#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <assert.h>
#include "net.h"


extern FILE *debugf;


struct store_item{
	char *id;
	net_callback_t *cb;
	void *payload;
};

static i64 store_cap=16,store_len=0;
static struct store_item *store=NULL;

static net_callback_t *push_callback=NULL;
static net_callback_t *history_callback=NULL;


#define ALPHABET "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

static void uniqid8(char *dst){
	static i64 static_id=0;
	static const int alphabet_len=strlen(ALPHABET);

	int id=static_id;
	static_id++;
	for(int i=7;i>=0;i--){
		dst[i]=ALPHABET[id%alphabet_len];
		id/=alphabet_len;
	}
}

void net_set_push_callback(net_callback_t *callback){
	push_callback=callback;
}

void net_set_history_callback(net_callback_t *callback){
	history_callback=callback;
}

__attribute__((format (printf, 4, 5)))
bool net_sendf(int fd,net_callback_t *callback,void *payload,const char *format,...){
	if(store==NULL){
		store=malloc(store_cap*sizeof(struct store_item));
	} else if(store_len==store_cap){
		store_cap*=2;
		store=realloc(store,store_cap*sizeof(struct store_item));
	}
	assert(store);

	fprintf(debugf,"net_sendf(%d,%p,\"%s\",...)\n",fd,callback,format);

	va_list ap,ap2;
	va_start(ap,format);
	va_copy(ap2,ap);
	i64 len=vsnprintf(NULL,0,format,ap2);
	va_end(ap2);
	assert(len>=0);

	char *buf=malloc(9+len+2);
	assert(buf);
	uniqid8(buf);
	buf[8]=' ';
	i64 len2=vsprintf(buf+9,format,ap);
	va_end(ap);
	assert(len2==len);
	buf[9+len]='\n';
	buf[9+len+1]='\0';

	store[store_len].id=malloc(9);
	assert(store[store_len].id);
	memcpy(store[store_len].id,buf,8);
	store[store_len].id[8]='\0';
	store[store_len].cb=callback;
	store[store_len].payload=payload;
	store_len++;
	
	i64 cursor=0,total=9+len+1;
	while(cursor<total){
		i64 nwr=send(fd,buf+cursor,total-cursor,0);
		if(nwr<=0)return false;
		cursor+=nwr;
	}
	free(buf);
	return true;
}

void net_handle_recv(int fd,const char *msg){
	i64 msglen=strlen(msg);
	const char *p=strchr(msg,' ');
	if(p==NULL){
		fprintf(debugf,"net_handle_recv: no space in message <%s>\n",msg);
		return;
	}
	i64 taglen=p-msg;

	net_callback_t *cb=NULL;
	void *payload=NULL;
	if(taglen==5&&memcmp(msg,"_push",5)==0){
		cb=push_callback;
	} else if(*p!='\0'&&memcmp(p+1,"history_message",15)==0){
		cb=history_callback;
	} else {
		if(taglen!=8){
			fprintf(debugf,"net_handle_recv: tag not length 8 <%s>\n",msg);
			return;
		}
		for(i64 i=0;i<store_len;i++){
			if(memcmp(store[i].id,msg,taglen)==0){
				cb=store[i].cb;
				payload=store[i].payload;
				memmove(store+i,store+(i+1),(store_len-i-1)*sizeof(struct store_item));
				store_len--;
				break;
			}
		}
		if(cb==NULL){
			fprintf(debugf,"net_handle_recv: no viable callback found <%s>\n",msg);
			return;
		}
	}

	const char *cmd=p+1;
	p=strchr(cmd,' ');
	if(p==NULL)p=msg+msglen;
	i64 cmdlen=p-cmd;

	// Now `p` points to the space (or '\0') after the command name

	if(cmdlen==2&&memcmp(cmd,"ok",2)==0){
		cb(fd,(struct net_response){.type=NET_OK},payload);
	} else if(cmdlen==6&&memcmp(cmd,"number",6)==0){
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no number argument <%s>\n",msg);
			return;
		}
		const char *nump=p+1;
		struct net_response res=(struct net_response){
			.type=NET_NUMBER
		};
		const char *endp;
		res.number=strtol(nump,(char**)&endp,10);
		if(nump[0]=='\0'||*endp!='\0'){
			fprintf(debugf,"net_handle_recv: invalid number argument <%s>\n",msg);
			return;
		}
		cb(fd,res,payload);
	} else if(cmdlen==5&&memcmp(cmd,"error",5)==0){
		struct net_response res=(struct net_response){
			.type=NET_ERROR,
			.error=strdup(*p=='\0'?p:p+1)
		};
		cb(fd,res,payload);
		free(res.error);
	} else if(cmdlen==4&&memcmp(cmd,"name",4)==0){
		struct net_response res=(struct net_response){
			.type=NET_NAME,
			.name=strdup(*p=='\0'?p:p+1)
		};
		cb(fd,res,payload);
		free(res.name);
	} else if(cmdlen==4&&memcmp(cmd,"ping",4)==0){
		// Do nothing
	} else if(cmdlen==4&&memcmp(cmd,"pong",4)==0){
		struct net_response res=(struct net_response){
			.type=NET_PONG
		};
		cb(fd,res,payload);
	} else if(cmdlen==4&&memcmp(cmd,"list",4)==0){
		struct net_response res=(struct net_response){.type=NET_LIST};
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no list count <%s>\n",msg);
			return;
		}
		const char *cursor=p+1;
		p=strchr(cursor,' ');
		res.nitems=strtol(cursor,NULL,10);
		if(res.nitems<=0){
			fprintf(debugf,"net_handle_recv: -- 0 items <%s>\n",msg);
			res.nitems=0;
			res.items=NULL;
			cb(fd,res,payload);
			return;
		}
		res.items=malloc(res.nitems*sizeof(char*));
		assert(res.items);
		cursor=p;
		for(i64 i=0;i<res.nitems;i++){
			if(cursor==NULL||*cursor=='\0'){
				free(res.items);
				fprintf(debugf,"net_handle_recv: short list <%s>\n",msg);
				return;
			}
			cursor++;
			p=strchr(cursor,' ');
			if(p==NULL)p=msg+msglen;
			res.items[i]=malloc(p-cursor+1);
			assert(res.items[i]);
			memcpy(res.items[i],cursor,p-cursor);
			res.items[i][p-cursor]='\0';
			fprintf(debugf,"net_handle_recv: -- item \"%s\" <%s>\n",res.items[i],msg);
			cursor=p;
		}
		cb(fd,res,payload);
		for(i64 i=0;i<res.nitems;i++){
			free(res.items[i]);
		}
		free(res.items);
	} else if(cmdlen==7&&memcmp(cmd,"message",7)==0){
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no arguments to 'message' <%s>\n",msg);
			return;
		}
		const char *roomp=p+1;
		p=strchr(roomp,' ');
		const char *q,*r;
		if(p==NULL||(q=strchr(p+1,' '))==NULL||(r=strchr(q+1,' '))==NULL){
			fprintf(debugf,"net_handle_recv: not enough arguments to 'message' <%s>\n",msg);
			return;
		}
		i64 roomlen=p-roomp;
		const char *usernamep=p+1;
		i64 usernamelen=q-usernamep;
		const char *stampp=q+1;
		i64 stamplen=r-stampp;
		const char *textp=r+1;
		i64 textlen=msglen-(textp-msg);

		struct net_response res;
		res.type=NET_MESSAGE;
		const char *endp;
		res.timestamp=strtoll(stampp,(char**)&endp,10);
		if(endp-stampp!=stamplen){
			fprintf(debugf,"net_handle_recv: timestamp not a number in 'message' <%s>\n",msg);
			return;
		}
		res.room=malloc(roomlen+1);
		res.username=malloc(usernamelen+1);
		res.message=malloc(textlen+1);
		assert(res.room&&res.username&&res.message);
		memcpy(res.room,roomp,roomlen);
		res.room[roomlen]='\0';
		memcpy(res.username,usernamep,usernamelen);
		res.username[usernamelen]='\0';
		memcpy(res.message,textp,textlen);
		res.message[textlen]='\0';
		cb(fd,res,payload);
		free(res.room);
		free(res.username);
		free(res.message);
	} else if(cmdlen==7&&memcmp(cmd,"history",7)==0){
		struct net_response res;
		res.type=NET_OK;
		cb(fd,res,payload);
	} else if(cmdlen==15&&memcmp(cmd,"history_message",15)==0){
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no arguments to 'history_message' <%s>\n",msg);
			return;
		}
		p=strchr(p+1,' ');
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no arguments past index to 'history_message' <%s>\n",msg);
			return;
		}
		const char *roomp=p+1;
		p=strchr(roomp,' ');
		const char *q,*r;
		if(p==NULL||(q=strchr(p+1,' '))==NULL||(r=strchr(q+1,' '))==NULL){
			fprintf(debugf,"net_handle_recv: not enough arguments to 'history_message' <%s>\n",msg);
			return;
		}
		i64 roomlen=p-roomp;
		const char *usernamep=p+1;
		i64 usernamelen=q-usernamep;
		const char *stampp=q+1;
		i64 stamplen=r-stampp;
		const char *textp=r+1;
		i64 textlen=msglen-(textp-msg);

		struct net_response res;
		res.type=NET_HISTORY;
		const char *endp;
		res.timestamp=strtoll(stampp,(char**)&endp,10);
		if(endp-stampp!=stamplen){
			fprintf(debugf,"net_handle_recv: timestamp not a number in 'history_message' <%s>\n",msg);
			return;
		}
		res.room=malloc(roomlen+1);
		res.username=malloc(usernamelen+1);
		res.message=malloc(textlen+1);
		assert(res.room&&res.username&&res.message);
		memcpy(res.room,roomp,roomlen);
		res.room[roomlen]='\0';
		memcpy(res.username,usernamep,usernamelen);
		res.username[usernamelen]='\0';
		memcpy(res.message,textp,textlen);
		res.message[textlen]='\0';
		cb(fd,res,payload);
		free(res.room);
		free(res.username);
		free(res.message);
	} else if(cmdlen==4&&memcmp(cmd,"join",4)==0){
		const char *q;
		if(*p=='\0'||(q=strchr(p+1,' '))==NULL){
			fprintf(debugf,"net_handle_recv: not enough arguments to 'join' <%s>\n",msg);
			return;
		}
		const char *roomp=p+1;
		i64 roomlen=q-roomp;
		const char *userp=q+1;
		i64 userlen=msglen-(userp-msg);

		struct net_response res;
		res.type=NET_JOIN;
		res.room=malloc(roomlen+1);
		res.username=malloc(userlen+1);
		assert(res.room&&res.username);
		memcpy(res.room,roomp,roomlen);
		res.room[roomlen]='\0';
		memcpy(res.username,userp,userlen);
		res.username[userlen]='\0';
		cb(fd,res,payload);
		free(res.room);
		free(res.username);
	} else if(cmdlen==6&&memcmp(cmd,"invite",6)==0){
		if(*p=='\0'){
			fprintf(debugf,"net_handle_recv: no arguments to 'invite' <%s>\n",msg);
			return;
		}
		const char *roomp=p+1;
		i64 roomlen=msglen-(roomp-msg);

		struct net_response res;
		res.type=NET_INVITE;
		res.room=malloc(roomlen+1);
		assert(res.room);
		memcpy(res.room,roomp,roomlen);
		res.room[roomlen]='\0';
		cb(fd,res,payload);
		free(res.room);
	} else if(cmdlen==6&&memcmp(cmd,"online",6)==0){
		const char *q;
		if(*p=='\0'||(q=strchr(p+1,' '))==NULL){
			fprintf(debugf,"net_handle_recv: not enough arguments to 'online' <%s>\n",msg);
			return;
		}
		const char *nump=p+1;
		const char *usernamep=q+1;
		const char *endp;
		struct net_response res=(struct net_response){
			.type=NET_ONLINE,
			.online.username=strdup(usernamep),
			.online.num=strtol(nump,(char**)&endp,10)
		};
		if(nump[0]==' '||*endp!=' '){
			fprintf(debugf,"net_handle_recv: invalid number argument to 'online' <%s>\n",msg);
			return;
		}
		cb(fd,res,payload);
		free(res.online.username);
	} else {
		fprintf(debugf,"net_handle_recv: unknown command <%s>\n",msg);
	}
}