#include <lua.h>

#include <lauxlib.h>

#include <glib.h>

#include <stdio.h>    // popen, pclose, fileno

#include "util.h"

#include "glib_types.h"

static gchar lglib_io_buffer[128];

void lglib_io_callback_destroy (lglib_io_callback_t *cb)

{

	luaL_unref (cb->L, LUA_REGISTRYINDEX, cb->reference);

	pclose (cb->fd);

	luaL_free (cb->L, cb);

}

// data/nil

static gboolean lglib_io_callback (GIOChannel *source, GIOCondition *condition, lglib_io_callback_t *cb)

{

	gsize read = 0;

	int status;

	lua_rawgeti (cb->L, LUA_REGISTRYINDEX, cb->reference);

	status = g_io_channel_read_chars (source, lglib_io_buffer, 128, &read, NULL);

	if (read) {

		lua_pushlstring (cb->L, lglib_io_buffer, read);

	} else if (status == G_IO_STATUS_EOF) {

		lua_pushnil (cb->L);

	} else {

		return status != G_IO_STATUS_ERROR;

	}

	if (lua_pcall (cb->L, 1, 1, 0))

		lua_error (cb->L);

	return lua_toboolean (cb->L, -1);

}

// command function

static int lglib_io_new (lua_State *L)

{

	const char *command = luaL_checkstring (L, 1);

	lglib_io_callback_t *cb;

	FILE *fd;

	GIOChannel *channel;

	//const char *charset;

	luaL_argcheck (L, lua_isfunction (L, 2), 2, "function expected");

	fd = popen (command, "r");

	if (!fd) {

		lua_pushstring (L, "Error opening pipe");

		lua_error (L);

	}

	channel = g_io_channel_unix_new (fileno (fd));

	//if (!g_get_charset (&charset))

	//	g_io_channel_set_encoding (channel, charset, NULL);

	cb = luaL_malloc (L, sizeof (lglib_io_callback_t));

	cb->reference = luaL_ref (L, LUA_REGISTRYINDEX);

	cb->L         = L;

	cb->fd        = fd;

	g_io_add_watch_full (channel, G_PRIORITY_HIGH_IDLE, G_IO_IN,

				(GSourceFunc)lglib_io_callback, cb,

				(GDestroyNotify)lglib_io_callback_destroy);

	return 0;

}

static const luaL_Reg lglib_io_reg_f[] = {

	{ "new", lglib_io_new },

	{ NULL,  NULL         },

};

int luaopen_glib_io (lua_State *L)

{

	luaL_register (L, "g.io", lglib_io_reg_f);

	return 1;

}