#include <lua.h>
#include <lauxlib.h>
#include <glib.h>
#include <loudmouth/loudmouth.h>
#include <stdio.h>

#include "util.h"
#include "lm_types.h"

/// lm.ssl
/// Object, containing information about ssl abilities for connection.
/// Create, set parameters, and attach to connection with 'ssl' method.

/// ssl status
/// String, representing what problem have current ssl session.
/// G:
const string2enum_t llm_ssl_status[] = {
	{ "no cert found",             LM_SSL_STATUS_NO_CERT_FOUND             },
	{ "untrusted cert",            LM_SSL_STATUS_UNTRUSTED_CERT            },
	{ "cert expired",              LM_SSL_STATUS_CERT_EXPIRED              },
	{ "cert not activated",        LM_SSL_STATUS_CERT_NOT_ACTIVATED        },
	{ "cert hostname mismatch",    LM_SSL_STATUS_CERT_HOSTNAME_MISMATCH    },
	{ "cert fingerprint mismatch", LM_SSL_STATUS_CERT_FINGERPRINT_MISMATCH },
	{ "generic error",             LM_SSL_STATUS_GENERIC_ERROR             },
	{ NULL,                        0                                       }, // XXX
};

/// ssl callback function
/// User function, called when ssl error happens.
/// XXX: add lm connection object to args? it is not in API, but can be useful,
/// though, with upvalues it is not required.
/// A: lm ssl object, ssl status
/// R: boolean (false if connection process should be terminated)
LmSSLResponse llm_ssl_callback (LmSSL *ssl, LmSSLStatus status, llm_callback_t *cb)
{
	int ret;
	lua_rawgeti (cb->L, LUA_REGISTRYINDEX, cb->reference);
	llm_ssl_bless (cb->L, ssl);
	// XXX lm_ssl_unref (ssl);
	luaL_pushenum (cb->L, status, llm_ssl_status);
	if (lua_pcall (cb->L, 2, 0, 0)) {
		// XXX lua_error (cb->L);
		lua_pop (cb->L, 1);
		return LM_SSL_RESPONSE_CONTINUE;
	}
	ret = lua_toboolean (cb->L, -1);
	lua_pop (cb->L, 1);
	if (ret)
		return LM_SSL_RESPONSE_CONTINUE;
	else
		return LM_SSL_RESPONSE_STOP;
}

static void string2fingerprint (const char *string, char *buffer)
{
	int i;
	for (i = 0; i < 16; i++) {
		int h = g_ascii_xdigit_value ((char)string[i*3]);
		int l = g_ascii_xdigit_value ((char)string[i*3+1]);
		buffer[i] = (char) ((h >= 0 && l >= 0) ? h*16 + l : 0);
	}
}

/// lm.ssl.new
/// Creates new ssl object for use with connection.
/// You can specify server key fingerprint, callback function for error handling,
/// both, or neither. Though, fingerprint should go before callback function.
/// SSL fingerprint is a string like '01:23:45:67:89:AB:CD:EF:FE:DC:BA:98:76:54:32:10'.
/// A: string (optional ssl fingerprint), ssl callback function (optional)
/// R: lm ssl object
static int llm_ssl_new (lua_State *L)
{
	int args = lua_gettop (L);
	LmSSL *ssl;
	if (args == 0)
		ssl = lm_ssl_new (NULL, NULL, NULL, NULL);
	else if (args == 1 && !lua_isfunction (L, 1)) {
		gchar buffer[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
		const char *fingerprint = luaL_checkstring (L, 1);

		if (lua_objlen (L, 1) > 46)
			string2fingerprint (fingerprint, buffer);
		ssl = lm_ssl_new (buffer, NULL, NULL, NULL);
		lua_pop (L, 1);
	} else {
		llm_callback_t *cb;
		gchar buffer[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";

		if (args > 1) {
			const char *fingerprint = luaL_checkstring (L, 1);
			if (lua_objlen (L, 1) > 46)
				string2fingerprint (fingerprint, buffer);
			luaL_argcheck (L, lua_isfunction (L, 2), 2, "function expected");
		} else
			luaL_argcheck (L, lua_isfunction (L, 1), 1, "function expected");
		
		cb = luaL_malloc (L, sizeof (llm_callback_t));
		cb->reference = luaL_ref (L, LUA_REGISTRYINDEX);
		cb->L = L;

		ssl = lm_ssl_new ((args > 1) ? buffer : NULL, (LmSSLFunction)llm_ssl_callback,
							cb, (GDestroyNotify)llm_callback_destroy);
		lua_pop (L, 1);
	}
	llm_ssl_bless (L, ssl);
	lm_ssl_unref (ssl); // XXX
	return 1;
}

/// lm.ssl.bless
/// Blesses given pointer to lm ssl object.
/// A: lightuserdata (C lm ssl object)
/// R: lm ssl object
static int llm_ssl_bless_lua (lua_State *L)
{
	luaL_argcheck (L, lua_islightuserdata (L, 1), 1, "lm ssl lightuserdata expected");
	llm_ssl_bless (L, lua_touserdata (L, 1));
	lua_remove (L, -2);
	return 1;
}

/// lm.ssl.supported
/// Indicates if SSL is supported by loudmouth library.
/// R: boolean
static int llm_ssl_supported (lua_State *L)
{
	lua_pushboolean (L, lm_ssl_is_supported ());
	return 1;
}

/// ssl:fingerprint
/// Returns fingerprint of remote server.
/// R: string or nil
static int llm_ssl_fingerprint (lua_State *L)
{
	char buffer[48];
	llm_ssl_t *object = luaL_checklm_ssl (L, 1);
	const gchar *fingerprint = lm_ssl_get_fingerprint (object->ssl);
	if (fingerprint == NULL)
		lua_pushnil (L);
	else {
		snprintf (buffer, 48,
			  "%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:"
			  "%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX:%02hhX",
			  fingerprint[0], fingerprint[1], fingerprint[2], fingerprint[3],
			  fingerprint[4], fingerprint[5], fingerprint[6], fingerprint[7],
			  fingerprint[8], fingerprint[9], fingerprint[10], fingerprint[11],
			  fingerprint[12], fingerprint[13], fingerprint[14], fingerprint[15]);
		lua_pushlstring (L, buffer, 47);
	}
	lua_remove (L, -2);
	return 1;
}

/// ssl:pointer
/// Returns pointer to underlying C structure.
/// R: lightuserdata
static int llm_ssl_pointer (lua_State *L)
{
	llm_ssl_t *object = luaL_checklm_ssl (L, 1);
	lua_pushlightuserdata (L, object->ssl);
	lua_remove (L, -2);
	return 1;
}

static int llm_ssl_gc (lua_State *L)
{
	llm_ssl_t *object = luaL_checklm_ssl (L, 1);
	lm_ssl_unref (object->ssl);
	lua_pop (L, 1);
	return 0;
}

const static luaL_Reg llm_ssl_reg_f[] = {
	{ "new",       llm_ssl_new       },
	{ "bless",     llm_ssl_bless_lua },
	{ "supported", llm_ssl_supported },
	{ NULL,        NULL              },
};

const static luaL_Reg llm_ssl_reg_m[] = {
	{ "fingerprint", llm_ssl_fingerprint },
	{ "pointer",     llm_ssl_pointer     },
	{ "__gc",        llm_ssl_gc          },
	{ NULL,          NULL                },
};

int luaopen_lm_ssl (lua_State *L)
{
	luaL_newmetatable (L, "loudmouth.ssl");
	lua_pushstring (L, "__index");
	lua_pushvalue (L, -2);
	lua_settable (L, -3);
	luaL_register (L, NULL, llm_ssl_reg_m);
	lua_pop (L, 1);
	luaL_register (L, "lm.ssl", llm_ssl_reg_f);
	return 1;
}