/* Definition of repository tables used by chat
*/
static const char zChatSchema1[] =
@ CREATE TABLE repository.chat(
@   msgid INTEGER PRIMARY KEY AUTOINCREMENT,
@   mtime JULIANDAY,       -- Time for this entry - Julianday Zulu
@   lmtime TEXT,           -- Localtime when message originall sent
@   xfrom TEXT,            -- Login of the sender
@   xmsg  TEXT,            -- Raw, unformatted text of the message
@   file  BLOB,            -- Text of the uploaded file, or NULL
@   fname TEXT,            -- Filename of the uploaded file, or NULL
@   fmime TEXT,            -- MIMEType of the upload file, or NULL
@   mdel INT               -- msgid of another message to delete
@ );
;


/*
** Make sure the repository data tables used by chat exist.  Create them
** if they do not.
*/
static void chat_create_tables(void){
  if( !db_table_exists("repository","chat") ){
    db_multi_exec(zChatSchema1/*works-like:""*/);
  }else if( !db_table_has_column("repository","chat","lmtime") ){
    if( !db_table_has_column("repository","chat","mdel") ){
      db_multi_exec("ALTER TABLE chat ADD COLUMN mdel INT");
    }
    db_multi_exec("ALTER TABLE chat ADD COLUMN lmtime TEXT");
  }
}

/*
** Delete old content from the chat table.
*/
static void chat_purge(void){

  nByte = atoi(PD("file:bytes",0));
  zMsg = PD("msg","");
  db_begin_write();
  chat_purge();
  if( nByte==0 ){
    if( zMsg[0] ){
      db_multi_exec(
        "INSERT INTO chat(mtime,lmtime,xfrom,xmsg)"
        "VALUES(julianday('now'),%Q,%Q,%Q)",
        P("lmtime"), g.zLogin, zMsg
      );
    }
  }else{
    Stmt q;
    Blob b;
    db_prepare(&q,
        "INSERT INTO chat(mtime,lmtime,xfrom,xmsg,file,fname,fmime)"
        "VALUES(julianday('now'),%Q,%Q,%Q,:file,%Q,%Q)",
        P("lmtime"), g.zLogin, zMsg, PD("file:filename",""),
        PD("file:mimetype","application/octet-stream"));
    blob_init(&b, P("file"), nByte);
    db_bind_blob(&q, ":file", &b);
    db_step(&q);
    db_finalize(&q);
    blob_reset(&b);
  }

** Format of the json:
**
** |    {
** |      "msg":[
** |        {
** |           "msgid": integer // message id
** |           "mtime": text    // When sent:  YYYY-MM-DD HH:MM:SS UTC
** |           "lmtime: text    // Localtime where the message was sent from
** |           "xfrom": text    // Login name of sender
** |           "uclr":  text    // Color string associated with the user
** |           "xmsg":  text    // HTML text of the message
** |           "fsize": integer // file attachment size in bytes
** |           "fname": text    // Name of file attachment
** |           "fmime": text    // MIME-type of file attachment
** |           "mdel":  integer // message id of prior message to delete
** |        }
** |      ]
** |    }
**
** The "fname" and "fmime" fields are only present if "fsize" is greater
** than zero.  The "xmsg" field may be an empty string if "fsize" is zero.
**
** The "msgid" values will be in increasing order.
**
** The "mdel" will only exist if "xmsg" is an empty string and "fsize" is zero.
**
** The "lmtime" value might be known, in which case it is omitted.
**
** The messages are ordered oldest first unless "before" is provided, in which
** case they are sorted newest first (to facilitate the client-side UI update).
*/
void chat_poll_webpage(void){
  Blob json;                  /* The json to be constructed and returned */
  sqlite3_int64 dataVersion;  /* Data version.  Used for polling. */

  login_check_credentials();
  if( !g.perm.Chat ) return;
  chat_create_tables();
  cgi_set_content_type("text/json");
  dataVersion = db_int64(0, "PRAGMA data_version");
  blob_append_sql(&sql,
    "SELECT msgid, datetime(mtime), xfrom, xmsg, length(file),"
    "       fname, fmime, %s, lmtime"
    "  FROM chat ",
    msgBefore>0 ? "0 as mdel" : "mdel");
  if( msgid<=0 || msgBefore>0 ){
    db_begin_write();
    chat_purge();
    db_commit_transaction();
  }

      const char *zDate = db_column_text(&q1, 1);
      const char *zFrom = db_column_text(&q1, 2);
      const char *zRawMsg = db_column_text(&q1, 3);
      int nByte = db_column_int(&q1, 4);
      const char *zFName = db_column_text(&q1, 5);
      const char *zFMime = db_column_text(&q1, 6);
      int iToDel = db_column_int(&q1, 7);
      const char *zLMtime = db_column_text(&q1, 8);
      char *zMsg;
      if(cnt++){
        blob_append(&json, ",\n", 2);
      }
      blob_appendf(&json, "{\"msgid\":%d,", id);
      blob_appendf(&json, "\"mtime\":\"%.10sT%sZ\",", zDate, zDate+11);
      if( zLMtime && zLMtime[0] ){
        blob_appendf(&json, "\"lmtime\":%!j,", zLMtime);
      }
      blob_appendf(&json, "\"xfrom\":%!j,", zFrom);
      blob_appendf(&json, "\"uclr\":%!j,", hash_color(zFrom));

      zMsg = chat_format_to_html(zRawMsg ? zRawMsg : "");
      blob_appendf(&json, "\"xmsg\":%!j,", zMsg);
      fossil_free(zMsg);

      if( nByte==0 ){
        blob_appendf(&json, "\"fsize\":0");
      }else{
        blob_appendf(&json, "\"fsize\":%d,\"fname\":%!j,\"fmime\":%!j",
               nByte, zFName, zFMime);
      }

      if( iToDel ){
        blob_appendf(&json, ",\"mdel\":%d}", iToDel);
      }else{
        blob_append(&json, "}", 1);
      }
    }
    db_reset(&q1);