#'Save CSTools objects of class 's2dv_cube' containing experiments or observed 
#'data in NetCDF format
#'
#'@author Perez-Zanon Nuria, \email{nuria.perez@bsc.es}
#'
#'@description This function allows to divide and save a object of class 
#''s2dv_cube' into a NetCDF file, allowing to reload the saved data using 
#'\code{CST_Load} function.
#'
#'@param data An object of class \code{s2dv_cube}.
#'@param destination A character string containing the directory name in which 
#'  to save the data. NetCDF file for each starting date are saved into the 
#'  folder tree: \cr
#'  destination/experiment/variable/. By default the function 
#'  creates and saves the data into the folder "CST_Data" in the working 
#'  directory.
#'@param extra_string A character string to be include as part of the file name, 
#'  for instance, to identify member or realization. It would be added to the 
#'  file name between underscore characters.
#'@param unique_file A logical value indicating if all object is saved in a 
#'  unique file (TRUE) or in separated directories (FALSE). When it is FALSE, 
#'  the array is separated for dataset, variable and start date.
#'
#'@seealso \code{\link{CST_Load}}, \code{\link{as.s2dv_cube}} and \code{\link{s2dv_cube}}
#'
#'@examples
#'\dontrun{
#'library(CSTools)
#'data <- lonlat_temp$exp
#'destination <- "./path2/"
#'CST_SaveExp(data = data, destination = destination)
#'}
#'
#'@import ncdf4
#'@importFrom s2dv Reorder InsertDim
#'@importFrom ClimProjDiags Subset
#'@import multiApply
#'@export
CST_SaveExp <- function(data, destination = "./CST_Data", unique_file = TRUE, 
                        extra_string = NULL) {
  # Check 's2dv_cube'
  if (!inherits(data, 's2dv_cube')) {
    stop("Parameter 'data' must be of the class 's2dv_cube', ",
         "as output by CSTools::CST_Load.")
  }
  # Check object structure
  if (!all(c('data', 'coords', 'attrs') %in% names(data))) {
    stop("Parameter 'data' must have 'data', 'coords' and 'attrs' elements ",
         "within the 's2dv_cube' structure.")
  }
  # sdate_dim
  if (!any(names(data$coords) %in% .KnownStartDateNames())) {
    stop("Start date dimension name do not match with any of the ", 
         "accepted names by the package.")
  }
  sdate_dim <- names(data$coords)[which(names(data$coords) %in% .KnownStartDateNames())]
  if (length(sdate_dim) > 1) {
    warning("Found more than one start date dimension. Only the first one ", 
            "will be used.")
    sdate_dim <- sdate_dim[1]
  }
  sdates <- data$coords[[sdate_dim]]
  # varname
  if (!is.character(data$attrs$Variable$varName)) {
    stop("Element 'varName' mustbe a character string.")
  }
  varname <- data$attrs$Variable$varName
  # metadata
  if (!inherits(data$attrs$Variable$metadata, 'list')) {
    stop("Element $attrs$Variable$metadata must be a list.")
  }
  if (!any(names(data$attrs$Variable$metadata) %in% names(data$coords))) {
    warning("Metadata is not found for any coordinate.")
  } else if (!any(names(data$attrs$Variable$metadata) %in% 
                  data$attrs$Variable$varName)) {
    warning("Metadata is not found for any variable.")
  }
  # Coordinate attributes
  if (!any(names(data$coords) %in% .KnownLonNames()) | 
      !any(names(data$coords) %in% .KnownLatNames())) {
    stop("Spatial coordinate names do not match any of the names accepted by ",
         "the package.")
  }
  lon_dim <- names(data$coords)[which(names(data$coords) %in% .KnownLonNames())]
  lat_dim <- names(data$coords)[which(names(data$coords) %in% .KnownLatNames())]
  # Dates
  time_values <- data$attrs$Dates
  if (is.null(dim(time_values))) {
    stop("Dates element in '$data$attrs$Dates' must have time dimensios.")
  }

  SaveExp(data = data$data,
          destination = destination, 
          coords = data$coords,
          startdates = data$coords[[sdate_dim]],
          Dates = data$attrs$Dates, 
          Dataset = data$attrs$Datasets, 
          varname = data$attrs$Variable$varName,
          metadata = data$attrs$Variable$metadata,
          extra_string = extra_string, 
          unique_file = unique_file)
}
#'Save an experiment in a format compatible with CST_Load
#'@description This function is created for compatibility with CST_Load/Load for 
#'saving post-processed datasets such as those calibrated of downscaled with 
#'CSTools functions
#'
#'@author Perez-Zanon Nuria, \email{nuria.perez@bsc.es}
#'
#'@param data An multi-dimensional array with named dimensions (longitude, 
#'  latitude, time, member, sdate).
#'@param destination A character string indicating the path where to store the 
#'  NetCDF files.
#'@param coords A named list with elements of the coordinates corresponding to 
#'  the dimensions of the data parameter. The names and length of each element 
#'  must correspond to the names of the dimensions. If any coordinate is not 
#'  provided, it is set as an index vector with the values from 1 to the length 
#'  of the corresponding dimension.
#'@param startdates A vector of dates indicating the initialization date of each 
#'  simulations.
#'@param Dates A matrix of dates with the corresponding sdate and forecast time
#'  dimension.
#'@param Dataset A vector of character string indicating the names of the 
#'  datasets.
#'@param varname A character string indicating the name of the variable to be 
#'  saved.
#'@param metadata A named list where each element is a variable containing the
#'  corresponding information. The information must be contained in a list of 
#'  lists for each variable.
#'@param unique_file A logical value indicating if all object is saved in a 
#'  unique file (TRUE) or in separated directories (FALSE). When it is FALSE, 
#'  the array is separated for dataset, variable and start date.
#'@param extra_string A character string to be include as part of the file name, 
#'  for instance, to identify member or realization.
#'
#'@return The function creates as many files as sdates per dataset. Each file 
#'could contain multiple members. It would be added to the file name between 
#'underscore characters. The path will be created with the name of the variable 
#'and each Datasets.
#' 
#'@examples
#'\dontrun{
#'data <- lonlat_temp$exp$data
#'lon <- lonlat_temp$exp$coords$lon
#'lat <- lonlat_temp$exp$coords$lat
#'coords <- list(lon = lon, lat = lat)
#'Dataset <- lonlat_temp$exp$attrs$Dataset
#'varname <- 'tas'
#'Dates <- lonlat_temp$exp$attrs$Dates
#'destination = './path/'
#'metadata <- lonlat_temp$exp$attrs$Variable$metadata
#'SaveExp(data = data, destination = destination, coords = coords, 
#'        Dataset = Dataset, varname = varname, Dates = Dates, 
#'        metadata = metadata, unique_file = TRUE)
#'}
#'@import ncdf4
#'@importFrom s2dv Reorder InsertDim
#'@import multiApply
#'@importFrom ClimProjDiags Subset
#'@export
SaveExp <- function(data, destination, Dates, coords = NULL, 
                    Dataset = NULL, varname = NULL, metadata = NULL, 
                    startdates = NULL, unique_file = FALSE, 
                    extra_string = NULL) {
  ## Initial input parameter checks:
  # data
  if (is.null(data)) {
    stop("Parameter 'data' cannot be NULL.")
  }
  dimnames <- names(dim(data))
  if (is.null(dimnames)) {
    stop("Parameter 'data' must be an array with named dimensions.")
  }
  # destination
  if (!is.character(destination) & length(destination) > 1) {
    stop("Parameter 'destination' must be a character string of one element ",
         "indicating the name of the file (including the folder if needed) ",
         "where the data will be saved.")
  }
  # Dates
  if (is.null(Dates)) {
    stop("Parameter 'Dates' cannot be NULL.")
  }
  # varname
  if (is.null(varname)) {
    warning("Parameter 'varname' is NULL. It will be assigned to 'X'.")
    varname <- 'X'
  } else if (length(varname) > 1) {
    multiple_vars <- TRUE
  } else {
    multiple_vars <- FALSE
  }
  if (!all(sapply(varname, is.character))) {
    stop("Parameter 'varname' must be a character string with the ",
         "variable names.")
  }
  ## Coordinates
  # longitude and latitude
  if (!is.null(coords)) {
    if (!all(names(coords) %in% dimnames)) {
      coords <- coords[-which(!names(coords) %in% dimnames)]
    }
    for (i_coord in dimnames) {
      if (i_coord %in% names(coords)) {
        if (length(coords[[i_coord]]) != dim(data)[i_coord]) {
          warning(paste0("Coordinate '", i_coord, "' has different lenght as ",
                         "its dimension and it will not be used."))
          coords[[i_coord]] <- 1:dim(data)[i_coord]
        }
      } else {
        warning(paste0("Coordinate '", i_coord, "' is not provided ",
                       "and it will be set as index in element coords."))
        coords[[i_coord]] <- 1:dim(data)[i_coord]
      }
    }
  } else {
    coords <- sapply(dimnames, function(x) 1:dims[x])
  }

  ## Dimensions checks:
  # Spatial coordinates
  if (!any(dimnames %in% .KnownLonNames()) | 
      !any(dimnames %in% .KnownLatNames())) {
    stop("Spatial coordinate names do not match any of the names accepted by ",
         "the package.")
  }
  lon_dim <- dimnames[which(dimnames %in% .KnownLonNames())]
  lat_dim <- dimnames[which(dimnames %in% .KnownLatNames())]
  if (length(lon_dim) > 1) {
    warning("Found more than one longitudinal dimension. Only the first one ", 
            "will be used.")
    lon_dim <- lon_dim[1]
  }
  if (length(lat_dim) > 1) {
    warning("Found more than one latitudinal dimension. Only the first one ", 
            "will be used.")
    lat_dim <- lat_dim[1]
  }
  # ftime_dim
  if (!any(dimnames %in% .KnownForecastTimeNames())) {
    stop("Forecast time dimension name do not match with any of the ", 
         "accepted names by the package.")
  }
  ftime_dim <- dimnames[which(dimnames %in% .KnownForecastTimeNames())]
  if (length(ftime_dim) > 1) {
    warning("Found more than one forecast time dimension. Only the first one ", 
            "will be used.")
    ftime_dim <- ftime_dim[1]
  }
  # sdate_dim
  if (!any(dimnames %in% .KnownStartDateNames())) {
    stop("Start date dimension name do not match with any of the ", 
         "accepted names by the package.")
  }
  sdate_dim <- dimnames[which(dimnames %in% .KnownStartDateNames())]
  multiple_sdates <- FALSE
  if (length(sdate_dim) == 0) {
    stop("Start date dimension name do not match with any of the ", 
         "accepted names by the package. The accepted start date names ", 
         "are: 'sdate', 'sdates', 'syear', 'sweek' and 'sday'.")
  } else if (length(sdate_dim) > 1) {
    multiple_sdates <- TRUE
    stop("Found more than one start date dimension. This functionality is not developed yet.")
  }
  # Dates dimension check
  if (is.null(dim(Dates))) {
    stop("Parameter 'Dates' must have dimension names.")
  }
  if (all(names(dim(Dates)) == c(ftime_dim, sdate_dim)) | 
      all(names(dim(Dates)) == c(sdate_dim, ftime_dim))) {
    if (is.null(startdates)) {
      startdates <- Subset(Dates, along = ftime_dim, 1, drop = 'selected')
    }
  } else {
    stop("Parameter 'Dates' must have start date dimension and ", 
         "forecast time diemension.")
  }

  # memb_dim
  if (!any(dimnames %in% .KnownMemberNames())) {
    memb_dim <- NULL
  } else {
    memb_dim <- dimnames[which(dimnames %in% .KnownMemberNames())]
    if (length(memb_dim) > 1) {
      stop("Found more than one member dimension. This functionality is not developed yet.")
    }
  }
  if (any(dimnames == 'level')) {
    stop("Ask for saving 3Dim fields to the mantainer.")
  }
  # extra_string
  if (!is.null(extra_string)) {
    if (!is.character(extra_string)) {
      stop("Parameter 'extra_string' must be a character string.")
    }
  }
  # dataset
  dataset_pos <- which(dimnames %in% c('dataset', 'dat'))
  dat_dim <- names(dim(data))[dataset_pos]
  dims <- dim(data)
  if (length(dataset_pos) == 0) {
    warning("Dataset dimension is not found in 'data'. ",
            "All data is stored in the same 'dataset' folder.")
    data <- InsertDim(data, posdim = 1, lendim = 1, name = "dataset")
    dimnames <- names(dim(data))
    dataset_pos <- 1
    dat_dim <- "dataset"
  } else if (length(dataset_pos) > 1) {
    stop("There is more than one 'dataset' dimension in data.")
  }
  n_datasets <- dim(data)[dataset_pos] # number of folder by dataset
  # dataset names
  if (is.null(Dataset)) {
    warning("Parameter 'Dataset' is NULL. Files will be saved with a ", 
            "directory name of 'XXX'.")
    Dataset <- rep('XXX', n_datasets )
  }
  datasets <- Dataset
  if (n_datasets > length(datasets)) {
    warning("Dimension 'dataset' in 'data' is greater than those listed in ",
            "element 'Datasets' and the first element will be reused.")
    datasets <- c(datasets, rep(datasets[1], n_datasets - length(datasets)))
  } else if (n_datasets < length(datasets)) {
    warning("Dimension 'dataset' in 'data' is smaller than those listed in ",
            "element 'Datasets' and only the firsts elements will be used.")
    datasets <- datasets[1:n_datasets]
  }
  # From Load
  if (inherits(datasets, 'list')) {
    datasets <- names(datasets)
  }
  # var
  var_dim <- NULL
  if (any(c('var', 'vars', 'variable', 'variables') %in% dimnames)) {
    var_pos <- which(dimnames %in% c('var', 'vars', 'variable', 'variables'))
    var_dim <- names(dim(data))[var_pos]
    if (length(var_pos) > 1) {
      warning("There is more than one 'variable' dimension in data.")
      var_pos <- var_pos[1]
    }
    if (dims[var_pos] == 1) {
      num_vars <- 1
    } else {
      num_vars <- dim(data)[var_pos]
    }
  } else {
    num_vars <- 1
    var_dim <- NULL
  }
  known_dim_names <- c("var", "vars", "dat", "dataset", "nlevel", "levels", "level", 
                       .KnownLatNames(), .KnownLonNames(), .KnownForecastTimeNames(), 
                       .KnownStartDateNames())
  dim_names <- names(dim(data))
  if (any(dim_names != c(dat_dim, var_dim, sdate_dim, lon_dim, 
                         lat_dim, memb_dim, ftime_dim))) {
    data <- Reorder(data, c(dat_dim, var_dim, sdate_dim, lon_dim, 
                            lat_dim, memb_dim, ftime_dim))
  }
  # Dimensions definition
  defined_dims <- NULL
  extra_info_dim <- NULL
  filedims <- names(dim(data))[which(!names(dim(data)) %in% c(dat_dim, var_dim, 
                                                              sdate_dim, ftime_dim))]
  for (i_coord in filedims) {
    dim_info <- list()
    # vals
    if (i_coord %in% names(coords)) {
      dim_info[['vals']] <- as.vector(coords[[i_coord]])
    } else {
      dim_info[['vals']] <- 1:dim(data)[i_coord]
    }
    # name
    dim_info[['name']] <- i_coord
    # len
    dim_info[['len']] <- as.numeric(dim(data)[i_coord])
    # unlim
    dim_info[['unlim']] <- FALSE
    # create_dimvar
    dim_info[['create_dimvar']] <- TRUE
    ## metadata
    if (i_coord %in% names(metadata)) {
      if ('variables' %in% names(attributes(metadata[[i_coord]]))) {
        # from Start: 'lon' or 'lat'
        attrs <- attributes(metadata[[i_coord]])[['variables']][[i_coord]]
        i_coord_info <- attrs[!sapply(attrs, inherits, 'list')]
      } else if (inherits(metadata[[i_coord]], 'list')) {
        # from Start and Load: main var
        i_coord_info <- metadata[[i_coord]]
      } else if (!is.null(attributes(metadata[[i_coord]]))) {
        # from Load
        i_coord_info <- attributes(metadata[[i_coord]])
      } else {
        stop("Metadata is not correct.")
      }
      # len
      if ('size' %in% names(i_coord_info)) {
        if (i_coord_info[['size']] != dim(data)[i_coord]) {
          dim_info[['original_len']] <- i_coord_info[['size']]
          i_coord_info[['size']] <- NULL
        }
      }
      # units
      if (!('units' %in% names(i_coord_info))) {
        dim_info[['units']] <- ''
      } else {
        dim_info[['units']] <- i_coord_info[['units']]
        i_coord_info[['units']] <- NULL
      }
      # calendar
      if (!('calendar' %in% names(i_coord_info))) {
        dim_info[['calendar']] <- NA
      } else {
        dim_info[['calendar']] <- i_coord_info[['calendar']]
        i_coord_info[['calendar']] <- NULL
      }
      # longname
      if ('long_name' %in% names(i_coord_info)) {
        dim_info[['longname']] <- i_coord_info[['long_name']]
        i_coord_info[['long_name']] <- NULL
      } else if ('longname' %in% names(i_coord_info)) {
        dim_info[['longname']] <- i_coord_info[['longname']]
        i_coord_info[['longname']] <- NULL
      } else {
        dim_info[['longname']] <- i_coord
      }
      # extra information
      if (!is.null(names(i_coord_info))) {
        extra_info_dim[[i_coord]] <- i_coord_info
      }
    } else {
      # units
      dim_info[['units']] <- "adim"
      # longname
      dim_info[['longname']] <- i_coord
      # calendar
      dim_info[['calendar']] <- NA
    }
    new_dim <- list(ncdim_def(name = dim_info[['name']], units = dim_info[['units']], 
                              vals = dim_info[['vals']], unlim = dim_info[['unlim']], 
                              create_dimvar = dim_info[['create_dimvar']], 
                              calendar = dim_info[['calendar']], 
                              longname = dim_info[['longname']]))
    names(new_dim) <- i_coord
    defined_dims <- c(defined_dims, new_dim)
  }

  defined_vars <- list()
  if (!unique_file) {
    for (i in 1:n_datasets) {
      path <- file.path(destination, datasets[i], varname)
      for (j in 1:num_vars) {
        dir.create(path[j], recursive = TRUE)
        sdates <- gsub("-", "", startdates)
        dim(sdates) <- c(length(sdates))
        names(dim(sdates)) <- sdate_dim
        Apply(data = list(data, sdates, Dates),
              target_dims = list(c(memb_dim, ftime_dim, lat_dim, lon_dim), 
                                 NULL, ftime_dim),
              fun = .saveExp, ftime_dim = ftime_dim, defined_dims = defined_dims, 
              varname = varname[j], 
              metadata_var = metadata[[varname[j]]], 
              destination = path[j], extra_info_dim = extra_info_dim, 
              extra_string = extra_string)
      }
    }
  } else {
    # dataset definition
    # From here
    new_dim <- list(ncdim_def(name = dat_dim, units = "adim",
                              vals = 1 : dim(data)[dat_dim],
                              longname = 'dataset', create_dimvar = TRUE))
    names(new_dim) <- dat_dim
    defined_dims <- c(new_dim, defined_dims)
    extra_info_dim[[dat_dim]] <- list(datasets = paste(datasets, collapse = ', '))
    # sdate definition
    sdates <- Subset(Dates, along = ftime_dim, 1, drop = 'selected')
    differ <- as.numeric((sdates - sdates[1])/3600)
    new_dim <- list(ncdim_def(name = sdate_dim, units = paste('hours since', sdates[1]),
                              vals = differ,
                              longname = sdate_dim, create_dimvar = TRUE))
    names(new_dim) <- sdate_dim
    defined_dims <- c(defined_dims, new_dim)
    extra_info_dim[[sdate_dim]] <- list(sdates = paste(sdates, collapse = ', '))
    # ftime definition
    ftime_dates <- Subset(Dates, along = sdate_dim, 1, drop = 'selected')
    differ <- as.numeric((ftime_dates - ftime_dates[1])/3600)
    # DOUBT HERE: which values we take?
    dim_time <- list(ncdim_def(name = ftime_dim, units = paste('hours since', Dates[1]),
                     vals = differ, calendar = 'proleptic_gregorian',
                     longname = ftime_dim, unlim = TRUE))
    names(dim_time) <- ftime_dim
    defined_dims <- c(defined_dims, dim_time)

    # var definition
    defined_vars <- list()
    extra_info_var <- NULL
    for (j in 1:num_vars) {
      var_info <- list()
      i_var_info <- metadata[[varname[j]]][!sapply(metadata[[varname[j]]], inherits, 'list')]
      ## Define metadata
      # name
      var_info[['name']] <- varname[j]
      # units
      if ('units' %in% names(i_var_info)) {
        var_info[['units']] <- i_var_info[['units']]
        i_var_info[['units']] <- NULL
      } else {
        var_info[['units']] <- ''
      }
      # dim
      var_info[['dim']] <- defined_dims
      # missval
      if ('missval' %in% names(i_var_info)) {
        var_info[['missval']] <- i_var_info[['missval']]
        i_var_info[['missval']] <- NULL
      } else {
        var_info[['missval']] <- NULL
      }
      # longname
      if (any(c('longname', 'long_name') %in% names(i_var_info))) {
        longname <- names(i_var_info)[which(names(i_var_info) %in% c('longname', 'long_name'))]
        var_info[['longname']] <- i_var_info[[longname]]
        i_var_info[[longname]] <- NULL
      } else {
        var_info[['longname']] <- varname[j]
      }
      # prec
      if ('prec' %in% names(i_var_info)) {
        var_info[['prec']] <- i_var_info[['prec']]
        i_var_info[['prec']] <- NULL
      } else {
        prec <- typeof(data)
        if (prec == 'character') {
          var_info[['prec']] <- 'char'
        }
        if (any(prec %in% c('short', 'float', 'double', 'integer', 'char', 'byte'))) {
          var_info[['prec']] <- prec
        } else {
          var_info[['prec']] <- 'double'
        }
      }
      # extra information
      if (!is.null(names(i_var_info))) {
        extra_info_var[[varname[j]]] <- i_var_info
      }
      new_var <- list(ncvar_def(name = var_info[['name']],
                                units = var_info[['units']],
                                dim = var_info[['dim']], 
                                missval = var_info[['missval']],
                                longname = var_info[['longname']], 
                                prec = var_info[['prec']]))

      names(new_var) <- varname[j]
      defined_vars <- c(defined_vars, new_var)
    }
    if (is.null(extra_string)) {
      file_name <- paste0(varname[j], ".nc")
    } else {
      file_name <- paste0(varname[j], "_", extra_string, ".nc")
    }
    full_filename <- file.path(destination, file_name)
    file_nc <- nc_create(full_filename, defined_vars)
    if (is.null(var_dim)) {
      ncvar_put(file_nc, varname, vals = data)
    } else {
      for (j in 1:num_vars) {
        ncvar_put(file_nc, defined_vars[[j]]$name, 
                  vals = Subset(data, var_dim, j, drop = 'selected'))
      }
    }
    # Additional dimension attributes
    for (dim in names(defined_dims)) {
      if (dim %in% names(extra_info_dim)) {
        for (info_dim in names(extra_info_dim[[dim]])) {
          ncatt_put(file_nc, dim, info_dim, as.character(extra_info_dim[[dim]][[info_dim]]))
        }
      }
    }
    # Additional dimension attributes
    for (var in names(defined_vars)) {
      if (var %in% names(extra_info_var)) {
        for (info_var in names(extra_info_var[[var]])) {
          ncatt_put(file_nc, var, info_var, as.character(extra_info_var[[var]][[info_var]]))
        }
      }
    }
    nc_close(file_nc)
  }
}

.saveExp <- function(data, sdates, dates, ftime_dim, varname, units, defined_dims, 
                     metadata_var, destination, extra_info_dim = NULL, 
                     extra_string = NULL) {
  
  differ <- as.numeric((dates - dates[1])/3600)
  dim_time <- list(ncdim_def(name = ftime_dim, units = paste('hours since', Dates[1]),
                        vals = differ, calendar = 'proleptic_gregorian',
                        longname = ftime_dim, unlim = TRUE))
  names(dim_time) <- ftime_dim
  defined_dims <- c(defined_dims, dim_time)
  ## Define var metadata
  var_info <- NULL
  extra_info_var <- NULL
  i_var_info <- metadata_var[!sapply(metadata_var, inherits, 'list')]

  # name
  var_info[['name']] <- varname
  # units
  if ('units' %in% names(i_var_info)) {
    var_info[['units']] <- i_var_info[['units']]
    i_var_info[['units']] <- NULL
  } else {
    var_info[['units']] <- ''
  }
  # dim
  var_info[['dim']] <- defined_dims
  # missval
  if ('missval' %in% names(i_var_info)) {
    var_info[['missval']] <- i_var_info[['missval']]
    i_var_info[['missval']] <- NULL
  } else {
    var_info[['missval']] <- NULL
  }
  # longname
  if (any(c('longname', 'long_name') %in% names(i_var_info))) {
    longname <- names(i_var_info)[which(names(i_var_info) %in% c('longname', 'long_name'))]
    var_info[['longname']] <- i_var_info[[longname]]
    i_var_info[[longname]] <- NULL
  } else {
    var_info[['longname']] <- varname
  }
  # prec
  if ('prec' %in% names(i_var_info)) {
    var_info[['prec']] <- i_var_info[['prec']]
    i_var_info[['prec']] <- NULL
  } else {
    prec <- typeof(data)
    if (prec == 'character') {
      var_info[['prec']] <- 'char'
    }
    if (any(prec %in% c('short', 'float', 'double', 'integer', 'char', 'byte'))) {
      var_info[['prec']] <- prec
    } else {
      var_info[['prec']] <- 'double'
    }
  }
  # extra information
  if (!is.null(names(i_var_info))) {
    extra_info_var <- i_var_info
  }
  datanc <- ncvar_def(name = var_info[['name']],
                      units = var_info[['units']],
                      dim = var_info[['dim']], 
                      missval = var_info[['missval']],
                      longname = var_info[['longname']], 
                      prec = var_info[['prec']])

  if (is.null(extra_string)) {
    file_name <- paste0(varname, "_", sdates, ".nc")
  } else {
    file_name <- paste0(varname, "_", extra_string, "_", sdates, ".nc")
  }
  full_filename <- file.path(destination, file_name)
  file_nc <- nc_create(full_filename, datanc)
  ncvar_put(file_nc, datanc, data)
  # Additional attributes
  for (dim in names(defined_dims)) {
    if (dim %in% names(extra_info_dim)) {
      for (info_dim in names(extra_info_dim[[dim]])) {
        ncatt_put(file_nc, dim, info_dim, as.character(extra_info_dim[[dim]][[info_dim]]))
      }
    }
  }
  # Additional dimension attributes
  if (!is.null(extra_info_var)) {
    for (info_var in names(extra_info_var)) {
      ncatt_put(file_nc, varname, info_var, as.character(extra_info_var[[info_var]]))
    }
  }
  nc_close(file_nc)
}