#include "luastack.hpp"
#include "util.hpp"
#include <iostream>

LuaSpecial LuaRegistry(LUA_REGISTRYINDEX);
LuaNilMarker LuaNil;
LuaNewTableMarker LuaNewTable;

LuaFunctionReg::LuaFunctionReg(const char *m, const char *n, lua_CFunction f) {
    mode_ = m;
    name_ = n;
    func_ = f;
    next_ = LuaFunctionRegistry;
    LuaFunctionRegistry = this;
}

LuaFunctionReg::List LuaFunctionReg::all() {
    LuaFunctionReg::List result;
    for (const LuaFunctionReg *r = LuaFunctionRegistry; r != 0; r = r->next_) {
        result.push_back(r);
    }
    return result;
}

LuaFunctionReg *LuaFunctionReg::LuaFunctionRegistry;


lua_Integer LuaStack::ckinteger(LuaSlot s) const {
    luaL_checktype(L_, s, LUA_TNUMBER);
    return lua_tointeger(L_, s);
}

lua_Number LuaStack::cknumber(LuaSlot s) const {
    luaL_checktype(L_, s, LUA_TNUMBER);
    return lua_tonumber(L_, s);
}

std::string LuaStack::ckstring(LuaSlot s) const {
    luaL_checktype(L_, s, LUA_TSTRING);
    size_t len;
    const char *str = lua_tolstring(L_, s, &len);
    return std::string(str, len);
}

lua_State *LuaStack::ckthread(LuaSlot s) const {
    luaL_checktype(L_, s, LUA_TTHREAD);
    return lua_tothread(L_, s);
}

void LuaStack::count_slots_finalize(int narg, int nvar, int nret) {
    narg_ = narg;
    nret_ = nret;
    nvar_ = nvar;
    ngap_ = nret - nvar - narg;
    if (ngap_ < 0) ngap_ = 0;

    int argtop = lua_gettop(L_);
    argpos_ = argtop + 1 - narg_;
    gappos_ = argpos_ + narg_;
    varpos_ = gappos_ + ngap_;
    retpos_ = varpos_ + nvar_;

    rettop_ = retpos_ + nret_ - 1;
    finaltop_ = argpos_ + nret_ - 1;
}

void LuaStack::clear_frame() {
    lua_settop(L_, varpos_ - 1);
    for (int i = 0; i < nvar_ + nret_; i++) {
        lua_pushnil(L_);
    }
}

int LuaStack::result() {
    lua_settop(L_, rettop_);
    int i = finaltop_;
    for (int j = 0; j < nret_; j++) {
        lua_replace(L_, i);
        i -= 1;
    }
    lua_settop(L_, finaltop_);
    return nret_;
}

void LuaStack::pop_any_value(lua_Integer &s) const {
    luaL_checktype(L_, -1, LUA_TNUMBER);
    s = lua_tointeger(L_, -1);
    lua_pop(L_, 1);
}

void LuaStack::pop_any_value(lua_Number &s) const {
    luaL_checktype(L_, -1, LUA_TNUMBER);
    s = lua_tonumber(L_, -1);
    lua_pop(L_, 1);
}
    

void LuaStack::pop_any_value(std::string &s) const {
    luaL_checktype(L_, -1, LUA_TSTRING);
    size_t len;
    const char *str = lua_tolstring(L_, -1, &len);
    s = std::string(str, len);
    lua_pop(L_, 1);
}

void LuaStack::clearmetatable(LuaSlot tab) const {
    lua_pushnil(L_);
    lua_setmetatable(L_, tab);
}

void LuaStack::setmetatable(LuaSlot tab, LuaSlot mt) const {
    lua_pushvalue(L_, mt);
    lua_setmetatable(L_, tab);
}

void LuaStack::getmetatable(LuaSlot mt, LuaSlot tab) const {
    lua_getmetatable(L_, tab);
    lua_replace(L_, mt);
}

void LuaStack::checknometa(LuaSlot index) const {
    if (lua_istable(L_, index)) {
        if (!lua_getmetatable(L_, index)) {
            return;
        }
    }
    luaL_error(L_, "expected simple table with no metatable");
}

int LuaStack::next(LuaSlot tab, LuaSlot key, LuaSlot value) const {
    lua_pushvalue(L_, key);
    int ret = lua_next(L_, tab);
    if (ret != 0) {
        lua_replace(L_, value);
        lua_replace(L_, key);
    }
    return ret;
}

void LuaStack::getglobaltable(LuaSlot target) const {
    lua_pushglobaltable(L_);
    lua_replace(L_, target);
}

void LuaStack::newtable(LuaSlot target) const {
    lua_newtable(L_);
    lua_replace(L_, target);
}

lua_State *LuaStack::newthread(LuaSlot target) const {
    lua_State *result = lua_newthread(L_);
    lua_replace(L_, target);
    return result;
}

void LuaStack::getclass(LuaSlot classtab, LuaSlot classname) const {
    lua_checkstack(L_, 20);
    LuaVar globtab, cname;
    LuaStack LS(L_, globtab, cname);

    // Convert class name to a table.
    if (LS.isstring(classname)) {
        if (LS.rawequal(classname, "_G")) {
            luaL_error(L_, "_G is explicitly not allowed as a class name");
        }
        LS.getglobaltable(globtab);
        LS.rawget(classtab, globtab, classname);
        if (!LS.istable(classtab)) {
            luaL_error(L_, "Not a class: %s", lua_tostring(L_, classname));
        }
        LS.rawget(cname, classtab, "__class");
        if (!LS.rawequal(cname, classname)) {
            luaL_error(L_, "Not a class: %s", lua_tostring(L_, classname));
        }
    } else {
        LS.set(classtab, classname);
        if (!LS.istable(classtab)) {
            luaL_error(L_, "parameter must be a class");
        }
        LS.rawget(cname, classtab, "__class");
        if (!LS.isstring(cname)) {
            luaL_error(L_, "table is not a class");
        }
    }

    // OK, we're done.
    LS.result();
}

void LuaStack::makeclass(LuaSlot classtab, LuaSlot classname) const {
    lua_checkstack(L_, 20);
    LuaVar globtab;
    LuaStack LS(L_, globtab);

    // Validate the class name.
    if (!LS.isstring(classname)) {
        luaL_error(L_, "Not a class name: %s", lua_tostring(L_, classname));
    }
    if (LS.rawequal(classname, "_G")) {
        luaL_error(L_, "_G is explicitly not allowed as a class name");
    }

    // Fetch the global environment from the registry.
    LS.getglobaltable(globtab);
    
    // Get the classtab from the global environment.
    // Create it if it doesn't exist.
    LS.rawget(classtab, globtab, classname);
    if (LS.isnil(classtab)) {
        LS.newtable(classtab);
        LS.rawset(globtab, classname, classtab);
    }

    // If the name isn't bound to a table, abort.
    if (!LS.istable(classtab)) {
        luaL_error(L_, "%s is not a class", ckstring(classname).c_str());
    }

    // Repair the special fields.
    LS.rawset(classtab, "__index", classtab);
    LS.rawset(classtab, "__class", classname);

    // Put the stack back.
    LS.result();
}

void LuaStack::makesubtable(LuaSlot sub, LuaSlot tab, const char *name) const {
    rawget(sub, tab, name);
    if (istable(sub)) {
        return;
    } else if (isnil(sub)) {
        newtable(sub);
        rawset(tab, name, sub);
        return;
    } else {
        luaL_error(L_, "%s is not a table", name);
    }
}

void LuaStack::cleartable(LuaSlot tab) const {
    checktable(tab);
    lua_pushnil(L_);
    while (lua_next(L_, tab.index()) != 0) {
        lua_pop(L_, 1); // Pop the old value.
        lua_pushvalue(L_, -1); // Clone the key
        lua_pushnil(L_); // Push the new value.
        lua_settable(L_, tab.index());
    }
}

void LuaStack::check_nret(int xnret, int otop, int nret) const {
    int ntop = lua_gettop(L_);
    if ((nret != xnret)||(ntop != otop + xnret)) {
        luaL_error(L_, "expected %d return values", xnret);
    }
}