// Copyright 2022 System76 <info@system76.com>
// SPDX-License-Identifier: MPL-2.0

//! Implementation details for the horizontal layout of a segmented button.

use super::model::{Model, Selectable};
use super::style::StyleSheet;
use super::widget::{SegmentedButton, SegmentedVariant};

use iced::{Length, Rectangle, Size};
use iced_core::layout;

/// Horizontal [`SegmentedButton`].
pub type HorizontalSegmentedButton<'a, SelectionMode, Message> =
    SegmentedButton<'a, Horizontal, SelectionMode, Message>;

/// A type marker defining the horizontal variant of a [`SegmentedButton`].
pub struct Horizontal;

/// Horizontal implementation of the [`SegmentedButton`].
///
/// For details on the model, see the [`segmented_button`](super) module for more details.
#[must_use]
pub fn horizontal<SelectionMode: Default, Message>(
    model: &Model<SelectionMode>,
) -> SegmentedButton<Horizontal, SelectionMode, Message>
where
    Model<SelectionMode>: Selectable,
{
    SegmentedButton::new(model)
}

impl<'a, SelectionMode, Message> SegmentedVariant
    for SegmentedButton<'a, Horizontal, SelectionMode, Message>
where
    Model<SelectionMode>: Selectable,
    SelectionMode: Default,
{
    fn variant_appearance(
        theme: &crate::Theme,
        style: &crate::theme::SegmentedButton,
    ) -> super::Appearance {
        theme.horizontal(style)
    }

    #[allow(clippy::cast_precision_loss)]
    fn variant_button_bounds(&self, mut bounds: Rectangle, nth: usize) -> Rectangle {
        let num = self.model.items.len();
        if num != 0 {
            let spacing = f32::from(self.spacing);
            bounds.width = ((num as f32).mul_add(-spacing, bounds.width) + spacing) / num as f32;

            if nth != 0 {
                bounds.x += (nth as f32).mul_add(bounds.width, nth as f32 * spacing);
            }
        }

        bounds
    }

    #[allow(clippy::cast_precision_loss)]
    #[allow(clippy::cast_possible_truncation)]
    #[allow(clippy::cast_sign_loss)]
    fn variant_layout(&self, renderer: &crate::Renderer, limits: &layout::Limits) -> layout::Node {
        let limits = limits.width(self.width);
        let (mut width, height) = self.max_button_dimensions(renderer, limits.max());

        let num = self.model.items.len();
        let spacing = f32::from(self.spacing);

        if num != 0 {
            width = (num as f32).mul_add(width, num as f32 * spacing) - spacing;
        }

        let size = limits
            .height(Length::Fixed(height))
            .resolve(Size::new(width, height));

        layout::Node::new(size)
    }
}