class HlsProxyController < ActionController::Base
  # Proxy pubblico verso MediaMTX HLS.
  # Dev: tutto passa da Rails (/hls/*).
  # Prod: edge inoltra /hls/ a MediaMTX; il redirect cookie di MediaMTX punta a
  # /live/match_{uuid}/… che deve essere gestito da #live_match (fallback).
  def show
    proxy_mediamtx_path(params[:path].to_s)
  end

  def live_match
    session_id = params[:session_id].to_s
    return head :not_found unless session_id.match?(/\A[0-9a-f-]{36}\z/i)

    segments = params[:segments].presence || "index.m3u8"
    proxy_mediamtx_path("live/match_#{session_id}/#{segments}")
  end

  private

  def proxy_mediamtx_path(upstream_path)
    return head :not_found if upstream_path.blank?

    upstream = "#{MatchLiveTv.mediamtx_hls_url}/#{upstream_path}"
    upstream = "#{upstream}?#{request.query_string}" if request.query_string.present?
    cookie = request.headers["Cookie"].presence || "cookieCheck=1"

    5.times do
      response = hls_conn.get(upstream) { |req| req.headers["Cookie"] = cookie }

      if response.status.in?([301, 302, 307, 308])
        location = response.headers["location"].to_s
        cookie = cookie_from_set_header(response.headers["set-cookie"]).presence || cookie
        upstream = resolve_upstream_url(location)
        next
      end

      return render_proxied_response(response)
    end

    head :bad_gateway
  rescue Faraday::Error => e
    Rails.logger.warn("[HlsProxy] #{upstream_path}: #{e.message}")
    head :bad_gateway
  end

  def resolve_upstream_url(location)
    return location if location.start_with?("http://", "https://")

    base = MatchLiveTv.mediamtx_hls_url.sub(%r{/$}, "")
    location.start_with?("/") ? "#{base}#{location}" : "#{base}/#{location}"
  end

  def render_proxied_response(response)
    body = response.body.to_s
    content_type = response.headers["content-type"].to_s

    if m3u8_playlist?(content_type, body)
      public_hls_base = "#{request.base_url}/hls"
      body = body.gsub(%r{(?<=["'(\s])/live/(match_[0-9a-f-]{36}/)}, "/hls/live/\\1")
      body = body.gsub(%r{\A/live/(match_[0-9a-f-]{36}/)}, "/hls/live/\\1")
    end

    response.headers.each do |key, value|
      next if %w[transfer-encoding connection content-length content-encoding].include?(key.downcase)

      if key.downcase == "location"
        headers[key] = rewrite_public_location(value)
      else
        headers[key] = value
      end
    end

    render body: body, status: response.status, content_type: content_type.presence
  end

  def rewrite_public_location(location)
    loc = location.to_s
    if loc.start_with?("/live/match_")
      return loc.sub(%r{\A/live/}, "/hls/")
    end
    if loc.include?("/live/match_")
      return loc.gsub(%r{/(live/match_[0-9a-f-]{36}/)}, "/hls/live/\\1")
    end
    loc
  end

  def m3u8_playlist?(content_type, body)
    return true if content_type.include?("mpegurl") || content_type.include?("m3u8")

    body.lstrip.start_with?("#EXTM3U")
  end

  def cookie_from_set_header(set_cookie_header)
    set_cookie_header.to_s[/cookieCheck=[^;]+/]
  end

  def hls_conn
    @hls_conn ||= Faraday.new do |f|
      f.adapter Faraday.default_adapter
      f.options.timeout = 15
      f.options.open_timeout = 5
    end
  end
end