/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file
 */

/* Extension envelope
 * ------------------
 *
 * Authors: Stephan Bosch
 * Specification: RFC 5228
 * Implementation: full
 * Status: testing
 *
 */

#include "lib.h"
#include "str-sanitize.h"
#include "array.h"

#include "sieve-common.h"
#include "sieve-extensions.h"
#include "sieve-commands.h"
#include "sieve-stringlist.h"
#include "sieve-code.h"
#include "sieve-address.h"
#include "sieve-comparators.h"
#include "sieve-match-types.h"
#include "sieve-address-parts.h"
#include "sieve-message.h"

#include "sieve-validator.h"
#include "sieve-generator.h"
#include "sieve-interpreter.h"
#include "sieve-dump.h"
#include "sieve-match.h"

/*
 * Forward declarations
 */

static const struct sieve_command_def envelope_test;
const struct sieve_operation_def envelope_operation;
const struct sieve_extension_def envelope_extension;

/*
 * Extension
 */

static bool
ext_envelope_validator_load(const struct sieve_extension *ext,
			    struct sieve_validator *valdtr);
static bool
ext_envelope_interpreter_load(const struct sieve_extension *ext,
			      const struct sieve_runtime_env *renv,
			      sieve_size_t *address);

static bool
ext_envelope_validator_validate(const struct sieve_extension *ext,
				struct sieve_validator *valdtr, void *context,
				struct sieve_ast_argument *require_arg,
				bool required);
static int
ext_envelope_interpreter_run(const struct sieve_extension *this_ext,
			     const struct sieve_runtime_env *renv,
			     void *context, bool deferred);

const struct sieve_extension_def envelope_extension = {
	.name = "envelope",
	.interpreter_load = ext_envelope_interpreter_load,
	.validator_load = ext_envelope_validator_load,
	SIEVE_EXT_DEFINE_OPERATION(envelope_operation)
};
const struct sieve_validator_extension
envelope_validator_extension = {
	.ext = &envelope_extension,
	.validate = ext_envelope_validator_validate
};
const struct sieve_interpreter_extension
envelope_interpreter_extension = {
	.ext_def = &envelope_extension,
	.run = ext_envelope_interpreter_run
};

static bool
ext_envelope_validator_load(const struct sieve_extension *ext,
			    struct sieve_validator *valdtr)
{
	/* Register new test */
	sieve_validator_register_command(valdtr, ext, &envelope_test);

	sieve_validator_extension_register(valdtr, ext,
					   &envelope_validator_extension, NULL);
	return TRUE;
}

static bool
ext_envelope_interpreter_load(const struct sieve_extension *ext,
			      const struct sieve_runtime_env *renv,
			      sieve_size_t *address ATTR_UNUSED)
{
	sieve_interpreter_extension_register(renv->interp, ext,
					     &envelope_interpreter_extension,
					     NULL);
	return TRUE;
}

static bool
ext_envelope_validator_validate(const struct sieve_extension *ext,
				struct sieve_validator *valdtr,
				void *context ATTR_UNUSED,
				struct sieve_ast_argument *require_arg,
				bool required)
{
	if (required) {
		enum sieve_compile_flags flags =
			sieve_validator_compile_flags(valdtr);

		if ((flags & SIEVE_COMPILE_FLAG_NO_ENVELOPE) != 0) {
			sieve_argument_validate_error(
				valdtr, require_arg,
				"the %s extension cannot be used in this context "
				"(needs access to message envelope)",
				sieve_extension_name(ext));
			return FALSE;
		}
	}
	return TRUE;
}

static int
ext_envelope_interpreter_run(const struct sieve_extension *ext,
			     const struct sieve_runtime_env *renv,
			     void *context ATTR_UNUSED, bool deferred)
{
	const struct sieve_execute_env *eenv = renv->exec_env;

	if ((eenv->flags & SIEVE_EXECUTE_FLAG_NO_ENVELOPE) != 0) {
		if (!deferred) {
			sieve_runtime_error(
				renv, NULL,
				"the %s extension cannot be used in this context "
				"(needs access to message envelope)",
				sieve_extension_name(ext));
		}
		return SIEVE_EXEC_FAILURE;
	}
	return SIEVE_EXEC_OK;
}

/*
 * Envelope test
 *
 * Syntax
 *   envelope [COMPARATOR] [ADDRESS-PART] [MATCH-TYPE]
 *     <envelope-part: string-list> <key-list: string-list>
 */

static bool
tst_envelope_registered(struct sieve_validator *valdtr,
			const struct sieve_extension *ext,
			struct sieve_command_registration *cmd_reg);
static bool
tst_envelope_validate(struct sieve_validator *valdtr,
		      struct sieve_command *tst);
static bool
tst_envelope_generate(const struct sieve_codegen_env *cgenv,
		      struct sieve_command *ctx);

static const struct sieve_command_def envelope_test = {
	.identifier = "envelope",
	.type = SCT_TEST,
	.positional_args= 2,
	.subtests = 0,
	.block_allowed = FALSE,
	.block_required = FALSE,
	.registered = tst_envelope_registered,
	.validate = tst_envelope_validate,
	.generate = tst_envelope_generate
};

/*
 * Envelope operation
 */

static bool
ext_envelope_operation_dump(const struct sieve_dumptime_env *denv,
			    sieve_size_t *address);
static int
ext_envelope_operation_execute(const struct sieve_runtime_env *renv,
			       sieve_size_t *address);

const struct sieve_operation_def envelope_operation = {
	.mnemonic = "ENVELOPE",
	.ext_def = &envelope_extension,
	.dump = ext_envelope_operation_dump,
	.execute = ext_envelope_operation_execute
};

/*
 * Envelope parts
 *
 * FIXME: not available to extensions
 */

struct sieve_envelope_part {
	const char *identifier;

	const struct smtp_address *const *(*get_addresses)
		(const struct sieve_runtime_env *renv);
	const char * const *(*get_values)
		(const struct sieve_runtime_env *renv);
};

static const struct smtp_address *const *
_from_part_get_addresses(const struct sieve_runtime_env *renv);
static const char *const *
_from_part_get_values(const struct sieve_runtime_env *renv);
static const struct smtp_address *const *
_to_part_get_addresses(const struct sieve_runtime_env *renv);
static const char *const *
_to_part_get_values(const struct sieve_runtime_env *renv);
static const char *const *
_auth_part_get_values(const struct sieve_runtime_env *renv);

static const struct sieve_envelope_part _from_part = {
	"from",
	_from_part_get_addresses,
	_from_part_get_values,
};

static const struct sieve_envelope_part _to_part = {
	"to",
	_to_part_get_addresses,
	_to_part_get_values,
};

static const struct sieve_envelope_part _auth_part = {
	"auth",
	NULL,
	_auth_part_get_values,
};

static const struct sieve_envelope_part *_envelope_parts[] = {
	/* Required */
	&_from_part, &_to_part,

	/* Non-standard */
	&_auth_part
};

static unsigned int _envelope_part_count = N_ELEMENTS(_envelope_parts);

static const struct sieve_envelope_part *
_envelope_part_find(const char *identifier)
{
	unsigned int i;

	for (i = 0; i < _envelope_part_count; i++) {
		if (strcasecmp(_envelope_parts[i]->identifier,
			       identifier) == 0)
			return _envelope_parts[i];
	}

	return NULL;
}

/* Envelope parts implementation */

static const struct smtp_address *const *
_from_part_get_addresses(const struct sieve_runtime_env *renv)
{
	ARRAY(const struct smtp_address *) envelope_values;
	const struct smtp_address *address =
		sieve_message_get_sender(renv->msgctx);

	t_array_init(&envelope_values, 2);

	if (address == NULL)
		address = smtp_address_create_temp(NULL, NULL);
	array_append(&envelope_values, &address, 1);

	(void)array_append_space(&envelope_values);
	return array_idx(&envelope_values, 0);
}

static const char *const *
_from_part_get_values(const struct sieve_runtime_env *renv)
{
	ARRAY(const char *)envelope_values;
	const struct smtp_address *address =
		sieve_message_get_sender(renv->msgctx);
	const char *value;

	t_array_init(&envelope_values, 2);

	value = "";
	if (!smtp_address_isnull(address))
		value = smtp_address_encode(address);
	array_append(&envelope_values, &value, 1);

	(void)array_append_space(&envelope_values);

	return array_idx(&envelope_values, 0);
}

static const struct smtp_address *const *
_to_part_get_addresses(const struct sieve_runtime_env *renv)
{
	ARRAY(const struct smtp_address *) envelope_values;
	const struct smtp_address *address =
		sieve_message_get_orig_recipient(renv->msgctx);

	if (address != NULL && address->localpart != NULL) {
		t_array_init(&envelope_values, 2);

		array_append(&envelope_values, &address, 1);

		(void)array_append_space(&envelope_values);
		return array_idx(&envelope_values, 0);
	}
	return NULL;
}

static const char *const *
_to_part_get_values(const struct sieve_runtime_env *renv)
{
	ARRAY(const char *) envelope_values;
	const struct smtp_address *address =
		sieve_message_get_orig_recipient(renv->msgctx);

	t_array_init(&envelope_values, 2);

	if (address != NULL && address->localpart != NULL) {
		const char *value = smtp_address_encode(address);
		array_append(&envelope_values, &value, 1);
	}

	(void)array_append_space(&envelope_values);

	return array_idx(&envelope_values, 0);
}

static const char *const *
_auth_part_get_values(const struct sieve_runtime_env *renv)
{
	const struct sieve_execute_env *eenv = renv->exec_env;
	ARRAY(const char *) envelope_values;

	t_array_init(&envelope_values, 2);

	if (eenv->msgdata->auth_user != NULL)
		array_append(&envelope_values, &eenv->msgdata->auth_user, 1);

	(void)array_append_space(&envelope_values);

	return array_idx(&envelope_values, 0);
}

/*
 * Envelope address list
 */

/* Forward declarations */

static int
sieve_envelope_address_list_next_string_item(struct sieve_stringlist *_strlist,
					     string_t **str_r);
static int
sieve_envelope_address_list_next_item(struct sieve_address_list *_addrlist,
				      struct smtp_address *addr_r,
				      string_t **unparsed_r);
static void
sieve_envelope_address_list_reset(struct sieve_stringlist *_strlist);

/* Stringlist object */

struct sieve_envelope_address_list {
	struct sieve_address_list addrlist;

	struct sieve_stringlist *env_parts;

	const struct smtp_address *const *cur_addresses;
	const char * const *cur_values;

	int value_index;
};

static struct sieve_address_list *
sieve_envelope_address_list_create(const struct sieve_runtime_env *renv,
				   struct sieve_stringlist *env_parts)
{
	struct sieve_envelope_address_list *addrlist;

	addrlist = t_new(struct sieve_envelope_address_list, 1);
	addrlist->addrlist.strlist.runenv = renv;
	addrlist->addrlist.strlist.exec_status = SIEVE_EXEC_OK;
	addrlist->addrlist.strlist.next_item =
		sieve_envelope_address_list_next_string_item;
	addrlist->addrlist.strlist.reset = sieve_envelope_address_list_reset;
	addrlist->addrlist.next_item = sieve_envelope_address_list_next_item;
	addrlist->env_parts = env_parts;

	return &addrlist->addrlist;
}

static int
sieve_envelope_address_list_next_item(struct sieve_address_list *_addrlist,
				      struct smtp_address *addr_r,
				      string_t **unparsed_r)
{
	struct sieve_envelope_address_list *addrlist =
		(struct sieve_envelope_address_list *)_addrlist;
	const struct sieve_runtime_env *renv = _addrlist->strlist.runenv;

	if (addr_r != NULL)
		smtp_address_init(addr_r, NULL, NULL);
	if (unparsed_r != NULL) *unparsed_r = NULL;

	while (addrlist->cur_addresses == NULL &&
	       addrlist->cur_values == NULL) {
		const struct sieve_envelope_part *epart;
		string_t *envp_item = NULL;
		int ret;

		/* Read next header value from source list */
		if ((ret = sieve_stringlist_next_item(addrlist->env_parts,
						      &envp_item)) <= 0)
			return ret;

		if (_addrlist->strlist.trace) {
			sieve_runtime_trace(
				_addrlist->strlist.runenv, 0,
				"getting `%s' part from message envelope",
				str_sanitize(str_c(envp_item), 80));
		}

		if ((epart=_envelope_part_find(str_c(envp_item))) != NULL) {
			addrlist->value_index = 0;

			if (epart->get_addresses != NULL) {
				/* Field contains addresses */
				addrlist->cur_addresses =
					epart->get_addresses(renv);

				/* Drop empty list */
				if (addrlist->cur_addresses != NULL &&
				    addrlist->cur_addresses[0] == NULL)
					addrlist->cur_addresses = NULL;
			}

			if (addrlist->cur_addresses == NULL &&
			    epart->get_values != NULL) {
				/* Field contains something else */
				addrlist->cur_values = epart->get_values(renv);

				/* Drop empty list */
				if (addrlist->cur_values != NULL &&
				    addrlist->cur_values[0] == NULL)
					addrlist->cur_values = NULL;
			}
		}
	}

	/* Return next item */
	if (addrlist->cur_addresses != NULL) {
		const struct smtp_address *addr =
			addrlist->cur_addresses[addrlist->value_index];

		if (addr->localpart == NULL) {
			/* Null path <> */
			if (unparsed_r != NULL)
				*unparsed_r = t_str_new_const("", 0);
		} else {
			if (addr_r != NULL)
				*addr_r = *addr;
		}

		/* Advance to next value */
		addrlist->value_index++;
		if (addrlist->cur_addresses[addrlist->value_index] == NULL) {
			addrlist->cur_addresses = NULL;
			addrlist->value_index = 0;
		}
	} else {
		if (unparsed_r != NULL) {
			const char *value =
				addrlist->cur_values[addrlist->value_index];

			*unparsed_r = t_str_new_const(value, strlen(value));
		}

		/* Advance to next value */
		addrlist->value_index++;
		if (addrlist->cur_values[addrlist->value_index] == NULL) {
			addrlist->cur_values = NULL;
			addrlist->value_index = 0;
		}
	}

	return 1;
}

static int
sieve_envelope_address_list_next_string_item(struct sieve_stringlist *_strlist,
					     string_t **str_r)
{
	struct sieve_address_list *addrlist =
		(struct sieve_address_list *)_strlist;
	struct smtp_address addr;
	int ret;

	if ((ret=sieve_envelope_address_list_next_item(addrlist, &addr,
						       str_r)) <= 0)
		return ret;

	if (addr.localpart != NULL) {
		const char *addr_str = smtp_address_encode(&addr);
		if (str_r != NULL)
			*str_r = t_str_new_const(addr_str, strlen(addr_str));
	}
	return 1;
}

static void
sieve_envelope_address_list_reset(struct sieve_stringlist *_strlist)
{
	struct sieve_envelope_address_list *addrlist =
		(struct sieve_envelope_address_list *)_strlist;

	sieve_stringlist_reset(addrlist->env_parts);
	addrlist->cur_addresses = NULL;
	addrlist->cur_values = NULL;
	addrlist->value_index = 0;
}

/*
 * Command Registration
 */

static bool
tst_envelope_registered(struct sieve_validator *valdtr,
			const struct sieve_extension *ext ATTR_UNUSED,
			struct sieve_command_registration *cmd_reg)
{
	/* The order of these is not significant */
	sieve_comparators_link_tag(valdtr, cmd_reg, SIEVE_MATCH_OPT_COMPARATOR);
	sieve_match_types_link_tags(valdtr, cmd_reg, SIEVE_MATCH_OPT_MATCH_TYPE);
	sieve_address_parts_link_tags(valdtr, cmd_reg, SIEVE_AM_OPT_ADDRESS_PART);
	return TRUE;
}

/*
 * Validation
 */

static int
_envelope_part_is_supported(void *context, struct sieve_ast_argument *arg)
{
	const struct sieve_envelope_part **not_address =
		(const struct sieve_envelope_part **) context;

	if (sieve_argument_is_string_literal(arg)) {
		const struct sieve_envelope_part *epart;

		if ((epart=_envelope_part_find(
			sieve_ast_strlist_strc(arg))) != NULL) {
			if (epart->get_addresses == NULL) {
				if (*not_address == NULL)
					*not_address = epart;
			}
			return 1;
		}
		return 0;
	}
	return 1; /* Can't check at compile time */
}

static bool
tst_envelope_validate(struct sieve_validator *valdtr, struct sieve_command *tst)
{
	struct sieve_ast_argument *arg = tst->first_positional;
	struct sieve_ast_argument *epart;
	struct sieve_comparator cmp_default =
		SIEVE_COMPARATOR_DEFAULT(i_ascii_casemap_comparator);
	struct sieve_match_type mcht_default =
		SIEVE_MATCH_TYPE_DEFAULT(is_match_type);
	const struct sieve_envelope_part *not_address = NULL;

	if (!sieve_validate_positional_argument(valdtr, tst, arg,
						"envelope part", 1,
						SAAT_STRING_LIST)) {
		return FALSE;
	}

	if (!sieve_validator_argument_activate(valdtr, tst, arg, FALSE))
		return FALSE;

	/* Check whether supplied envelope parts are supported
	 *   FIXME: verify dynamic envelope parts at runtime
	 */
	epart = arg;
	if (sieve_ast_stringlist_map(&epart, (void *) &not_address,
				     _envelope_part_is_supported) <= 0) {
		i_assert(epart != NULL);
		sieve_argument_validate_error(
			valdtr, epart,
			"specified envelope part '%s' is not supported by the envelope test",
			str_sanitize(sieve_ast_strlist_strc(epart), 64));
		return FALSE;
	}

	if (not_address != NULL) {
		struct sieve_ast_argument *addrp_arg =
			sieve_command_find_argument(tst, &address_part_tag);

		if (addrp_arg != NULL) {
			sieve_argument_validate_error(
				valdtr, addrp_arg,
				"address part ':%s' specified while non-address envelope part '%s' "
				"is tested with the envelope test",
			sieve_ast_argument_tag(addrp_arg),
					       not_address->identifier);
			return FALSE;
		}
	}

	arg = sieve_ast_argument_next(arg);

	if (!sieve_validate_positional_argument(valdtr, tst, arg, "key list", 2,
						SAAT_STRING_LIST))
		return FALSE;

	if (!sieve_validator_argument_activate(valdtr, tst, arg, FALSE))
		return FALSE;

	/* Validate the key argument to a specified match type */
	return sieve_match_type_validate(valdtr, tst, arg,
					 &mcht_default, &cmp_default);
}

/*
 * Code generation
 */

static bool
tst_envelope_generate(const struct sieve_codegen_env *cgenv,
		      struct sieve_command *cmd)
{
	(void)sieve_operation_emit(cgenv->sblock, cmd->ext,
				   &envelope_operation);

	/* Generate arguments */
	if (!sieve_generate_arguments(cgenv, cmd, NULL))
		return FALSE;
	return TRUE;
}

/*
 * Code dump
 */

static bool
ext_envelope_operation_dump(const struct sieve_dumptime_env *denv,
			    sieve_size_t *address)
{
	sieve_code_dumpf(denv, "ENVELOPE");
	sieve_code_descend(denv);

	/* Handle any optional arguments */
	if (sieve_addrmatch_opr_optional_dump(denv, address, NULL) != 0)
		return FALSE;

	return (sieve_opr_stringlist_dump(denv, address, "envelope part") &&
		sieve_opr_stringlist_dump(denv, address, "key list"));
}

/*
 * Interpretation
 */

static int
ext_envelope_operation_execute(const struct sieve_runtime_env *renv,
			       sieve_size_t *address)
{
	struct sieve_comparator cmp =
		SIEVE_COMPARATOR_DEFAULT(i_ascii_casemap_comparator);
	struct sieve_match_type mcht =
		SIEVE_MATCH_TYPE_DEFAULT(is_match_type);
	struct sieve_address_part addrp =
		SIEVE_ADDRESS_PART_DEFAULT(all_address_part);
	struct sieve_stringlist *env_part_list, *value_list, *key_list;
	struct sieve_address_list *addr_list;
	int match, ret;

	/*
	 * Read operands
	 */

	/* Read optional operands */
	if (sieve_addrmatch_opr_optional_read(renv, address, NULL, &ret,
					      &addrp, &mcht, &cmp) < 0)
		return ret;

	/* Read envelope-part */
	if ((ret = sieve_opr_stringlist_read(renv, address, "envelope-part",
					     &env_part_list)) <= 0)
		return ret;

	/* Read key-list */
	if ((ret = sieve_opr_stringlist_read(renv, address, "key-list",
					     &key_list)) <= 0)
		return ret;

	/*
	 * Perform test
	 */

	sieve_runtime_trace(renv, SIEVE_TRLVL_TESTS, "envelope test");

	/* Create value stringlist */
	addr_list = sieve_envelope_address_list_create(renv, env_part_list);
	value_list = sieve_address_part_stringlist_create(renv, &addrp,
							  addr_list);

	/* Perform match */
	if ((match = sieve_match(renv, &mcht, &cmp,
				 value_list, key_list, &ret)) < 0)
		return ret;

	/* Set test result for subsequent conditional jump */
	sieve_interpreter_set_test_result(renv->interp, match > 0);
	return SIEVE_EXEC_OK;
}