.log_env <- new.env(parent = emptyenv())
.log_env$file <- NULL

log_init <- function() {
  log_dir <- Sys.getenv("LOG_DIR", "/logs")
  if (!dir.exists(log_dir))
    dir.create(log_dir, recursive = TRUE, showWarnings = FALSE)
  fname <- paste0(format(Sys.Date(), "%Y-%m-%d"), "_log.jsonl")
  .log_env$file <- file.path(log_dir, fname)

  v <- tryCatch(
    as.character(utils::packageVersion("listkeeper")),
    error = function(e) "unknown"
  )
  .log_write("INFO", "startup",
    version   = v,
    r_version = paste(R.version$major, R.version$minor, sep = "."),
    platform  = R.version$platform,
    api_url   = Sys.getenv("API_URL", "http://localhost:8000")
  )
}

.log_write <- function(level, msg, ...) {
  if (is.null(.log_env$file)) return(invisible(NULL))
  entry <- c(
    list(ts = format(Sys.time(), "%Y-%m-%dT%H:%M:%OS3"), level = level, msg = msg),
    list(...)
  )
  line <- jsonlite::toJSON(entry, auto_unbox = TRUE)
  cat(line, "\n", file = .log_env$file, append = TRUE, sep = "")
  invisible(NULL)
}

log_info  <- function(msg, ...) .log_write("INFO",  msg, ...)
log_debug <- function(msg, ...) .log_write("DEBUG", msg, ...)
log_error <- function(msg, ...) .log_write("ERROR", msg, ...)