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

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
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)
    @id = id
    @name = name
    @purchases = {}
  end
  
  def to_s
    id
  end

  attr_reader :id
  attr_accessor :name, :purchases
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_of_prev('monday').to_time < 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|
    persons[row['id']] = Person.new(row['id'],row['name'])
  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,draft)
  counter = 0

  # Iterate through persons who have purchased something in the given timeframe
  persons.each do |id, person|
    counter += 1

    yaml = YAML_BASE.clone
    yaml["to"] = person.name
    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"]
      hash = {description: products[id].description,
              pieceprice: products[id].price.to_i,
              price: products[id].price.to_i*amount, amount: amount}

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

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

    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, Options[:draft])