module ChartsLookup

# File lib/charts_lookup.rb, line 80
def error_report(message)
  { error: true, report: ChartsReport.error(message) }
end

# File lib/charts_lookup.rb, line 60
def lookup(country_query, fetch:, limit: MAX_ENTRIES)
  resolved = ChartsCountry.resolve(country_query)
  return error_report(resolved[:error]) if resolved[:error]

  html = fetch.call(ChartsCountry.weekly_url(resolved[:code]))
  parsed = parse_page(html, limit: limit)
  entries = parsed[:entries]
  return error_report("No chart data found for #{resolved[:name]}.") if entries.empty?

  name = parsed[:country_name] || resolved[:name]
  report = ChartsReport.build(
    country_name: name,
    chart_date: parsed[:chart_date],
    entries: entries
  )
  { report: report, entries: entries }
rescue StandardError
  error_report("Could not fetch Spotify charts — try again shortly.")
end

# File lib/charts_lookup.rb, line 36
def parse_chart_date(doc)
  title = doc.at("span.pagetitle")&.text.to_s
  match = title.match(/ - (\d{4}\/\d{2}\/\d{2})/)
  date = match ? match[1].strip : nil
  date if date&.match?(CHART_DATE_PATTERN)
end

# File lib/charts_lookup.rb, line 30
def parse_country_name(doc)
  title = doc.at("span.pagetitle")&.text.to_s
  match = title.match(/Spotify Weekly Chart - (.+?) - /)
  match ? match[1].strip : nil
end

# File lib/charts_lookup.rb, line 43
def parse_entries(doc, limit: MAX_ENTRIES)
  rows = doc.css("table#spotifyweekly tbody tr")
  rows.filter_map do |row|
    cells = row.css("td")
    next if cells.length < 3

    position = cells[0].text.to_s.strip.to_i
    next unless position.positive?

    change = cells[1].text.to_s.strip
    label = cells[2].at("div")&.text.to_s.gsub(/\s+/, " ").strip
    next if label.empty?

    { position: position, change: change, label: label }
  end.first(limit)
end

# File lib/charts_lookup.rb, line 19
def parse_page(html, limit: MAX_ENTRIES)
  doc = Nokogiri.HTML(html.to_s)
  country_name = parse_country_name(doc)
  chart_date = parse_chart_date(doc)
  entries = parse_entries(doc, limit: limit)

  { country_name: country_name, chart_date: chart_date, entries: entries }
rescue StandardError
  { country_name: nil, chart_date: nil, entries: [] }
end