class LeadmailDelivery
  attr_reader :settings

  def initialize(settings)
    @settings = settings
  end

  def deliver!(message)
    payload = build_payload(message)
    response = http_client.post('/emails/send', payload)

    unless response.success?
      raise LeadmailDeliveryError, "LeadMail API error: #{response.status} - #{response.body}"
    end

    response_data = JSON.parse(response.body)
    message.header['X-LeadMail-Log-ID'] = response_data.dig('data', 'log_id')
    Rails.logger.info("Email sent via LeadMail: log_id=#{response_data.dig('data', 'log_id')}, to=#{message.to.inspect}")
    response
  rescue StandardError => e
    Rails.logger.error("LeadMail delivery failed: #{e.message}\nPayload: #{payload.inspect}")
    raise
  end

  private

  def build_payload(message)
    {
      from: extract_from(message),
      to: extract_recipients(message.to),
      cc: extract_recipients(message.cc),
      bcc: extract_recipients(message.bcc),
      reply_to: extract_reply_to(message),
      subject: message.subject,
      html_body: html_body(message),
      text_body: text_body(message),
      attachments: extract_attachments(message),
      options: {
        on_verification_failure: 'strip',
        allow_disposable: false
      }
    }.compact
  end

  def extract_from(message)
    from_address = message.from&.first
    from_display = message[:from]&.display_names&.first

    {
      email: from_address,
      name: from_display
    }.compact
  end

  def extract_recipients(addresses)
    return nil if addresses.blank?

    Array(addresses).map { |email| { email: email } }
  end

  def extract_reply_to(message)
    reply_to_address = message.reply_to&.first
    return nil if reply_to_address.blank?

    { email: reply_to_address }
  end

  def html_body(message)
    return message.html_part.body.to_s if message.html_part.present?
    return message.body.to_s if message.content_type&.start_with?('text/html')

    nil
  end

  def text_body(message)
    return message.text_part.body.to_s if message.text_part.present?
    return message.body.to_s if message.content_type&.start_with?('text/plain')

    nil
  end

  def extract_attachments(message)
    return nil if message.attachments.blank?

    message.attachments.map do |attachment|
      {
        filename: attachment.filename,
        mime_type: attachment.mime_type || 'application/octet-stream',
        content: Base64.strict_encode64(attachment.body.to_s)
      }
    end
  end

  def http_client
    @http_client ||= Faraday.new(
      url: settings[:api_url],
      headers: {
        'Authorization' => "Bearer #{settings[:token]}",
        'Content-Type' => 'application/json'
      }
    )
  end
end

class LeadmailDeliveryError < StandardError; end