
# ------------------------------------------------------------------------

#' cli progress handlers
#'
#' The progress handler(s) to use can be selected with global options.
#'
#' There are three options that specify which handlers will be selected,
#' but most of the time you only need to use one of them. You can set these
#' options to a character vector, the names of the built-in cli handlers you
#' want to use:
#'
#' * If `cli.progress_handlers_only` is set, then these handlers are used,
#'   without considering others and without checking if they are able to
#'   handle a progress bar. This option is mainly intended for testing
#'   purposes.
#' * The handlers named in `cli.progress_handlers` are checked if they are
#'   able to handle the progress bar, and from the ones that are, the first
#'   one is selected. This is usually the option that the end use would want
#'   to set.
#' * The handlers named in `cli.progress_handlers_force` are always appended
#'   to the ones selected via `cli.progress_handlers`. This option is useful
#'   to add an additional handler, e.g. a logger that writes to a file.
#'
#' # The built-in progress handlers
#'
#' ### `cli`
#'
#' Use cli's internal status bar, the last line of the screen, to show the
#' progress bar. This handler is always able to handle all progress bars.
#'
#' ### `logger`
#'
#' Log progress updates to the screen, with one line for each update and with
#' time stamps. This handler is always able to handle all progress bars.
#'
#' ### `progressr`
#'
#' Use the progressr package to create
#' progress bars. This handler is always able to handle all progress bars.
#' (The progressr package needs to be installed.)
#'
#' ### `rstudio`
#'
#' Use [RStudio's job panel](https://www.rstudio.com/blog/rstudio-1-2-jobs/)
#' to show the progress bars. This handler is available at the RStudio console,
#' in recent versions of RStudio.
#'
#' ### `say`
#'
#' Use the macOS `say` command to announce progress events in speech (type
#' `man say` on a terminal for more info). Set the `cli.progress_say_frequency`
#' option to set the minimum delay between `say` invocations, the default is
#' three seconds. This handler is available on macOS, if the `say` command is
#' on the path.
#'
#' The external command and its arguments can be configured with options:
#'
#' * `cli_progress_say_args`: command line arguments, e.g. you can use this
#'   to select a voice on macOS,
#' * `cli_progress_say_command`: external command to run,
#' * `cli_progress_say_frequency`: wait at least this many seconds between
#'   calling the external command.
#'
#' ### `shiny`
#'
#' Use [shiny's progress bars][shiny::Progress]. This handler is available if a
#' shiny app is running.
#'
#' @return `cli_progress_builtin_handlers()` returns the names of the
#' currently supported progress handlers.
#'
#' @export

# TODO: examples

cli_progress_builtin_handlers <- function() {
  names(builtin_handlers())
}

cli_progress_select_handlers <- function(bar, .envir) {
  hnd <- getOption("cli.progress_handlers", c("shiny", "cli"))
  frc <- getOption("cli.progress_handlers_force")
  onl <- getOption("cli.progress_handlers_only")

  bin <- builtin_handlers()
  if (!is.null(onl)) return(bin[onl])

  hnd_imp <- bin[hnd]
  hnd_able <- Filter(function(h) is.null(h$able) || h$able(bar, .envir), hnd_imp)
  if (length(hnd_able) > 1) hnd_able <- hnd_able[1]

  c(hnd_able, bin[frc])
}

# ------------------------------------------------------------------------

builtin_handler_cli <- list(
  add = function(bar, .envir) {
    bar$cli_statusbar <- cli_status(
      bar$format,
      msg_done = bar$format_done %||% bar$format,
      msg_failed = bar$format_failed %||% bar$format,
      .auto_close = FALSE,
      .envir = .envir,
      )
    bar$last_shown <- bar$current
    bar$justadded <- TRUE
  },

  set = function(bar, .envir) {
    if (isTRUE(bar$justadded)) {
      bar$justadded <- FALSE
      return()
    }
    bar$last_shown <- bar$current
    cli_status_update(id = bar$cli_statusbar, bar$format, .envir = .envir)
  },

  complete = function(bar, .envir, result) {
    if (isTRUE(bar$added)) {
      if (bar$clear) {
        # Show the full bar non-dynamic ttys
        if (!is_dynamic_tty() &&
            !identical(bar$last_shown, bar$current)) {
          cli_status_update(id = bar$cli_statusbar, bar$format, .envir = .envir)
        }
        cli_status_clear(bar$cli_statusbar, result = "clear", .envir = .envir)
      } else {
        if (result == "done" && !is.na(bar$total)) bar$current <- bar$total
        cli_status_clear(
          bar$cli_statusbar,
          result = result,
          msg_done = bar$format_done %||% bar$format,
          msg_failed = bar$format_failed %||% bar$format,
          .envir = .envir
        )
      }
    }
    bar$cli_statusbar <- TRUE
  },

  output = function(bar, .envir, text) {
    cli_verbatim(text)
  }
)

# ------------------------------------------------------------------------

builtin_handler_progressr <- list(
  add = function(bar, .envir) {
    steps <- if (is.na(bar$total)) 0 else bar$total
    bar$progressr_last <- 0L
    bar$progressr_progressor <- asNamespace("progressr")$progressor(
      steps,
      auto_finish = FALSE,
      on_exit = TRUE,
      envir = .envir,
      label = bar$name %||% NA_character_
    )
  },

  set = function(bar, .envir) {
    amount <- bar$current - bar$progressr_last
    bar$last <- bar$current
    if (!is.null(bar$progressr_progressor) && amount > 0) {
      bar$progressr_progressor(amount = amount)
    }
  },

  complete = function(bar, .envir, result) {
    amount <- bar$current - bar$progressr_last
    bar$last <- bar$current
    if (!is.null(bar$progressr_progressor) && amount > 0) {
      bar$progressr_progressor(amount = amount, type = "finish")
    }
  },

  output = function(bar, .envir, text) {
    if (!is.null(bar$progressr_progressor)) {
      bar$progressr_progressor(message = text, class = "sticky", amount = 0)
    }
  }
)

# ------------------------------------------------------------------------

logger_out <- function(bar, event) {
  cat(sep = "", format_iso_8601(Sys.time()), " ", bar$id, " ",
      bar$current, "/", bar$total, " ", event, "\n")
}

builtin_handler_logger <- list(
  create = function(bar, .envir) {
    logger_out(bar, "created")
  },

  add = function(bar, .envir) {
    logger_out(bar, "added")
  },

  set = function(bar, .envir) {
    logger_out(bar, "updated")
  },

  complete = function(bar, .envir, result) {
    logger_out(bar, paste0("terminated (", result, ")"))
  },

  output = function(bar, .envir, text) {
    logger_out(bar, text)
  }
)

# ------------------------------------------------------------------------

say_out <- function(text) {
  say <- getOption("cli.progress_say_command", "say")
  args <- getOption("cli.progress_say_args", character())
  processx::process$new(say, c(args, text))
}

say_update <- function(bar) {
  now <- .Call(clic_get_time)
  freq <- getOption("cli.progress_say_frequency", 3.0)
  if (is.null(bar$say_last) || now - bar$say_last > freq) {
    txt <- if (is.na(bar$total)) bar$current else cli__pb_percent(bar)
    bar$say_proc <- say_out(txt)
    bar$say_last <- now
  }
}

builtin_handler_say <- list(
  able = function(bar, .envir) {
    if (!is.null(getOption("cli.progress_say_command"))) return(TRUE)
    Sys.info()[["sysname"]] == "Darwin" && Sys.which("say") != ""
  },

  add = function(bar, .envir) {
    ## Nothing to do here
  },

  set = function(bar, .envir) {
    say_update(bar)
  },

  complete = function(bar, .envir, result) {
    if (!is.null(bar$say_proc)) {
      bar$say_proc$kill()
      say_out("done")
    }
  }
)

# ------------------------------------------------------------------------

builtin_handler_rstudio <- list(
  able = function(bar, .envir) {
    tryCatch(
      .Platform$GUI == "Rstudio" && rstudioapi::isAvailable(),
      error = function(err) FALSE
    )
  },

  add = function(bar, .envir) {
    total <- if (is.na(bar$total)) 0L else as.integer(bar$total)
    bar$status <- bar$status %||% ""
    rstudio_id <- rstudioapi::jobAdd(
      name = bar$name %||% "",
      status = bar$status,
      progressUnits = total,
      running = TRUE,
      show = FALSE
    )
    # so the name is not duplicated in the format string as well
    if (is.na(bar$total)) bar$name <- NULL
    bar$rstudio_id <- rstudio_id
    bar$rstudio_status <- bar$status
  },

  set = function(bar, .envir) {
    if (!is.na(bar$total)) {
      rstudioapi::jobSetProgress(bar$rstudio_id, bar$current)
      if (bar$rstudio_status != bar$status) {
        rstudioapi::jobSetStatus(bar$rstudio_id, bar$status)
        bar$rstudio_status <- bar$status
      }
    } else {
      status <- fmt(
        cli_text(bar$format, .envir = .envir),
        collapse = TRUE,
        strip_newline = TRUE
      )
      rstudioapi::jobSetStatus(bar$rstudio_id, status)
    }
  },

  complete = function(bar, .envir, results) {
    if (!is.null(bar$rstudio_id)) {
      rstudioapi::jobRemove(bar$rstudio_id)
    }
  },

  output = function(bar, .envir, text) {
    rstudioapi::jobAddOutput(bar$rstudio_id, text)
  }
)

# ------------------------------------------------------------------------

shiny_detail <- function(bar, .envir) {
  status <- if (is.null(bar$format_orig)) {
    bar$status %||% ""
  } else {
    fmt(
      cli_text(bar$format, .envir = .envir),
      collapse = TRUE,
      strip_newline = TRUE
    )
  }
  output <- bar$shiny_output %||% ""
  paste0(
    status,
    if (status != "" && output != "") "\n",
    output
  )
}

last_lines <- function(txt, keep = 5) {
  txt <- sub("^\n*", "", txt)
  txt <- sub("\n*$", "", txt)
  lines <- strwrap(txt, width = 40)
  paste(utils::tail(lines, keep), collapse = "\n")
}

builtin_handler_shiny <- list(
  able = function(bar, .envir) {
    "shiny" %in% loadedNamespaces() && shiny::isRunning()
  },

  add = function(bar, .envir) {
    bar$shiny_progress <- shiny::Progress$new(
      shiny::getDefaultReactiveDomain(),
      min = 0,
      max = bar$total
    )
    bar$shiny_progress$set(
      message = bar$name %||% "",
      detail = shiny_detail(bar, .envir)
    )
  },

  set = function(bar, .envir) {
    bar$shiny_progress$set(
      value = bar$current,
      detail = shiny_detail(bar, .envir)
    )
  },

  complete = function(bar, .envir, results) {
    if (!is.null(bar$shiny_progress)) {
      bar$shiny_progress$set(
        value = bar$current,
        detail = shiny_detail(bar, .envir)
      )
      bar$shiny_progress$close()
    }
    bar$shiny_progress <- NULL
  },

  output = function(bar, .envir, text) {
    bar$shiny_output <-
      last_lines(paste0(bar$shiny_output, " \u2022 ", text))
    bar$shiny_progress$set(
      value = bar$current,
      detail = shiny_detail(bar, .envir)
    )
  }
)

# ------------------------------------------------------------------------

builtin_handlers <- function() {
  list(
    cli = builtin_handler_cli,
    logger = builtin_handler_logger,
    progressr = builtin_handler_progressr,
    rstudio = builtin_handler_rstudio,
    say = builtin_handler_say,
    shiny = builtin_handler_shiny
  )
}
