/*
 * Copyright (C) 2021  P. J. McDermott
 *
 * This file is part of Maze Fight
 *
 * Maze Fight 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 3 of the License, or
 * (at your option) any later version.
 *
 * Maze Fight 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 Maze Fight.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <SDL.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "../char.h"
#include "char.h"

struct mf_char *
mf_char_new(size_t size)
{
	struct mf_char *c;

	c = calloc(1, size);
	if (c == NULL) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't create character: %s",
				strerror(errno));
		return NULL;
	}

	return c;
}

void
mf_char_get_vector(struct mf_char *c, int *x, int *y, int *travel,
		int *dx, int *dy)
{
	*x      = c->cur_x;
	*y      = c->cur_y;
	*travel = c->travel;
	switch (c->cur_dir) {
		case MF_CHAR_DIR_U_: *dx =  0; *dy = -1; break;
		case MF_CHAR_DIR_D_: *dx =  0; *dy =  1; break;
		case MF_CHAR_DIR_L_: *dx = -1; *dy =  0; break;
		case MF_CHAR_DIR_R_: *dx =  1; *dy =  0; break;
		default:             *dx =  0; *dy =  0; break;
	}
}

int
mf_char_update(struct mf_char *c)
{
	int dx;
	int dy;

	if (c->travel > 0) {
		/* Currently moving */
		c->travel += c->speed;
		if (c->travel >= c->cell_width) {
			/* Reached next cell */
			c->cur_x = c->new_x;
			c->cur_y = c->new_y;
			c->travel -= c->cell_width;
			if (c->step(c) < 0) {
				return -1;
			}
			if (c->cur_dir == c->new_dir) {
				/* Want to continue straight */
			} else {
				/* Want to stop or turn */
				c->travel = 0;
			}
		} else {
			/* Farther to go */
			goto end;
		}
	}
	if (c->new_dir != MF_CHAR_DIR_N_ && c->cur_dir != c->new_dir) {
		/* Want to turn */
		c->old_dir = c->cur_dir;
		c->cur_dir = c->new_dir;
		c->new_dir = MF_CHAR_DIR_N_;
		c->turning = c->turn_time + 1;
	}
	if (c->turning > 0) {
		/* Turning */
		--c->turning;
	}
	if (c->turning == 0) {
		/* Done turning */
		if (c->new_dir != MF_CHAR_DIR_N_) {
			/* Want to move */
			switch (c->new_dir) {
				case MF_CHAR_DIR_U_: dx =  0; dy = -1; break;
				case MF_CHAR_DIR_D_: dx =  0; dy =  1; break;
				case MF_CHAR_DIR_L_: dx = -1; dy =  0; break;
				case MF_CHAR_DIR_R_: dx =  1; dy =  0; break;
				default:             dx =  0; dy =  0; break;
			}
			c->new_dir = MF_CHAR_DIR_N_;
			if (mf_maze_is_wall(c->maze, c->cur_x, c->cur_y,
						dx, dy)) {
				goto end;
			}
			c->new_x = c->cur_x + dx;
			c->new_y = c->cur_y + dy;
			c->travel += c->speed;
		} else {
			if (c->turn(c) < 0) {
				return -1;
			}
		}
	}

 end:
	return c->update(c);
}

int
mf_char_collision(struct mf_char *c1, struct mf_char *c2, int handle)
{
	if (c1->cur_x == c2->cur_x && c1->cur_y == c2->cur_y) goto hit;
	if (c1->cur_x == c2->new_x && c1->cur_y == c2->new_y) goto hit;
	if (c1->new_x == c2->cur_x && c1->new_y == c2->cur_y) goto hit;
	if (c1->new_x == c2->new_x && c1->new_y == c2->new_y) goto hit;

	return 0;

 hit:
	if (handle == SDL_TRUE) {
		c1->collide(c1);
		c2->collide(c2);
	}
	return 1;
}

int
mf_char_render(struct mf_char *c, SDL_Renderer *renderer)
{
	int    e   = 0;
	int    cx;
	int    cy;
	double fx;
	double ofx;
	int    r;
	int    x;
	int    y;
	int    i;
	int    oy;
	int    fr;
	int    hy;
	int    ox;

	cx = c->cur_x * c->cell_width + c->cell_width / 2;
	cy = c->cur_y * c->cell_width + c->cell_width / 2;
	switch (c->cur_dir) {
		case MF_CHAR_DIR_U_:
			cy -= c->travel;
			if (c->old_dir == MF_CHAR_DIR_L_) {
				fx = -2.0;
			} else {
				fx =  2.0;
			}
			break;
		case MF_CHAR_DIR_D_: cy += c->travel; fx =  0.0; break;
		case MF_CHAR_DIR_L_: cx -= c->travel; fx = -1.0; break;
		case MF_CHAR_DIR_R_: cx += c->travel; fx =  1.0; break;
		default:                              fx =  0.0; break;
	}
	switch (c->old_dir) {
		case MF_CHAR_DIR_U_:
			if (c->cur_dir == MF_CHAR_DIR_L_) {
				ofx = -2.0;
			} else {
				ofx =  2.0;
			}
			break;
		case MF_CHAR_DIR_D_: ofx =  0.0; break;
		case MF_CHAR_DIR_L_: ofx = -1.0; break;
		case MF_CHAR_DIR_R_: ofx =  1.0; break;
		default:             ofx =  0.0; break;
	}
	r = c->cell_width / 2 - c->padding;
	fx = ofx + (fx - ofx) * (c->turn_time - c->turning) / c->turn_time;
	fx *= r;

	/*
	 * Head
	 */

	if (SDL_SetRenderDrawColor(renderer,
				c->head_color.r, c->head_color.g,
				c->head_color.b, c->head_color.a) < 0) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't render character: %s",
				SDL_GetError());
		e = -1;
	}

#define _mf_char_px(X, Y) \
	do { \
		if (SDL_RenderDrawPoint(renderer, cx + X, cy + Y) < 0) { \
			SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
					"Couldn't render widget: %s", \
					SDL_GetError()); \
			e = -1; \
		} \
	} while (0)

	/* TODO: This is one pixel larger than it should be. */
	for (x = 0, y = r; y > x; ++x) {
		y = round(sqrt((r-0.5)*(r-0.5) - (x-0.5)*(x-0.5)) + 0.5);
		for (i = 0; i <=   y; ++i) _mf_char_px(  x,   i);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(0-x,   i);
		for (i = 0; i >= 0-y; --i) _mf_char_px(0-x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(  i,   x);
		for (i = 0; i <=   y; ++i) _mf_char_px(  i, 0-x);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  i,   x);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  i, 0-x);
	}

#undef _mf_char_px

	/*
	 * Smile
	 */

	if (SDL_SetRenderDrawColor(renderer,
				c->smil_color.r, c->smil_color.g,
				c->smil_color.b, c->smil_color.a) < 0) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't render character: %s",
				SDL_GetError());
		e = -1;
	}

	oy = r * c->smile_y;
	fr = r * c->smile_r;

#define _mf_char_px(X, Y) \
	do { \
		hy = round(sqrt((r-0.5)*(r-0.5) - \
					(X+fx-0.5)*(X+fx-0.5)) + 0.5); \
		if (Y + oy < 0-hy || Y + oy > hy) continue; \
		if (SDL_RenderDrawPoint(renderer, cx + fx + X, cy + oy + Y) \
				< 0) { \
			SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
					"Couldn't render widget: %s", \
					SDL_GetError()); \
			e = -1; \
		} \
	} while (0)

	for (x = 0, y = fr; y > x; ++x) {
		y = round(sqrt((fr-0.5)*(fr-0.5) - (x-0.5)*(x-0.5)) + 0.5);
		for (i = 0; i <=   y; ++i) _mf_char_px(  x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(0-x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(  i,   x);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  i,   x);
	}

#undef _mf_char_px

	/*
	 * Eyes
	 */

	if (SDL_SetRenderDrawColor(renderer,
				c->eyes_color.r, c->eyes_color.g,
				c->eyes_color.b, c->eyes_color.a) < 0) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't render character: %s",
				SDL_GetError());
		e = -1;
	}

	ox = r * c->eye_x;
	oy = r * c->eye_y;
	fr = r * c->eye_r;

#define _mf_char_px(X, Y) \
	do { \
		hy = round(sqrt((r-0.5)*(r-0.5) - \
					(X+fx-ox-0.5)*(X+fx-ox-0.5)) + 0.5); \
		if (Y - oy >= 0-hy && Y - oy <= hy) { \
			if (SDL_RenderDrawPoint(renderer, \
						cx + fx - ox + X, cy - oy + Y) \
					< 0) { \
				SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
						"Couldn't render widget: %s", \
						SDL_GetError()); \
				e = -1; \
			} \
		} \
		hy = round(sqrt((r-0.5)*(r-0.5) - \
					(X+fx+ox-0.5)*(X+fx+ox-0.5)) + 0.5); \
		if (Y - oy >= 0-hy && Y - oy <= hy) { \
			if (SDL_RenderDrawPoint(renderer, \
						cx + fx + ox + X, cy - oy + Y) \
					< 0) { \
				SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
						"Couldn't render widget: %s", \
						SDL_GetError()); \
				e = -1; \
			} \
		} \
	} while (0)

	for (x = 0, y = fr; y > x; ++x) {
		y = round(sqrt((fr-0.5)*(fr-0.5) - (x-0.5)*(x-0.5)) + 0.5);
		for (i = 0; i <=   y; ++i) _mf_char_px(  x,   i);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(0-x,   i);
		for (i = 0; i >= 0-y; --i) _mf_char_px(0-x,   i);
		for (i = 0; i <=   y; ++i) _mf_char_px(  i,   x);
		for (i = 0; i <=   y; ++i) _mf_char_px(  i, 0-x);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  i,   x);
		for (i = 0; i >= 0-y; --i) _mf_char_px(  i, 0-x);
	}

#undef _mf_char_px

	if (e < 0) {
		return e;
	}
	return c->render(c, renderer);
}

void
mf_char_destroy(struct mf_char **c_p)
{
	struct mf_char *c;

	if (c_p == NULL || *c_p == NULL) {
		return;
	}
	c = *c_p;

	c->destroy(c);
	free(c);
	c = NULL;
}