#include "animation.h"
#include "gpu.h"
#include "model_format_glb.h"

#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <string.h>

#define W 800
#define H 600

#define DT (1'000'000 / 60) // Assume 60 Hz for now

#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))

static void
key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
{
	(void)window;
	(void)scancode;
	(void)mods;

	if (action != GLFW_PRESS)
		return;

	switch (key) {
	case GLFW_KEY_Q:
		glfwSetWindowShouldClose(window, GL_TRUE);
		break;
	}
}

int main(int argc, char *argv[])
{
	// Read model from passed path
	if (argc != 2) {
		fprintf(stderr, "Usage: %s PATH/TO/MODEL\n", argv[0]);
		return 1;
	}
	model_t model = model_format_glb_read(argv[1]);

	// Set up window
	glfwInit();
	glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
	glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
	GLFWwindow *window = glfwCreateWindow(W, H, "Foo", nullptr, nullptr);
	assert(window);

	// Register input callbacks
	glfwSetKeyCallback(window, key_callback);

	// Initialise GPU and load model
	gpu_ctx_t gpu;
	gpu_model_t gpu_models[2];
	gpu_init(&gpu, window, "Foo");
	gpu_model_load(&gpu, &model, gpu_models + 0);
	gpu_model_load(&gpu, &model, gpu_models + 1);

	const vec3_t cam = { 0, 4, -8 };
	const vec3_t tgt = { 0, 0, 0 };
	const vec3_t up = { 0, 1, 0 };
	const vec3_t light = { 2, 2, -1 };
	const mat4_t view = mat4_lookat(cam, tgt, up);
	const mat4_t proj = mat4_perspective((float)W / H, PI / 8, 0.1, 100.0);
	const mat4_t vp = mat4_mul(proj, view);
	const mat4_t light_view = mat4_lookat(light, tgt, up);
	const mat4_t light_proj = mat4_orthographic(5, 5, 10);
	const mat4_t light_vp = mat4_mul(light_proj, light_view);
	mat4_t transforms[NELEMS(gpu_models)] = {
		mat4_mul(
		    MAT4_TRANSLATE(1, 0, 0),
		    (mat4_t) {
		        { 0, 0, -1, 0 },
		        { -1, 0, 0, 0 },
		        { 0, 1, 0, 0 },
		        { 0, 0, 0, 1 },
		    }),
		mat4_mul(
		    MAT4_TRANSLATE(2, 0, 0),
		    mat4_mul(
		        MAT4_ROTATE_Y(PI),
		        (mat4_t) {
		            { 0, 0, -1, 0 },
		            { -1, 0, 0, 0 },
		            { 0, 1, 0, 0 },
		            { 0, 0, 0, 1 },
		        })),
	};

	// Set up animation
	animation_state_t anim = animation_init(&model);
	animation_start(&anim, &model, 0);

	while (!glfwWindowShouldClose(window)) {
		glfwPollEvents();

		transforms[0] = mat4_mul(MAT4_ROTATE_Y(PI / 170), transforms[0]);
		transforms[1] = mat4_mul(MAT4_ROTATE_Y(-PI / 340), transforms[1]);

		animation_update(&anim, &model, DT);

		const mat4_t *bone_matrices[NELEMS(gpu_models)] = {
			anim.bone_matrices,
			anim.bone_matrices,
		};
		gpu_render(
		    &gpu, vp, light_vp, NELEMS(gpu_models), gpu_models,
		    bone_matrices, transforms);
	}

	// Clean up
	animation_cleanup(&anim);
	gpu_model_cleanup(&gpu, gpu_models + 0);
	gpu_model_cleanup(&gpu, gpu_models + 1);
	gpu_cleanup(&gpu);
	model_cleanup(&model);
	glfwDestroyWindow(window);
	glfwTerminate();

	return 0;
}