use {Event, WindowBuilder};
use libc;
use std::{mem, ptr};
use std::sync::atomics::AtomicBool;

mod events;
mod ffi;

pub struct Window {
    display: *mut ffi::Display,
    window: ffi::Window,
    im: ffi::XIM,
    ic: ffi::XIC,
    context: ffi::GLXContext,
    is_closed: AtomicBool,
    wm_delete_window: ffi::Atom,
}

pub struct MonitorID(uint);

pub fn get_available_monitors() -> Vec<MonitorID> {
    unimplemented!()
}

pub fn get_primary_monitor() -> MonitorID {
    unimplemented!()
}

impl MonitorID {
    pub fn get_name(&self) -> Option<String> {
        Some("<Unknown>".to_string())
    }

    pub fn get_dimensions(&self) -> (uint, uint) {
        unimplemented!()
    }
}

impl Window {
    pub fn new(builder: WindowBuilder) -> Result<Window, String> {
        // TODO: temporary
        let dimensions = builder.dimensions;

        // calling XOpenDisplay
        let display = unsafe {
            let display = ffi::XOpenDisplay(ptr::null());
            if display.is_null() {
                return Err(format!("XOpenDisplay failed"));
            }
            display
        };

        // TODO: set error handler?

        // getting the FBConfig
        let fb_config = unsafe {
            static VISUAL_ATTRIBUTES: [libc::c_int, ..23] = [
                ffi::GLX_X_RENDERABLE,  1,
                ffi::GLX_DRAWABLE_TYPE, ffi::GLX_WINDOW_BIT,
                ffi::GLX_RENDER_TYPE,   ffi::GLX_RGBA_BIT,
                ffi::GLX_X_VISUAL_TYPE, ffi::GLX_TRUE_COLOR,
                ffi::GLX_RED_SIZE,      8,
                ffi::GLX_GREEN_SIZE,    8,
                ffi::GLX_BLUE_SIZE,     8,
                ffi::GLX_ALPHA_SIZE,    8,
                ffi::GLX_DEPTH_SIZE,    24,
                ffi::GLX_STENCIL_SIZE,  8,
                ffi::GLX_DOUBLEBUFFER,  1,
                0
            ];

            let mut num_fb: libc::c_int = mem::uninitialized();

            let fb = ffi::glXChooseFBConfig(display, ffi::XDefaultScreen(display),
                VISUAL_ATTRIBUTES.as_ptr(), &mut num_fb);
            if fb.is_null() {
                return Err(format!("glXChooseFBConfig failed"));
            }
            let preferred_fb = *fb;     // TODO: choose more wisely
            ffi::XFree(fb as *const libc::c_void);
            preferred_fb
        };

        // getting the visual infos
        let visual_infos = unsafe {
            let vi = ffi::glXGetVisualFromFBConfig(display, fb_config);
            if vi.is_null() {
                return Err(format!("glXChooseVisual failed"));
            }
            let vi_copy = *vi;
            ffi::XFree(vi as *const libc::c_void);
            vi_copy
        };

        // getting the root window
        let root = unsafe { ffi::XDefaultRootWindow(display) };

        // creating the color map
        let cmap = unsafe {
            let cmap = ffi::XCreateColormap(display, root,
                visual_infos.visual, ffi::AllocNone);
            // TODO: error checking?
            cmap
        };

        // creating
        let mut set_win_attr = {
            let mut swa: ffi::XSetWindowAttributes = unsafe { mem::zeroed() };
            swa.colormap = cmap;
            swa.event_mask = ffi::ExposureMask | ffi::ResizeRedirectMask |
                ffi::VisibilityChangeMask | ffi::KeyPressMask | ffi::PointerMotionMask |
                ffi::KeyPressMask | ffi::KeyReleaseMask | ffi::ButtonPressMask |
                ffi::ButtonReleaseMask | ffi::KeymapStateMask;
            swa
        };

        // finally creating the window
        let window = unsafe {
            let dimensions = dimensions.unwrap_or((800, 600));

            let win = ffi::XCreateWindow(display, root, 50, 50, dimensions.val0() as libc::c_uint,
                dimensions.val1() as libc::c_uint, 0, visual_infos.depth, ffi::InputOutput,
                visual_infos.visual, ffi::CWColormap | ffi::CWEventMask,
                &mut set_win_attr);
            win
        };

        // creating window, step 2
        let wm_delete_window = unsafe {
            use std::c_str::ToCStr;

            ffi::XMapWindow(display, window);
            let mut wm_delete_window = ffi::XInternAtom(display,
                "WM_DELETE_WINDOW".to_c_str().as_ptr() as *const libc::c_char, 0);
            ffi::XSetWMProtocols(display, window, &mut wm_delete_window, 1);
            ffi::XStoreName(display, window, mem::transmute(builder.title.as_slice().as_ptr()));
            ffi::XFlush(display);

            wm_delete_window
        };

        // getting the pointer to glXCreateContextAttribs
        let create_context_attribs = unsafe {
            let mut addr = ffi::glXGetProcAddress(b"glXCreateContextAttribs".as_ptr()
                as *const u8) as *const ();

            if addr.is_null() {
                addr = ffi::glXGetProcAddress(b"glXCreateContextAttribsARB".as_ptr()
                    as *const u8) as *const ();
            }
            
            addr.to_option().map(|addr| {
                let addr: extern "system" fn(*mut ffi::Display, ffi::GLXFBConfig, ffi::GLXContext,
                    ffi::Bool, *const libc::c_int) -> ffi::GLXContext = mem::transmute(addr);
                addr
            })
        };

        // creating IM
        let im = unsafe {
            let im = ffi::XOpenIM(display, ptr::null(), ptr::mut_null(), ptr::mut_null());
            if im.is_null() {
                return Err(format!("XOpenIM failed"));
            }
            im
        };

        // creating input context
        let ic = unsafe {
            use std::c_str::ToCStr;

            let ic = ffi::XCreateIC(im, "inputStyle".to_c_str().as_ptr(),
                ffi::XIMPreeditNothing | ffi::XIMStatusNothing, "clientWindow".to_c_str().as_ptr(),
                window, ptr::null());
            if ic.is_null() {
                return Err(format!("XCreateIC failed"));
            }
            ffi::XSetICFocus(ic);
            ic
        };

        // creating GL context
        let context = unsafe {
            let mut attributes = Vec::new();

            if builder.gl_version.is_some() {
                let version = builder.gl_version.as_ref().unwrap();
                attributes.push(ffi::GLX_CONTEXT_MAJOR_VERSION);
                attributes.push(version.val0() as libc::c_int);
                attributes.push(ffi::GLX_CONTEXT_MINOR_VERSION);
                attributes.push(version.val1() as libc::c_int);
            }

            attributes.push(0);
 
            let context = if create_context_attribs.is_some() {
                let create_context_attribs = create_context_attribs.unwrap();
                create_context_attribs(display, fb_config, ptr::null(), 1,
                    attributes.as_ptr())
            } else {
                ffi::glXCreateNewContext(display, fb_config, ffi::GLX_RGBA_TYPE, ptr::null(), 1)
            };

            if context.is_null() {
                return Err(format!("GL context creation failed"));
            }

            context
        };

        // creating the window object
        let window = Window {
            display: display,
            window: window,
            im: im,
            ic: ic,
            context: context,
            is_closed: AtomicBool::new(false),
            wm_delete_window: wm_delete_window,
        };

        // calling glViewport
        unsafe {
            let ptr = window.get_proc_address("glViewport");
            assert!(!ptr.is_null());
            let ptr: extern "system" fn(libc::c_int, libc::c_int, libc::c_int, libc::c_int) =
                mem::transmute(ptr);
            let dimensions = window.get_inner_size().unwrap();
            ptr(0, 0, dimensions.val0() as libc::c_int, dimensions.val1() as libc::c_int);
        }

        // returning
        Ok(window)
    }

    pub fn is_closed(&self) -> bool {
        use std::sync::atomics::Relaxed;
        self.is_closed.load(Relaxed)
    }

    pub fn set_title(&self, title: &str) {
        unsafe {
            ffi::XStoreName(self.display, self.window,
                mem::transmute(title.as_slice().as_ptr()));
        }
    }

    fn get_geometry(&self) -> Option<(int, int, uint, uint)> {
        unsafe {
            use std::mem;

            let mut root: ffi::Window = mem::uninitialized();
            let mut x: libc::c_int = mem::uninitialized();
            let mut y: libc::c_int = mem::uninitialized();
            let mut width: libc::c_uint = mem::uninitialized();
            let mut height: libc::c_uint = mem::uninitialized();
            let mut border: libc::c_uint = mem::uninitialized();
            let mut depth: libc::c_uint = mem::uninitialized();

            if ffi::XGetGeometry(self.display, self.window,
                &mut root, &mut x, &mut y, &mut width, &mut height,
                &mut border, &mut depth) == 0
            {
                return None;
            }

            Some((x as int, y as int, width as uint, height as uint))
        }
    }

    pub fn get_position(&self) -> Option<(int, int)> {
        self.get_geometry().map(|(x, y, _, _)| (x, y))
    }

    pub fn set_position(&self, x: int, y: int) {
        unsafe { ffi::XMoveWindow(self.display, self.window, x as libc::c_int, y as libc::c_int) }
    }

    pub fn get_inner_size(&self) -> Option<(uint, uint)> {
        self.get_geometry().map(|(_, _, w, h)| (w, h))
    }

    pub fn get_outer_size(&self) -> Option<(uint, uint)> {
        unimplemented!()
    }

    pub fn set_inner_size(&self, x: uint, y: uint) {
        unimplemented!()
    }

    pub fn poll_events(&self) -> Vec<Event> {
        use std::mem;
        
        let mut events = Vec::new();
        
        loop {
            use std::num::Bounded;

            let mut xev = unsafe { mem::uninitialized() };
            let res = unsafe { ffi::XCheckMaskEvent(self.display, Bounded::max_value(), &mut xev) };

            if res == 0 {
                let res = unsafe { ffi::XCheckTypedEvent(self.display, ffi::ClientMessage, &mut xev) };

                if res == 0 {
                    break
                }
            }

            match xev.type_ {
                ffi::KeymapNotify => {
                    unsafe { ffi::XRefreshKeyboardMapping(&xev) }
                },

                ffi::ClientMessage => {
                    use Closed;
                    use std::sync::atomics::Relaxed;

                    let client_msg: &ffi::XClientMessageEvent = unsafe { mem::transmute(&xev) };

                    if client_msg.l[0] == self.wm_delete_window as libc::c_long {
                        self.is_closed.store(true, Relaxed);
                        events.push(Closed);
                    }
                },

                ffi::ResizeRequest => {
                    use Resized;
                    let rs_event: &ffi::XResizeRequestEvent = unsafe { mem::transmute(&xev) };
                    events.push(Resized(rs_event.width as uint, rs_event.height as uint));
                },

                ffi::MotionNotify => {
                    use MouseMoved;
                    let event: &ffi::XMotionEvent = unsafe { mem::transmute(&xev) };
                    events.push(MouseMoved((event.x as int, event.y as int)));
                },

                ffi::KeyPress | ffi::KeyRelease => {
                    use {KeyboardInput, Pressed, Released, ReceivedCharacter, KeyModifiers};
                    let event: &mut ffi::XKeyEvent = unsafe { mem::transmute(&xev) };

                    if event.type_ == ffi::KeyPress {
                        let raw_ev: *mut ffi::XKeyEvent = event;
                        unsafe { ffi::XFilterEvent(mem::transmute(raw_ev), self.window) };
                    }

                    let state = if xev.type_ == ffi::KeyPress { Pressed } else { Released };

                    let written = unsafe {
                        use std::str;

                        let mut buffer: [u8, ..16] = [mem::uninitialized(), ..16];
                        let raw_ev: *mut ffi::XKeyEvent = event;
                        let count = ffi::Xutf8LookupString(self.ic, mem::transmute(raw_ev), 
                            mem::transmute(buffer.as_mut_ptr()),
                            buffer.len() as libc::c_int, ptr::mut_null(), ptr::mut_null());

                        str::from_utf8(buffer.as_slice().slice_to(count as uint))
                            .unwrap_or("").to_string()
                    };

                    for chr in written.as_slice().chars() {
                        events.push(ReceivedCharacter(chr));
                    }

                    let keysym = unsafe {
                        ffi::XKeycodeToKeysym(self.display, event.keycode as ffi::KeyCode, 0)
                    };

                    let vkey =  events::keycode_to_element(keysym as libc::c_uint);

                    events.push(KeyboardInput(state, event.keycode as u8,
                        vkey, KeyModifiers::empty()));
                    //
                },

                ffi::ButtonPress | ffi::ButtonRelease => {
                    use {MouseInput, Pressed, Released};
                    use {LeftMouseButton, RightMouseButton, MiddleMouseButton, OtherMouseButton};
                    let event: &ffi::XButtonEvent = unsafe { mem::transmute(&xev) };

                    let state = if xev.type_ == ffi::ButtonPress { Pressed } else { Released };

                    let button = match event.button {
                        ffi::Button1 => Some(LeftMouseButton),
                        ffi::Button2 => Some(MiddleMouseButton),
                        ffi::Button3 => Some(RightMouseButton),
                        ffi::Button4 => Some(OtherMouseButton(4)),
                        ffi::Button5 => Some(OtherMouseButton(5)),
                        _ => None
                    };

                    match button {
                        Some(button) => 
                            events.push(MouseInput(state, button)),
                        None => ()
                    };
                },

                _ => ()
            }
        }

        events
    }

    pub fn wait_events(&self) -> Vec<Event> {
        use std::mem;

        loop {
            // this will block until an event arrives, but doesn't remove
            //  it from the queue
            let mut xev = unsafe { mem::uninitialized() };
            unsafe { ffi::XPeekEvent(self.display, &mut xev) };

            // calling poll_events()
            let ev = self.poll_events();
            if ev.len() >= 1 {
                return ev;
            }
        }
    }

    pub unsafe fn make_current(&self) {
        let res = ffi::glXMakeCurrent(self.display, self.window, self.context);
        if res == 0 {
            fail!("glXMakeCurrent failed");
        }
    }

    pub fn get_proc_address(&self, addr: &str) -> *const () {
        use std::c_str::ToCStr;
        use std::mem;

        unsafe {
            addr.with_c_str(|s| {
                ffi::glXGetProcAddress(mem::transmute(s)) as *const ()
            })
        }
    }

    pub fn swap_buffers(&self) {
        unsafe { ffi::glXSwapBuffers(self.display, self.window) }
    }
}

impl Drop for Window {
    fn drop(&mut self) {
        unsafe { ffi::glXDestroyContext(self.display, self.context); }
        unsafe { ffi::XDestroyIC(self.ic); }
        unsafe { ffi::XCloseIM(self.im); }
        unsafe { ffi::XDestroyWindow(self.display, self.window); }
        unsafe { ffi::XCloseDisplay(self.display); }
    }
}