// SPDX-FileCopyrightText: 2024 Lizzy Fleckenstein <lizzy@vlhl.dev>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdint.h>
#include <png.h>
#include <endian.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "content.h"
#include "peer.h"
#include "str.h"

typedef enum {
	MAP_VALLEY,
	MAP_ISLAND,
	MAP_MOUNTAIN,
	MAP_CAVE,
	MAP_NUM,
} map_type;

typedef struct {
	const char *filename;
	str name;
	map_type type;
	uint32_t width;
	uint32_t height;
	int32_t off_x;
	int32_t off_y;
	int8_t z; // caves: -1
	node *nodes;
} map;

typedef struct {
	str motd;
	array(map) maps;
} game;

typedef struct {
	str name;
	int32_t x, y;
	peer net;
} player;

node *map_local_node(map *m, int32_t x, int32_t y)
{
	if (x < 0 || y < 0 || (uint32_t) x >= m->width || (uint32_t) y >= m->height)
		return NULL;

	node *n = &m->nodes[x*m->width+y];
	if (!n->present)
		return NULL;

	return n;
}

node *map_node(game *g, int32_t x, int32_t y, int8_t z)
{
	for (size_t i = 0; i < g->maps.len; i++) {
		map *m = &g->maps.data[i];
		if (m->z != z)
			continue;
		node *n = map_local_node(m, x - m->off_x, y - m->off_y);
		if (n != NULL)
			return n;
	}
	return NULL;
}

/*
void map_load_node(map *m, uint32_t x, uint32_t y, uint32_t color)
{
	
}*/

bool map_load(map *m)
{
#define TRY(expr, ...) if (!(expr)) { \
	fprintf(stderr, __VA_ARGS__); \
	if (file != NULL) fclose(file); \
	png_destroy_read_struct(&png, &info, NULL); \
	return false; }

	FILE *file = NULL;
	png_structp png = NULL;
	png_infop info = NULL;

	TRY((file = fopen(m->filename, "r")) != NULL, "failed to open %s\n", m->filename);

	TRY(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL),
		"png_create_read_struct failed\n");

	TRY(info = png_create_info_struct(png), "png_create_info_struct failed\n");

	png_init_io(png, file);
	png_read_info(png, info);

	png_uint_32 width = png_get_image_width(png, info);
	png_uint_32 height = png_get_image_height(png, info);
	png_byte color_type = png_get_color_type(png, info);

	TRY(width == m->width, "%s: width mismatch\n", m->filename);
	TRY(height == m->height, "%s: height mismatch\n", m->filename);
	TRY(color_type == PNG_COLOR_TYPE_RGB, "%s: color type is not RGB\n", m->filename);

	uint32_t colors[100] = {0};

	png_uint_32 pitch = png_get_rowbytes(png, info);
	png_byte row[pitch];
	for (png_uint_32 y = 0; y < height; y++) {
		png_read_row(png, row, NULL);

		for (png_uint_32 x = 0; x < width; x++) {
			png_bytep p = &row[x*3];

			uint32_t color = ((uint32_t) p[2]) | (((uint32_t) p[1]) << 8) | (((uint32_t) p[0]) << 16);
			for (size_t i = 0; i < 100; i++) {
				if (colors[i] == color) {
					break;
				} else if (colors[i] == 0) {
					colors[i] = color;
					printf("#%06x\n", color);
					break;
				}
			}
		}
	}

	fclose(file);
	png_destroy_read_struct(&png, &info, NULL);
	return true;
#undef TRY	
}

int net_listen(const char *host, const char *port)
{
	struct addrinfo *info = NULL, hints = {0};
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;

	int err;
	if ((err = getaddrinfo(host, port, &hints, &info))) {
		fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err));
		return -1;
	}

#define TRY(op, val) if ((val) < 0) { perror(op); freeaddrinfo(info); return -1; }

	int fd;
	TRY("socket", fd = socket(info->ai_family, info->ai_socktype, info->ai_protocol))

	int flag = 1;
	TRY("setsockopt", setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void *) &flag, sizeof flag));

	TRY("bind", bind(fd, info->ai_addr, info->ai_addrlen))
	TRY("listen", listen(fd, 3))

#undef TRY

	freeaddrinfo(info);
	return fd;

}

int game_exit(game *g, int ret)
{
	free(g->motd.data);

	if (g->maps.data)
		for (size_t i = 0; i < g->maps.len; i++) {
			free(g->maps.data[i].name.data);
			free(g->maps.data[i].nodes);
		}
		
	free(g->maps.data);

	exit(ret);
}

int main()
{
	game g = {0};

	g.motd = str_clone(S("Welcome to test server"));

	g.maps.len = 1;
	g.maps.data = malloc(g.maps.len * sizeof *g.maps.data);
	g.maps.data[0] = (map) {
		.filename = "assets/map_valley.png",
		.name = str_clone(S("Valley")),
		.type = MAP_VALLEY,
		.off_x = -50,
		.off_y = -50,
		.z = 0,
		.width = 100,
		.height = 100,
		.nodes = NULL,
	};

	if (!map_load(&g.maps.data[0]))
		game_exit(&g, EXIT_FAILURE);

	int accept_fd = net_listen("0.0.0.0", "4560");
	if (accept_fd < 0)
		game_exit(&g, EXIT_FAILURE);

	for (;;) {
		int clt_sock = accept(accept_fd, NULL, NULL);
		if (clt_sock < 0) {
			perror("accept");
			continue;
		}

		if (fcntl(clt_sock, F_SETFL, fcntl(clt_sock, F_GETFL, 0) | O_NONBLOCK) < 0) {
			perror("fcntl");
			continue;
		}		
	}
	
}