// curl:
// man curl_easy_init CURLOPT_URL curl_easy_setopt CURLOPT_WRITEFUNCTION libcurl-errors curl_easy_strerror
// https://curl.se/libcurl/
// https://curl.se/libcurl/c/
// https://curl.se/libcurl/c/libcurl-tutorial.html
// https://stackoverflow.com/a/2329792

// json-c:
// pacman -Qs json c
// https://github.com/json-c/json-c#using
// https://github.com/json-c/json-c/blob/master/tests/test2.c
// https://github.com/rbtylee/tutorial-jsonc/blob/master/tutorial/legacy.md
// https://github.com/rbtylee/tutorial-jsonc/blob/master/tutorial/parsing2.md

// libnotify:
// https://gitlab.gnome.org/GNOME/libnotify/-/blob/master/tests/test-basic.c?ref_type=heads
// https://gnome.pages.gitlab.gnome.org/libnotify/index.html

// compile, maybe wrong:
// https://stackoverflow.com/a/39120702
// cc -Wall -lcurl -ljson-c $(pkg-config --cflags --libs libnotify) ./dynotify.c
// or:
// cc -Wall $(pkg-config --cflags --libs libnotify libcurl json-c) ./dynotify.c
// misc:
// /usr/lib/pkgconfig/libnotify.pc

#include<stdio.h> // for sprintf
#include<stdbool.h> // for bool
#include<stdlib.h> // for realloc
#include<string.h> // for memcpy
#include<unistd.h> // for sleep
#include<curl/curl.h> // MIT
#include<json-c/json.h> // MIT
#include<libnotify/notify.h> //LGPL

#define DYROOM_ID_LEN 9
// utf-8 most chinese characters 3 bytes, my longest name currently is 2 chinese characters, 2*3=6, +1 for \0
// but gcc will not error when not consider \0, maybe the complier auto add one more element?
#define DYROOM_NAME_LEN 6

struct memory {
	char *response;
	size_t size;
};

struct dyroom {
	// another way: `const char *name;`
	const char name[DYROOM_NAME_LEN];
	const unsigned int id;
	bool up;
};

// /home/xyz/archive/programs/private_archive_codes/c/c_primer_plus/practices/Chapter14/14-1monthStruct.c 
struct dyroom room[5]={
	{"阿冉",4605243,false},
	{"甜汤",2766480,false},
	{"少君",9640128,false},
	{"她她",236288,false},
	{"郑正",10883525,false}
};

// copy from `man CURLOPT_WRITEFUNCTION`
static size_t cb(char *data, size_t size, size_t nmemb, void *clientp)
{
	size_t realsize = size * nmemb;
	struct memory *mem = (struct memory *)clientp;

	char *ptr = realloc(mem->response, mem->size + realsize + 1);
	if(!ptr)
		return 0;  /* out of memory! */

	mem->response = ptr;
	memcpy(&(mem->response[mem->size]), data, realsize);
	mem->size += realsize;
	mem->response[mem->size] = 0;

	return realsize;
}

int main (void)
{
	// man libcurl-errors
	CURLcode res;
	// `man curl_easy_init`: "It is encouraged to reuse easy handles for repeated transfers.", so I choose to reuse it
	CURL *curl = curl_easy_init();
	NotifyNotification *n;
	notify_init ("dynotify");

	if(curl) {
		for(;;)
		{
			for(int i=0;i<5;i++)
			{
				// manpage assign 0 to struct, it seems because C11 when cast 0 to void* is same as NULL? see:
				// https://www.geeksforgeeks.org/null-pointer-in-c/
				struct memory chunk = {0};
				char url[29+DYROOM_ID_LEN];
				sprintf(url, "https://www.douyu.com/betard/%d", room[i].id);

				curl_easy_setopt(curl, CURLOPT_URL, url);
				curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, cb);
				curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
				res = curl_easy_perform(curl);
				// man curl_easy_strerror
				if(res != CURLE_OK)
				{
					fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
					free(chunk.response);
					break;
				}
				//printf("%s\n",chunk.response);

				json_object *root;
				root=json_tokener_parse(chunk.response);
				if (json_object_get_int(json_object_object_get(json_object_object_get(root,"room"),"show_status")) == 1)
				{
					if(!room[i].up)
					{
						// 开播 is 2*3=6 bytes
						char msg[DYROOM_NAME_LEN+6];
						sprintf(msg,"%s开播",room[i].name);

						n = notify_notification_new (msg, NULL, NULL);
						notify_notification_set_urgency(n, NOTIFY_URGENCY_CRITICAL);
						notify_notification_show (n, NULL);

						room[i].up=true;
					}
				}
				else if(room[i].up)
					room[i].up=false;

				free(chunk.response);
				// must call json_object_put to free *root, else memory leak!
				json_object_put(root);
			}
			sleep(60);
		}
		curl_easy_cleanup(curl);
	}

	g_object_unref (G_OBJECT (n));
	return 0;
}