;;; gravy.el: calculate how much money fell out of the sky onto each of us.
;;;
;;; Instructions: load this file, then run "M-x gravy".
;;;
;;; Notes: The math assumes that capital gains is a percentage taken
;;; from the profits.

(defun gravy ()
  (interactive)
  (let* ((buf (get-buffer-create "*Gravy*"))

         ;; First we figure out how big a bowl of gravy this is
         (investment           4200.0)   ; The total amount we put in
         (gross-receipts       33977.42) ; What got wired into Karl's account
         (taxable-gains        (- gross-receipts investment))
         (tax-rate             0.40)     ; Uncle Sam do care about the rest
         (after-taxes          (- gross-receipts (* taxable-gains tax-rate)))

         ;; Then we figure out how much of it Karl has already eaten
         (wire-out-fee         25.0)     ; Karl paid to send a wire transfer
         (wire-in-fee          25.0)     ; Karl probably paid for wire in, too
         (FedEx-fee            15.0)     ; Karl mails documents with all speed
         (deutsche-banc-fee    53.0)     ; Their brochure lists this charge
         (kinkos-krap           5.0)     ; We need copies of all forms
         (karl-tax-accountant  80.0)     ; (est.) (H.R. Block of 2 years ago)
         (misc-expenses        (+ wire-out-fee wire-in-fee FedEx-fee
                                  deutsche-banc-fee kinkos-krap
                                  karl-tax-accountant))

         ;; So the total volume of gravy remaining is...
         (net-receipts         (- after-taxes misc-expenses))

         ;; And each of us gets a portion thusly:
         (lefty-percentage     17.8571)  ; Lefty put in $750 of $4200
         (fitz-percentage      52.8571)  ; Fitz put in $2220 of $4200
         (karl-percentage      29.2857)  ; Karl put in $1230 of $4200
         (lefty-net            (* net-receipts (/ lefty-percentage 100)))
         (fitz-net             (* net-receipts (/ fitz-percentage 100)))
         (karl-net             (* net-receipts (/ karl-percentage 100)))
         )
    (save-excursion
      (set-buffer buf)
      (delete-region (point-min) (point-max))
      (insert "\nThat's some mighty fine gravy there, Maw:\n\n")
      (insert
       (format
        "   Lefty: $%d\n   Fitz:  $%d\n   Karl:  $%d\n"
        lefty-net fitz-net karl-net)))
    (display-buffer buf)))