re_ui 0.31.3

use std::sync::Arc;

use egui::text::TextWrapping;
use egui::{Align, Align2, NumExt as _, RichText, Ui};

use super::{
    ContentContext, DesiredWidth, ListItemContent, ListItemContentButtonsExt, ListVisuals,
};
use crate::list_item::item_buttons::ItemButtons;
use crate::{DesignTokens, Icon, LabelStyle, UiExt as _};

/// [`ListItemContent`] that displays a simple label with optional icon and buttons.
#[expect(clippy::type_complexity)]
pub struct LabelContent<'a> {
    text: egui::WidgetText,

    //TODO(ab): these should probably go as WidgetText already implements that
    subdued: bool,
    weak: bool,
    italics: bool,
    strong: bool,

    label_style: LabelStyle,
    icon_fn: Option<Box<dyn FnOnce(&mut egui::Ui, egui::Rect, ListVisuals) + 'a>>,
    buttons: ItemButtons<'a>,

    text_wrap_mode: Option<egui::TextWrapMode>,
    min_desired_width: Option<f32>,
}

impl<'a> LabelContent<'a> {
    pub fn new(text: impl Into<egui::WidgetText>) -> Self {
        Self {
            text: text.into(),

            subdued: false,
            weak: false,
            italics: false,
            strong: false,

            label_style: Default::default(),
            icon_fn: None,
            buttons: ItemButtons::default(),

            text_wrap_mode: None,
            min_desired_width: None,
        }
    }

    /// Render this as a header item.
    ///
    /// Text will be strong and smaller.
    /// For best results, use this with [`super::ListItem::header`].
    pub fn header(text: impl Into<RichText>) -> Self {
        Self::new(text.into().size(DesignTokens::list_header_font_size())).strong(true)
    }

    /// Set the subdued state of the item.
    ///
    /// Note: takes precedence over [`Self::weak`] if set.
    // TODO(ab): this is a hack to implement the behavior of the blueprint tree UI, where active
    // widget are displayed in a subdued state (container, hidden views/entities). One
    // slightly more correct way would be to override the color using a (color, index) pair
    // related to the design system table.
    #[inline]
    pub fn subdued(mut self, subdued: bool) -> Self {
        self.subdued = subdued;
        self
    }

    /// Set the weak state of the item.
    ///
    /// Note: [`Self::subdued`] takes precedence if set.
    // TODO(ab): should use design token instead
    #[inline]
    pub fn weak(mut self, weak: bool) -> Self {
        self.weak = weak;
        self
    }

    /// Render text in italic.
    // TODO(ab): should use design token instead
    #[inline]
    pub fn italics(mut self, italics: bool) -> Self {
        self.italics = italics;
        self
    }

    /// Set the text to be strong.
    #[inline]
    pub fn strong(mut self, strong: bool) -> Self {
        self.strong = strong;
        self
    }

    /// Style the label for an unnamed items.
    ///
    /// The styling is applied on top of to [`Self::weak`] and [`Self::subdued`]. It also implies [`Self::italics`].
    // TODO(ab): should use design token instead
    #[inline]
    pub fn label_style(mut self, style: crate::LabelStyle) -> Self {
        self.label_style = style;
        self
    }

    /// Should we truncate text if it is too long?
    #[inline]
    pub fn truncate(mut self, truncate: bool) -> Self {
        self.text_wrap_mode = Some(if truncate {
            egui::TextWrapMode::Truncate
        } else {
            egui::TextWrapMode::Extend
        });
        self
    }

    /// Set the minimum desired for the content.
    ///
    /// This defaults to zero.
    #[inline]
    pub fn min_desired_width(mut self, min_desired_width: f32) -> Self {
        self.min_desired_width = Some(min_desired_width);
        self
    }

    /// Provide an [`Icon`] to be displayed on the left of the item.
    #[inline]
    pub fn with_icon(self, icon: &'a Icon) -> Self {
        self.with_icon_fn(|ui, rect, visuals| {
            icon.as_image().tint(visuals.icon_tint()).paint_at(ui, rect);
        })
    }

    /// Provide a custom closure to draw an icon on the left of the item.
    #[inline]
    pub fn with_icon_fn(
        mut self,
        icon_fn: impl FnOnce(&mut egui::Ui, egui::Rect, ListVisuals) + 'a,
    ) -> Self {
        self.icon_fn = Some(Box::new(icon_fn));
        self
    }

    fn get_text_wrap_mode(&self, ui: &egui::Ui) -> egui::TextWrapMode {
        if let Some(text_wrap_mode) = self.text_wrap_mode {
            text_wrap_mode
        } else if crate::is_in_resizable_panel(ui) {
            egui::TextWrapMode::Truncate // The user can resize the panl to see the full text
        } else {
            egui::TextWrapMode::Extend // Show everything
        }
    }
}

impl ListItemContent for LabelContent<'_> {
    fn ui(self: Box<Self>, ui: &mut Ui, context: &ContentContext<'_>) {
        let text_wrap_mode = self.get_text_wrap_mode(ui);

        let Self {
            mut text,
            subdued,
            weak,
            italics,
            strong,
            label_style,
            icon_fn,
            buttons,
            text_wrap_mode: _,
            min_desired_width: _,
        } = *self;

        let tokens = ui.tokens();
        let small_icon_size = tokens.small_icon_size;
        let icon_rect = egui::Rect::from_center_size(
            context.rect.left_center() + egui::vec2(small_icon_size.x / 2., 0.0),
            small_icon_size,
        );

        let mut text_rect = context.rect;
        if icon_fn.is_some() {
            text_rect.min.x += icon_rect.width() + tokens.text_to_icon_padding();
        }

        // text styling
        if italics || label_style == LabelStyle::Unnamed {
            text = text.italics();
        }

        let mut visuals = context.visuals;
        visuals.strong |= strong;

        let mut text_color = visuals.text_color();

        if weak {
            text_color = ui.style().visuals.gray_out(text_color);
        } else if subdued {
            text_color = text_color.gamma_multiply(0.5);
        }

        // Draw icon
        if let Some(icon_fn) = icon_fn {
            icon_fn(ui, icon_rect, visuals);
        }

        buttons.show_and_shrink_rect(ui, context, &mut text_rect);

        // Draw text
        let mut layout_job = Arc::unwrap_or_clone(text.into_layout_job(
            ui.style(),
            egui::FontSelection::Default,
            Align::LEFT,
        ));
        layout_job.wrap = TextWrapping::from_wrap_mode_and_width(text_wrap_mode, text_rect.width());

        let galley = ui.fonts_mut(|fonts| fonts.layout_job(layout_job));

        // this happens here to avoid cloning the text
        context.response.widget_info(|| {
            egui::WidgetInfo::selected(
                egui::WidgetType::SelectableLabel,
                ui.is_enabled(),
                context.list_item.selected,
                galley.text(),
            )
        });

        let text_pos = Align2::LEFT_CENTER
            .align_size_within_rect(galley.size(), text_rect)
            .min;

        ui.painter().galley(text_pos, galley, text_color);
    }

    fn desired_width(&self, ui: &Ui) -> DesiredWidth {
        let tokens = ui.tokens();
        let text_wrap_mode = self.get_text_wrap_mode(ui);

        let measured_width = {
            //TODO(ab): ideally there wouldn't be as much code duplication with `Self::ui`
            let mut text = self.text.clone();
            if self.italics || self.label_style == LabelStyle::Unnamed {
                text = text.italics();
            }

            let layout_job = Arc::unwrap_or_clone(text.clone().into_layout_job(
                ui.style(),
                egui::FontSelection::Default,
                Align::LEFT,
            ));
            let galley = ui.fonts_mut(|fonts| fonts.layout_job(layout_job));

            let mut desired_width = galley.size().x;

            if self.icon_fn.is_some() {
                desired_width += tokens.small_icon_size.x + tokens.text_to_icon_padding();
            }

            // The `ceil()` is needed to avoid some rounding errors which leads to text being
            // truncated even though we allocated enough space.
            desired_width.ceil()
        };

        if text_wrap_mode == egui::TextWrapMode::Extend {
            let min_desired_width = self.min_desired_width.unwrap_or(0.0);
            DesiredWidth::Exact(measured_width.at_least(min_desired_width))
        } else {
            // If the user set an explicit min-width, use it.
            // Otherwise, show at least `default_min_width`, unless the text is even short.
            let default_min_width = 64.0;
            let min_desired_width = self
                .min_desired_width
                .unwrap_or_else(|| measured_width.min(default_min_width));
            DesiredWidth::AtLeast(min_desired_width)
        }
    }
}

impl<'a> ListItemContentButtonsExt<'a> for LabelContent<'a> {
    fn buttons(&self) -> &ItemButtons<'a> {
        &self.buttons
    }

    fn buttons_mut(&mut self) -> &mut ItemButtons<'a> {
        &mut self.buttons
    }
}