module BomRadarFetch

# File lib/bom_radar_fetch.rb, line 78
def background_url(product_id)
  path = format(BomRadarConfig::BACKGROUND_PATH, product_id: product_id)
  "#{BomRadarConfig::BASE_URL}#{path}"
end

# File lib/bom_radar_fetch.rb, line 74
def default_fetch
  ->(url) { RabbotHttp.fetch(url, user_agent: BomRadarConfig::USER_AGENT) }
end

# File lib/bom_radar_fetch.rb, line 83
def fetch_background(product_id, fetch: default_fetch)
  bytes = fetch.call(background_url(product_id))
  return nil if bytes.nil? || bytes.to_s.empty?

  decoded = BomRadarPng.decode_indices(bytes.to_s.b)
  decoded.merge(bytes: bytes.to_s.b)
rescue StandardError
  nil
end

# File lib/bom_radar_fetch.rb, line 63
def fetch_frame(product_id, fetch: default_fetch)
  html = fetch_loop(product_id, fetch: fetch)
  frame = latest_frame(html)
  return nil unless frame

  bytes = fetch.call(frame[:url])
  return nil if bytes.nil? || bytes.to_s.empty?

  frame.merge(bytes: bytes.to_s.b)
end

# File lib/bom_radar_fetch.rb, line 59
def fetch_loop(product_id, fetch: default_fetch)
  fetch.call(loop_url(product_id))
end

# File lib/bom_radar_fetch.rb, line 50
def format_timestamp(time, zone: "Australia/Brisbane")
  return nil unless time

  local = time.getlocal(TZInfo::Timezone.get(zone).period_for_utc(time).utc_total_offset)
  local.strftime("%H:%M %Z")
rescue TZInfo::TimezoneNotFound, StandardError
  time.utc.strftime("%H:%M UTC")
end

# File lib/bom_radar_fetch.rb, line 28
def latest_frame(html)
  paths = parse_image_paths(html)
  path = paths.last
  return nil unless path

  {
    path: path,
    url: "#{BomRadarConfig::BASE_URL}#{path}",
    timestamp: parse_timestamp(path)
  }
end

# File lib/bom_radar_fetch.rb, line 20
def loop_url(product_id)
  "#{BomRadarConfig::BASE_URL}/products/#{product_id}.loop.shtml"
end

# File lib/bom_radar_fetch.rb, line 24
def parse_image_paths(html)
  html.to_s.scan(IMAGE_PATH_PATTERN).flatten
end

# File lib/bom_radar_fetch.rb, line 40
def parse_timestamp(path)
  match = path.to_s.match(TIMESTAMP_PATTERN)
  return nil unless match

  stamp = match[1]
  Time.utc(stamp[0, 4].to_i, stamp[4, 2].to_i, stamp[6, 2].to_i, stamp[8, 2].to_i, stamp[10, 2].to_i)
rescue ArgumentError
  nil
end