# 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!

class Transaction
  def initialize(time, person, product, amount: 1)
    @time = time
    @person = person
    @product = product
    @amount = amount
  end
  
  attr_accessor :time, :person, :product, :amount
end

class Product
  def initialize(id, description, price)
    @id = id
    @description = description
    @price = price
  end

  def to_s
    "#{@id} => #{@description}, #{@price}"
  end
  
  attr_accessor :id, :description, :price
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],amount: row[3])
  end
  rows
end

def read_db(db)
  transactions = Array.new
  db.query("SELECT * FROM Transactions").each do |trans|
    if date_of_prev('monday').to_time < trans["time"]
      transactions << Transaction.new(trans["time"], trans["buyer"],
                          trans["product"], amount: trans["amount"])
    end
  end
  return transactions
end

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

def generate_receipt(persons,draft)
  counter = 0

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

    yaml = YAML_BASE.clone
    yaml["to"] = Names[person]
    yaml["invoice-nr"] = Time.now.strftime('%Y%W') + "-" + counter.to_s
    
    # Iterate through products purchased and write data to yaml hash
    products.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

# Utility

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)

# Initialize product and member hashses
Products = Hash.new
Names = Hash.new
Prices = Hash.new
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

db.query("SELECT * FROM Persons").each do |member|
  Names[member['id']] = member['name']
end

partition = partition_transactions(read_db(db))
generate_receipt(partition,Options[:draft])