//! iOS support
//!
//! # Building app
//! To build ios app you will need rustc built for this targets:
//!
//!  - armv7-apple-ios
//!  - armv7s-apple-ios
//!  - i386-apple-ios
//!  - aarch64-apple-ios
//!  - x86_64-apple-ios
//!
//! Then
//!
//! ```
//! cargo build --target=...
//! ```
//! The simplest way to integrate your app into xcode environment is to build it
//! as a static library. Wrap your main function and export it.
//!
//! ```rust, ignore
//! #[no_mangle]
//! pub extern fn start_glutin_app() {
//!     start_inner()
//! }
//!
//! fn start_inner() {
//!    ...
//! }
//!
//! ```
//!
//! Compile project and then drag resulting .a into Xcode project. Add glutin.h to xcode.
//!
//! ```c
//! void start_glutin_app();
//! ```
//!
//! Use start_glutin_app inside your xcode's main function.
//!
//!
//! # App lifecycle and events
//!
//! iOS environment is very different from other platforms and you must be very
//! careful with it's events. Familiarize yourself with
//! [app lifecycle](https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIApplicationDelegate_Protocol/).
//!
//!
//! This is how those event are represented in glutin:
//!
//!  - applicationDidBecomeActive is Focused(true)
//!  - applicationWillResignActive is Focused(false)
//!  - applicationDidEnterBackground is Suspended(true)
//!  - applicationWillEnterForeground is Suspended(false)
//!  - applicationWillTerminate is Closed
//!
//! Keep in mind that after Closed event is received every attempt to draw with
//! opengl will result in segfault.
//!
//! Also note that app will not receive Closed event if suspended, it will be SIGKILL'ed

#![cfg(target_os = "ios")]
#![deny(warnings)]

use std::collections::VecDeque;
use std::ptr;
use std::mem;
use std::os::raw::c_void;

use libc;
use libc::c_int;
use objc::runtime::{Class, Object, Sel, BOOL, YES };
use objc::declare::{ ClassDecl };

use native_monitor::NativeMonitorId;
use { CreationError, CursorState, MouseCursor, Event, WindowAttributes };
use events::{ Touch, TouchPhase };

mod ffi;
use self::ffi::{
    setjmp,
    UIApplicationMain,
    CFTimeInterval,
    CFRunLoopRunInMode,
    kCFRunLoopDefaultMode,
    kCFRunLoopRunHandledSource,
    id,
    nil,
    NSString,
    CGFloat,
    longjmp,
    CGRect,
    CGPoint
 };

static mut jmpbuf: [c_int;27] = [0;27];

#[derive(Clone)]
pub struct MonitorId;

pub struct Window {
    delegate_state: *mut DelegateState
}

#[derive(Clone)]
pub struct WindowProxy;

pub struct PollEventsIterator<'a> {
    window: &'a Window,
}

pub struct WaitEventsIterator<'a> {
    window: &'a Window,
}

#[derive(Debug)]
struct DelegateState {
    events_queue: VecDeque<Event>,
    window: id,
    controller: id,
    size: (u32,u32),
    scale: f32
}


impl DelegateState {
    #[inline]
    fn new(window: id, controller:id, size: (u32,u32), scale: f32) -> DelegateState {
        DelegateState {
            events_queue: VecDeque::new(),
            window: window,
            controller: controller,
            size: size,
            scale: scale
        }
    }
}

#[inline]
pub fn get_available_monitors() -> VecDeque<MonitorId> {
    let mut rb = VecDeque::new();
    rb.push_back(MonitorId);
    rb
}

#[inline]
pub fn get_primary_monitor() -> MonitorId {
    MonitorId
}

impl MonitorId {
    #[inline]
    pub fn get_name(&self) -> Option<String> {
        Some("Primary".to_string())
    }

    #[inline]
    pub fn get_native_identifier(&self) -> NativeMonitorId {
        NativeMonitorId::Unavailable
    }

    #[inline]
    pub fn get_dimensions(&self) -> (u32, u32) {
        unimplemented!()
    }
}

#[derive(Clone, Default)]
pub struct PlatformSpecificWindowBuilderAttributes;

impl Window {

    pub fn new(_: &WindowAttributes, _: &PlatformSpecificWindowBuilderAttributes) -> Result<Window, CreationError>
    {
        unsafe {
            if setjmp(mem::transmute(&mut jmpbuf)) != 0 {
                let app: id = msg_send![Class::get("UIApplication").unwrap(), sharedApplication];
                let delegate: id = msg_send![app, delegate];
                let state: *mut c_void = *(&*delegate).get_ivar("glutinState");
                let state = state as *mut DelegateState;

                let window = Window {
                    delegate_state: state
                };

                return Ok(window)
            }
        }

        Window::create_delegate_class();
        Window::create_view_class();
        Window::start_app();

        Err(CreationError::OsError(format!("Couldn't create UIApplication")))
    }

    fn create_delegate_class() {
        extern fn did_finish_launching(this: &mut Object, _: Sel, _: id, _: id) -> BOOL {
            unsafe {
                let main_screen: id = msg_send![Class::get("UIScreen").unwrap(), mainScreen];
                let bounds: CGRect = msg_send![main_screen, bounds];
                let scale: CGFloat = msg_send![main_screen, nativeScale];

                let window: id = msg_send![Class::get("UIWindow").unwrap(), alloc];
                let window: id = msg_send![window, initWithFrame:bounds.clone()];

                let size = (bounds.size.width as u32, bounds.size.height as u32);

                let view_controller: id = msg_send![Class::get("MainViewController").unwrap(), alloc];
                let view_controller: id = msg_send![view_controller, init];

                let _: () = msg_send![window, setRootViewController:view_controller];
                let _: () = msg_send![window, makeKeyAndVisible];

                let state = Box::new(DelegateState::new(window, view_controller, size, scale as f32));
                let state_ptr: *mut DelegateState = mem::transmute(state);
                this.set_ivar("glutinState", state_ptr as *mut c_void);


                let _: () = msg_send![this, performSelector:sel!(postLaunch:) withObject:nil afterDelay:0.0];
            }
            YES
        }

        extern fn post_launch(_: &Object, _: Sel, _: id) {
            unsafe { longjmp(mem::transmute(&mut jmpbuf),1); }
        }

        extern fn did_become_active(this: &Object, _: Sel, _: id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);
                state.events_queue.push_back(Event::Focused(true));
            }
        }

        extern fn will_resign_active(this: &Object, _: Sel, _: id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);
                state.events_queue.push_back(Event::Focused(false));
            }
        }

        extern fn will_enter_foreground(this: &Object, _: Sel, _: id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);
                state.events_queue.push_back(Event::Suspended(false));
            }
        }

        extern fn did_enter_background(this: &Object, _: Sel, _: id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);
                state.events_queue.push_back(Event::Suspended(true));
            }
        }

        extern fn will_terminate(this: &Object, _: Sel, _: id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);
                // push event to the front to garantee that we'll process it
                // immidiatly after jump
                state.events_queue.push_front(Event::Closed);
                longjmp(mem::transmute(&mut jmpbuf),1);
            }
        }

        extern fn handle_touches(this: &Object, _: Sel, touches: id, _:id) {
            unsafe {
                let state: *mut c_void = *this.get_ivar("glutinState");
                let state = &mut *(state as *mut DelegateState);

                let touches_enum: id = msg_send![touches, objectEnumerator];

                loop {
                    let touch: id = msg_send![touches_enum, nextObject];
                    if touch == nil {
                        break
                    }
                    let location: CGPoint = msg_send![touch, locationInView:nil];
                    let touch_id = touch as u64;
                    let phase: i32 = msg_send![touch, phase];

                    state.events_queue.push_back(Event::Touch(Touch {
                        id: touch_id,
                        location: (location.x as f64, location.y as f64),
                        phase: match phase {
                            0 => TouchPhase::Started,
                            1 => TouchPhase::Moved,
                            // 2 is UITouchPhaseStationary and is not expected here
                            3 => TouchPhase::Ended,
                            4 => TouchPhase::Cancelled,
                            _ => panic!("unexpected touch phase: {:?}", phase)
                        }
                    }));
                }
            }
        }

        let app_delegate_class = Class::get("AppDelegate").unwrap();
        let mut decl = ClassDecl::new("UIResponder", app_delegate_class).unwrap();

        unsafe {
            decl.add_method(sel!(application:didFinishLaunchingWithOptions:),
                            did_finish_launching as extern fn(&mut Object, Sel, id, id) -> BOOL);

            decl.add_method(sel!(applicationDidBecomeActive:),
                            did_become_active as extern fn(&Object, Sel, id));

            decl.add_method(sel!(applicationWillResignActive:),
                            will_resign_active as extern fn(&Object, Sel, id));

            decl.add_method(sel!(applicationWillEnterForeground:),
                            will_enter_foreground as extern fn(&Object, Sel, id));

            decl.add_method(sel!(applicationDidEnterBackground:),
                            did_enter_background as extern fn(&Object, Sel, id));

            decl.add_method(sel!(applicationWillTerminate:),
                            will_terminate as extern fn(&Object, Sel, id));


            decl.add_method(sel!(touchesBegan:withEvent:),
                            handle_touches as extern fn(this: &Object, _: Sel, _: id, _:id));

            decl.add_method(sel!(touchesMoved:withEvent:),
                            handle_touches as extern fn(this: &Object, _: Sel, _: id, _:id));

            decl.add_method(sel!(touchesEnded:withEvent:),
                            handle_touches as extern fn(this: &Object, _: Sel, _: id, _:id));

            decl.add_method(sel!(touchesCancelled:withEvent:),
                            handle_touches as extern fn(this: &Object, _: Sel, _: id, _:id));


            decl.add_method(sel!(postLaunch:),
                            post_launch as extern fn(&Object, Sel, id));

            decl.add_ivar::<*mut c_void>("glutinState");

            decl.register();
        }
    }

    fn create_view_class() {
        let main_vc_class = Class::get("MainViewController").unwrap();
        let decl = ClassDecl::new("UIViewController", main_vc_class).unwrap();

        decl.register();
    }

    #[inline]
    fn start_app() {
        unsafe {
            UIApplicationMain(0, ptr::null(), nil, NSString::alloc(nil).init_str("AppDelegate"));
        }
    }

    #[inline]
    pub fn set_title(&self, _: &str) {
    }

    #[inline]
    pub fn show(&self) {
    }

    #[inline]
    pub fn hide(&self) {
    }

    #[inline]
    pub fn get_position(&self) -> Option<(i32, i32)> {
        None
    }

    #[inline]
    pub fn set_position(&self, _x: i32, _y: i32) {
    }

    #[inline]
    pub fn get_inner_size(&self) -> Option<(u32, u32)> {
        unsafe { Some((&*self.delegate_state).size) }
    }

    #[inline]
    pub fn get_outer_size(&self) -> Option<(u32, u32)> {
        self.get_inner_size()
    }

    #[inline]
    pub fn set_inner_size(&self, _x: u32, _y: u32) {
    }

    #[inline]
    pub fn poll_events(&self) -> PollEventsIterator {
        PollEventsIterator {
            window: self
        }
    }

    #[inline]
    pub fn wait_events(&self) -> WaitEventsIterator {
        WaitEventsIterator {
            window: self
        }
    }

    #[inline]
    pub fn platform_display(&self) -> *mut libc::c_void {
        unimplemented!();
    }

    #[inline]
    pub fn platform_window(&self) -> *mut libc::c_void {
        unimplemented!()
    }

    #[inline]
    pub fn set_window_resize_callback(&mut self, _: Option<fn(u32, u32)>) {
    }

    #[inline]
    pub fn set_cursor(&self, _: MouseCursor) {
    }

    #[inline]
    pub fn set_cursor_state(&self, _: CursorState) -> Result<(), String> {
        Ok(())
    }

    #[inline]
    pub fn hidpi_factor(&self) -> f32 {
        unsafe { (&*self.delegate_state) }.scale
    }

    #[inline]
    pub fn set_cursor_position(&self, _x: i32, _y: i32) -> Result<(), ()> {
        unimplemented!();
    }

    #[inline]
    pub fn create_window_proxy(&self) -> WindowProxy {
        WindowProxy
    }

}

impl WindowProxy {
    #[inline]
    pub fn wakeup_event_loop(&self) {
        unimplemented!()
    }
}


impl<'a> Iterator for WaitEventsIterator<'a> {
    type Item = Event;

    #[inline]
    fn next(&mut self) -> Option<Event> {
        loop {
            if let Some(ev) = self.window.poll_events().next() {
                return Some(ev);
            }
        }
    }
}

impl<'a> Iterator for PollEventsIterator<'a> {
    type Item = Event;

    fn next(&mut self) -> Option<Event> {
        unsafe {
            let state = &mut *self.window.delegate_state;

            if let Some(event) = state.events_queue.pop_front() {
                return Some(event)
            }

            // jump hack, so we won't quit on willTerminate event before processing it
            if setjmp(mem::transmute(&mut jmpbuf)) != 0 {
                return state.events_queue.pop_front()
            }

            // run runloop
            let seconds: CFTimeInterval = 0.000002;
            while CFRunLoopRunInMode(kCFRunLoopDefaultMode, seconds, 1) == kCFRunLoopRunHandledSource {}

            state.events_queue.pop_front()
        }
    }
}