//! Polygon rooms are the standard rooms in graf karto. They can take the form of anything that a
//! [Polygon](crate::math::Polygon) can have.

use super::Mappable;
use crate::colours::DEFAULT_COLOURS;
use crate::math::{self, Polygon, Rect, Triangle};
use crate::transform::Transform;
use crate::transformable::NonRigidTransformable;
use crate::FLOAT_MARGIN;
use nalgebra::{Matrix3, Point2};
use raylib::drawing::{RaylibDraw, RaylibDrawHandle};

/// Data type for the Polygon room.
pub type PolygonRoomData = Polygon<f64>;

/// A polygon room, which can be placed and modified in the world.
pub struct PolygonRoom {
    data: PolygonRoomData,
    // The polygon shape, but in triangles, so the polygon does not have to be triangulated every frame.
    triangulated: Vec<Triangle<f64>>,
    selected: bool,
}

impl PolygonRoom {
    /// Create a room from the given polygon data.
    pub fn from_data(data: PolygonRoomData) -> Self {
        Self {
            data: data.clone(),
            triangulated: math::triangulate(data, FLOAT_MARGIN),
            selected: false,
        }
    }

    // When the internal polygon changes, it must be retriangulated to be drawn on the screen
    // properly, so this function must be called any time that happens.
    fn retriangulate(&mut self) {
        self.triangulated = math::triangulate(self.data.clone(), FLOAT_MARGIN);
    }
}

impl Mappable for PolygonRoom {
    fn draw(&self, rld: &mut RaylibDrawHandle, transform: &Transform) {
        for triangle in &self.triangulated {
            rld.draw_triangle(
                transform.point_m_to_px(&triangle.corners()[0]),
                transform.point_m_to_px(&triangle.corners()[1]),
                transform.point_m_to_px(&triangle.corners()[2]),
                if self.selected() {
                    DEFAULT_COLOURS.room_selected
                } else {
                    DEFAULT_COLOURS.room_normal
                },
            )
        }
    }

    fn set_selected(&mut self, selected: bool) {
        self.selected = selected;
    }

    fn selected(&self) -> bool {
        self.selected
    }

    fn bounding_rect(&self) -> Rect<f64> {
        Rect::bounding_rect_n(&self.data.corners())
    }

    fn as_non_rigid(&self) -> Option<&dyn NonRigidTransformable> {
        Some(self as &dyn NonRigidTransformable)
    }

    fn as_non_rigid_mut(&mut self) -> Option<&mut dyn NonRigidTransformable> {
        Some(self as &mut dyn NonRigidTransformable)
    }
}

impl NonRigidTransformable for PolygonRoom {
    fn apply_matrix(&mut self, matrix: &Matrix3<f64>) {
        for corner in self.data.corners_mut() {
            *corner = matrix
                .transform_point(&Point2::new(corner.x, corner.y))
                .into();
        }

        self.retriangulate();
    }
}