#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <civetweb.h>
#include <openssl/opensslconf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/rand.h>
#include <openssl/ts.h>
#include <openssl/bn.h>

/* Name of config entry that defines the OID file. */
# define ENV_OID_FILE            "oid_file"

static ASN1_OBJECT *txt2obj(const char *oid);
static CONF *load_config_file(const char *configfile);

/* Reply related functions. */
static int reply_command(CONF *conf, char *section, char *engine,
		char *queryfile, char *passin, char *inkey,
		const EVP_MD *md, char *signer, char *chain,
		const char *policy, char *in, int token_in,
		char *out, int token_out, int text);
static TS_RESP *read_PKCS7(BIO *in_bio);
static TS_RESP *create_response(CONF *conf, const char *section, char *engine,
		char *queryfile, char *passin,
		char *inkey, const EVP_MD *md, char *signer,
		char *chain, const char *policy);
static ASN1_INTEGER *serial_cb(TS_RESP_CTX *ctx, void *data);
static ASN1_INTEGER *next_serial(const char *serialfile);
static int save_ts_serial(const char *serialfile, ASN1_INTEGER *serial);

# define B_FORMAT_TEXT   0x8000
# define FORMAT_UNDEF    0
# define FORMAT_TEXT    (1 | B_FORMAT_TEXT)     /* Generic text */
# define FORMAT_ASN1     4                      /* ASN.1/DER */


/*
   int ts_http_respond(short event, ad_conn_t *conn, void *userdata) {
   if (event & AD_EVENT_READ) {
   if (ad_http_get_status(conn) == AD_HTTP_REQ_DONE) {
   ad_http_response(conn, 200, "text/html", "Hello World", 11);
   return ad_http_is_keepalive_request(conn) ? AD_DONE : AD_CLOSE;
   }
   }
   return AD_OK;
   }

   int http_default_handler(short event, ad_conn_t *conn, void *userdata) {
   if (event & AD_EVENT_READ) {
   if (ad_http_get_status(conn) == AD_HTTP_REQ_DONE) {
   ad_http_response(conn, 501, "text/html", "Not implemented", 15);
   return AD_CLOSE; // Close connection.
   }
   }
   return AD_OK;
   }
   */


// This function will be called by civetweb on every new request.
static int begin_request_handler(struct mg_connection *conn)
{
	const struct mg_request_info *request_info = mg_get_request_info(conn);
	char content[100];

	// Prepare the message we're going to send
	int content_length = snprintf(content, sizeof(content),
			"Hello from civetweb! Remote port: %d",
			request_info->remote_port);

	// Send HTTP reply to the client
	mg_printf(conn,
			"HTTP/1.1 200 OK\r\n"
			"Content-Type: text/plain\r\n"
			"Content-Length: %d\r\n"        // Always set Content-Length
			"\r\n"
			"%s",
			content_length, content);

	// Returning non-zero tells civetweb that our function has replied to
	// the client, and civetweb should not send client any more data.
	return 1;
}

int http_server_start() {
	struct mg_context *ctx;
	struct mg_callbacks callbacks;

	// List of options. Last element must be NULL.
	const char *options[] = {"listening_ports", "8080", NULL};

	// Prepare callbacks structure. We have only one callback, the rest are NULL.
	memset(&callbacks, 0, sizeof(callbacks));
	callbacks.begin_request = begin_request_handler;

	// Start the web server.
	ctx = mg_start(&callbacks, NULL, options);

	// Wait until user hits "enter". Server is running in separate thread.
	// Navigating to http://localhost:8080 will invoke begin_request_handler().
	getchar();

	// Stop the server.
	mg_stop(ctx);

	return 0;
}

/*
 * Configuration file-related function definitions.
 */

static ASN1_OBJECT *txt2obj(const char *oid)
{
	ASN1_OBJECT *oid_obj = NULL;

	if ((oid_obj = OBJ_txt2obj(oid, 0)) == NULL)
//		BIO_printf(bio_err, "cannot convert %s to OID\n", oid);

	return oid_obj;
}

//static CONF *load_config_file(const char *configfile)
//{
//	CONF *conf = app_load_config(configfile);
//
//	if (conf != NULL) {
//		const char *p;
//
////		BIO_printf(bio_err, "Using configuration from %s\n", configfile);
//		p = NCONF_get_string(conf, NULL, ENV_OID_FILE);
//		if (p != NULL) {
//			BIO *oid_bio = BIO_new_file(p, "r");
//			if (!oid_bio)
//				ERR_print_errors(bio_err);
//			else {
//				OBJ_create_objects(oid_bio);
//				BIO_free_all(oid_bio);
//			}
//		} else
//			ERR_clear_error();
//		if (!add_oid_section(conf))
//			ERR_print_errors(bio_err);
//	}
//	return conf;
//}

/*
 * Reply-related method definitions.
 */

static int reply_command(CONF *conf, char *section, char *engine,
		char *queryfile, char *passin, char *inkey,
		const EVP_MD *md, char *signer, char *chain,
		const char *policy, char *in, int token_in,
		char *out, int token_out, int text)
{
	int ret = 0;
	TS_RESP *response = NULL;
	BIO *in_bio = NULL;
	BIO *query_bio = NULL;
	BIO *inkey_bio = NULL;
	BIO *signer_bio = NULL;
	BIO *out_bio = NULL;
    BIO *bio_err;

	if (in != NULL) {
		if ((in_bio = BIO_new_file(in, "rb")) == NULL)
			goto end;
		if (token_in) {
			response = read_PKCS7(in_bio);
		} else {
			response = d2i_TS_RESP_bio(in_bio, NULL);
		}
	} else {
		response = create_response(conf, section, engine, queryfile,
				passin, inkey, md, signer, chain, policy);
//		if (response)
//			BIO_printf(bio_err, "Response has been generated.\n");
//		else
//			BIO_printf(bio_err, "Response is not generated.\n");
	}
	if (response == NULL)
		goto end;

	/* Write response. */
	if (text) {
//		if ((out_bio = bio_open_default(out, 'w', FORMAT_TEXT)) == NULL)
//			goto end;
		if (token_out) {
			TS_TST_INFO *tst_info = TS_RESP_get_tst_info(response);
			if (!TS_TST_INFO_print_bio(out_bio, tst_info))
				goto end;
		} else {
			if (!TS_RESP_print_bio(out_bio, response))
				goto end;
		}
	} else {
//		if ((out_bio = bio_open_default(out, 'w', FORMAT_ASN1)) == NULL)
//			goto end;
		if (token_out) {
			PKCS7 *token = TS_RESP_get_token(response);
			if (!i2d_PKCS7_bio(out_bio, token))
				goto end;
		} else {
			if (!i2d_TS_RESP_bio(out_bio, response))
				goto end;
		}
	}

	ret = 1;

end:
	ERR_print_errors(bio_err);
	BIO_free_all(in_bio);
	BIO_free_all(query_bio);
	BIO_free_all(inkey_bio);
	BIO_free_all(signer_bio);
	BIO_free_all(out_bio);
	TS_RESP_free(response);
	return ret;
}

/* Reads a PKCS7 token and adds default 'granted' status info to it. */
static TS_RESP *read_PKCS7(BIO *in_bio)
{
	int ret = 0;
	PKCS7 *token = NULL;
	TS_TST_INFO *tst_info = NULL;
	TS_RESP *resp = NULL;
	TS_STATUS_INFO *si = NULL;

	if ((token = d2i_PKCS7_bio(in_bio, NULL)) == NULL)
		goto end;
	if ((tst_info = PKCS7_to_TS_TST_INFO(token)) == NULL)
		goto end;
	if ((resp = TS_RESP_new()) == NULL)
		goto end;
	if ((si = TS_STATUS_INFO_new()) == NULL)
		goto end;
//	if (!TS_STATUS_INFO_set_status(si, TS_STATUS_GRANTED))
//		goto end;
	if (!TS_RESP_set_status_info(resp, si))
		goto end;
	TS_RESP_set_tst_info(resp, token, tst_info);
	token = NULL;               /* Ownership is lost. */
	tst_info = NULL;            /* Ownership is lost. */
	ret = 1;

end:
	PKCS7_free(token);
	TS_TST_INFO_free(tst_info);
	if (!ret) {
		TS_RESP_free(resp);
		resp = NULL;
	}
	TS_STATUS_INFO_free(si);
	return resp;
}

static TS_RESP *create_response(CONF *conf, const char *section, char *engine,
		char *queryfile, char *passin,
		char *inkey, const EVP_MD *md, char *signer,
		char *chain, const char *policy)
{
	int ret = 0;
	TS_RESP *response = NULL;
	BIO *query_bio = NULL;
	TS_RESP_CTX *resp_ctx = NULL;

	if ((query_bio = BIO_new_file(queryfile, "rb")) == NULL)
		goto end;
	if ((section = TS_CONF_get_tsa_section(conf, section)) == NULL)
		goto end;
	if ((resp_ctx = TS_RESP_CTX_new()) == NULL)
		goto end;
	if (!TS_CONF_set_serial(conf, section, serial_cb, resp_ctx))
		goto end;
# ifndef OPENSSL_NO_ENGINE
	if (!TS_CONF_set_crypto_device(conf, section, engine))
		goto end;
# endif
	if (!TS_CONF_set_signer_cert(conf, section, signer, resp_ctx))
		goto end;
	if (!TS_CONF_set_certs(conf, section, chain, resp_ctx))
		goto end;
	if (!TS_CONF_set_signer_key(conf, section, inkey, passin, resp_ctx))
		goto end;

//	if (md) {
//		if (!TS_RESP_CTX_set_signer_digest(resp_ctx, md))
//			goto end;
//	} else if (!TS_CONF_set_signer_digest(conf, section, NULL, resp_ctx)) {
//		goto end;
//	}

	if (!TS_CONF_set_def_policy(conf, section, policy, resp_ctx))
		goto end;
	if (!TS_CONF_set_policies(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_digests(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_accuracy(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_clock_precision_digits(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_ordering(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_tsa_name(conf, section, resp_ctx))
		goto end;
	if (!TS_CONF_set_ess_cert_id_chain(conf, section, resp_ctx))
		goto end;
	if ((response = TS_RESP_create_response(resp_ctx, query_bio)) == NULL)
		goto end;
	ret = 1;

end:
	if (!ret) {
		TS_RESP_free(response);
		response = NULL;
	}
	TS_RESP_CTX_free(resp_ctx);
	BIO_free_all(query_bio);
	return response;
}

static ASN1_INTEGER *serial_cb(TS_RESP_CTX *ctx, void *data)
{
	const char *serial_file = (const char *)data;
	ASN1_INTEGER *serial = next_serial(serial_file);

	if (!serial) {
		TS_RESP_CTX_set_status_info(ctx, TS_STATUS_REJECTION,
				"Error during serial number "
				"generation.");
		TS_RESP_CTX_add_failure_info(ctx, TS_INFO_ADD_INFO_NOT_AVAILABLE);
	} else
		save_ts_serial(serial_file, serial);

	return serial;
}

static ASN1_INTEGER *next_serial(const char *serialfile)
{
	int ret = 0;
	BIO *in = NULL;
	ASN1_INTEGER *serial = NULL;
	BIGNUM *bn = NULL;

	if ((serial = ASN1_INTEGER_new()) == NULL)
		goto err;

	if ((in = BIO_new_file(serialfile, "r")) == NULL) {
		ERR_clear_error();
//		BIO_printf(bio_err, "Warning: could not open file %s for "
//				"reading, using serial number: 1\n", serialfile);
		if (!ASN1_INTEGER_set(serial, 1))
			goto err;
	} else {
		char buf[1024];
		if (!a2i_ASN1_INTEGER(in, serial, buf, sizeof(buf))) {
//			BIO_printf(bio_err, "unable to load number from %s\n",
//					serialfile);
			goto err;
		}
		if ((bn = ASN1_INTEGER_to_BN(serial, NULL)) == NULL)
			goto err;
		ASN1_INTEGER_free(serial);
		serial = NULL;
		if (!BN_add_word(bn, 1))
			goto err;
		if ((serial = BN_to_ASN1_INTEGER(bn, NULL)) == NULL)
			goto err;
	}
	ret = 1;

err:
	if (!ret) {
		ASN1_INTEGER_free(serial);
		serial = NULL;
	}
	BIO_free_all(in);
	BN_free(bn);
	return serial;
}

static int save_ts_serial(const char *serialfile, ASN1_INTEGER *serial)
{
	int ret = 0;
	BIO *out = NULL;

	if ((out = BIO_new_file(serialfile, "w")) == NULL)
		goto err;
	if (i2a_ASN1_INTEGER(out, serial) <= 0)
		goto err;
	if (BIO_puts(out, "\n") <= 0)
		goto err;
	ret = 1;
err:
	if (!ret)
//		BIO_printf(bio_err, "could not save serial number to %s\n",
//				serialfile);
	BIO_free_all(out);
	return ret;
}