class CapitalOneStatement

# File lib/parse_capitalone_pdf_statement.rb, line 59
def initialize(pdf_path)
  @card_number        = nil
  @dec_from_prev_year = nil
  @year               = nil
  @start_date         = nil
  @end_date           = nil
  @previous_balance   = nil
  @new_balance        = nil
  @total_payments     = nil
  @total_transactions = nil
  @total_fees         = nil
  @payments           = []
  @transactions       = []
  @fees               = []

  parse_from_pdf pdf_path

  %w{payments transactions fees}.each do |type|
    trxs  = "@#{type}"
    total = "@total_#{type}"

    instance_variable_set(trxs, instance_variable_get(trxs).sort_by {|trx| trx[:id]})

    check_total(
      type,
      instance_variable_get(total),
      instance_variable_get(trxs).inject(0) {|sum, trx| sum += trx[:amount]}
    )
  end
end

# File lib/parse_capitalone_pdf_statement.rb, line 90
def to_json(*args)
  {
    :start_date         => @start_date,
    :end_date           => @end_date,
    :previous_balance   => @previous_balance,
    :total_payments     => @total_payments,
    :total_fees         => @total_fees,
    :total_transactions => @total_transactions,
    :new_balance        => @new_balance,
    :payments           => @payments,
    :transactions       => @transactions,
    :fees               => @fees
  }.to_json(*args)
end

# File lib/parse_capitalone_pdf_statement.rb, line 227
def check_parse_state
  raise "Failed to determine billing cycle dates" if @year.nil?
  raise "Failed to determine card number"         if @card_number.nil?
end

# File lib/parse_capitalone_pdf_statement.rb, line 232
def check_total(type, expected, actual)
  return if actual.round(2) == expected.round(2)

  raise "Calculated %s mismatch %.2f != %.2f" % [
    type,
    actual,
    expected
  ]
end

# File lib/parse_capitalone_pdf_statement.rb, line 115
def method_missing(name, *args)
  return unless name =~ /show_text/

  if args.any? {|str| str.to_s =~ DATE_REGEX}
    self.offset     = ($1.upcase == 'DEC' && $3.upcase == 'JAN') ? 1 : 0
    self.year       = $5.to_i
    self.start_date = Date.parse('%s-%s-%s' % [year - offset, $1, $2])
    self.end_date   = Date.parse('%s-%s-%s' % [year, $3, $4])
  end
end

# File lib/parse_capitalone_pdf_statement.rb, line 222
def parse_amount(amount)
  num = amount.gsub(/[^\d.]/, '').to_f
  amount.start_with?(?() ? -num : num
end

# File lib/parse_capitalone_pdf_statement.rb, line 107
def parse_from_pdf(pdf_path)
  PDF::Reader.new(pdf_path).pages.each_with_index do |page, page_num|
    if @year.nil?
      walker = Struct.new(:year, :offset, :start_date, :end_date) do
        def respond_to?(_)
          true
        end

        def method_missing(name, *args)
          return unless name =~ /show_text/

          if args.any? {|str| str.to_s =~ DATE_REGEX}
            self.offset     = ($1.upcase == 'DEC' && $3.upcase == 'JAN') ? 1 : 0
            self.year       = $5.to_i
            self.start_date = Date.parse('%s-%s-%s' % [year - offset, $1, $2])
            self.end_date   = Date.parse('%s-%s-%s' % [year, $3, $4])
          end
        end
      end.new

      page.walk walker

      @dec_from_prev_year = walker.offset == 1
      @year               = walker.year
      @start_date         = walker.start_date
      @end_date           = walker.end_date
    end

    enum = page.text.split("\n").each

    loop do
      current_line = enum.next
      enum.next until (enum.peek rescue nil) != ''
      next_line    = (enum.peek rescue nil)

      parse_pdf_line page_num, current_line, next_line
    end
  end
end

# File lib/parse_capitalone_pdf_statement.rb, line 147
def parse_pdf_line(page_num, line, next_line)
  if line =~ CARD_NUMBER_REGEX
    @card_number = $1.to_i
  end

  if @previous_balance.nil?
    amount_strs = line.scan AMOUNT_REGEX
    if amount_strs.size == 5
      @previous_balance,
      @total_payments,
      @total_fees,
      @total_transactions,
      @new_balance = amount_strs.map {|amount| parse_amount(amount)}

      @total_payments = -@total_payments
    end
  end

  if line =~ FEES_REGEX && $1 != '$0.00'
    check_parse_state
    @fees << Transaction.new(
      @fees.size + 1,
      @card_number,
      @end_date, "CAPITAL ONE MEMBER FEE",
      $1,
      parse_amount($1)
    )
  end

  if line =~ INTEREST_REGEX && $1 != '$0.00'
    check_parse_state
    @fees << Transaction.new(
      @fees.size + 1,
      @card_number,
      @end_date, "INTEREST CHARGE:PURCHASES",
      $1,
      parse_amount($1)
    )
  end

  transactions, payments = [(0..78), (80..-1)].map do |index|
    str      = line     .to_s[index].to_s
    next_str = next_line.to_s[index].to_s

    repair_transaction_line str, next_str
  end.map do |str|
    parse_transaction(str)
  end.compact.partition do |trx|
    trx[:amount] >= 0
  end

  @transactions += transactions
  @payments     += payments
end

# File lib/parse_capitalone_pdf_statement.rb, line 210
def parse_transaction(line)
  return nil unless line =~ TRANSACTION_REGEX &&
                    $4   != "CAPITAL ONE MEMBER FEE"

  check_parse_state

  year = ($3.upcase == 'DEC' && @dec_from_prev_year) ? @year - 1 : @year
  date = Date.parse('%s-%s-%s' % [year, $3, $2])

  Transaction.new($1.to_i, @card_number, date, $4, $5, parse_amount($5))
end

# File lib/parse_capitalone_pdf_statement.rb, line 202
def repair_transaction_line(line, next_line)
  if next_line =~ AMOUNT_ONLY_REGEX && !(line =~ AMOUNT_REGEX)
    line += " #{next_line.strip}"
  else
    line
  end
end

# File lib/parse_capitalone_pdf_statement.rb, line 111
def respond_to?(_)
  true
end