mod global;
mod handlers;
mod tree;
mod region;

pub use self::global::CompositorGlobal;
use self::handlers::CompositorHandler;
pub use self::tree::RoleStatus;
use self::tree::SurfaceData;

use wayland_server::protocol::{wl_buffer, wl_output, wl_surface};
use wayland_server::resource_is_registered;

/// Description of which part of a surface
/// should be considered damaged and needs to be redrawn
pub enum Damage {
    /// The whole surface must be considered damaged (this is the default)
    Full,
    /// A rectangle containing the damaged zone, in surface coordinates
    Surface(Rectangle),
    /// A rectangle containing the smaazed zone, in buffer coordinates
    ///
    /// Note: Buffer scaling must be taken into consideration
    Buffer(Rectangle)
}

/// Data associated with a surface, aggreged by the handlers
///
/// Most of the fields of this struct represent a double-buffered state, which
/// should only be applied once a `commit` request is received from the surface.
///
/// You are responsible for setting those values as you see fit to avoid
/// processing them two times.
pub struct SurfaceAttributes<U> {
    /// Buffer defining the contents of the surface
    ///
    /// The tuple represent the coordinates of this buffer
    /// relative to the location of the current buffer.
    ///
    /// If set to `Some(None)`, it means the user specifically asked for the
    /// surface to be unmapped.
    ///
    /// You are free to set this field to `None` to avoid processing it several
    /// times. It'll be set to `Some(...)` if the user attaches a buffer (or NULL) to
    /// the surface.
    pub buffer: Option<Option<(wl_buffer::WlBuffer, (i32, i32))>>,
    /// Scale of the contents of the buffer, for higher-resolution contents.
    ///
    /// If it matches the one of the output displaying this surface, no change
    /// is necessary.
    pub buffer_scale: i32,
    /// Transform under which interpret the contents of the buffer
    ///
    /// If it matches the one of the output displaying this surface, no change
    /// is necessary.
    pub buffer_transform: wl_output::Transform,
    /// Region of the surface that is guaranteed to be opaque
    ///
    /// By default the whole surface is potentially transparent
    pub opaque_region: Option<RegionAttributes>,
    /// Region of the surface that is sensitive to user input
    ///
    /// By default the whole surface should be sensitive
    pub input_region: Option<RegionAttributes>,
    /// Damage rectangle
    ///
    /// Hint provided by the client to suggest that only this part
    /// of the surface was changed and needs to be redrawn
    pub damage: Damage,
    /// Subsurface-related attribute
    ///
    /// Is `Some` if this surface is a sub-surface
    ///
    /// **Warning:** Changing this field by yourself can cause panics.
    pub subsurface_attributes: Option<SubsurfaceAttributes>,
    /// User-controlled data
    ///
    /// This is your field to host whatever you need.
    pub user_data: U,
}

impl<U: Default> Default for SurfaceAttributes<U> {
    fn default() -> SurfaceAttributes<U> {
        SurfaceAttributes {
            buffer: None,
            buffer_scale: 1,
            buffer_transform: wl_output::Transform::Normal,
            opaque_region: None,
            input_region: None,
            damage: Damage::Full,
            subsurface_attributes: None,
            user_data: Default::default(),
        }
    }
}

/// Attributes defining the behaviour of a sub-surface relative to its parent
pub struct SubsurfaceAttributes {
    /// Horizontal location of the top-left corner of this sub-surface relative to
    /// the top-left corner of its parent
    pub x: i32,
    /// Vertical location of the top-left corner of this sub-surface relative to
    /// the top-left corner of its parent
    pub y: i32,
    /// Sync status of this sub-surface
    ///
    /// If `true`, this surface should be repainted synchronously with its parent
    /// if `false`, it should be considered independant of its parent regarding
    /// repaint timings.
    pub sync: bool,
}

impl Default for SubsurfaceAttributes {
    fn default() -> SubsurfaceAttributes {
        SubsurfaceAttributes {
            x: 0,
            y: 0,
            sync: true,
        }
    }
}

/// Kind of a rectangle part of a region
#[derive(Copy,Clone)]
pub enum RectangleKind {
    /// This rectangle should be added to the region
    Add,
    /// The intersection of this rectangle with the region should
    /// be removed from the region
    Subtract,
}

/// A rectangle defined by its top-left corner and dimensions
#[derive(Copy,Clone)]
pub struct Rectangle {
    /// horizontal position of the top-leftcorner of the rectangle, in surface coordinates
    pub x: i32,
    /// vertical position of the top-leftcorner of the rectangle, in surface coordinates
    pub y: i32,
    /// width of the rectangle
    pub width: i32,
    /// height of the rectangle
    pub height: i32,
}

/// Description of the contents of a region
///
/// A region is defined as an union and difference of rectangle.
///
/// This struct contains an ordered Vec containing the rectangles defining
/// a region. They should be added or substracted in this order to compute the
/// actual contents of the region.
#[derive(Clone)]
pub struct RegionAttributes {
    /// List of rectangle part of this region
    pub rects: Vec<(RectangleKind, Rectangle)>,
}

impl Default for RegionAttributes {
    fn default() -> RegionAttributes {
        RegionAttributes { rects: Vec::new() }
    }
}

/// A Compositor global token
///
/// This token can be cloned at will, and is the entry-point to
/// access data associated with the wl_surface and wl_region managed
/// by the `CompositorGlobal` that provided it.
#[derive(Copy,Clone)]
pub struct CompositorToken<U> {
    hid: usize,
    _data: ::std::marker::PhantomData<*mut U>,
}

fn make_token<U>(hid: usize) -> CompositorToken<U> {
    CompositorToken {
        hid: hid,
        _data: ::std::marker::PhantomData,
    }
}

impl<U: Send + 'static> CompositorToken<U> {
    /// Access the data of a surface
    ///
    /// The closure will be called with the contents of the data associated with this surface.
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn with_surface_data<F>(&self, surface: &wl_surface::WlSurface, f: F)
        where F: FnOnce(&mut SurfaceAttributes<U>)
    {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::with_data(surface, f);
        }
    }

    /// Access the data of a surface tree
    ///
    /// The provided closure is called successively on the surface and all its child subsurfaces,
    /// in a depth-first order.
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn with_surface_tree<F>(&self, surface: &wl_surface::WlSurface, f: F) -> Result<(), ()>
        where F: FnMut(&wl_surface::WlSurface, &mut SurfaceAttributes<U>) -> bool
    {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::map_tree(surface, f);
        }
        Ok(())
    }

    /// Retrieve the parent of this surface
    ///
    /// Returns `None` is this surface is a root surface
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn get_parent(&self, surface: &wl_surface::WlSurface) -> Option<wl_surface::WlSurface> {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::get_parent(surface)
        }
    }
    
    /// Retrieve the role status this surface
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn role_status(&self, surface: &wl_surface::WlSurface) -> RoleStatus {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::role_status(surface)
        }
    }

    /// Register that this surface has a role
    ///
    /// This makes this surface impossible to become a subsurface, as
    /// a surface can only have a single role at a time.
    ///
    /// Fails if the surface already has a role.
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn give_role(&self, surface: &wl_surface::WlSurface) -> Result<(),()> {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::give_role(surface)
        }
    }

    /// Register that this surface has no role
    ///
    /// It is a noop if this surface already didn't have one, but fails if
    /// the role was "subsurface". This role is automatically managed and as such
    /// cannot be removed manually.
    ///
    /// If the surface is not managed by the CompositorGlobal that provided this token, this
    /// will panic (having more than one compositor is not supported).
    pub fn remove_role(&self, surface: &wl_surface::WlSurface) -> Result<(),()> {
        assert!(resource_is_registered::<_, CompositorHandler<U>>(surface, self.hid),
                "Accessing the data of foreign surfaces is not supported.");
        unsafe {
            SurfaceData::<U>::remove_role(surface)
        }
    }
}