// pathfinder/demo/android/rust/src/main.rs
//
// Copyright © 2019 The Pathfinder Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#[macro_use]
extern crate lazy_static;

use jni::objects::{GlobalRef, JByteBuffer, JClass, JObject, JString, JValue};
use jni::{JNIEnv, JavaVM};
use pathfinder_demo::window::{Event, SVGPath, View, Window, WindowSize};
use pathfinder_demo::DemoApp;
use pathfinder_demo::Options;
use pathfinder_geometry::vector::{Vector2I, vec2i};
use pathfinder_geometry::rect::RectI;
use pathfinder_gl::GLVersion;
use pathfinder_resources::ResourceLoader;
use std::cell::RefCell;
use std::io::Error as IOError;
use std::mem;
use std::os::raw::c_void;
use std::path::PathBuf;
use std::sync::Mutex;

lazy_static! {
    static ref EVENT_QUEUE: Mutex<Vec<Event>> = Mutex::new(vec![]);
}

thread_local! {
    static DEMO_APP: RefCell<Option<DemoApp<WindowImpl>>> = RefCell::new(None);
    static JAVA_ACTIVITY: RefCell<Option<JavaActivity>> = RefCell::new(None);
    static JAVA_RESOURCE_LOADER: RefCell<Option<JavaResourceLoader>> = RefCell::new(None);
}

static RESOURCE_LOADER: AndroidResourceLoader = AndroidResourceLoader;

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_init(
    env: JNIEnv,
    class: JClass,
    activity: JObject,
    loader: JObject,
    width: i32,
    height: i32,
) {
    let logical_size = vec2i(width, height);
    let window_size = WindowSize {
        logical_size,
        backing_scale_factor: 1.0,
    };
    let window = WindowImpl { size: logical_size };
    let options = Options::default();

    JAVA_ACTIVITY.with(|java_activity| {
        *java_activity.borrow_mut() = Some(JavaActivity::new(env.clone(), activity));
    });
    JAVA_RESOURCE_LOADER.with(|java_resource_loader| {
        *java_resource_loader.borrow_mut() = Some(JavaResourceLoader::new(env, loader));
    });
    DEMO_APP.with(|demo_app| {
        gl::load_with(|name| egl::get_proc_address(name) as *const c_void);
        *demo_app.borrow_mut() = Some(DemoApp::new(window, window_size, options));
    });
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_prepareFrame(
    env: JNIEnv,
    class: JClass,
) -> i32 {
    DEMO_APP.with(|demo_app| {
        let mut event_queue = EVENT_QUEUE.lock().unwrap();
        match *demo_app.borrow_mut() {
            Some(ref mut demo_app) => {
                demo_app.prepare_frame(mem::replace(&mut *event_queue, vec![])) as i32
            }
            None => 0,
        }
    })
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_drawScene(
    env: JNIEnv,
    class: JClass,
) {
    DEMO_APP.with(|demo_app| {
        if let Some(ref mut demo_app) = *demo_app.borrow_mut() {
            demo_app.draw_scene()
        }
    })
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_finishDrawingFrame(
    env: JNIEnv,
    class: JClass,
) {
    DEMO_APP.with(|demo_app| {
        if let Some(ref mut demo_app) = *demo_app.borrow_mut() {
            demo_app.finish_drawing_frame()
        }
    })
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushWindowResizedEvent(
    env: JNIEnv,
    class: JClass,
    width: i32,
    height: i32,
) {
    EVENT_QUEUE
        .lock()
        .unwrap()
        .push(Event::WindowResized(WindowSize {
            logical_size: vec2i(width, height),
            backing_scale_factor: 1.0,
        }))
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushMouseDownEvent(
    _: JNIEnv,
    _: JClass,
    x: i32,
    y: i32,
) {
    EVENT_QUEUE.lock().unwrap().push(Event::MouseDown(vec2i(x, y)))
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushMouseDraggedEvent(
    _: JNIEnv,
    _: JClass,
    x: i32,
    y: i32,
) {
    EVENT_QUEUE.lock().unwrap().push(Event::MouseDragged(vec2i(x, y)))
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushZoomEvent(
    _: JNIEnv,
    _: JClass,
    factor: f32,
    center_x: i32,
    center_y: i32,
) {
    EVENT_QUEUE.lock().unwrap().push(Event::Zoom(factor, vec2i(center_x, center_y)))
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushLookEvent(
    _: JNIEnv,
    _: JClass,
    pitch: f32,
    yaw: f32,
) {
    EVENT_QUEUE.lock().unwrap().push(Event::Look { pitch, yaw })
}

#[no_mangle]
pub unsafe extern "system" fn Java_graphics_pathfinder_pathfinderdemo_PathfinderDemoRenderer_pushOpenSVGEvent(
    env: JNIEnv,
    _: JClass,
    string: JObject,
) {
    let string: String = env.get_string(JString::from(string)).unwrap().into();
    EVENT_QUEUE
        .lock()
        .unwrap()
        .push(Event::OpenSVG(SVGPath::Resource(string)))
}

struct WindowImpl {
    size: Vector2I,
}

impl Window for WindowImpl {
    fn gl_version(&self) -> GLVersion {
        GLVersion::GLES3
    }

    fn viewport(&self, view: View) -> RectI {
        let mut width = self.size.x();
        let mut offset_x = 0;
        let height = self.size.y();
        if let View::Stereo(index) = view {
            width = width / 2;
            offset_x = (index as i32) * width;
        }
        let size = vec2i(width, height);
        let offset = vec2i(offset_x, 0);
        RectI::new(offset, size)
    }

    fn make_current(&mut self, _view: View) {}

    fn present(&mut self) {}

    fn resource_loader(&self) -> &dyn ResourceLoader {
        &RESOURCE_LOADER
    }

    fn create_user_event_id(&self) -> u32 {
        0
    }

    fn push_user_event(message_type: u32, message_data: u32) {}

    fn present_open_svg_dialog(&mut self) {
        JAVA_ACTIVITY.with(|java_activity| {
            let mut java_activity = java_activity.borrow_mut();
            let java_activity = java_activity.as_mut().unwrap();
            let env = java_activity.vm.get_env().unwrap();
            env.call_method(
                java_activity.activity.as_obj(),
                "presentOpenSVGDialog",
                "()V",
                &[],
            )
            .unwrap();
        });
    }

    fn run_save_dialog(&self, extension: &str) -> Result<PathBuf, ()> {
        // TODO(pcwalton)
        Err(())
    }
}

struct AndroidResourceLoader;

impl ResourceLoader for AndroidResourceLoader {
    fn slurp(&self, path: &str) -> Result<Vec<u8>, IOError> {
        JAVA_RESOURCE_LOADER.with(|java_resource_loader| {
            let java_resource_loader = java_resource_loader.borrow();
            let java_resource_loader = java_resource_loader.as_ref().unwrap();
            let loader = java_resource_loader.loader.as_obj();
            let env = java_resource_loader.vm.get_env().unwrap();
            match env
                .call_method(
                    loader,
                    "slurp",
                    "(Ljava/lang/String;)Ljava/nio/ByteBuffer;",
                    &[JValue::Object(*env.new_string(path).unwrap())],
                )
                .unwrap()
            {
                JValue::Object(object) => {
                    let byte_buffer = JByteBuffer::from(object);
                    Ok(Vec::from(
                        env.get_direct_buffer_address(byte_buffer).unwrap(),
                    ))
                }
                _ => panic!("Unexpected return value!"),
            }
        })
    }
}

struct JavaActivity {
    activity: GlobalRef,
    vm: JavaVM,
}

impl JavaActivity {
    fn new(env: JNIEnv, activity: JObject) -> JavaActivity {
        JavaActivity {
            activity: env.new_global_ref(activity).unwrap(),
            vm: env.get_java_vm().unwrap(),
        }
    }
}

struct JavaResourceLoader {
    loader: GlobalRef,
    vm: JavaVM,
}

impl JavaResourceLoader {
    fn new(env: JNIEnv, loader: JObject) -> JavaResourceLoader {
        JavaResourceLoader {
            loader: env.new_global_ref(loader).unwrap(),
            vm: env.get_java_vm().unwrap(),
        }
    }
}