/*
    Copyright (C) 2018-2019 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    DCP-o-matic is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "gl_video_view.h"
#include "film_viewer.h"
#include "wx_util.h"
#include "lib/image.h"
#include "lib/dcpomatic_assert.h"
#include "lib/exceptions.h"
#include "lib/cross.h"
#include "lib/player_video.h"
#include "lib/butler.h"
#include <boost/bind/bind.hpp>
#include <iostream>

#ifdef DCPOMATIC_OSX
#include <OpenGL/glu.h>
#include <OpenGL/glext.h>
#include <OpenGL/CGLTypes.h>
#include <OpenGL/OpenGL.h>
#endif

#ifdef DCPOMATIC_LINUX
#include <GL/glu.h>
#include <GL/glext.h>
#endif

#ifdef DCPOMATIC_WINDOWS
#include <GL/glu.h>
#include <GL/glext.h>
#include <GL/wglext.h>
#endif

using std::cout;
using std::shared_ptr;
using boost::optional;
#if BOOST_VERSION >= 106100
using namespace boost::placeholders;
#endif


static void
check_gl_error (char const * last)
{
	GLenum const e = glGetError ();
	if (e != GL_NO_ERROR) {
		throw GLError (last, e);
	}
}


GLVideoView::GLVideoView (FilmViewer* viewer, wxWindow *parent)
	: VideoView (viewer)
	, _context (nullptr)
	, _have_storage (false)
	, _vsync_enabled (false)
	, _playing (false)
	, _one_shot (false)
{
	_canvas = new wxGLCanvas (parent, wxID_ANY, 0, wxDefaultPosition, wxDefaultSize, wxFULL_REPAINT_ON_RESIZE);
	_canvas->Bind (wxEVT_PAINT, boost::bind(&GLVideoView::update, this));
	_canvas->Bind (wxEVT_SIZE, boost::bind(&GLVideoView::size_changed, this, _1));

	_canvas->Bind (wxEVT_TIMER, boost::bind(&GLVideoView::check_for_butler_errors, this));
	_timer.reset (new wxTimer(_canvas));
	_timer->Start (2000);
}


void
GLVideoView::size_changed (wxSizeEvent const& ev)
{
	_canvas_size = ev.GetSize ();
	Sized ();
}



GLVideoView::~GLVideoView ()
{
	boost::this_thread::disable_interruption dis;

	try {
		_thread.interrupt ();
		_thread.join ();
	} catch (...) {}

	glDeleteTextures (1, &_id);
}

void
GLVideoView::check_for_butler_errors ()
{
	if (!_viewer->butler()) {
		return;
	}

	try {
		_viewer->butler()->rethrow ();
	} catch (DecodeError& e) {
		error_dialog (get(), e.what());
	} catch (dcp::ReadError& e) {
		error_dialog (get(), wxString::Format(_("Could not read DCP: %s"), std_to_wx(e.what())));
	}
}


/** Called from the UI thread */
void
GLVideoView::update ()
{
	if (!_canvas->IsShownOnScreen()) {
		return;
	}

#ifdef DCPOMATIC_OSX
	/* macOS gives errors if we don't do this (and therefore [NSOpenGLContext setView:]) from the main thread */
	ensure_context ();
#endif

	if (!_thread.joinable()) {
		_thread = boost::thread (boost::bind(&GLVideoView::thread, this));
	}

	request_one_shot ();
}


void
GLVideoView::ensure_context ()
{
	if (!_context) {
		_context = new wxGLContext (_canvas);
		_canvas->SetCurrent (*_context);
	}
}

void
GLVideoView::draw (Position<int> inter_position, dcp::Size inter_size)
{
	glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	check_gl_error ("glClear");

	glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
	check_gl_error ("glClearColor");
	glEnable (GL_TEXTURE_2D);
	check_gl_error ("glEnable GL_TEXTURE_2D");
	glEnable (GL_BLEND);
	check_gl_error ("glEnable GL_BLEND");
	glDisable (GL_DEPTH_TEST);
	check_gl_error ("glDisable GL_DEPTH_TEST");
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	auto const size = _canvas_size.load();
	int const width = size.GetWidth();
	int const height = size.GetHeight();

	if (width < 64 || height < 0) {
		return;
	}

	glViewport (0, 0, width, height);
	check_gl_error ("glViewport");
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity ();

DCPOMATIC_DISABLE_WARNINGS
	gluOrtho2D (0, width, height, 0);
DCPOMATIC_ENABLE_WARNINGS
	check_gl_error ("gluOrtho2d");
	glMatrixMode (GL_MODELVIEW);
	glLoadIdentity ();

	glTranslatef (0, 0, 0);

	dcp::Size const out_size = _viewer->out_size ();

	if (_size) {
		/* Render our image (texture) */
		glBegin (GL_QUADS);
		glTexCoord2f (0, 1);
		glVertex2f (0, _size->height);
		glTexCoord2f (1, 1);
		glVertex2f (_size->width, _size->height);
		glTexCoord2f (1, 0);
		glVertex2f (_size->width, 0);
		glTexCoord2f (0, 0);
		glVertex2f (0, 0);
		glEnd ();
	} else {
		/* No image, so just fill with black */
		glBegin (GL_QUADS);
		glColor3ub (0, 0, 0);
		glVertex2f (0, 0);
		glVertex2f (out_size.width, 0);
		glVertex2f (out_size.width, out_size.height);
		glVertex2f (0, out_size.height);
		glVertex2f (0, 0);
		glEnd ();
	}

	if (!_viewer->pad_black() && out_size.width < width) {
		glBegin (GL_QUADS);
		/* XXX: these colours are right for GNOME; may need adjusting for other OS */
		glColor3ub (240, 240, 240);
		glVertex2f (out_size.width, 0);
		glVertex2f (width, 0);
		glVertex2f (width, height);
		glVertex2f (out_size.width, height);
		glEnd ();
		glColor3ub (255, 255, 255);
	}

	if (!_viewer->pad_black() && out_size.height < height) {
		glColor3ub (240, 240, 240);
		int const gap = (height - out_size.height) / 2;
		glBegin (GL_QUADS);
		glVertex2f (0, 0);
		glVertex2f (width, 0);
		glVertex2f (width, gap);
		glVertex2f (0, gap);
		glEnd ();
		glBegin (GL_QUADS);
		glVertex2f (0, gap + out_size.height + 1);
		glVertex2f (width, gap + out_size.height + 1);
		glVertex2f (width, 2 * gap + out_size.height + 2);
		glVertex2f (0, 2 * gap + out_size.height + 2);
		glEnd ();
		glColor3ub (255, 255, 255);
	}

	if (_viewer->outline_content()) {
		glColor3ub (255, 0, 0);
		glBegin (GL_LINE_LOOP);
		glVertex2f (inter_position.x, inter_position.y + (height - out_size.height) / 2);
		glVertex2f (inter_position.x + inter_size.width, inter_position.y + (height - out_size.height) / 2);
		glVertex2f (inter_position.x + inter_size.width, inter_position.y + (height - out_size.height) / 2 + inter_size.height);
		glVertex2f (inter_position.x, inter_position.y + (height - out_size.height) / 2 + inter_size.height);
		glEnd ();
		glColor3ub (255, 255, 255);
	}

	glFlush();
	check_gl_error ("glFlush");

	_canvas->SwapBuffers();
}

void
GLVideoView::set_image (shared_ptr<const Image> image)
{
	if (!image) {
		_size = optional<dcp::Size>();
		return;
	}

	DCPOMATIC_ASSERT (image->pixel_format() == AV_PIX_FMT_RGB24);
	DCPOMATIC_ASSERT (!image->aligned());

	if (image->size() != _size) {
		_have_storage = false;
	}

	_size = image->size ();
	glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
	check_gl_error ("glPixelStorei");
	if (_have_storage) {
		glTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, _size->width, _size->height, GL_RGB, GL_UNSIGNED_BYTE, image->data()[0]);
		check_gl_error ("glTexSubImage2D");
	} else {
		glTexImage2D (GL_TEXTURE_2D, 0, GL_RGB8, _size->width, _size->height, 0, GL_RGB, GL_UNSIGNED_BYTE, image->data()[0]);
		_have_storage = true;
		check_gl_error ("glTexImage2D");
	}

	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	check_gl_error ("glTexParameteri");

	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	check_gl_error ("glTexParameterf");
}

void
GLVideoView::start ()
{
	VideoView::start ();

	boost::mutex::scoped_lock lm (_playing_mutex);
	_playing = true;
	_thread_work_condition.notify_all ();
}

void
GLVideoView::stop ()
{
	boost::mutex::scoped_lock lm (_playing_mutex);
	_playing = false;
}


void
GLVideoView::thread_playing ()
{
	if (length() != dcpomatic::DCPTime()) {
		dcpomatic::DCPTime const next = position() + one_video_frame();

		if (next >= length()) {
			_viewer->finished ();
			return;
		}

		get_next_frame (false);
		set_image_and_draw ();
	}

	while (true) {
		optional<int> n = time_until_next_frame();
		if (!n || *n > 5) {
			break;
		}
		get_next_frame (true);
		add_dropped ();
	}
}


void
GLVideoView::set_image_and_draw ()
{
	shared_ptr<PlayerVideo> pv = player_video().first;
	if (pv) {
		set_image (pv->image(bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true));
		draw (pv->inter_position(), pv->inter_size());
		_viewer->image_changed (pv);
	}
}


void
GLVideoView::thread ()
try
{
	start_of_thread ("GLVideoView");

#if defined(DCPOMATIC_OSX)
	/* Without this we see errors like
	 * ../src/osx/cocoa/glcanvas.mm(194): assert ""context"" failed in SwapBuffers(): should have current context [in thread 700006970000]
	 */
	WXGLSetCurrentContext (_context->GetWXGLContext());
#else
	/* We must call this here on Linux otherwise we get no image (for reasons
	 * that aren't clear).  However, doing ensure_context() from this thread
	 * on macOS gives
	 * "[NSOpenGLContext setView:] must be called from the main thread".
	 */
	ensure_context ();
#endif

#if defined(DCPOMATIC_LINUX) && defined(DCPOMATIC_HAVE_GLX_SWAP_INTERVAL_EXT)
	if (_canvas->IsExtensionSupported("GLX_EXT_swap_control")) {
		/* Enable vsync */
		Display* dpy = wxGetX11Display();
		glXSwapIntervalEXT (dpy, DefaultScreen(dpy), 1);
		_vsync_enabled = true;
	}
#endif

#ifdef DCPOMATIC_WINDOWS
	if (_canvas->IsExtensionSupported("WGL_EXT_swap_control")) {
		/* Enable vsync */
		PFNWGLSWAPINTERVALEXTPROC swap = (PFNWGLSWAPINTERVALEXTPROC) wglGetProcAddress("wglSwapIntervalEXT");
		if (swap) {
			swap (1);
			_vsync_enabled = true;
		}
	}

#endif

#ifdef DCPOMATIC_OSX
	/* Enable vsync */
	GLint swapInterval = 1;
	CGLSetParameter (CGLGetCurrentContext(), kCGLCPSwapInterval, &swapInterval);
	_vsync_enabled = true;
#endif

	glGenTextures (1, &_id);
	check_gl_error ("glGenTextures");
	glBindTexture (GL_TEXTURE_2D, _id);
	check_gl_error ("glBindTexture");
	glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
	check_gl_error ("glPixelStorei");

	while (true) {
		boost::mutex::scoped_lock lm (_playing_mutex);
		while (!_playing && !_one_shot) {
			_thread_work_condition.wait (lm);
		}
		lm.unlock ();

		if (_playing) {
			thread_playing ();
		} else if (_one_shot) {
			_one_shot = false;
			set_image_and_draw ();
		}

		boost::this_thread::interruption_point ();
		dcpomatic_sleep_milliseconds (time_until_next_frame().get_value_or(0));
	}

	/* XXX: leaks _context, but that seems preferable to deleting it here
	 * without also deleting the wxGLCanvas.
	 */
}
catch (boost::thread_interrupted& e)
{
	store_current ();
}


VideoView::NextFrameResult
GLVideoView::display_next_frame (bool non_blocking)
{
	NextFrameResult const r = get_next_frame (non_blocking);
	request_one_shot ();
	return r;
}


void
GLVideoView::request_one_shot ()
{
	boost::mutex::scoped_lock lm (_playing_mutex);
	_one_shot = true;
	_thread_work_condition.notify_all ();
}