require "prawn"
require "prawn/qrcode"
require "rqrcode"

# PDF ticket generator service using Prawn
#
# Generates PDF tickets with QR codes for event entry validation
# Includes event details, venue information, and unique QR code for each ticket
class TicketPdfGenerator
  # Suppress Prawn's internationalization warning for built-in fonts
  Prawn::Fonts::AFM.hide_m17n_warning = true
  attr_reader :ticket

  def initialize(ticket)
    @ticket = ticket
  end

  def generate
    Prawn::Document.new(page_size: [ 350, 600 ], margin: 20) do |pdf|
      # Header
      pdf.fill_color "2D1B69"
      pdf.font "Helvetica", style: :bold, size: 24
      pdf.text "ApéroNight", align: :center
      pdf.move_down 10

      # Event name
      pdf.fill_color "000000"
      pdf.font "Helvetica", style: :bold, size: 18
      pdf.text ticket.event.name, align: :center
      pdf.move_down 20

      # Ticket info box
      pdf.stroke_color "E5E7EB"
      pdf.fill_color "F9FAFB"
      pdf.rounded_rectangle [ 0, pdf.cursor ], 310, 120, 10
      pdf.fill_and_stroke

      pdf.move_down 10
      pdf.fill_color "000000"
      pdf.font "Helvetica", size: 12

      # Ticket details
      pdf.text "Ticket Type:", style: :bold
      pdf.text ticket.ticket_type.name
      pdf.move_down 8

      pdf.text "Price:", style: :bold
      pdf.text "€#{ticket.price_euros}"
      pdf.move_down 8

      pdf.text "Date & Time:", style: :bold
      pdf.text ticket.event.start_time.strftime("%B %d, %Y at %I:%M %p")
      pdf.move_down 20

      # Venue information
      pdf.fill_color "374151"
      pdf.font "Helvetica", style: :bold, size: 14
      pdf.text "Venue Information"
      pdf.move_down 8

      pdf.font "Helvetica", size: 11
      pdf.text ticket.event.venue_name, style: :bold
      pdf.text ticket.event.venue_address
      pdf.move_down 20

      # QR Code
      pdf.fill_color "000000"
      pdf.font "Helvetica", style: :bold, size: 14
      pdf.text "Ticket QR Code", align: :center
      pdf.move_down 10

      # Ensure all required data is present before generating QR code
      if ticket.qr_code.blank?
        raise "Ticket QR code is missing"
      end

      # Build QR code data with safe association loading
      qr_code_data = build_qr_code_data(ticket)

      # Validate QR code data before creating QR code
      if qr_code_data.blank? || qr_code_data == "{}"
        Rails.logger.error "QR code data is empty: ticket_id=#{ticket.id}, qr_code=#{ticket.qr_code}, event_id=#{ticket.ticket_type&.event_id}, user_id=#{ticket.order&.user_id}"
        raise "QR code data is empty or invalid"
      end

      # Ensure qr_code_data is a proper string for QR code generation
      unless qr_code_data.is_a?(String) && qr_code_data.length > 2
        Rails.logger.error "QR code data is not a valid string: #{qr_code_data.inspect} (class: #{qr_code_data.class})"
        raise "QR code data must be a valid string"
      end

      qrcode = RQRCode::QRCode.new(qr_code_data)
      pdf.print_qr_code(qrcode, extent: 120, align: :center)

      pdf.move_down 15

      # QR code text
      pdf.font "Helvetica", size: 8
      pdf.fill_color "6B7280"
      pdf.text "QR Code: #{ticket.qr_code[0..7]}...", align: :center

      # Footer
      pdf.move_down 30
      pdf.stroke_color "E5E7EB"
      pdf.horizontal_line 0, 310
      pdf.move_down 10

      pdf.font "Helvetica", size: 8
      pdf.fill_color "6B7280"
      pdf.text "This ticket is valid for one entry only.", align: :center
      pdf.text "Present this ticket at the venue entrance.", align: :center
      pdf.move_down 5
      pdf.text "Generated on #{Time.current.strftime('%B %d, %Y at %I:%M %p')}", align: :center
    end.render
  end

  private

  def build_qr_code_data(ticket)
    # Try multiple approaches to get valid QR code data
    begin
      # Primary approach: full JSON with all data
      data = {
        ticket_id: ticket.id,
        qr_code: ticket.qr_code,
        event_id: ticket.ticket_type&.event_id,
        user_id: ticket.order&.user_id
      }.compact

      # Ensure we have the minimum required data
      if data[:ticket_id] && data[:qr_code]
        return data.to_json
      end
    rescue StandardError => e
      Rails.logger.warn "Failed to build complex QR data: #{e.message}"
    end

    # Fallback approach: just use the ticket's QR code string
    begin
      return ticket.qr_code.to_s if ticket.qr_code.present?
    rescue StandardError => e
      Rails.logger.warn "Failed to use ticket QR code: #{e.message}"
    end

    # Final fallback: simple ticket identifier
    "TICKET-#{ticket.id}"
  end
end