use {
    std::rc::Rc,
    crate::{
        makepad_platform::*,
        draw_list_2d::ManyInstances,
        geometry::GeometryQuad2D,
        icon_atlas::{CxIconAtlas, CxIconArgs},
        cx_2d::Cx2d,
        turtle::{Walk, Size}
    },
};


live_design!{
    
    DrawIcon = {{DrawIcon}} {
        color: #fff
        
        uniform u_brightness: float
        uniform u_curve: float
        
        texture tex: texture2d
        varying pos: vec2,
        varying tex_coord1: vec2
        varying clipped: vec2
        
        fn clip_and_transform_vertex(self, rect_pos: vec2, rect_size: vec2) -> vec4 {
            let clipped: vec2 = clamp(
                self.geom_pos * rect_size + rect_pos,
                self.draw_clip.xy,
                self.draw_clip.zw
            )
            self.pos = (clipped - rect_pos) / rect_size
            
            self.tex_coord1 = mix(
                self.icon_t1.xy,
                self.icon_t2.xy,
                self.pos.xy
            )
            
            // only pass the clipped position forward
            return self.camera_projection * (self.camera_view * (self.view_transform * vec4(
                clipped.x,
                clipped.y,
                self.draw_depth + self.draw_zbias,
                1.
            )))
        }
        
        fn vertex(self) -> vec4 {
            return self.clip_and_transform_vertex(self.rect_pos, self.rect_size)
        }
        
        fn get_color(self) -> vec4 {
            return self.color;
        }
        
        fn pixel(self) -> vec4 {
            let dx = dFdx(vec2(self.tex_coord1.x * 2048.0, 0.)).x;
            let dp = 1.0 / 2048.0;
            
            // basic hardcoded mipmapping so it stops 'swimming' in VR
            // mipmaps are stored in red/green/blue channel
            let s = sample2d_rt(self.tex, self.tex_coord1.xy).x;
            s = pow(s, self.u_curve);
            let col = self.get_color(); //color!(white);//get_color();
            return vec4(s * col.rgb * self.u_brightness * col.a, s * col.a);
        }
    }
}

#[derive(Live)]
#[repr(C)]
pub struct DrawIcon {
    #[live(1.0)] pub brightness: f32,
    #[live(0.6)] pub curve: f32,
    #[live(0.5)] pub linearize: f32,
    
    #[live] pub svg_file: LiveDependency,
    #[live] pub svg_path: Rc<String>,
    #[live] pub translate: DVec2,
    #[live(1.0)] pub scale: f64,
    
    #[rust] pub many_instances: Option<ManyInstances>,
    #[live] pub geometry: GeometryQuad2D,
    #[deref] pub draw_vars: DrawVars,
    #[calc] pub rect_pos: Vec2,
    #[calc] pub rect_size: Vec2,
    #[calc] pub draw_clip: Vec4,
    #[live(1.0)] pub draw_depth: f32,
    
    #[live] pub color: Vec4,
    #[calc] pub icon_t1: Vec2,
    #[calc] pub icon_t2: Vec2,
}

impl LiveHook for DrawIcon{
    fn before_apply(&mut self, cx: &mut Cx, apply_from: ApplyFrom, index: usize, nodes: &[LiveNode]){
        self.draw_vars.before_apply_init_shader(cx, apply_from, index, nodes, &self.geometry);
    }
    fn after_apply(&mut self, cx: &mut Cx, apply_from: ApplyFrom, index: usize, nodes: &[LiveNode]) {
        self.draw_vars.after_apply_update_self(cx, apply_from, index, nodes, &self.geometry);
    }
}

impl DrawIcon {
    
    pub fn new_draw_call(&self, cx: &mut Cx2d) {
        cx.new_draw_call(&self.draw_vars);
    }
    
    pub fn append_to_draw_call(&self, cx: &mut Cx2d) {
        cx.new_draw_call(&self.draw_vars);
    }
    
    pub fn begin_many_instances(&mut self, cx: &mut Cx2d) {
        let icon_atlas_rc = cx.icon_atlas_rc.clone();
        let icon_atlas = icon_atlas_rc.0.borrow();
        let mi = cx.begin_many_aligned_instances(&self.draw_vars);
        self.update_draw_call_vars(&*icon_atlas);
        self.many_instances = mi;
    }
    
    pub fn end_many_instances(&mut self, cx: &mut Cx2d) {
        if let Some(mi) = self.many_instances.take() {
            let new_area = cx.end_many_instances(mi);
            self.draw_vars.area = cx.update_area_refs(self.draw_vars.area, new_area);
        }
    }
    
    pub fn draw_walk(&mut self, cx: &mut Cx2d, mut walk: Walk) {
        let icon_atlas_rc = cx.icon_atlas_rc.clone();
        let mut icon_atlas = icon_atlas_rc.0.borrow_mut();
        let icon_atlas = &mut*icon_atlas;
        if let Some((path_hash, bounds)) = icon_atlas.get_icon_bounds(cx, &self.svg_path, self.svg_file.as_ref()) {
            let width_is_fit = walk.width.is_fit();
            let height_is_fit = walk.height.is_fit();
            let peek_rect = cx.peek_walk_turtle(walk);
            let mut scale = 1.0;

            if width_is_fit {
                if !height_is_fit {
                    scale = peek_rect.size.y / bounds.size.y
                };
                walk.width = Size::Fixed(bounds.size.x * self.scale * scale);
            }
            if height_is_fit {
                if !width_is_fit {
                    scale = peek_rect.size.x / bounds.size.x
                };
                walk.height = Size::Fixed(bounds.size.y * self.scale * scale);
            }
            if !width_is_fit && !height_is_fit {
                scale = (peek_rect.size.y / bounds.size.y).min(peek_rect.size.x / bounds.size.x);
            }
            let rect = cx.walk_turtle(walk);
            if rect.is_nan(){
                return
            }

            let dpi_factor = cx.current_dpi_factor();
            
            // we should snap the subpixel to 8x8 steps
            let dpi_pos = rect.pos * dpi_factor;
            let snapped_pos = dpi_pos.floor();
            let snapped_size = (rect.size * dpi_factor).ceil() + dvec2(1.0, 1.0);
            let subpixel = dvec2(
                ((dpi_pos.x - snapped_pos.x) * 8.0).floor() / 8.0,
                ((dpi_pos.y - snapped_pos.y) * 8.0).floor() / 8.0
            );
            
            // ok now we need to snap our rect to real pixels
            let slot = icon_atlas.get_icon_slot(CxIconArgs {
                linearize: self.linearize as f64,
                size: snapped_size,
                scale: self.scale * scale * dpi_factor,
                translate: self.translate - bounds.pos,
                subpixel: subpixel 
            }, path_hash);
            
            // lets snap the pos/size to actual pixels
            self.rect_pos = (snapped_pos / dpi_factor).into();
            self.rect_size = (snapped_size / dpi_factor).into();
            
            self.icon_t1 = slot.t1;
            self.icon_t2 = slot.t2;
            
            if let Some(mi) = &mut self.many_instances {
                mi.instances.extend_from_slice(self.draw_vars.as_slice());
            }
            else if self.draw_vars.can_instance() {
                self.update_draw_call_vars(icon_atlas);
                let new_area = cx.add_aligned_instance(&self.draw_vars);
                self.draw_vars.area = cx.update_area_refs(self.draw_vars.area, new_area);
            }
        }
    }
    
    pub fn update_draw_call_vars(&mut self, atlas: &CxIconAtlas) {
        self.draw_vars.texture_slots[0] = Some(atlas.texture_id);
        self.draw_vars.user_uniforms[0] = self.brightness;
        self.draw_vars.user_uniforms[1] = self.curve;
    }
    
}