/*
 * modelview: shows a .kmdl model and plays and blends its animations
 *
 * build:  ./build.sh -d -m model,image,debug examples
 * run:    obj/modelview [models/fox.kmdl] [pack file]
 * models: obj/konmodel art/models/Fox.glb assets/models/fox.kmdl -t models/
 *
 * mouse drag turns the camera, the wheel or up and down zoom, space picks the next clip,
 * left and right change the speed, f flat, l light, w wireframe, p pause
 * with the developer build the console (`) knows clips, clip, blend, and the variables flat light wire spin speed amount
 */

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

#include "konprogram.h"
#include "konmodel.h"

#if !defined(KON_MODULE_MODEL) || !defined(KON_MODULE_IMAGE) || !defined(KON_MODULE_DEBUG)
#error "build with: ./build.sh -d -m model,image,debug examples"
#endif

typedef struct viewer {
	kon_program_t *program;
	const char *name;
	kon_model_t *model;
	kon_light_t light;

	kon_vec3_t center;
	float size, floorY, yaw, pitch, distance;
	int dragging, dragX, dragY;
	int ortho;

	int clip, blendClip;
	float time, speed, amount;
	int paused, spin, flat, lit, wire;
} viewer_t;

static void say(viewer_t *viewer, const char *text)
{
	printf("%s\n", text);
	kon_debugLog(viewer->program->debug, "%s", text);
}

static void sayClip(viewer_t *viewer)
{
	char text[128];
	const kon_model_t *model = viewer->model;

	if (model->clipCount == 0) {
		say(viewer, "this model has no clips");
		return;
	}
	if (viewer->blendClip >= 0 && viewer->amount > 0.0f) {
		snprintf(text, sizeof text, "playing %s blended with %s (%.2f)", model->clips[viewer->clip].name, model->clips[viewer->blendClip].name, viewer->amount);
	} else {
		snprintf(text, sizeof text, "playing %s", model->clips[viewer->clip].name);
	}
	say(viewer, text);
}

static int findClip(const kon_model_t *model, const char *word)
{
	int i;

	if (word[0] >= '0' && word[0] <= '9') {
		i = atoi(word);
		return i < model->clipCount ? i : -1;
	}
	return kon_modelFindClip(model, word);
}

static void cmdClips(kon_debug_t *debug, void *user, int argc, char **argv)
{
	viewer_t *viewer = user;
	int i;

	(void)argc; (void)argv;
	for (i = 0; i < viewer->model->clipCount; i++) {
		kon_debugLog(debug, "%d  %s  %.2fs", i, viewer->model->clips[i].name, viewer->model->clips[i].duration);
	}
	if (viewer->model->clipCount == 0) kon_debugLog(debug, "no clips");
}

static void cmdClip(kon_debug_t *debug, void *user, int argc, char **argv)
{
	viewer_t *viewer = user;
	int clip;

	if (argc < 2) {
		kon_debugLog(debug, "clip <name or number>, see clips");
		return;
	}
	clip = findClip(viewer->model, argv[1]);
	if (clip < 0) {
		kon_debugLog(debug, "no clip called %s", argv[1]);
		return;
	}
	viewer->clip = clip;
	viewer->time = 0.0f;
	sayClip(viewer);
}

static void cmdBlend(kon_debug_t *debug, void *user, int argc, char **argv)
{
	viewer_t *viewer = user;
	int clip;

	if (argc < 2) {
		kon_debugLog(debug, "blend <name or number> [amount 0 to 1], or blend off");
		return;
	}
	if (strcmp(argv[1], "off") == 0) {
		viewer->blendClip = -1;
		sayClip(viewer);
		return;
	}
	clip = findClip(viewer->model, argv[1]);
	if (clip < 0) {
		kon_debugLog(debug, "no clip called %s", argv[1]);
		return;
	}
	viewer->blendClip = clip;
	viewer->amount = argc > 2 ? (float)atof(argv[2]) : 0.5f;
	if (viewer->amount < 0.0f) viewer->amount = 0.0f;
	if (viewer->amount > 1.0f) viewer->amount = 1.0f;
	sayClip(viewer);
}

/* the bounds of the first frame of the first clip, so the camera fits even if the model is far from the origin */
static void measure(viewer_t *viewer)
{
	const kon_model_t *model = viewer->model;
	kon_mat4_t skin[KON_MODEL_MAX_BONES];
	kon_vec3_t lo = KON_VEC3(1e30f, 1e30f, 1e30f), hi = KON_VEC3(-1e30f, -1e30f, -1e30f);
	int m, i, k;

	kon_modelSample(model, model->clipCount ? 0 : -1, 0.0f, 0, skin);
	for (m = 0; m < model->meshCount; m++) {
		const kon_modelMesh_t *mesh = &model->meshes[m];

		for (i = 0; i < mesh->vertexCount; i++) {
			kon_vec3_t p = mesh->vertices[i].position;

			if (mesh->weights) {
				kon_vec3_t sum = KON_VEC3_ZERO;
				for (k = 0; k < 4; k++) {
					float w = mesh->weights[i * 4 + k];
					if (w > 0.0f) sum = kon_vec3Add(sum, kon_vec3Scale(kon_mat4MulPoint(skin[mesh->joints[i * 4 + k]], p), w));
				}
				p = sum;
			}
			if (p.x < lo.x) lo.x = p.x;
			if (p.y < lo.y) lo.y = p.y;
			if (p.z < lo.z) lo.z = p.z;
			if (p.x > hi.x) hi.x = p.x;
			if (p.y > hi.y) hi.y = p.y;
			if (p.z > hi.z) hi.z = p.z;
		}
	}
	if (lo.x > hi.x) {
		lo = KON_VEC3(-1, -1, -1);
		hi = KON_VEC3(1, 1, 1);
	}
	viewer->center = kon_vec3Scale(kon_vec3Add(lo, hi), 0.5f);
	viewer->size = kon_vec3Length(kon_vec3Sub(hi, lo));
	viewer->floorY = lo.y;
}

static void drawFloor(viewer_t *viewer, kon_framebuffer_t *game, kon_mat4_t viewProjection)
{
	float step = viewer->size / 10.0f;
	int i;

	for (i = -5; i <= 5; i++) {
		kon_vec3_t a = KON_VEC3(viewer->center.x + i * step, viewer->floorY, viewer->center.z - 5 * step);
		kon_vec3_t b = KON_VEC3(viewer->center.x + i * step, viewer->floorY, viewer->center.z + 5 * step);
		kon_vec3_t c = KON_VEC3(viewer->center.x - 5 * step, viewer->floorY, viewer->center.z + i * step);
		kon_vec3_t d = KON_VEC3(viewer->center.x + 5 * step, viewer->floorY, viewer->center.z + i * step);

		kon_drawLine3D(game, viewProjection, a, b, 0xFF4A5566);
		kon_drawLine3D(game, viewProjection, c, d, 0xFF4A5566);
	}
}

static void animate(viewer_t *viewer, kon_pose_t *pose)
{
	const kon_model_t *model = viewer->model;

	kon_poseRest(model, pose);
	if (model->clipCount == 0) return;
	kon_poseClip(model, NULL, viewer->clip, viewer->time, 1, pose);

	if (viewer->blendClip >= 0 && viewer->amount > 0.0f) {
		kon_pose_t other;
		float durationA = model->clips[viewer->clip].duration, durationB = model->clips[viewer->blendClip].duration;
		/* both clips are at the same point of their cycle, so walking into running keeps the feet in step */
		float phase = durationA > 0.0f ? fmodf(viewer->time, durationA) / durationA : 0.0f;

		kon_poseRest(model, &other);
		kon_poseClip(model, NULL, viewer->blendClip, phase * durationB, 1, &other);
		kon_poseBlend(model, pose, &other, viewer->amount, NULL, pose);
	}
}

static int event(kon_program_t *program, const kon_event_t *ev, void *user)
{
	viewer_t *viewer = user;

	(void)program;
	if (ev->type == KON_EVENT_MOUSE_DOWN && ev->mouseButton == KON_MOUSE_LEFT) {
		viewer->dragging = 1;
		viewer->dragX = ev->mouseX;
		viewer->dragY = ev->mouseY;
	} else if (ev->type == KON_EVENT_MOUSE_UP && ev->mouseButton == KON_MOUSE_LEFT) {
		viewer->dragging = 0;
	} else if (ev->type == KON_EVENT_MOUSE_MOVE && viewer->dragging) {
		viewer->yaw -= (float)(ev->mouseX - viewer->dragX) * 0.01f;
		viewer->pitch += (float)(ev->mouseY - viewer->dragY) * 0.01f;
		if (viewer->pitch > 1.5f) viewer->pitch = 1.5f;
		if (viewer->pitch < -1.5f) viewer->pitch = -1.5f;
		viewer->dragX = ev->mouseX;
		viewer->dragY = ev->mouseY;
	} else if (ev->type == KON_EVENT_MOUSE_WHEEL) {
		viewer->distance *= powf(0.9f, (float)ev->wheel);
	} else if (ev->type == KON_EVENT_KEY_DOWN) {
		if (ev->key == KON_KEY_SPACE && viewer->model->clipCount) {
			viewer->clip = (viewer->clip + 1) % viewer->model->clipCount;
			viewer->time = 0.0f;
			sayClip(viewer);
		}
		if (ev->key == KON_KEY_F) viewer->flat = !viewer->flat;
		if (ev->key == KON_KEY_L) viewer->lit = !viewer->lit;
		if (ev->key == KON_KEY_W) viewer->wire = !viewer->wire;
		if (ev->key == KON_KEY_P) viewer->paused = !viewer->paused;
		if (ev->key == KON_KEY_O) viewer->ortho = !viewer->ortho;
		if (ev->key == KON_KEY_UP) viewer->distance *= 0.9f;
		if (ev->key == KON_KEY_DOWN) viewer->distance /= 0.9f;
		if (ev->key == KON_KEY_LEFT) viewer->speed *= 0.8f;
		if (ev->key == KON_KEY_RIGHT) viewer->speed *= 1.25f;
	} else {
		return 0;
	}
	return 1;
}

static void update(kon_program_t *program, double dt, void *user)
{
	viewer_t *viewer = user;

	(void)program;
	if (!viewer->paused) viewer->time += (float)dt * viewer->speed;
	if (viewer->spin) viewer->yaw += (float)dt * 0.5f;
}

static void draw(kon_program_t *program, kon_framebuffer_t *game, void *user)
{
	viewer_t *viewer = user;
	kon_pose_t pose;
	kon_mat4_t skin[KON_MODEL_MAX_BONES], viewProjection;
	kon_camera_t camera = kon_cameraDefault();
	kon_renderFlags_t flags = KON_RENDER_DEFAULT;

	(void)program;
	camera.target = viewer->center;
	camera.position = kon_vec3Add(viewer->center, kon_vec3Scale(KON_VEC3(cosf(viewer->pitch) * sinf(viewer->yaw), sinf(viewer->pitch), cosf(viewer->pitch) * cosf(viewer->yaw)), viewer->distance));
	camera.nearZ = viewer->size * 0.02f;
	camera.farZ = viewer->size * 20.0f;
	camera.orthoSize = viewer->distance * 0.4f;
	if (viewer->ortho) camera.projection = KON_PROJECTION_ORTHOGRAPHIC;
	viewProjection = kon_cameraViewProjection(&camera, game->width, game->height);

	animate(viewer, &pose);
	kon_poseSkin(viewer->model, &pose, skin);

	if (viewer->flat) flags |= KON_RENDER_FLAT;
	if (viewer->wire) flags |= KON_RENDER_WIREFRAME;

	drawFloor(viewer, game, viewProjection);
	kon_modelDraw(game, viewProjection, kon_mat4Identity(), viewer->model, skin, viewer->lit ? &viewer->light : NULL, flags);
}

static int init(kon_program_t *program, void *user)
{
	viewer_t *viewer = user;
	int type = kon_modelRegister(program->assets);

	viewer->program = program;
	viewer->model = type >= 0 ? kon_assetGetAs(program->assets, viewer->name, type) : NULL;
	if (!viewer->model) {
		fprintf(stderr, "modelview: could not load %s: %s\n", viewer->name, kon_assetsError(program->assets));
		fprintf(stderr, "run it from the project folder with assets/%s there (./build.sh -d for the loose files), or give it a pack\n", viewer->name);
		return 0;
	}

	kon_debugCommand(program->debug, "clips", "list the clips of the model", cmdClips, viewer);
	kon_debugCommand(program->debug, "clip", "clip <name or number>", cmdClip, viewer);
	kon_debugCommand(program->debug, "blend", "blend <clip> [amount], blend off", cmdBlend, viewer);
	kon_debugVar(program->debug, "flat", KON_VAR_BOOL, &viewer->flat);
	kon_debugVar(program->debug, "light", KON_VAR_BOOL, &viewer->lit);
	kon_debugVar(program->debug, "wire", KON_VAR_BOOL, &viewer->wire);
	kon_debugVar(program->debug, "spin", KON_VAR_BOOL, &viewer->spin);
	kon_debugVar(program->debug, "speed", KON_VAR_FLOAT, &viewer->speed);
	kon_debugVar(program->debug, "amount", KON_VAR_FLOAT, &viewer->amount);

	viewer->light = kon_lightDefault();
	viewer->lit = 1;
	viewer->speed = 1.0f;
	viewer->blendClip = -1;
	viewer->yaw = 0.8f;
	viewer->pitch = 0.25f;
	measure(viewer);
	viewer->distance = viewer->size * 0.9f;
	sayClip(viewer);
	return 1;
}

int main(int argc, char **argv)
{
	viewer_t viewer = {0};
	kon_programConfig_t config = {0};

	viewer.name = argc > 1 ? argv[1] : "models/fox.kmdl";
	config.title = "modelview";
	config.gameWidth = 640;
	config.gameHeight = 360;
	config.windowWidth = 960;
	config.windowHeight = 540;
	config.packPath = argc > 2 ? argv[2] : "obj/data.kpk";
	config.user = &viewer;
	config.init = init;
	config.event = event;
	config.update = update;
	config.draw = draw;
	return kon_programRun(&config);
}