// Some defaults for the game layout
#define DEBUG_DRAW true
#define VIEWPORT_WIDTH 1920
#define VIEWPORT_HEIGHT 1080
#define CONE_ANGLE 30
#define VSYNC_ENABLED true

#define DATA_DIR "../data"
#define DEFAULT_SCENE_FILE "hashmap_scene.json"
#define SCENE_SCHEMA_FILE "scene_schema.json"
#define MAX_ENTITIES 1000

#include <vector>

#if defined(_WIN32)
	#include <windows.h>
	#include <Winuser.h>
	#include <SDL.h>
#else
	#include <SDL2/SDL.h>
#endif

// TODO: replace aixlog with simpler logging
#if defined(_WIN32)
#pragma warning(push)
#pragma warning(disable : 4003)
#endif
#include "aixlog.hpp"

#include "gooey.h"
#include "hexgame.h"
#include "mesh.h"
#include "platform_wait_for_vblank.h"
#include "renderer.h"
#include "scene_loader.h"
#include "util.h"

using std::vector;

static game_state* g_game_state;
static render_state* g_render_state;
static vector<Point> g_polygon_select_vertices = {Point(), Point(), Point(), Point()};


bool
loadSceneFromJson(game_state* s, render_state* rs)
{
	slSceneDoc* sd = slLoadFile(DATA_DIR, DEFAULT_SCENE_FILE, SCENE_SCHEMA_FILE);

	if (sd != nullptr) {
		game_state* gs = g_game_state;
		render_state* rs = g_render_state;

		if (!slParseEntities(sd, gs->entities, gs->entity_count, MAX_ENTITIES, DATA_DIR)) {
			LOG(ERROR) << "Error loading Entities, exiting\n";
			slFreeSceneDoc(sd);
			return false;
		}

		slParseCamera(sd, rs->cam);
		slParseHexGrid(sd, gs->grid, rs->palette_image);

		if (slCreateHexRenderGroups(gs->grid, rs)) {
			if (!hgInit(gs->grid, rs->filled_hex_render_group, rs->hex_line_render_group, DATA_DIR)) {
				slFreeSceneDoc(sd);
				return false;
			}
		} else {
			LOG(ERROR) << "Error creating hexgrid render groups\n";
			slFreeSceneDoc(sd);
			return false;
		}

		if (!slParseLights(sd, rs->lights, rs->num_lights, rs->max_lights)) {
			LOG(ERROR) << "Error loading lights, exiting\n";
			slFreeSceneDoc(sd);
			return false;
		}
	} else {
		return false;
	}

	slFreeSceneDoc(sd);
	return true;
}

bool
init()
{
	// init global game state
	g_game_state = UTIL_ALLOC(1, game_state);
	g_game_state->entities = UTIL_ALLOC(MAX_ENTITIES, Entity);
	// TODO: I think this is necessary because we're using calloc to initialize gamestate
	//	which contains the hashtable.
	g_game_state->grid.hex_map = std::unordered_map<Hex, hex_info, hex_hashfunc>();
	// NOTE: testing hex_add
	g_game_state->grid.draw_mode = ADD_HEXES;
	// TODO: maybe add this as an option to scene json?
	g_game_state->grid.normal = v3f(0.f, 0.f, 1.f);

	// init global render state
	g_render_state = UTIL_ALLOC(1, render_state);
	g_render_state->is_debug_draw = DEBUG_DRAW;
	g_render_state->viewport_dims = v2i(VIEWPORT_WIDTH, VIEWPORT_HEIGHT);

	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
		LOG(ERROR) << "Error, SDL_Init: " << SDL_GetError() << "\n";
		return false;
	}

	if (!renInit(g_render_state)) {
		LOG(ERROR) << "Unable to initialize graphics, exiting\n";
		return false;
	}

	if (!gooInit(g_render_state->handles, g_render_state->viewport_dims))	{
		LOG(ERROR) << "Fooey, No Gooey!\n";
		return false;
	}

	if (!meInitAssimp()) {
		LOG(ERROR) << "Error initializing assimp\n";
		return false;
	}

	if (!loadSceneFromJson(g_game_state, g_render_state)) {
		LOG(ERROR) << "Error loading scene\n";
		return false;
	}

	if (!renCreateScene(g_render_state, g_game_state->entities, g_game_state->entity_count))
	{
		LOG(ERROR) << "Error in vertex data, exiting\n";
		return false;
	}

#if defined(_WIN32)
	LOG(DEBUG) << "TODO: Test SDL_Delay frame timer in win32\n";

	if (!platform_init(g_render_state->handles.window)) {
		LOG(ERROR) << "Couldn't get SDL platform info, exiting\n";
		return false;
	}
#endif

	return true;
}

v2i
mapMouseToViewport(int32 x, int32 y)
{
	v2i coords;
	coords.x = x;
	coords.y = g_render_state->viewport_dims.y - y;
	return coords;
}

void
startDrawHelper(int32 x, int32 y)
{
	hgResetHexes(g_game_state->grid);
	v2i dims = g_render_state->viewport_dims;
	v2f v = cameraUnproject(g_render_state->cam, x, y, dims.x, dims.y);
	hex_info *hex = hgGetSingleHex(g_game_state->grid, v.x, v.y);
	if (hex) {
		hex->selected = true;
		g_game_state->grid.start_hex = g_game_state->grid.current_hex = hex;
	}
}

void
handleMouseDown(SDL_MouseButtonEvent &e)
{
	game_state* gs = g_game_state;
	render_state* rs = g_render_state;
	v2i coords = mapMouseToViewport(e.x, e.y);
	v2i dims = rs->viewport_dims;

	switch (gs->grid.draw_mode) {
		case FILL:
			startDrawHelper(coords.x, coords.y);
			break;
		case LINE:
			startDrawHelper(coords.x, coords.y);
			break;
		case CONE_FILL:
			startDrawHelper(coords.x, coords.y);
			break;
		case PATHFINDING:
			break;
		case ADD_HEXES: {
			v3f ray = cameraCreateRay(rs->cam, coords, dims);
			v3f xsect;
			if (cameraIntersectPlane(rs->cam, ray, gs->grid.position, gs->grid.normal, xsect))
				hgAddHex(gs->grid, xsect, rs->filled_hex_render_group, rs->hex_line_render_group);
			break;
		}
		case REMOVE_HEXES: {
			v3f ray = cameraCreateRay(rs->cam, coords, dims);
			v3f xsect;
			if (cameraIntersectPlane(rs->cam, ray, gs->grid.position, gs->grid.normal, xsect))
				hgRemoveHex(gs->grid, xsect, rs->filled_hex_render_group, rs->hex_line_render_group);
			break;
		}
		case NONE:
		default:
			v2f v = cameraUnproject(rs->cam, coords.x, coords.y, dims.x, dims.y);
			hex_info *hxi = hgGetSingleHex(gs->grid, v.x, v.y);

			if (hxi) {
				hxi->selected = !hxi->selected;
				gs->grid.start_hex = gs->grid.current_hex = hxi;
			}

			break;
	}
}

void
handleMouseMove(SDL_MouseMotionEvent &e)
{
	game_state* gs = g_game_state;
	render_state* rs = g_render_state;
	v2i coords = mapMouseToViewport(e.x, e.y);
	v2i dims = rs->viewport_dims;
	v2f v = cameraUnproject(rs->cam, coords.x, coords.y, dims.x, dims.y);

	switch (gs->grid.draw_mode) {
		case FILL:
			hgUpdateHexFill(gs->grid, v.x, v.y);
			break;
		case LINE:
			hgUpdateHexLineDraw(gs->grid, v.x, v.y);
			break;
		case CONE_FILL:
			hgUpdateHexConeFill(gs->grid, v.x, v.y, CONE_ANGLE, g_polygon_select_vertices);
			break;
		case PATHFINDING:
			break;
		case ADD_HEXES: {
			if (gs->grid.is_selecting) {
				v3f ray = cameraCreateRay(rs->cam, coords, dims);
				v3f xsect;
				if (cameraIntersectPlane(rs->cam, ray, gs->grid.position, gs->grid.normal, xsect))
					hgAddHex(gs->grid, xsect, rs->filled_hex_render_group, rs->hex_line_render_group);
			}
			break;
		}
		case REMOVE_HEXES: {
			if (gs->grid.is_selecting) {
				v3f ray = cameraCreateRay(rs->cam, coords, dims);
				v3f xsect;
				if (cameraIntersectPlane(rs->cam, ray, gs->grid.position, gs->grid.normal, xsect))
					hgRemoveHex(gs->grid, xsect, rs->filled_hex_render_group, rs->hex_line_render_group);
			}
			break;
		}
		case NONE:
		default:
			break;
	}
}

bool
processSDLEvents()
{
	SDL_Event e;
	bool run = true;

	while (SDL_PollEvent(&e)) {
		// let gooey have event
		// TODO: need to check for both io.WantCaptureKeyboard and io.WantCaptureMouse
		// 	to fix bug with 'ESC' not passing through while in imgui
		bool gooey_wants =  gooProcessEvent(e);
		game_state* gs = g_game_state;

		switch (e.type) {
			case SDL_QUIT:
				run = false;
				break;
			case SDL_KEYDOWN:
				switch (e.key.keysym.sym) {
					case SDLK_ESCAPE: run = false; break;
					case SDLK_e: gs->is_moveforward = true; break;
					case SDLK_s: gs->is_moveleft = true; break;
					case SDLK_d: gs->is_movebackward = true; break;
					case SDLK_f: gs->is_moveright = true; break;
					case SDLK_SPACE: gs->is_moveup = true; break;
					case SDLK_c: gs->is_movedown = true; break;
					case SDLK_r: gs->is_rotateCW = true; break;
					case SDLK_w: gs->is_rotateCCW = true; break;
				}
				break;
			case SDL_KEYUP:
				switch (e.key.keysym.sym) {
					case SDLK_e: gs->is_moveforward = false; break;
					case SDLK_s: gs->is_moveleft = false; break;
					case SDLK_d: gs->is_movebackward = false; break;
					case SDLK_f: gs->is_moveright = false; break;
					case SDLK_SPACE: gs->is_moveup = false; break;
					case SDLK_c: gs->is_movedown = false; break;
					case SDLK_r: gs->is_rotateCW = false; break;
					case SDLK_w: gs->is_rotateCCW = false; break;
				}
				break;
			case SDL_MOUSEBUTTONDOWN:
				if (!gooey_wants) {
					if (e.button.button == SDL_BUTTON_LEFT) {
						gs->grid.is_selecting = true;
						handleMouseDown(e.button);
					} else if (e.button.button == SDL_BUTTON_RIGHT) {
						gs->is_camera_rotate = true;
					}
				}
				break;
			case SDL_MOUSEBUTTONUP:
				if (!gooey_wants) {
					if (e.button.button == SDL_BUTTON_LEFT)
						gs->grid.is_selecting = false;
					else if (e.button.button == SDL_BUTTON_RIGHT)
						gs->is_camera_rotate = false;
				}
				break;
			case SDL_MOUSEMOTION:
				if (!gooey_wants && gs->grid.is_selecting)
					handleMouseMove(e.motion);
				else if(!gooey_wants && gs->is_camera_rotate)
					cameraRotate(g_render_state->cam, e.motion.xrel, e.motion.yrel);
				break;
			default:
				break;
		}
	}

	return run;
}

bool
cleanUp(SDL_Handles &handles)
{
	gooFree();
	renFreeBuffers(g_render_state);	// renderer.h
	for (SDL_Surface *surface : handles.texSurfaces)
			SDL_FreeSurface(surface);
	meShutdownAssimp(); // mesh.h
	SDL_GL_DeleteContext(handles.glContext);
	SDL_DestroyWindow(handles.window);
	SDL_Quit();

	game_state* gs = g_game_state;

	for (uint i = 0; i < gs->entity_count; i++) {
		meFreeMeshGroup(gs->entities[i].mesh_group);
		rgFree(gs->entities[i].ren_group);
	}

	utilSafeFree(gs->entities);
	utilSafeFree(g_render_state);
	utilSafeFree(g_game_state);

	return true;
}

#if defined(_WIN32)
int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
				LPSTR lpCmdLine, int nShowCmd)
#else
int main(int argc, char* argv[])
#endif
{
#if defined(_WIN32)
	AixLog::Log::init<AixLog::SinkOutputDebugString>(AixLog::Severity::trace, AixLog::Type::normal);
#else
	AixLog::Log::init<AixLog::SinkCout>(AixLog::Severity::trace, AixLog::Type::normal);
#endif
	LOG(INFO) << "Application started\n";

	if (!init()) {
		LOG(ERROR) << "failed init, exiting\n";
		return -1;
	}

	// main loop

	const uint TARGET_FPS = 60;
	const uint FRAME_DELAY = 1000 / TARGET_FPS;
	uint frameStart, frameTime;

	while (processSDLEvents()) {
		frameStart = SDL_GetTicks();

		game_state* gs = g_game_state;
		render_state* rs = g_render_state;

		cameraMove(rs->cam, gs->is_moveup, gs->is_moveleft, gs->is_movedown, gs->is_moveright,
				gs->is_moveforward, gs->is_movebackward);

		renRenderFrame(rs, gs->grid, gs->entities, gs->entity_count);

		if (rs->is_debug_draw && gs->grid.draw_mode == CONE_FILL)
			renRenderDebug(rs, g_polygon_select_vertices);

		gooRender(gs, rs);

		SDL_GL_SwapWindow(rs->handles.window);

		// TODO: test SDL_Delay on Win32
		//platform_wait_for_vblank(VSYNC_ENABLED);
		frameTime = SDL_GetTicks() - frameStart;

		if (FRAME_DELAY > frameTime)
			SDL_Delay(FRAME_DELAY - frameTime);
	}

	cleanUp(g_render_state->handles);
	LOG(INFO) << "Application exiting\n";
	return 0;
}