# coding: utf-8
require 'yaml'
require 'mysql2'
require 'optparse'
require 'digest'

load 'config.rb'

Options = {}
OptionParser.new do |opts|
  opts.banner = "Usage: invoice.rb [options]"
  opts.on("-d", "--draft", "Generate invoices with 'DRAFT' watermark") do |d|
    Options[:draft] = d
  end
  opts.on("-v", "--verbose", "Run verbosely") do |v|
    Options[:verbose] = v
  end
  opts.on("-s", "--silent", "Run silently (overrules -v)") do |s|
    Options[:silent] = true
    Options[:verbose] = false
  end
  opts.on("-m", "--mobilepay", "Generate QR codes for MobilePay") do |m|
    require 'rqrcode'
    Options[:mobilepay] = true
  end
end.parse!


Transaction = Struct.new(:time, :person, :product, :amount)

Product = Struct.new(:id, :description, :price) do
  def to_s
    "#{id} => #{description}, #{price}"
  end
end

class Person
  def initialize(id, name, address)
    @id = id
    @name = name
    @address = address
    @purchases = {}
  end
  
  def to_s
    id
  end

  attr_reader :id
  attr_accessor :name, :purchases, :address
end

def read_file(file)
  rows = Array.new
  CSV.foreach(file, col_sep: ';', converters: :float) do |row|
    rows << Transaction.new(row[0],row[1],row[2],row[3])
  end
  rows
end

def load_transactions_from_db(db)
  transactions = Array.new
  db.query("SELECT * FROM Transactions").each do |row|
    if Date.today.monday?
      previous_monday = Date.today.to_time
    else
      previous_monday = date_of_prev('monday').to_time
    end
    if previous_monday < row["time"]
      transactions << Transaction.new(row["time"], row["buyer"],
                                      row["product"], row["amount"])
    end
  end
  return transactions
end

def load_persons_from_db(db)
  persons = {}
  db.query("SELECT * FROM Persons").each do |row|
    address = []
    if (row['address'])
      address << row['address']
    end
    person = Person.new(row['id'],row['name'],address)
    persons[row['id']] = person
    if Options[:verbose]
      puts "Found person: #{person}"
    end
  end
  
  return persons
end

def load_products_from_db(db)
  products = {}
  db.query("SELECT * FROM Products").each do |p|
    product = Product.new(p['id'], p['description'], p['price'])
    products[p['id']] = product
    if Options[:verbose]
      puts "Found product: #{product}"
    end
  end
  
  return products
end

# Partition transactions into the persons who they belong to
def partition_transactions(transactions,persons)
  transactions.each do |t|
    # Initialize data structures if not already done
    if !(persons[t.person].purchases[t.product])
      persons[t.person].purchases[t.product] = 0
    end
    
    persons[t.person].purchases[t.product] += t.amount
  end
  
  return persons
end

def generate_receipt(persons,products,db,draft)
  counter = 0

  # Iterate through persons who have purchased something in the given timeframe
  persons.each do |id, person|
    # Skip persons with no transactions
    if person.purchases.empty?
      if Options[:verbose]
        puts "Skipping #{id} with no transactions"
      end
      next
    end

    counter += 1
    total_payment = 0
    
    yaml = YAML_BASE.clone
    yaml["to"] = [person.name].concat person.address
    yaml["invoice-nr"] = Time.now.strftime('%Y%W') + "-" + counter.to_s


    
    # Iterate through products purchased and write data to yaml hash
    person.purchases.each do |id, amount|
      yaml["service"] = Array.new unless yaml["service"]
      piece_price = products[id].price.to_i
      price = piece_price.to_i*amount
      hash = {description: products[id].description,
              pieceprice: piece_price,
              price: price, amount: amount}
      total_payment += price

      # Convert Symbols to Strings to ensure compatibility with pandoc
      yaml["service"] << Hash[hash.map{ |k, v| [k.to_s, v] }]
    end
    total_payment = total_payment * 0.90

    # Write draft watermark on invoice if marked as draft
    if draft
      yaml["draft"] = "true"
      yaml["drafttext"] = "Udkast"
    end

    # Generate QR code for MobilePay if option set
    if Options[:mobilepay]
      mobilepay_url = "https://mobilepay.dk/da-dk/pages/betal.aspx?phone=#{MOBILEPAY_PHONE_NUMBER}&amount=#{total_payment.round(2)}&comment=Tilbagebetaling%20-%20Faktura%20nr.%20#{yaml["invoice-nr"]}&lock=1"
      if Options[:verbose]
        puts "Generating QR code for #{id} with URL #{mobilepay_url}"
      end
      yaml["qrcode"] = true
      

      qrcode = RQRCode::QRCode.new(mobilepay_url)
      image = qrcode.as_png(
          resize_gte_to: false,
          resize_exactly_to: false,
          fill: 'white',
          color: 'black',
          size: 480,
          border_modules: 4,
          module_px_size: 6,
          file: nil # path to write
          )
      File.open("./pandoc/qr.png","w+") do |file|
        file << image
      end
    end
    
    # Convert Symbols to Strings to ensure compatibility with pandoc
    output = Hash[yaml.map{ |k, v| [k.to_s, v] }].to_yaml
    output += "---\n"
    
    # Write output to file
    File.open("./pandoc/details.yml","w+") do |file|
      file << output
    end

    # Generate PDF using pandoc
    `cd pandoc/; make -B`
    `cp pandoc/output.pdf #{OUTPUT_PATH}/#{yaml["invoice-nr"]}.pdf`

    # Upload PDF to MySQL database
    File.open("pandoc/output.pdf") do |file|
      data = file.read
      hash = Digest::MD5.new.hexdigest data
      statement = db.prepare("INSERT INTO Invoices (id, person, data, hash) VALUES (?, ?, ?, ?)
                              ON DUPLICATE KEY UPDATE person = ?, data = ?, hash = ?")
      result = statement.execute(yaml["invoice-nr"],id,data,hash,id,data,hash)
    end

    puts "#{person}: #{yaml["invoice-nr"]}.pdf" unless Options[:silent]
  end
end

def date_of_next(day)
  date  = Date.parse(day)
  delta = date > Date.today ? 0 : 7
  date + delta
end

def date_of_prev(day)
  date = Date.parse(day)
  delta = date < Date.today ? 0 : 7
  date - delta
end

#################

db = Mysql2::Client.new(:host => DB_HOST, :username => DB_USER, :database => DB_DB)

transactions = load_transactions_from_db(db)
persons = load_persons_from_db(db)
products = load_products_from_db(db)

generate_receipt(partition_transactions(transactions,persons), products, db, Options[:draft])