# ===== LOAD LIBRARIES =====
library(httr)
library(jsonlite)

# ===== CONFIGURATION =====
# set host, like http://localhost:8000, to where your Data Hub is running
DH_HOST <- ""

# Your personal API authentication token
# ATTENTION: tokens should not be added to production code!
# I.e, use a .Renviron file to store the token and set it like this:
# DH_TOKEN <- Sys.getenv("DH_TOKEN")
DH_TOKEN <- ""

# ===== MAIN FUNCTION =====
dh_data <- function(query) {
  url <- paste0(DH_HOST, "/api/datalayers/data")
  response <- GET(
    url,
    query = query,
    add_headers("X-API-Key" = DH_TOKEN)
  )

  # Check if the request was successful (status code 200)
  if (status_code(response) == 200) {
    d <- fromJSON(content(response, "text", flatten = TRUE, encoding = "UTF-8"))
  } else {
    stop(sprintf("Request failed (%d): %s",
                 status_code(response),
                 content(response, as = "text")))
  }

  df <- as.data.frame(d$data)

  # Convert the time column to proper date type
  temporal_column <- d$temporal_column
  temporal_format <- d$temporal_format

  # R would fill in missing date parts with the current date.
  # as.Date("2020",format="%Y") -> 2020-<current month>-<current day> and not 2020-01-01
  if (temporal_column == "year") {
    df[[temporal_column]] <- as.Date(paste0(as.character(df[[temporal_column]]), "-01-01"))
    temporal_format <- "%Y-%m-%d"
  }

  df[[temporal_column]] <- as.Date(as.character(df[[temporal_column]]), format = temporal_format)

  return(df)
}


# ===== EXAMPLE USAGE =====
osm_roads_trunk_df <- dh_data(list(
  datalayer_key = "osm_roads_trunk"
  # Optional filters:
  # shape_key = "",
  # shape_type_key = "",
  # start_date = "",
  # end_date = ""
))