// std
use std::cell::Cell;
use std::f32::consts::PI;
use std::sync::Arc;
// pbrt
use crate::core::camera::{Camera, CameraSample};
use crate::core::film::Film;
use crate::core::geometry::{nrm_abs_dot_vec3f, vec3_dot_vec3f};
use crate::core::geometry::{
    Bounds2f, Bounds2i, Normal3f, Point2f, Point2i, Point3f, Ray, RayDifferential, Vector3f,
};
use crate::core::interaction::InteractionCommon;
use crate::core::light::VisibilityTester;
use crate::core::medium::{Medium, MediumInterface};
use crate::core::paramset::ParamSet;
use crate::core::pbrt::lerp;
use crate::core::pbrt::{Float, Spectrum};
use crate::core::sampling::concentric_sample_disk;
use crate::core::transform::{AnimatedTransform, Transform};

// see perspective.h

pub struct PerspectiveCamera {
    // inherited from Camera (see camera.h)
    pub camera_to_world: AnimatedTransform,
    pub shutter_open: Float,
    pub shutter_close: Float,
    pub film: Arc<Film>,
    pub medium: Option<Arc<Medium>>,
    // inherited from ProjectiveCamera (see camera.h)
    // camera_to_screen: Transform,
    pub raster_to_camera: Transform,
    // screen_to_raster: Transform,
    // raster_to_screen: Transform,
    pub lens_radius: Float,
    pub focal_distance: Float,
    // private data (see perspective.h)
    pub dx_camera: Vector3f,
    pub dy_camera: Vector3f,
    pub a: Float,
    // extra parameters
    clipping_start: Float, // ADDED
}

impl PerspectiveCamera {
    pub fn new(
        camera_to_world: AnimatedTransform,
        screen_window: Bounds2f,
        shutter_open: Float,
        shutter_close: Float,
        lens_radius: Float,
        focal_distance: Float,
        fov: Float,
        film: Arc<Film>,
        medium: Option<Arc<Medium>>,
        clipping_start: Float,
    ) -> Self {
        // see perspective.cpp
        let camera_to_screen: Transform = Transform::perspective(fov, 1e-2, 1000.0);
        // see camera.h
        // compute projective camera screen transformations
        let scale1 = Transform::scale(
            film.full_resolution.x as Float,
            film.full_resolution.y as Float,
            1.0,
        );
        let scale2 = Transform::scale(
            1.0 / (screen_window.p_max.x - screen_window.p_min.x),
            1.0 / (screen_window.p_min.y - screen_window.p_max.y),
            1.0,
        );
        let translate = Transform::translate(&Vector3f {
            x: -screen_window.p_min.x,
            y: -screen_window.p_max.y,
            z: 0.0,
        });
        let screen_to_raster = scale1 * scale2 * translate;
        let raster_to_screen = Transform::inverse(&screen_to_raster);
        let raster_to_camera = Transform::inverse(&camera_to_screen) * raster_to_screen;
        // see perspective.cpp
        // compute differential changes in origin for perspective camera rays
        let dx_camera: Vector3f = raster_to_camera.transform_point(&Point3f {
            x: 1.0,
            y: 0.0,
            z: 0.0,
        }) - raster_to_camera.transform_point(&Point3f {
            x: 0.0,
            y: 0.0,
            z: 0.0,
        });
        let dy_camera: Vector3f = raster_to_camera.transform_point(&Point3f {
            x: 0.0,
            y: 1.0,
            z: 0.0,
        }) - raster_to_camera.transform_point(&Point3f {
            x: 0.0,
            y: 0.0,
            z: 0.0,
        });
        // compute image plane bounds at $z=1$ for _PerspectiveCamera_
        let res: Point2i = film.full_resolution;
        let mut p_min: Point3f = raster_to_camera.transform_point(&Point3f {
            x: 0.0,
            y: 0.0,
            z: 0.0,
        });
        // Point3f p_max = RasterToCamera(Point3f(res.x, res.y, 0));
        let mut p_max: Point3f = raster_to_camera.transform_point(&Point3f {
            x: res.x as Float,
            y: res.y as Float,
            z: 0.0,
        });
        p_min /= p_min.z;
        p_max /= p_max.z;
        let a: Float = ((p_max.x - p_min.x) * (p_max.y - p_min.y)).abs();

        PerspectiveCamera {
            camera_to_world,
            shutter_open,
            shutter_close,
            film,
            medium,
            // camera_to_screen,
            raster_to_camera,
            // screen_to_raster,
            // raster_to_screen,
            lens_radius,
            focal_distance,
            dx_camera,
            dy_camera,
            a,
            clipping_start,
        }
    }
    pub fn create(
        params: &ParamSet,
        cam2world: AnimatedTransform,
        film: Arc<Film>,
        medium: Option<Arc<Medium>>,
        clipping_start: Float,
    ) -> Arc<Camera> {
        let shutteropen: Float = params.find_one_float("shutteropen", 0.0);
        let shutterclose: Float = params.find_one_float("shutterclose", 1.0);
        // TODO: std::swap(shutterclose, shutteropen);
        assert!(shutterclose >= shutteropen);
        let lensradius: Float = params.find_one_float("lensradius", 0.0);
        let focaldistance: Float = params.find_one_float("focaldistance", 1e6);
        let frame: Float = params.find_one_float(
            "frameaspectratio",
            (film.full_resolution.x as Float) / (film.full_resolution.y as Float),
        );
        let mut screen: Bounds2f = Bounds2f::default();
        if frame > 1.0 {
            screen.p_min.x = -frame;
            screen.p_max.x = frame;
            screen.p_min.y = -1.0;
            screen.p_max.y = 1.0;
        } else {
            screen.p_min.x = -1.0;
            screen.p_max.x = 1.0;
            screen.p_min.y = -1.0 / frame;
            screen.p_max.y = 1.0 / frame;
        }
        let sw: Vec<Float> = params.find_float("screenwindow");
        if !sw.is_empty() && sw.len() == 4 {
            screen.p_min.x = sw[0];
            screen.p_max.x = sw[1];
            screen.p_min.y = sw[2];
            screen.p_max.y = sw[3];
        }
        let fov: Float = params.find_one_float("fov", 90.0);
        // let halffov: Float =
        //     params.find_one_float(String::from("halffov"), -1.0);
        // TODO: if (halffov > 0.f)
        // TODO: let perspective_camera: Arc<Camera + Sync + Send> =
        Arc::new(Camera::Perspective(Box::new(PerspectiveCamera::new(
            cam2world,
            screen,
            shutteropen,
            shutterclose,
            lensradius,
            focaldistance,
            fov,
            film,
            medium,
            clipping_start,
        ))))
    }
    // Camera
    pub fn generate_ray_differential(&self, sample: &CameraSample, ray: &mut Ray) -> Float {
        // TODO: ProfilePhase prof(Prof::GenerateCameraRay);
        // compute raster and camera sample positions
        let p_film: Point3f = Point3f {
            x: sample.p_film.x,
            y: sample.p_film.y,
            z: 0.0,
        };
        let p_camera: Point3f = self.raster_to_camera.transform_point(&p_film);
        let dir: Vector3f = Vector3f {
            x: p_camera.x,
            y: p_camera.y,
            z: p_camera.z,
        }
        .normalize();
        let mut diff: RayDifferential = RayDifferential {
            rx_origin: ray.o,
            ry_origin: ray.o,
            rx_direction: (Vector3f {
                x: p_camera.x,
                y: p_camera.y,
                z: p_camera.z,
            } + self.dx_camera)
                .normalize(),
            ry_direction: (Vector3f {
                x: p_camera.x,
                y: p_camera.y,
                z: p_camera.z,
            } + self.dy_camera)
                .normalize(),
        };
        // *ray = RayDifferential(Point3f(0, 0, 0), dir);
        let mut in_ray: Ray = Ray {
            o: Point3f::default(),
            d: dir,
            t_max: Cell::new(std::f32::INFINITY),
            time: lerp(sample.time, self.shutter_open, self.shutter_close),
            medium: None,
            differential: Some(diff),
        };
        // modify ray for depth of field
        if self.lens_radius > 0.0 as Float {
            // sample point on lens
            let p_lens: Point2f = concentric_sample_disk(&sample.p_lens) * self.lens_radius;
            // compute point on plane of focus
            let ft: Float = self.focal_distance / in_ray.d.z;
            let p_focus: Point3f = in_ray.position(ft);
            // update ray for effect of lens
            in_ray.o = Point3f {
                x: p_lens.x,
                y: p_lens.y,
                z: 0.0 as Float,
            };
            in_ray.d = (p_focus - in_ray.o).normalize();
        }
        // compute offset rays for _PerspectiveCamera_ ray differentials
        if self.lens_radius > 0.0 as Float {
            // compute _PerspectiveCamera_ ray differentials accounting for lens

            // sample point on lens
            let p_lens: Point2f = concentric_sample_disk(&sample.p_lens) * self.lens_radius;
            let dx: Vector3f = Vector3f::from(p_camera + self.dx_camera).normalize();
            let ft: Float = self.focal_distance / dx.z;
            let p_focus: Point3f = Point3f::default() + (dx * ft);
            diff.rx_origin = Point3f {
                x: p_lens.x,
                y: p_lens.y,
                z: 0.0 as Float,
            };
            diff.rx_direction = (p_focus - diff.rx_origin).normalize();
            let dy: Vector3f = Vector3f::from(p_camera + self.dy_camera).normalize();
            let ft: Float = self.focal_distance / dy.z;
            let p_focus: Point3f = Point3f::default() + (dy * ft);
            diff.ry_origin = Point3f {
                x: p_lens.x,
                y: p_lens.y,
                z: 0.0 as Float,
            };
            diff.ry_direction = (p_focus - diff.ry_origin).normalize();
            // replace differential
            in_ray.differential = Some(diff);
        }
        // ray->medium = medium;
        if let Some(ref medium_arc) = self.medium {
            in_ray.medium = Some(medium_arc.clone());
        } else {
            in_ray.medium = None;
        }
        *ray = self.camera_to_world.transform_ray(&in_ray);
        1.0
    }
    pub fn we(&self, ray: &Ray, p_raster2: Option<&mut Point2f>) -> Spectrum {
        // interpolate camera matrix and check if $\w{}$ is forward-facing
        let mut c2w: Transform = Transform::default();
        self.camera_to_world.interpolate(ray.time, &mut c2w);
        let cos_theta: Float = vec3_dot_vec3f(
            &ray.d,
            &c2w.transform_vector(&Vector3f {
                x: 0.0 as Float,
                y: 0.0 as Float,
                z: 1.0 as Float,
            }),
        );
        if cos_theta <= 0.0 as Float {
            return Spectrum::default();
        }
        // map ray $(\p{}, \w{})$ onto the raster grid
        let p_focus = if self.lens_radius > 0.0 as Float {
            ray.position(self.focal_distance / cos_theta)
        } else {
            ray.position(1.0 as Float / cos_theta)
        };
        let p_raster: Point3f = Transform::inverse(&self.raster_to_camera)
            .transform_point(&Transform::inverse(&c2w).transform_point(&p_focus));
        // return raster position if requested
        if let Some(p_raster2) = p_raster2 {
            *p_raster2 = Point2f {
                x: p_raster.x,
                y: p_raster.y,
            };
        }
        // return zero importance for out of bounds points
        let sample_bounds: Bounds2i = self.film.get_sample_bounds();
        if p_raster.x < (sample_bounds.p_min.x as Float)
            || p_raster.x >= (sample_bounds.p_max.x as Float)
            || p_raster.y < (sample_bounds.p_min.y as Float)
            || p_raster.y >= (sample_bounds.p_max.y as Float)
        {
            return Spectrum::default();
        }
        // compute lens area of perspective camera
        let lens_area = if self.lens_radius != 0.0 as Float {
            PI * self.lens_radius * self.lens_radius
        } else {
            1.0 as Float
        };
        // return importance for point on image plane
        let cos_2_theta: Float = cos_theta * cos_theta;
        Spectrum::new(1.0 as Float / (self.a * lens_area * cos_2_theta * cos_2_theta))
    }
    pub fn pdf_we(&self, ray: &Ray) -> (Float, Float) {
        let mut pdf_pos: Float = 0.0;
        let mut pdf_dir: Float = 0.0;
        // interpolate camera matrix and fail if $\w{}$ is not forward-facing
        let mut c2w: Transform = Transform::default();
        self.camera_to_world.interpolate(ray.time, &mut c2w);
        let cos_theta: Float = vec3_dot_vec3f(
            &ray.d,
            &c2w.transform_vector(&Vector3f {
                x: 0.0,
                y: 0.0,
                z: 1.0,
            }),
        );
        if cos_theta <= 0.0 as Float {
            // *pdf_pos = *pdf_dir = 0;
            return (pdf_pos, pdf_dir);
        }
        // map ray $(\p{}, \w{})$ onto the raster grid
        // Point3f p_focus = ray((self.lens_radius > 0 ? self.focal_distance : 1) / cos_theta);
        let t = if self.lens_radius > 0.0 as Float {
            self.focal_distance / cos_theta
        } else {
            1.0 as Float / cos_theta
        };
        let p_focus: Point3f = ray.position(t);
        let p_raster: Point3f = Transform::inverse(&self.raster_to_camera)
            .transform_point(&Transform::inverse(&c2w).transform_point(&p_focus));
        // return zero probability for out of bounds points
        let sample_bounds: Bounds2i = self.film.get_sample_bounds();
        if p_raster.x < sample_bounds.p_min.x as Float
            || p_raster.x >= sample_bounds.p_max.x as Float
            || p_raster.y < sample_bounds.p_min.y as Float
            || p_raster.y >= sample_bounds.p_max.y as Float
        {
            // *pdf_pos = *pdf_dir = 0;
            return (pdf_pos, pdf_dir);
        }
        // compute lens area of perspective camera
        // Float lens_area = self.lens_radius != 0 ? (Pi * self.lens_radius * self.lens_radius) : 1;
        let lens_area = if self.lens_radius != 0.0 as Float {
            PI * self.lens_radius * self.lens_radius
        } else {
            1.0 as Float
        };
        pdf_pos = 1.0 as Float / lens_area;
        pdf_dir = 1.0 as Float / (self.a * cos_theta * cos_theta * cos_theta);
        (pdf_pos, pdf_dir)
    }
    pub fn sample_wi<'a, 'b>(
        &self,
        iref: &'a InteractionCommon,
        lens_intr: &'b mut InteractionCommon,
        u: Point2f,
        wi: &mut Vector3f,
        pdf: &mut Float,
        p_raster: &mut Point2f,
        vis: &mut VisibilityTester<'a, 'b>,
    ) -> Spectrum {
        // uniformly sample a lens interaction _lensIntr_
        let p_lens: Point2f = concentric_sample_disk(&u) * self.lens_radius;
        let p_lens_world: Point3f = self.camera_to_world.transform_point(
            iref.time,
            &Point3f {
                x: p_lens.x,
                y: p_lens.y,
                z: 0.0 as Float,
            },
        );
        // Interaction lens_intr(p_lens_world, iref.time, medium);
        lens_intr.p = p_lens_world;
        lens_intr.time = iref.time;
        lens_intr.n = Normal3f::from(self.camera_to_world.transform_vector(
            iref.time,
            &Vector3f {
                x: 0.0 as Float,
                y: 0.0 as Float,
                z: 1.0 as Float,
            },
        ));
        if let Some(ref medium_arc) = self.medium {
            lens_intr.medium_interface = Some(Arc::new(MediumInterface::new(
                Some(medium_arc.clone()),
                Some(medium_arc.clone()),
            )));
        } else {
            lens_intr.medium_interface = None;
        }
        // populate arguments and compute the importance value
        *wi = lens_intr.p - iref.p;
        let dist: Float = wi.length();
        *wi /= dist;

        // compute PDF for importance arriving at _iref_

        // compute lens area of perspective camera
        let lens_area = if self.lens_radius != 0.0 as Float {
            PI * self.lens_radius * self.lens_radius
        } else {
            1.0 as Float
        };
        *pdf = (dist * dist) / (nrm_abs_dot_vec3f(&lens_intr.n, wi) * lens_area);
        let ray = lens_intr.spawn_ray(&-*wi);
        vis.p0 = Some(&iref);
        vis.p1 = Some(lens_intr);
        self.we(&ray, Some(p_raster))
    }
    pub fn get_shutter_open(&self) -> Float {
        self.shutter_open
    }
    pub fn get_shutter_close(&self) -> Float {
        self.shutter_close
    }
    pub fn get_film(&self) -> Arc<Film> {
        self.film.clone()
    }
    // ADDED
    pub fn get_clipping_start(&self) -> Float {
        self.clipping_start
    }
    pub fn adjust_to_clipping_start(&self, sample: &CameraSample, ray: &mut Ray) {
        let p_film: Point3f = Point3f {
            x: sample.p_film.x,
            y: sample.p_film.y,
            z: 0.0,
        };
        let p_camera: Point3f = self.raster_to_camera.transform_point(&p_film);
        let dir: Vector3f = Vector3f {
            x: p_camera.x,
            y: p_camera.y,
            z: p_camera.z,
        }
        .normalize();
        let o: Point3f = Point3f {
            x: dir.x * self.clipping_start / dir.z,
            y: dir.y * self.clipping_start / dir.z,
            z: self.clipping_start,
        };
        ray.o = self.camera_to_world.transform_point(ray.time, &o);
    }
}