#include "nest/bird.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "nest/iface.h"
#include "conf/conf.h"
#include "filter/filter.h"
#include "lua.h"
#include "sysdep/linux/wireguard.h"

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

static linpool *lua_lp;

static void lua_pushwgdevice(lua_State *L, wg_device *dev);
static void lua_pushwgpeer(lua_State *L, wg_peer *peer);

static int luaB_err(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1)
    log(L_WARN "bird.err() accepts exactly 1 argument");

  if (n < 1)
    return 0;

  log(L_ERR "%s", lua_tostring(L, 1));
  return 0;
}

static int luaB_warn(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1)
    log(L_WARN "bird.warn() accepts exactly 1 argument");

  if (n < 1)
    return 0;

  log(L_WARN "%s", lua_tostring(L, 1));
  return 0;
}

static int luaB_info(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1)
    log(L_WARN "bird.info() accepts exactly 1 argument");

  if (n < 1)
    return 0;

  log(L_INFO "%s", lua_tostring(L, 1));
  return 0;
}

static int luaB_trace(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1)
    log(L_WARN "bird.trace() accepts exactly 1 argument");

  if (n < 1)
    return 0;

  log(L_TRACE "%s", lua_tostring(L, 1));
  return 0;
}

static int luaB_wg_get_device(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "get_device needs exactly 1 argument");
    return 0;
  }

  const char *device_name = lua_tolstring(L, 1, NULL);
  log(L_WARN "WG: device name %s", device_name);
  lua_pop(L, 1);

  wg_device *dev = NULL;

  if (wg_get_device(&dev, device_name) < 0) {
    return luaL_error(L, "Wireguard error opening %s", device_name);
  }

  log(L_WARN "WG: device %p", dev);
  lua_pushwgdevice(L, dev);
  return 1;
}

static int luaB_wg_device_first_peer(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "first_peer needs exactly 0 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  wg_device *dev = lua_touserdata(L, -1);
  lua_pop(L, 1);
  lua_pushwgpeer(L, dev->first_peer);

  return 1;
}

static int luaB_wg_peer_next_peer(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "next_peer needs exactly 0 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  wg_peer *peer = lua_touserdata(L, -1);
  lua_pop(L, 1);
  lua_pushwgpeer(L, peer->next_peer);

  return 1;
}

#define lua_sett(L, idx, val, what) do {	\
  lua_pushstring(L, idx); \
  lua_push##what(L, val); \
  lua_settable(L, -3); \
} while (0)

#define lua_settableaddr(L, idx, val)	    lua_sett(L, idx, val, addr)
#define lua_settableipaddr(L, idx, val)	    lua_sett(L, idx, val, ipaddr)
#define lua_settablecfunction(L, idx, val)  lua_sett(L, idx, val, cfunction)
#define lua_settableinteger(L, idx, val)    lua_sett(L, idx, val, integer)
#define lua_settableip4(L, idx, val)	    lua_sett(L, idx, val, ip4)
#define lua_settablelightuserdata(L, idx, val)  lua_sett(L, idx, val, lightuserdata)
#define lua_settableeattr(L, idx, val)	    lua_sett(L, idx, val, eattr)
#define lua_settablewgdevice(L, idx, val)  lua_sett(L, idx, val, wgdevice)
#define lua_settablevalue(L, idx, val)	    lua_sett(L, idx, val, value)

#define lua_setglobalcfunction(L, n, val)   do { \
  lua_pushcfunction(L, val); \
  lua_setglobal(L, n); \
} while (0)

static int luaB_generic_concat(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 2) {
    log(L_WARN "__concat needs exactly 2 arguments");
    return 0;
  }

  const char *a, *b;
  size_t la, lb;

  a = luaL_tolstring(L, 1, &la);
  b = luaL_tolstring(L, 2, &lb);

  if (a == NULL) {
    a = "";
    la = 0;
  }

  if (b == NULL) {
    b = "";
    lb = 0;
  }

  char *c = alloca(la + lb + 1);
  memcpy(c, a, la);
  memcpy(c + la, b, lb);
  c[la + lb] = 0;

  lua_pushlstring(L, c, la + lb);

  return 1;
}

static int luaB_ip4_tostring(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "__tostring needs exactly 1 argument");
    return 0;
  }

  lua_pushliteral(L, "addr");
  lua_gettable(L, 1);
  lua_Integer a = lua_tointeger(L, -1);
  char c[IP4_MAX_TEXT_LENGTH];
  bsnprintf(c, IP4_MAX_TEXT_LENGTH, "%I4", a);

  lua_pushstring(L, c);
  return 1;
}

static void lua_puship4(lua_State *L, ip4_addr a) {
  lua_newtable(L);
  lua_settableinteger(L, "addr", ip4_to_u32(a));

  lua_newtable(L);
  lua_settablecfunction(L, "__tostring", luaB_ip4_tostring);
  lua_settablecfunction(L, "__concat", luaB_generic_concat);
  lua_setmetatable(L, -2);
}

static int luaB_addr_tostring(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "__tostring needs exactly 1 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  net_addr *addr = lua_touserdata(L, -1);
  lua_pop(L, 1);

  char c[NET_MAX_TEXT_LENGTH+1];
  net_format(addr, c, sizeof(c));
  lua_pushstring(L, c);
  return 1;
}

static void lua_pushaddr(lua_State *L, net_addr *addr) {
  lua_newtable(L);
  lua_settablelightuserdata(L, "_internal", addr);

  lua_newtable(L);
  lua_settablecfunction(L, "__tostring", luaB_addr_tostring);
  lua_settablecfunction(L, "__concat", luaB_generic_concat);
  lua_setmetatable(L, -2);
}

static int luaB_ipaddr_tostring(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 1) {
    log(L_WARN "__tostring needs exactly 1 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  ip_addr *addr = lua_touserdata(L, -1);
  log(L_DEBUG "luaB_ipaddr_tostring %p", addr);
  lua_pop(L, 1);

  if (!addr)
    return 0;
  char c[IPA_MAX_TEXT_LENGTH+1];
  if (ipa_is_ip4(*addr))
    ip4_ntop(ipa_to_ip4(*addr), c);
  else
    ip6_ntop(ipa_to_ip6(*addr), c);
  lua_pushstring(L, c);
  return 1;
}

static void lua_pushipaddr(lua_State *L, ip_addr *addr) {
  lua_newtable(L);
  lua_settablelightuserdata(L, "_internal", addr);

  lua_newtable(L);
  lua_settablecfunction(L, "__tostring", luaB_ipaddr_tostring);
  lua_settablecfunction(L, "__concat", luaB_generic_concat);
  lua_setmetatable(L, -2);
}

static void lua_pushwgdevice(lua_State *L, wg_device *dev) {
  lua_newtable(L);
  lua_settablelightuserdata(L, "_internal", dev);
  lua_settablecfunction(L, "first_peer", luaB_wg_device_first_peer);

  lua_newtable(L);
  lua_settablevalue(L, "__index", -2-1);
  lua_setmetatable(L, -2);
}

static void lua_pushwgpeer(lua_State *L, wg_peer *peer) {
  lua_newtable(L);
  lua_settablelightuserdata(L, "_internal", peer);
  lua_settablecfunction(L, "next_peer", luaB_wg_peer_next_peer);

  wg_key_b64_string b64;
  wg_key_to_base64(b64, peer->public_key);
  lua_pushliteral(L, "public_key");
  lua_pushlstring(L, b64, strlen(b64));
  lua_settable(L, -3);

  lua_newtable(L);
  lua_settablevalue(L, "__index", -2-1);
  lua_setmetatable(L, -2);
}

static void lua_pusheattr(lua_State *L, eattr *ea) {
  /* if (ea->type == EAF_TYPE_IP_ADDRESS) { */
  /*   lua_settableinteger(L, "data", 17); */
  /*   /\* lua_pushaddr(L, "addr", (net_addr*)ea->u.ptr->data); *\/ */
  /* } */
  lua_newtable(L);
  lua_settableinteger(L, "id", ea->id);
  lua_settableinteger(L, "type", ea->type);
  if (ea->u.ptr && ea->u.ptr->data) {
    lua_pushliteral(L, "data");
    lua_pushlstring(L, ea->u.ptr->data, ea->u.ptr->length);
    lua_settable(L, -3);
  }

  /* lua_settablecfunction(L, "__tostring", luaB_addr_tostring); */
  /* lua_settablecfunction(L, "__concat", luaB_generic_concat); */
  /* lua_setmetatable(L, -2); */
}

static lua_bird_state *luaB_getinternalstate(lua_State *L) {
  lua_getglobal(L, "bird");
  lua_pushstring(L, "_internal_state");
  lua_gettable(L, -2);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  lua_bird_state *lbs = lua_touserdata(L, -1);
  lua_pop(L, 2); /* Pop the user data and then the table. The string is consumed by gettable(). */
  return lbs;
}

static int luaB_global_exception(lua_State *L, int value) {
  int n = lua_gettop(L);
  if (n > 1)
    log(L_WARN "Called exception with too many arguments.");

  lua_bird_state *lbs = luaB_getinternalstate(L);
  lbs->exception = value;

  lua_error(L);
  return 0;
}

static inline int luaB_accept(lua_State *L) { return luaB_global_exception(L, F_ACCEPT); }
static inline int luaB_reject(lua_State *L) { return luaB_global_exception(L, F_REJECT); }

lua_bird_state *luaB_init(lua_State *L, struct linpool *lp) {
  lua_newtable(L);

  lua_settablecfunction(L, "err", luaB_err);
  lua_settablecfunction(L, "warn", luaB_warn);
  lua_settablecfunction(L, "info", luaB_info);
  lua_settablecfunction(L, "trace", luaB_trace);

  lua_bird_state *lbs = lp_allocz(lp, sizeof(lua_bird_state));

  lua_settablelightuserdata(L, "_internal_state", lbs);

  lua_settableip4(L, "router_id", ip4_from_u32(config->router_id));

  lua_setglobal(L, "bird");

  lua_pushcfunction(L, luaB_accept);
  lua_setglobal(L, "accept");

  lua_pushcfunction(L, luaB_reject);
  lua_setglobal(L, "reject");

  lua_newtable(L);
  lua_settablecfunction(L, "get_device", luaB_wg_get_device);
  lua_setglobal(L, "wireguard");

  return lbs;
}

static int luaB_route_ea_find(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 2) {
    log(L_WARN "ea_find needs exactly 1 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  struct rte *e = lua_touserdata(L, -1);
  int ea = lua_tointeger(L, 2);
  lua_pop(L, 2);

  struct ea_list *eattrs = e->attrs->eattrs;
  eattr *t = ea_find(eattrs, ea);

  if (t) {
    lua_pusheattr(L, t);
    return 1;
  } else {
    log(L_ERR "eattr not found");
    return 0;
  }
}

/* ea_set_attr_data(id, flags, type, data(string) */
static int luaB_route_ea_set_attr_data(lua_State *L) {
  int n = lua_gettop(L);
  if (n != 5) {
    log(L_WARN "ea_set_attr_data needs exactly 4 argument");
    return 0;
  }

  lua_pushliteral(L, "_internal");
  lua_gettable(L, 1);
  if (!lua_isuserdata(L, -1))
    luaL_error(L, "fatal: bird internal state not found, type %d", lua_type(L, -1));

  struct rte *e = lua_touserdata(L, -1);

  log(L_INFO "rte flags %d", e->flags);
  if (e->attrs) {
    log(L_INFO "rta flags %d", e->attrs->aflags);
    if (e->attrs->eattrs) {
      log(L_INFO "eattr flags %d", e->attrs->eattrs->flags);
    }
  }
  log(L_WARN "******************************");

  uint id = lua_tointeger(L, 2);
  uint flags = lua_tointeger(L, 3);
  uint type = lua_tointeger(L, 4);
  size_t len = 0;
  const char *data = lua_tolstring(L, 5, &len);
  lua_pop(L, 5);

  struct ea_list **eattrs = &e->attrs->eattrs;
  if (!lua_lp)
    lua_lp = lp_new_default(&root_pool);
  ea_set_attr_data(eattrs, lua_lp, id, flags, type, data, len);
  lua_pushboolean(L, 1);
  return 0;
}

void luaB_push_route(lua_State *L, struct rte *e) {
  lua_newtable(L);
  lua_settablelightuserdata(L, "_internal", e);
  lua_settableaddr(L, "prefix", e->net->n.addr);
  lua_settableipaddr(L, "gw", &e->attrs->nh.gw);
  const char *ifname = "<unknown>";
  if (e->attrs->nh.iface) {
    ifname = e->attrs->nh.iface->name;
  }
  lua_pushliteral(L, "ifname");
  lua_pushlstring(L, ifname, strlen(ifname));
  lua_settable(L, -3);
  lua_settablecfunction(L, "ea_find", luaB_route_ea_find);
  lua_settablecfunction(L, "ea_set_attr_data", luaB_route_ea_set_attr_data);

  lua_newtable(L);
  lua_settablevalue(L, "__index", -2-1);
  lua_setmetatable(L, -2);

  lua_setglobal(L, "route");
}

void luaB_push_eattrs(lua_State *L, struct ea_list *ea) {
  lua_newtable(L);

  if (!ea) {
    log(L_ERR "Null eattrs");
  }

  lua_settablecfunction(L, "__tostring", luaB_addr_tostring);
  lua_setmetatable(L, -2);
}