,
            TextSize::Display => 32.0,
        };
        px_to_rems(base * self.font_scale)
    }

    pub fn radius(&self, size: Radius) -> Rems {
        let base = match size {
            Radius::Sm => 4.0,
            Radius::Md => 6.0,
            Radius::Lg => 8.0,
            Radius::Xl => 12.0,
        };
        px_to_rems(base * self.radius_scale)
    }

    pub fn elevation(&self, level: Elevation) -> Vec<BoxShadow> {
        let dark = self.mode == Mode::Dark;
        let layers: &[(f32, f32, f32)] = match (level, dark) {
            (Elevation::Raised, false) => &[(1.0, 2.0, 0.06)],
            (Elevation::Floating, false) => &[(1.0, 2.0, 0.04), (6.0, 16.0, 0.08)],
            (Elevation::Modal, false) => &[(2.0, 4.0, 0.04), (16.0, 40.0, 0.14)],
            (Elevation::Raised, true) => &[(1.0, 2.0, 0.4)],
            (Elevation::Floating, true) => &[(2.0, 4.0, 0.3), (8.0, 24.0, 0.45)],
            (Elevation::Modal, true) => &[(4.0, 8.0, 0.3), (20.0, 48.0, 0.55)],
        };
        layers
            .iter()
            .map(|&(y, blur, alpha)| shadow(self.colors.shadow.alpha(alpha), y, blur))
            .collect()
    }
}

fn shadow(color: Hsla, y: f32, blur: f32) -> BoxShadow {
    BoxShadow {
        color,
        offset: point(px(0.0), px(y)),
        blur_radius: px(blur),
        spread_radius: px(0.0),
    }
}