#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <lua.h>
#include <xbps.h>

/* Converts an XBPS object to a Lua value. */
int
xbps_obj_to_lua(lua_State *L, xbps_object_t obj)
{
	lua_Number n;
	xbps_object_t obj2;
	xbps_object_t allkeys, keysym;
	const char *ksymname;
	int tbl;

	switch (xbps_object_type(obj)) {
	case XBPS_TYPE_STRING:
		lua_pushstring(L, xbps_string_cstring_nocopy(obj));
		break;
	case XBPS_TYPE_NUMBER:
		lua_pushnumber(L, xbps_number_unsigned_integer_value(obj));
		break;
	case XBPS_TYPE_BOOL:
		lua_pushboolean(L, xbps_bool_true(obj));
		break;
	case XBPS_TYPE_ARRAY:
		lua_newtable(L);
		tbl = lua_gettop(L);
		for (unsigned int i = 0; i < xbps_array_count(obj); i++) {
			xbps_obj_to_lua(L, xbps_array_get(obj, i));
			lua_rawseti(L, tbl, i + 1);
		}
		break;
	case XBPS_TYPE_DICTIONARY:
		lua_newtable(L);
		tbl = lua_gettop(L);
		allkeys = xbps_dictionary_all_keys(obj);
		for (unsigned int i = 0; i < xbps_array_count(allkeys); i++) {
			keysym = xbps_array_get(allkeys, i);
			ksymname = xbps_dictionary_keysym_cstring_nocopy(keysym);
			obj2 = xbps_dictionary_get_keysym(obj, keysym);
			lua_pushstring(L, ksymname);
			if (xbps_obj_to_lua(L, obj2))
				lua_rawset(L, tbl);
			else
				lua_pop(L, 1);
		}
		xbps_object_release(allkeys);
		break;
	case XBPS_TYPE_DATA:
		/* install-script and remove-script - could just use string for these */
	default:
		return 0;
	}
	return 1;
}

struct luaxbps {
	struct xbps_handle xh;
};

int
luaxbps_new(lua_State *L)
{
	/* local self = userdata(sizeof(struct luaxbps)) */
	lua_newuserdata(L, sizeof(struct luaxbps));
	int self = lua_gettop(L);

	struct luaxbps *selfptr = lua_touserdata(L, self);
	memset(&selfptr->xh, 0, sizeof(struct xbps_handle));
	int err;
	if ((err = xbps_init(&selfptr->xh)) != 0) {
		lua_pushfstring(L, "Failed to initialize libxbps: %s", strerror(err));
		lua_error(L);
		/* not reached */
	}

	/* setmetatable(self, registry.luaxbps) */
	lua_pushstring(L, "luaxbps");
	lua_rawget(L, LUA_REGISTRYINDEX);
	lua_setmetatable(L, self);

	return 1;
}

struct xbps_list_state {
	lua_State *L;
	int list;
	int i;
};

int
xbps_list_callback(struct xbps_handle *xhp,
                   xbps_object_t obj,
                   const char *key,
                   void *arg,
                   bool *loop_done)
{
	struct xbps_list_state *state = arg;

	xbps_obj_to_lua(state->L, obj);

	/* state->list[state->i++] = obj */
	lua_rawseti(state->L, state->list, state->i++);

	return 0;
}

/* Gets a list of all installed packages. */
int
luaxbps_list_pkgs(lua_State *L)
{
	struct luaxbps *selfptr = lua_touserdata(L, lua_gettop(L));

	lua_newtable(L);

	struct xbps_list_state state;
	state.L = L;
	state.list = lua_gettop(L);
	state.i = 1;

	xbps_pkgdb_foreach_cb(&selfptr->xh, xbps_list_callback, &state);

	return 1;
}

int
luaxbps_gc(lua_State *L)
{
	struct luaxbps *selfptr = lua_touserdata(L, lua_gettop(L));

	if (selfptr)
		xbps_end(&selfptr->xh);

	return 0;
}

int
luaopen_luaxbps(lua_State *L)
{
	/* local luaxbps = {} */
	lua_newtable(L);
	int luaxbps = lua_gettop(L);

	/* luaxbps.__index = module */
	lua_pushstring(L, "__index");
	lua_pushvalue(L, luaxbps);
	lua_rawset(L, luaxbps);

	/* luaxbps.__gc = luaxbps_gc */
	lua_pushstring(L, "__gc");
	lua_pushcfunction(L, luaxbps_gc);
	lua_rawset(L, luaxbps);

	/* luaxbps.new = luaxbps_new */
	lua_pushstring(L, "new");
	lua_pushcfunction(L, luaxbps_new);
	lua_rawset(L, luaxbps);

	/* luaxbps.list_pkgs = luaxbps_list_pkgs */
	lua_pushstring(L, "list_pkgs");
	lua_pushcfunction(L, luaxbps_list_pkgs);
	lua_rawset(L, luaxbps);

	/* registry.luaxbps = luaxbps */
	lua_pushstring(L, "luaxbps");
	lua_pushvalue(L, luaxbps);
	lua_rawset(L, LUA_REGISTRYINDEX);

	return 1;
}