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

 */

#include "lib.h"

#include "md5.h"

#include "ioloop.h"

#include "str.h"

#include "str-sanitize.h"

#include "array.h"

#include "settings.h"

#include "sieve-common.h"

#include "sieve-error.h"

#include "sieve-extensions.h"

#include "sieve-message.h"

#include "sieve-code.h"

#include "sieve-runtime.h"

#include "sieve-interpreter.h"

#include "sieve-actions.h"

#include "sieve-result.h"

#include "ext-duplicate-settings.h"

#include "ext-duplicate-common.h"

/*

 * Extension configuration

 */

int ext_duplicate_load(const struct sieve_extension *ext, void **context_r)

{

  struct sieve_instance *svinst = ext->svinst;

  const struct ext_duplicate_settings *set;

  struct ext_duplicate_context *extctx;

  const char *error;

  if (settings_get(svinst->event, &ext_duplicate_setting_parser_info, 0,

       &set, &error) < 0) {

    e_error(svinst->event, "%s", error);

    return -1;

  }

  extctx = i_new(struct ext_duplicate_context, 1);

  extctx->set = set;

  *context_r = extctx;

  return 0;

}

void ext_duplicate_unload(const struct sieve_extension *ext)

{

  struct ext_duplicate_context *extctx = ext->context;

  if (extctx == NULL)

    return;

  settings_free(extctx->set);

  i_free(extctx);

}

/*

 * Duplicate_mark action

 */

struct act_duplicate_mark_data {

  const char *handle;

  unsigned int period;

  unsigned char hash[MD5_RESULTLEN];

  bool last:1;

};

static void

act_duplicate_mark_print(const struct sieve_action *action,

       const struct sieve_result_print_env *rpenv,

       bool *keep);

static void

act_duplicate_mark_finish(const struct sieve_action_exec_env *aenv,

        void *tr_context, int status);

static const struct sieve_action_def act_duplicate_mark = {

  .name = "duplicate_mark",

  .print = act_duplicate_mark_print,

  .finish = act_duplicate_mark_finish,

};

static void

act_duplicate_mark_print(const struct sieve_action *action,

       const struct sieve_result_print_env *rpenv,

       bool *keep ATTR_UNUSED)

{

  struct act_duplicate_mark_data *data =

    (struct act_duplicate_mark_data *)action->context;

  const char *last = (data->last ? " last" : "");

  if (data->handle != NULL) {

    sieve_result_action_printf(

      rpenv, "track%s duplicate with handle: %s",

      last, str_sanitize(data->handle, 128));

  } else {

    sieve_result_action_printf(rpenv, "track%s duplicate", last);

  }

}

static void

act_duplicate_mark_finish(const struct sieve_action_exec_env *aenv,

        void *tr_context ATTR_UNUSED, int status)

{

  const struct sieve_execute_env *eenv = aenv->exec_env;

  struct act_duplicate_mark_data *data =

    (struct act_duplicate_mark_data *)aenv->action->context;

  if (status != SIEVE_EXEC_OK) {

    e_debug(aenv->event, "Not marking duplicate (status=%s)",

      sieve_execution_exitcode_to_str(status));

    return;

  }

  e_debug(aenv->event, "Marking duplicate");

  /* Message was handled successfully, so track duplicate for this

   * message.

   */

  eenv->exec_status->significant_action_executed = TRUE;

  sieve_action_duplicate_mark(aenv, data->hash, sizeof(data->hash),

            ioloop_time + data->period);

}

/*

 * Duplicate checking

 */

struct ext_duplicate_handle {

  const char *handle;

  bool last:1;

  bool duplicate:1;

};

struct ext_duplicate_hash {

  unsigned char hash[MD5_RESULTLEN];

  ARRAY(struct ext_duplicate_handle) handles;

};

struct ext_duplicate_runtime_context {

  ARRAY(struct ext_duplicate_hash) hashes;

};

static void

ext_duplicate_hash(string_t *handle, const char *value, size_t value_len,

       bool last, unsigned char hash_r[])

{

  static const char *id = "sieve duplicate";

  struct md5_context md5ctx;

  md5_init(&md5ctx);

  md5_update(&md5ctx, id, strlen(id));

  if (last)

    md5_update(&md5ctx, "0", 1);

  else

    md5_update(&md5ctx, "+", 1);

  if (handle != NULL) {

    md5_update(&md5ctx, "h-", 2);

    md5_update(&md5ctx, str_c(handle), str_len(handle));

  } else {

    md5_update(&md5ctx, "default", 7);

  }

  md5_update(&md5ctx, value, value_len);

  md5_final(&md5ctx, hash_r);

}

int ext_duplicate_check(const struct sieve_runtime_env *renv, string_t *handle,

      const char *value, size_t value_len,

      sieve_number_t period, bool last, bool *duplicate_r)

{

  const struct sieve_execute_env *eenv = renv->exec_env;

  const struct sieve_extension *this_ext = renv->oprtn->ext;

  struct ext_duplicate_runtime_context *rctx;

  bool duplicate = FALSE;

  pool_t msg_pool = NULL, result_pool = NULL;

  unsigned char hash[MD5_RESULTLEN];

  struct ext_duplicate_hash *hash_record = NULL;

  struct ext_duplicate_handle *handle_record = NULL;

  struct act_duplicate_mark_data *act;

  int ret;

  *duplicate_r = FALSE;

  if (!sieve_execute_duplicate_check_available(eenv)) {

    sieve_runtime_warning(

      renv, NULL, "duplicate test: "

      "duplicate checking not available in this context");

    return SIEVE_EXEC_OK;

  }

  if (value == NULL)

    return SIEVE_EXEC_OK;

  /* Create hash */

  ext_duplicate_hash(handle, value, value_len, last, hash);

  /* Get context; find out whether duplicate was checked earlier */

  rctx = sieve_message_context_extension_get(renv->msgctx, this_ext);

  if (rctx == NULL) {

    /* Create context */

    msg_pool = sieve_message_context_pool(renv->msgctx);

    rctx = p_new(msg_pool, struct ext_duplicate_runtime_context, 1);

    sieve_message_context_extension_set(renv->msgctx, this_ext,

                rctx);

  } else if (array_is_created(&rctx->hashes)) {

    struct ext_duplicate_hash *record;

    array_foreach_modifiable(&rctx->hashes, record) {

      if (memcmp(record->hash, hash, MD5_RESULTLEN) == 0) {

        hash_record = record;

        break;

      }

    }

  }

  if (hash_record != NULL) {

    const struct ext_duplicate_handle *rhandle;

    array_foreach(&hash_record->handles, rhandle) {

      const char *handle_str =

        (handle == NULL ? NULL : str_c(handle));

      if (null_strcmp(rhandle->handle, handle_str) == 0 &&

          rhandle->last == last)

        return (rhandle->duplicate ?

                SIEVE_DUPLICATE_CHECK_RESULT_EXISTS :

          SIEVE_DUPLICATE_CHECK_RESULT_NOT_FOUND);

    }

  }

  result_pool = sieve_result_pool(renv->result);

  act = p_new(result_pool, struct act_duplicate_mark_data, 1);

  if (handle != NULL)

    act->handle = p_strdup(result_pool, str_c(handle));

  act->period = period;

  memcpy(act->hash, hash, MD5_RESULTLEN);

  act->last = last;

  /* Check duplicate */

  ret = sieve_execute_duplicate_check(eenv, hash, sizeof(hash),

              &duplicate);

  if (ret >= SIEVE_EXEC_OK && !duplicate && last) {

    unsigned char no_last_hash[MD5_RESULTLEN];

    /* Check for entry without :last */

    ext_duplicate_hash(handle, value, value_len,

           FALSE, no_last_hash);

    ret = sieve_execute_duplicate_check(

      eenv, no_last_hash, sizeof(no_last_hash),

      &duplicate);

  }

  if (ret < SIEVE_EXEC_OK) {

    sieve_runtime_critical(

      renv, NULL, "failed to check for duplicate",

      "failed to check for duplicate%s",

      (ret == SIEVE_EXEC_TEMP_FAILURE ?

       " (temporary failure)" : ""));

    return ret;

  }

  /* We may only mark the message as duplicate when Sieve script executes

     successfully; therefore defer this operation until successful result

     execution.

   */

  if (!duplicate || last) {

    if (sieve_result_add_action(renv, NULL, NULL,

              &act_duplicate_mark,

              NULL, act, 0, FALSE) < 0)

      return SIEVE_EXEC_FAILURE;

  }

  /* Cache result */

  if (msg_pool == NULL)

    msg_pool = sieve_message_context_pool(renv->msgctx);

  if (hash_record == NULL) {

    if (!array_is_created(&rctx->hashes))

      p_array_init(&rctx->hashes, msg_pool, 64);

    hash_record = array_append_space(&rctx->hashes);

    memcpy(hash_record->hash, hash, MD5_RESULTLEN);

    p_array_init(&hash_record->handles, msg_pool, 64);

  }

  handle_record = array_append_space(&hash_record->handles);

  if (handle != NULL)

    handle_record->handle = p_strdup(msg_pool, str_c(handle));

  handle_record->last = last;

  handle_record->duplicate = duplicate;

  *duplicate_r = duplicate;

  return SIEVE_EXEC_OK;

}