#include "globaldb.hpp"
#include "table.hpp"

// Get a table from the global database.
//
//   GLOBALNAME
//   if globalname is already present, and is a table, return it.
//   if globalname is already present, and not a table, error.
//   if globalname is not present, create and initialize it.
//
int lpx_globaldb_global(lua_State *L) {
    LuaArg globalname;
    LuaRet globaltab;
    LuaVar globaldb;
    LuaStack LS(L, globalname, globaltab, globaldb);

    LS.checktype(globalname, LUA_TSTRING);

    // Get a pointer to the globaldb.
    LS.getfield(globaldb, LUA_REGISTRYINDEX, "globaldb");
    if (!LS.istable(globaldb)) {
        LS.newtable(globaldb);
        LS.setfield(LUA_REGISTRYINDEX, "globaldb", globaldb);
    }

    // Get the globaltab from the globaldb, sanity check it.
    LS.rawget(globaltab, globaldb, globalname);
    if (LS.istable(globaltab)) {
        return LS.result();
    } else if (!LS.isnil(globaltab)) {
        luaL_error(L, "%s is not a global", LS.tostring(globalname).c_str());
    }

    // Create a new globaltab and store it in the globaldb.
    LS.newtable(globaltab);
    LS.rawset(globaldb, globalname, globaltab);
    LS.setfield(globaltab, "__global", globalname);
    return LS.result();
}

void luaopen_lpx_globaldb(lua_State *L) {
    LuaStack::reg(L, 0, "global", LuaArgCheck<1, lpx_globaldb_global>);
}