#!/usr/pkg/bin/Rscript

setup_app <- function() {
  theme <- list(
    "url" = list(color = "blue"),
    ".pkg" = list(color = "orange"),
    "it" = list("margin-bottom" = 1)
  )
  start_app(theme = theme, output = "stdout")
}

load_packages <- function() {
  tryCatch(
    {
      library(cli)
      library(httr)
      library(jsonlite)
      library(prettyunits)
      library(glue)
      library(parsedate)
      library(docopt)
    },
    error = function(e) {
      cli_alert_danger(
        "The {.pkg glue}, {.pkg httr}, {.pkg jsonlite}, {.pkg prettyunits},",
        " {.pkg parsedate} and {.pkg docopt} packages are needed!"
      )
      q(save = "no", status = 1)
    }
  )
}

news <- function(
  n = 10,
  day = FALSE,
  week = FALSE,
  since = NULL,
  reverse = FALSE
) {
  load_packages()
  setup_app()

  result <- if (day) news_day() else if (week) news_week() else if (
    !is.null(since)
  )
    news_since(since) else news_n(as.numeric(n))

  if (reverse) result <- rev(result)

  format_results(result)
  invisible()
}

news_day <- function() {
  date <- format_iso_8601(Sys.time() - as.difftime(1, units = "days"))
  ep <- glue("/-/pkgreleases?descending=true&endkey=%22{date}%22")
  do_query(ep)
}

news_week <- function() {
  date <- format_iso_8601(Sys.time() - as.difftime(7, units = "days"))
  ep <- glue("/-/pkgreleases?descending=true&endkey=%22{date}%22")
  do_query(ep)
}

news_since <- function(since) {
  date <- format_iso_8601(parse_date(since))
  ep <- glue("/-/pkgreleases?descending=true&endkey=%22{date}%22")
  do_query(ep)
}

news_n <- function(n) {
  ep <- glue("/-/pkgreleases?limit={n}&descending=true")
  do_query(ep)
}

do_query <- function(ep) {
  base <- "https://crandb.r-pkg.org"
  url <- glue("{base}{ep}")
  response <- GET(url)
  stop_for_status(response)
  fromJSON(content(response, as = "text"), simplifyVector = FALSE)
}

format_results <- function(results) {
  cli_div(theme = list(ul = list("list-style-type" = "")))
  cli_ol()
  lapply(results, format_result)
}

parse_arguments <- function() {
  "Usage:
  news.R [-r | --reverse] [-n num ]
  news.R [-r | --reverse] --day | --week | --since date
  news.R [-h | --help]

Options:
  -n num        Show the last 'n' releases [default: 10].
  --day         Show releases in the last 24 hours
  --week        Show releases in the last 7 * 24 hours
  --since date  Show releases since 'date'
  -r --reverse  Reverse the order, show older on top
  -h --help     Print this help message

New package releases on CRAN
" -> doc

  docopt(doc)
}

format_result <- function(result) {
  pkg <- result$package
  ago <- vague_dt(Sys.time() - parse_iso_8601(result$date))
  url <- paste0("https://r-pkg.org/pkg/", pkg$Package)
  cli_li()
  cli_text(
    "{.pkg {pkg$Package}} {pkg$Version} --
           {ago} by {.emph {pkg$Maintainer}}"
  )
  cli_text("{pkg$Title}")
  cli_text("{.url {url}}")
}

if (is.null(sys.calls())) {
  load_packages()
  opts <- parse_arguments()
  news(opts$n, opts$day, opts$week, opts$since, opts$reverse)
}
