//! Implemented interfaces for Rozinante.

use cairo_sys::*;
use gdk_pixbuf_sys::*;
use gdk_sys::*;
use gobject_sys::*;
use gtk_sys::*;
use maraiah::{c_str,
              durandal::{ffi, image::*},
              rozinante::{draw::*, editor}};
use std::marker::PhantomData;

/// Converts a `Color` to a `f64` triple.
fn flt_color(cr: impl Color) -> (f64, f64, f64)
{
   fn flt_color(n: u16) -> f64 {f64::from(n) / f64::from(u16::max_value())}

   (flt_color(cr.r()), flt_color(cr.g()), flt_color(cr.b()))
}

impl CacheImage for CrImage
{
   fn w(&self) -> Coord {unsafe {gdk_pixbuf_get_width(self.0)  as Coord}}
   fn h(&self) -> Coord {unsafe {gdk_pixbuf_get_height(self.0) as Coord}}
}

impl CrDrawArea
{
   pub const fn new(ctx: *mut cairo_t, w: f64, h: f64) -> Self
   {
      CrDrawArea{ctx, w: w as Coord, h: h as Coord}
   }
}

impl DrawArea for CrDrawArea
{
   type NativeImage = CrImage;

   fn w(&self) -> Coord {self.w}
   fn h(&self) -> Coord {self.h}

   fn clear(&mut self, cr: impl Color)
   {
      self.rect(Rect{x: 0, y: 0, w: self.w(), h: self.h()}, cr);

      let sl = FONT_SLANT_NORMAL;
      let wt = FONT_WEIGHT_NORMAL;

      unsafe {
         cairo_select_font_face(self.ctx, c_str!("Monospace"), sl, wt);
         cairo_set_font_size(self.ctx, 14.0);
         cairo_set_line_width(self.ctx, 1.0);
      }
   }

   fn line_width(&mut self, width: u8)
   {
      let width = f64::from(width);

      unsafe {
         cairo_set_line_width(self.ctx, width);
      }
   }

   fn line(&mut self, p1: Point, p2: Point, cr: impl Color)
   {
      let (r, g, b) = flt_color(cr);

      let x1 = f64::from(p1.0);
      let y1 = f64::from(p1.1);

      let x2 = f64::from(p2.0);
      let y2 = f64::from(p2.1);

      unsafe {
         cairo_set_source_rgb(self.ctx, r, g, b);
         cairo_move_to(self.ctx, x1, y1);
         cairo_line_to(self.ctx, x2, y2);
         cairo_stroke(self.ctx);
      }
   }

   fn rect(&mut self, rect: Rect, cr: impl Color)
   {
      let px = f64::from(rect.x);
      let py = f64::from(rect.y);
      let sx = f64::from(rect.w);
      let sy = f64::from(rect.h);

      let (r, g, b) = flt_color(cr);

      unsafe {
         cairo_set_source_rgb(self.ctx, r, g, b);
         cairo_rectangle(self.ctx, px, py, sx, sy);
         cairo_fill(self.ctx);
      }
   }

   fn text(&mut self, pos: Point, text: &str, cr: impl Color)
   {
      let (r, g, b) = flt_color(cr);

      let x = f64::from(pos.0);
      let y = f64::from(pos.1);

      let text = ffi::CString::new(text).unwrap();

      unsafe {
         cairo_set_source_rgb(self.ctx, r, g, b);
         cairo_move_to(self.ctx, x, y);
         cairo_show_text(self.ctx, text.as_ptr());
      }
   }

   fn image(&mut self, pos: Point, im: &Self::NativeImage)
   {
      let x = f64::from(pos.0);
      let y = f64::from(pos.1);

      unsafe {
         gdk_cairo_set_source_pixbuf(self.ctx, im.0, x, y);
         cairo_paint(self.ctx);
      }
   }
}

impl MapEditor
{
   /// Propagates updated information to widgets.
   pub fn cause_update(&mut self)
   {
      unsafe {
         gtk_widget_queue_draw(*self.draw);
      }
   }
}

impl std::ops::Deref for MapEditor
{
   type Target = editor::MapEditor;

   #[inline]
   fn deref(&self) -> &Self::Target {&self.edit}
}

impl std::ops::DerefMut for MapEditor
{
   #[inline]
   fn deref_mut(&mut self) -> &mut Self::Target {&mut self.edit}
}

impl<T> std::ops::Deref for Refc<'_, T>
{
   type Target = *mut T;

   fn deref(&self) -> &Self::Target {&self.p}
}

impl<T> Drop for Refc<'_, T>
{
   fn drop(&mut self)
   {
      unsafe {
         g_object_unref(self.p as _);
      }
   }
}

impl<T> Refc<'_, T>
{
   /// Creates a new `Refc` which will own an already referenced object.
   pub const fn new(p: *mut T) -> Self {Self{p, l: PhantomData}}

   /// Creates a new `Refc` which will hold a reference to the object.
   pub fn own(p: *mut T) -> Self {unsafe {g_object_ref(p as _);} Self::new(p)}
}

/// An image for a `CrDrawArea`.
pub struct CrImage(pub *const GdkPixbuf);

/// A `DrawArea` for a Cairo surface.
pub struct CrDrawArea
{
   ctx: *mut cairo_t,
   w:   Coord,
   h:   Coord,
}

/// Specialized map editor which has callbacks for frontend purposes.
pub struct MapEditor
{
   pub edit: editor::MapEditor,
   pub draw: Refc<'static, GtkWidget>,
}

/// A runtime reference to the map editor.
pub type MapEditorRef = std::cell::RefCell<MapEditor>;

/// A GObject owned pointer.
pub struct Refc<'a, T>
{
   p: *mut T,
   l: PhantomData<&'a *mut T>,
}

// EOF