/**
 * collectd - src/utils_cmds.h
 * Copyright (C) 2016 Sebastian 'tokkee' Harl
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *   Sebastian 'tokkee' Harl <sh at tokkee.org>
 **/

#ifndef UTILS_CMDS_H
#define UTILS_CMDS_H 1

#include "plugin.h"

#include <stdarg.h>

typedef enum {
  CMD_UNKNOWN = 0,
  CMD_FLUSH = 1,
  CMD_GETVAL = 2,
  CMD_LISTVAL = 3,
  CMD_PUTVAL = 4,
} cmd_type_t;
#define CMD_TO_STRING(type)                                                    \
  ((type) == CMD_FLUSH)                                                        \
      ? "FLUSH"                                                                \
      : ((type) == CMD_GETVAL)                                                 \
            ? "GETVAL"                                                         \
            : ((type) == CMD_LISTVAL)                                          \
                  ? "LISTVAL"                                                  \
                  : ((type) == CMD_PUTVAL) ? "PUTVAL" : "UNKNOWN"

typedef struct {
  double timeout;

  char **plugins;
  size_t plugins_num;
  identifier_t *identifiers;
  size_t identifiers_num;
} cmd_flush_t;

typedef struct {
  char *raw_identifier;
  identifier_t identifier;
} cmd_getval_t;

typedef struct {
  /* The raw identifier as provided by the user. */
  char *raw_identifier;

  /* An array of the fully parsed identifier and all value lists, and their
   * options as provided by the user. */
  value_list_t *vl;
  size_t vl_num;
} cmd_putval_t;

/*
 * NAME
 *   cmd_t
 *
 * DESCRIPTION
 *   The representation of a fully parsed command.
 */
typedef struct {
  cmd_type_t type;
  union {
    cmd_flush_t flush;
    cmd_getval_t getval;
    cmd_putval_t putval;
  } cmd;
} cmd_t;

/*
 * NAME
 *   cmd_options_t
 *
 * DESCRIPTIONS
 *   Optional settings for tuning the parser behavior.
 */
typedef struct {
  /* identifier_default_host: If non-NULL, the hostname is optional and will
   * default to the specified value. */
  char *identifier_default_host;
} cmd_options_t;

/*
 * NAME
 *   cmd_status_t
 *
 * DESCRIPTION
 *   Status codes describing the parse result.
 */
typedef enum {
  CMD_OK = 0,
  CMD_ERROR = -1,
  CMD_PARSE_ERROR = -2,
  CMD_UNKNOWN_COMMAND = -3,

  /* Not necessarily fatal errors. */
  CMD_NO_OPTION = 1,
} cmd_status_t;

/*
 * NAME
 *   cmd_error_handler_t
 *
 * DESCRIPTION
 *   An error handler describes a callback to be invoked when the parser
 *   encounters an error. The user data pointer will be passed to the callback
 *   as the first argument.
 */
typedef struct {
  void (*cb)(void *, cmd_status_t, const char *, va_list);
  void *ud;
} cmd_error_handler_t;

/*
 * NAME:
 *   cmd_error
 *
 * DESCRIPTION
 *   Reports an error via the specified error handler (if set).
 */
void cmd_error(cmd_status_t status, cmd_error_handler_t *err,
               const char *format, ...);

/*
 * NAME
 *   cmd_parse
 *
 * DESCRIPTION
 *   Parse a command string and populate a command object.
 *
 * PARAMETERS
 *   `buffer'  The command string to be parsed.
 *   `ret_cmd' The parse result will be stored at this location.
 *   `opts'    Parser options. If NULL, defaults will be used.
 *   `err'     An optional error handler to invoke on error.
 *
 * RETURN VALUE
 *   CMD_OK on success or the respective error code otherwise.
 */
cmd_status_t cmd_parse(char *buffer, cmd_t *ret_cmd, const cmd_options_t *opts,
                       cmd_error_handler_t *err);

cmd_status_t cmd_parsev(size_t argc, char **argv, cmd_t *ret_cmd,
                        const cmd_options_t *opts, cmd_error_handler_t *err);

void cmd_destroy(cmd_t *cmd);

/*
 * NAME
 *   cmd_parse_option
 *
 * DESCRIPTION
 *   Parses a command option which must be of the form:
 *     name=value with \ and spaces
 *
 * PARAMETERS
 *   `field'     The parsed input field with any quotes removed and special
 *               characters unescaped.
 *   `ret_key'   The parsed key will be stored at this location.
 *   `ret_value' The parsed value will be stored at this location.
 *
 * RETURN VALUE
 *   CMD_OK on success or an error code otherwise.
 *   CMD_NO_OPTION if `field' does not represent an option at all (missing
 *   equal sign).
 */
cmd_status_t cmd_parse_option(char *field, char **ret_key, char **ret_value,
                              cmd_error_handler_t *err);

/*
 * NAME
 *   cmd_error_fh
 *
 * DESCRIPTION
 *   An error callback writing the message to an open file handle using the
 *   format expected by the unixsock or exec plugins.
 *
 * PARAMETERS
 *   `ud'     Error handler user-data pointer. This must be an open
 *            file-handle (FILE *).
 *   `status' The error status code.
 *   `format' Printf-style format string.
 *   `ap'     Variable argument list providing the arguments for the format
 *            string.
 */
void cmd_error_fh(void *ud, cmd_status_t status, const char *format,
                  va_list ap);

#endif /* UTILS_CMDS_H */