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

LuaSpecial LuaRegistry(LUA_REGISTRYINDEX);
LuaSpecial LuaGlobals(LUA_GLOBALSINDEX);
LuaNilMarker LuaNil;
LuaNewTableMarker LuaNewTable;
LuaDiscardMarker LuaDiscard;

void LuaStack::make_tagged_pointer(LuaSlot target, void *ptr, LuaTypeTag tag, LuaDeleterFn del) {
    TaggedPointer *tp = (TaggedPointer*)lua_newuserdata(L_, sizeof(TaggedPointer));
    tp->ptr = ptr;
    tp->tag = tag;
    tp->del = del;
    lua_pushlightuserdata(L_, (void*)tag);
    lua_rawget(L_, LUA_REGISTRYINDEX);
    if (lua_isnil(L_, -1)) luaL_error(L_, "type not registered with LuaDefineType");
    lua_setmetatable(L_, -2);
    lua_replace(L_, target);
}

int LuaStack::collect_tagged_pointer(lua_State *L) {
    LuaStack::TaggedPointer *p = (LuaStack::TaggedPointer*)lua_touserdata(L, 1);
    if (p==0) {
        luaL_error(L, "lua deleter function received a non-userdata");
    }
    if (p->ptr == 0) {
        luaL_error(L, "lua object already deleted");
    }
    p->del(p->ptr);
    p->ptr = 0;
    return 0;
}

void LuaStack::register_all_userdata(lua_State *L) {
    LuaVar tab, lud;
    LuaStack LS(L, tab, lud);
    auto regs = LuaFunctionReg::all();
    for (const LuaFunctionReg *r : regs) {
        const std::string &name = r->get_name();
        lua_CFunction tag = r->get_func();
        std::string mode = r->get_mode();
        if (mode.find('t') != std::string::npos) { // Register type
            LS.newtable(tab);
            LS.setfield(tab, "type", name);
            LS.setfield(tab, "__gc", collect_tagged_pointer);
            LS.setlightuserdata(lud, (void *)tag);
            LS.rawset(LuaRegistry, lud, tab);
        }
    }
    LS.result();
}

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;


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(std::string &s) const {
    size_t len;
    const char *str = luaL_cklstring(L_, -1, &len);
    s = std::string(str, len);
    lua_pop(L_, 1);
}

void LuaStack::pop_any_value(LuaAcceptNilNumber &s) const {
    if (lua_isnil(L_, -1)) {
        s.v = 0.0;
    } else {
        s.v = luaL_cknumber(L_, -1);
    }
    lua_pop(L_, 1);
}

void LuaStack::pop_any_value(LuaAcceptNilInteger &s) const {
    if (lua_isnil(L_, -1)) {
        s.v = 0;
    } else {
        s.v = luaL_ckinteger(L_, -1);
    }
    lua_pop(L_, 1);
}

void LuaStack::pop_any_value(LuaAcceptNilString &s) const {
    if (lua_isnil(L_, -1)) {
        s.v = "";
    } else {
        size_t len;
        const char *str = luaL_cklstring(L_, -1, &len);
        s.v = std::string(str, len);
    }
    lua_pop(L_, 1);
}

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

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;
}

bool LuaStack::isemptytable(LuaSlot tab) const {
    if (lua_istable(L_, tab)) {
        lua_pushnil(L_);
        if (lua_next(L_, tab) == 0) {
            return true;
        }
        lua_pop(L_, 2);
    }
    return false;
}

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

void LuaStack::setlightuserdata(LuaSlot target, void *p) const {
    lua_pushlightuserdata(L_, p);
    lua_replace(L_, target);
}


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);
    }
}