From add6b39aece179a0e0ad425af72b8a043a0d3188 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Fri, 17 Mar 2017 19:57:12 +0100
Subject: History querying

---
 command.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 db.c      | 43 +++++++++++++++++++++++++++++++++++++++++++
 db.h      |  2 +-
 3 files changed, 93 insertions(+), 1 deletion(-)

diff --git a/command.c b/command.c
index 50b9534..a691171 100644
--- a/command.c
+++ b/command.c
@@ -253,6 +253,54 @@ static bool cmd_send(struct conn_data *data,const char *tag,const char **args){
 	return closed;
 }
 
+static bool cmd_history(struct conn_data *data,const char *tag,const char **args){
+	char *endp;
+	i64 nrequested=strtoll(args[1],&endp,10);
+	if(args[1][0]=='\0'||*endp!='\0'||nrequested<0){
+		debug("Connection fd=%d sent an invalid number for 'history': '%s'",data->fd,args[1]);
+		return true;
+	}
+
+	if(data->userid==-1){
+		send_error(data->fd,tag,"Not logged in");
+		return false;
+	}
+	i64 roomid=db_find_room(args[0]);
+	if(roomid==-1){
+		send_error(data->fd,tag,"Room not found");
+		return false;
+	}
+	if(!db_is_member(roomid,data->userid)){
+		send_error(data->fd,tag,"Not in that room");
+		return false;
+	}
+
+	struct db_message_list ml=db_get_messages(roomid,nrequested);
+	char *buf=NULL;
+	i64 len=asprintf(&buf,"%s history %" PRIi64 "\n",tag,ml.count);
+	assert(buf);
+	bool closed=send_raw_text(data->fd,buf,len);
+	free(buf);
+
+	if(closed){
+		db_nullify_message_list(ml);
+		return true;
+	}
+
+	for(i64 i=ml.count-1;i>=0;i--){
+		char *username=db_get_username(ml.list[i].userid);
+		len=asprintf(&buf,"%s history_item %" PRIi64 " %s %" PRIi64 " %s\n",
+				tag,ml.count-1-i,username,ml.list[i].timestamp,ml.list[i].message);
+		assert(buf);
+		closed=send_raw_text(data->fd,buf,len);
+		free(buf);
+		if(closed)break;
+	}
+
+	db_nullify_message_list(ml);
+	return closed;
+}
+
 
 struct cmd_info{
 	const char *cmdname;
@@ -269,6 +317,7 @@ static const struct cmd_info commands[]={
 	{"create_room",0,false,cmd_create_room},
 	{"invite",2,false,cmd_invite},
 	{"send",2,true,cmd_send},
+	{"history",2,false,cmd_history},
 };
 #define NCOMMANDS (sizeof(commands)/sizeof(commands[0]))
 
diff --git a/db.c b/db.c
index f89e628..983080f 100644
--- a/db.c
+++ b/db.c
@@ -244,6 +244,41 @@ void db_create_message(i64 roomid,i64 userid,i64 timestamp,const char *message){
 	SQLITE(finalize,stmt);
 }
 
+struct db_message_list db_get_messages(i64 roomid,i64 count){
+	sqlite3_stmt *stmt;
+	SQLITE(prepare_v2,database,
+			"select user, time, message "
+			"from Messages "
+			"where room = ? "
+			"order by time desc "
+			"limit ?"
+		,-1,&stmt,NULL);
+	SQLITE(bind_int64,stmt,1,roomid);
+	SQLITE(bind_int64,stmt,2,count);
+
+	struct db_message_list ml;
+	i64 cap=count;
+	ml.count=0;
+	ml.list=malloc(cap,struct db_message);
+
+	int ret;
+	while((ret=sqlite3_step(stmt))==SQLITE_ROW){
+		if(ml.count==cap){
+			die("sqlite gave too many rows while 'limit %" PRIi64 "' was present",count);
+		}
+		ml.list[ml.count].roomid=roomid;
+		ml.list[ml.count].userid=sqlite3_column_int64(stmt,0);
+		ml.list[ml.count].timestamp=sqlite3_column_int64(stmt,1);
+		ml.list[ml.count].message=strdup((const char*)sqlite3_column_text(stmt,2));
+		ml.count++;
+	}
+
+	if(ret!=SQLITE_DONE)die_sqlite("sqlite3_step");
+	SQLITE(finalize,stmt);
+
+	return ml;
+}
+
 
 void db_nullify_name_id(struct db_name_id ni){
 	if(ni.name)free(ni.name);
@@ -264,3 +299,11 @@ void db_nullify_user_list(struct db_user_list ul){
 	if(ul.list)free(ul.list);
 	ul.list=NULL;
 }
+
+void db_nullify_message_list(struct db_message_list ml){
+	for(i64 i=0;i<ml.count;i++){
+		free(ml.list[i].message);
+	}
+	if(ml.list)free(ml.list);
+	ml.list=NULL;
+}
diff --git a/db.h b/db.h
index f4fea4f..2377ec2 100644
--- a/db.h
+++ b/db.h
@@ -50,7 +50,7 @@ bool db_delete_user(i64 userid);
 i64 db_find_user(const char *name);  // -1 if not found
 
 void db_create_message(i64 roomid,i64 userid,i64 timestamp,const char *message);
-struct db_message_list db_get_messages(i64 roomid,i64 timestamp,i64 count);  // pass timestamp==-1 for last messages
+struct db_message_list db_get_messages(i64 roomid,i64 count);  // gets latest `count` messages
 
 void db_nullify_name_id(struct db_name_id ni);
 void db_nullify_room_list(struct db_room_list rl);
-- 
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