module RbInvoice

# File lib/rbinvoice.rb, line 158
def self.decimal_to_interval(time)
  "%d:%02d" % [time.to_i, (60*time) % 60]
end

# File lib/rbinvoice.rb, line 31
def self.earliest_task_date(hours)
  row = hours.sort_by { |row| parse_date(row[0]) }.first
  row ? row[0] : nil
end

# File lib/rbinvoice.rb, line 71
def self.escape_for_latex(str)
  (str || '').gsub('&', '\\\\&').   # tricky b/c '\&' has special meaning to gsub.
    gsub('"', '\texttt{"}').
    gsub('$', '\$').
    gsub('+', '$+$').
    gsub("\n", " \\\\\\\\ \n")
end

# File lib/rbinvoice.rb, line 173
def self.group_by_task(rows)
  rows.group_by{|r| r[1]}
end

# File lib/rbinvoice.rb, line 115
def self.hourly_breakdown(client, start_date, end_date, opts)
  hours = group_by_task(select_date_range(start_date, end_date, read_all_hours(client, opts)))
end

# File lib/rbinvoice.rb, line 152
def self.interval_to_decimal(time)
  return nil unless time
  d = Date._strptime(time, "%H:%M")
  BigDecimal.new(d[:hour] * 60 + d[:min]) / 60
end

# File lib/rbinvoice.rb, line 64
def self.make_pdf(tasks, start_date, end_date, filename, opts)
  write_latex(tasks, end_date, filename, opts)
  result = system("cd \"#{File.dirname(filename)}\" && pdflatex \"#{File.basename(filename, '.pdf')}\"")
  raise "Problem running LaTeX: $?" unless result
  RbInvoice::Options::add_invoice_to_data(tasks, start_date, end_date, filename, opts) unless opts[:no_data_file]
end

# File lib/rbinvoice.rb, line 119
def self.open_worksheet(spreadsheet, username, password)
  g = Google.new(spreadsheet, username, password)
  g.date_format = '%m/%d/%Y'
  g.default_sheet = g.sheets.first
  return g
end

# File lib/rbinvoice.rb, line 26
def self.parse_date(str)
  return str if str.class == Date
  Date.strptime(str, "%m/%d/%Y")
end

# File lib/rbinvoice.rb, line 130
def self.read_all_hours(client, opts)
  ss = nil
  begin
    ss = open_worksheet(opts[:spreadsheet], opts[:spreadsheet_user], opts[:spreadsheet_password])
  rescue Exception => e
    $stderr.puts "rbinvoice: Failed to open spreadsheet #{opts[:spreadsheet]}: #{$!}"
    exit 1
  end

  client = to_client_key(client)
  return 3.upto(ss.last_row).select { |row|
    to_client_key(ss.cell(row, COL_CLIENT) || '') == client
  }.map { |row|
    raise "Invalid task times: #{ss.cell(row, COL_START_TIME)}-#{ss.cell(row, COL_END_TIME)}" if ss.cell(row, COL_START_TIME) && ss.cell(row, COL_END_TIME) && ss.cell(row, COL_TOTAL_TIME) == '0:00:00'
    if ss.cell(row, COL_NOTES) == 'FREE'
      nil
    else
      [ss.cell(row, COL_DATE), ss.cell(row, COL_TASK), interval_to_decimal(ss.cell(row, COL_TOTAL_TIME))]
    end
  }.compact
end

# File lib/rbinvoice.rb, line 162
def self.select_date_range(start_date, end_date, hours)
  hours.select do |row|
    # puts "#{row[0].class}: #{row.join("\t")}"
    # Sometimes we get a String, sometimes a Date,
    # and changing the cell's format in the spreadsheet
    # doesn't have any effect. So do our best to support both:
    d = row[0].class == String ? parse_date(row[0]) : row[0]
    start_date <= d and d <= end_date
  end
end

# File lib/rbinvoice.rb, line 126
def self.to_client_key(client)
  client.downcase.gsub(' ', '')
end

# File lib/rbinvoice.rb, line 36
def self.write_invoices(client, start_date, end_date, filename, opts)
  if start_date and end_date
    tasks = hourly_breakdown(client, start_date, end_date, opts)
    make_pdf(tasks, start_date, end_date, filename, opts)
  else
    # Write all the outstanding spreadsheets
    freq = RbInvoice::Options::frequency_for_client(opts[:data], client)
    last_invoice = RbInvoice::Options::last_invoice_for_client(opts[:data], client)
    hours = read_all_hours(client, opts)
    earliest_date = if last_invoice
                   last_invoice[:end_date] + 1
                 else
                   parse_date(earliest_task_date(hours))
                 end
    start_date, end_date = RbInvoice::Options::find_invoice_bounds(earliest_date, freq)
    opts[:start_date] = start_date
    opts[:end_date] = end_date
    tasks = hourly_breakdown(client, start_date, end_date, opts)
    while tasks.size > 0
      filename = RbInvoice::Options::default_out_filename(opts)
      make_pdf(tasks, start_date, end_date, filename, opts)
      start_date, end_date = RbInvoice::Options::find_invoice_bounds(end_date + 1, freq)
      tasks = hourly_breakdown(client, start_date, end_date, opts)
      opts[:invoice_number] += 1
    end
  end
end

# File lib/rbinvoice.rb, line 79
def self.write_latex(tasks, invoice_date, filename, opts)
  template = File.open(opts[:template]) { |f| f.read }
  rate = opts[:rate]    # TODO: Support per-task rates
  full_name = RbInvoice::Options::full_name_for_client(opts[:data], opts, opts[:client])
  address = RbInvoice::Options::address_for_client(opts[:data], opts, opts[:client])
  description = RbInvoice::Options::description_for_client(opts[:data], opts, opts[:client])
  items = tasks.map{|task, details|
    task_total_hours = details.inject(0) {|t, row| t + row[2]}
    {
      'name' => escape_for_latex(task),
      'duration_decimal' => task_total_hours,
      'duration' => decimal_to_interval(task_total_hours),
      'price_decimal' => task_total_hours * rate,
      'price' => "%0.02f" % (task_total_hours * rate)
    }
  }


  args = Hash[
    {
      invoice_number: opts[:invoice_number],
      invoice_date: invoice_date.strftime("%d %B %Y"),
      line_items: items,
      total_duration: decimal_to_interval(items.inject(0) {|t, item| t + item['duration_decimal']}),
      total_price: "%0.02f" % items.inject(0) {|t, item| t + item['price_decimal']},
      dba: escape_for_latex(opts[:dba]),
      payment_due: opts[:payment_due],
      client_full_name: escape_for_latex(full_name),
      client_address: escape_for_latex(address),
      client_description: escape_for_latex(description),
    }.map{|k, v| [k.to_s, v]}
  ]
  latex = Liquid::Template.parse(template).render args
  File.open("#{filename.gsub(/\.pdf$/, '')}.tex", 'w') { |f| f.write(latex) }
end