#include <lualib.h>
#include "BLua.h"

#ifndef BUFFERSIZE
#define BUFFERSIZE	  2048
#endif

typedef GeneralException LuaException;

class LuaStatics : public Base {
  public:
    static const char * getF(lua_State *, void *, size_t *);
    static int luapanic(lua_State *) throw(GeneralException);
    static int destructor(lua_State *);
};

std::map<lua_State *, Lua *> Lua::lualist;

int LuaStatics::luapanic(lua_State * L) throw (GeneralException) {
    Lua::find(L)->showerror();
    throw LuaException("Error running Lua code, bailing out.");
}

Lua::Lua() : L(lua_open()) {
    lua_atpanic(L, LuaStatics::luapanic);
    lualist[L] = this;
}

Lua::Lua(lua_State * _L) : L(_L) {
    lua_atpanic(L, LuaStatics::luapanic);
    lualist[L] = this;
}

Lua::~Lua() {
    lua_setgcthreshold(L, 0);
    lua_close(L);
}

Lua::Lua(const Lua & l) throw (GeneralException) {
    throw GeneralException("Error: can't duplicate a Lua object.");
}

void Lua::open_base() {
    luaopen_base(L);
    lua_pop(L, 1);
}

void Lua::open_table() {
    luaopen_table(L);
    lua_pop(L, 1);
}

void Lua::open_io() {
    luaopen_io(L);
    lua_pop(L, 1);
}

void Lua::open_string() {
    luaopen_string(L);
    lua_pop(L, 1);
}

void Lua::open_math() {
    luaopen_math(L);
    lua_pop(L, 1);
}

void Lua::open_debug() {
    luaopen_debug(L);
    lua_pop(L, 1);
}

void Lua::declarefunc(const String & name, lua_CFunction f, int i) {
    lua_pushstring(L, name.to_charp());
    lua_pushcfunction(L, f);
    lua_settable(L, i);
}

void Lua::call(const String & f, int i, int nargs, int nresults) {
    lua_pushstring(L, f.to_charp());
    lua_gettable(L, i);
    lua_insert(L, -1 - nargs - nresults);
    lua_call(L, nargs, nresults);
}

void Lua::call(int nargs, int nresults) {
    lua_call(L, nargs, nresults);
}

void Lua::push() {
    lua_pushnil(L);
}

void Lua::push(lua_Number n) {
    lua_pushnumber(L, n);
}

void Lua::push(const String & s) {
    lua_pushlstring(L, s.to_charp(), s.strlen());
}

void Lua::push(bool b) {
    lua_pushboolean(L, b);
}

void Lua::push(void * p) {
    lua_pushlightuserdata(L, p);
}

void Lua::push(lua_CFunction f, int n) {
    lua_pushcclosure(L, f, n);
}

void Lua::pop(int n) {
    lua_pop(L, n);
}

void Lua::newtable() {
    lua_newtable(L);
}

void Lua::settable(int i) {
    lua_settable(L, i);
}

void Lua::gettable(int i) {
    lua_gettable(L, i);
}

int Lua::gettop() {
    return lua_gettop(L);
}

void Lua::error(const String & msg) {
    push(msg);
    lua_error(L);
}

int Lua::type(int i) {
    return lua_type(L, i);
}

bool Lua::isnil(int i) {
    return lua_isnil(L, i);
}

bool Lua::isboolean(int i) {
    return lua_isboolean(L, i);
}

bool Lua::isnumber(int i) {
    return lua_isnumber(L, i);
}

bool Lua::isstring(int i) {
    return lua_isstring(L, i);
}

bool Lua::istable(int i) {
    return lua_istable(L, i);
}

bool Lua::isfunction(int i) {
    return lua_isfunction(L, i);
}

bool Lua::iscfunction(int i) {
    return lua_iscfunction(L, i);
}

bool Lua::isuserdata(int i) {
    return lua_isuserdata(L, i);
}

bool Lua::islightuserdata(int i) {
    return lua_islightuserdata(L, i);
}
    bool toboolean(int = -1);
    lua_Number tonumber(int = -1);
    String tostring(int = -1);
    lua_CFunction tocfunction(int = -1);
    void * touserdata(int = -1);
    Lua * tothread(int = -1);

bool Lua::toboolean(int i) {
    return lua_toboolean(L, i);
}

lua_Number Lua::tonumber(int i) {
    return lua_tonumber(L, i);
}

String Lua::tostring(int i) {
    return String(lua_tostring(L, i));
}

lua_CFunction Lua::tocfunction(int i) {
    return lua_tocfunction(L, i);
}

void * Lua::touserdata(int i) {
    return lua_touserdata(L, i);
}

Lua * Lua::tothread(int i) {
    return find(lua_tothread(L, i));
}

struct LoadF {
    Handle * f;
    char buff[BUFFERSIZE];
};

const char * LuaStatics::getF(lua_State * L, void * ud, size_t * size) {
    LoadF *lf = (LoadF *)ud;
    (void)L;

    *size = lf->f->read(lf->buff, BUFFERSIZE);
    return (*size > 0) ? lf->buff : NULL;
}

void Lua::load(Handle * h) throw (GeneralException) {
    LoadF lf;
    int status;

    lf.f = h;

    status = lua_load(L, LuaStatics::getF, &lf, h->GetName().to_charp());

    if (status) {
	showerror();
	throw LuaException("Error loading lua chunk from Handle `" + h->GetName() + "'");
    }

    call();
}

Lua * Lua::thread() {
    return new Lua(lua_newthread(L));
}

Lua * Lua::find(lua_State * _L) throw (GeneralException) {
    std::map<lua_State *, Lua *>::iterator i;

    if ((i = lualist.find(_L)) == lualist.end()) {
	throw GeneralException("Unable to find the Lua object for this context");
    }

    return i->second;
}

void Lua::showerror() {
    int n = lua_gettop(L);
    int i;
    String t;

    printm(M_ERROR, "Lua object: Got an LUA error\n");
    printm(M_ERROR, "Inspecting LUA stack\n");

    if (n == 0) {
	printm(M_ERROR, "Stack empty\n");
	return;
    }

    for (i = 1; i <= n; i++) {
	switch(lua_type(L, i)) {
	case LUA_TNONE:
	    t = "Invalid";
	    break;
	case LUA_TNIL:
	    t = "(Nil)";
	    break;
	case LUA_TNUMBER:
	    t.set("(Number) %f", lua_tonumber(L, i));
	    break;
	case LUA_TBOOLEAN:
	    t.set("(Bool)   %s", lua_toboolean(L, i) ? "true" : "false");
	    break;
	case LUA_TSTRING:
	    t.set("(String) %s", lua_tostring(L, i));
	    break;
	case LUA_TTABLE:
	    t = "(Table)";
	    break;
	case LUA_TFUNCTION:
	    t = "(Function)";
	    break;
	default:
	    t = "Unknown";
	}

	printm(M_ERROR, String(i) + ": " + t + "\n");
    }
}

int Lua::getmetatable(int i) {
    return lua_getmetatable(L, i);
}

int Lua::setmetatable(int i) {
    return lua_setmetatable(L, i);
}

void LuaObject::push(Lua * L) throw (GeneralException) {
    if (pushed && wantdestruct) {
	throw GeneralException("Error: object is owned by the LUA script and can not be pushed.");
    }
    L->newtable();
    pushmembers(L);
    pushed = true;
}

void LuaObject::pushme(Lua * L, void * o) {
    L->push("__obj");
    L->push(o);
    L->settable();
}

void * LuaObject::getme(Lua * L, int i) throw (GeneralException) {
    void * r;

    L->push("__obj");
    L->gettable(i);
    if (!(r = L->touserdata())) {
	throw GeneralException("Lua object already destroyed");
    }
    L->pop();

    return r;
}

void LuaObject::pushit(Lua * L, const String & s, lua_CFunction f) {
    L->push(s);
    L->push(f);
    L->settable();
}

int LuaStatics::destructor(lua_State * _L) {
    Lua * L = Lua::find(_L);
    Base * b = (Base *) LuaObject::getme(L);
    delete b;
    L->push("__obj");
    L->push((void *) 0);
    L->settable();
    printm(M_INFO, "Destructing an object from LUA\n");
    return 0;
}


void LuaObject::pushdestruct(Lua * L) throw (GeneralException) {
    if (pushed) {
	throw GeneralException("Error: can't push destructor, object already pushed");
    }
    push(L);
    if (!L->getmetatable(1)) {
	L->newtable();
    }
    L->push("__gc");
    L->push(LuaStatics::destructor);
    L->settable();
    L->setmetatable(1);
    pushit(L, "destroy", LuaStatics::destructor);

    wantdestruct = true;
}