(defun two-pi-r-ledger-get-data (buf)
  (let ((items
          (with-temp-buffer
            (let ((exit-code (ledger-run-ledger buf "emacs")))
              (when (= 0 exit-code)
                (goto-char (point-min))
                (unless (eobp)
                  (unless (looking-at "(")
                    (error (buffer-string)))
                  (read (current-buffer))))))))
    items))

(defun two-pi-r-ledger-all-payees nil
  "Parse the ledger emacs output and get a list of everyone who's ever been paid"
  (let ((accounts (two-pi-r-ledger-get-data (current-buffer))))
    (remove-duplicates (mapcar #'fifth accounts) :test #'string=)))

(defun two-pi-r-ledger-all-accounts nil
  "Parse the ledger emacs output and get a list of every kind of account."
  (let* ((data (two-pi-r-ledger-get-data (current-buffer)))
         (intxns (mapcar #'sixth data))
         (outtxns (mapcar #'seventh data)))
    (remove-duplicates (append (mapcar #'cadr intxns)
                               (mapcar #'cadr outtxns))
                       :test #'string=)))
(setq *two-pi-r-allow-space-in-completion-map* (make-sparse-keymap))
(set-keymap-parent *two-pi-r-allow-space-in-completion-map* minibuffer-local-completion-map)
(define-key *two-pi-r-allow-space-in-completion-map* " " 'self-insert-command)
(defun two-pi-r-ledger-add-entry (date title in amount out)
  (interactive
   (let ((minibuffer-local-completion-map *two-pi-r-allow-space-in-completion-map*)
         (accounts (mapcar 'list (two-pi-r-ledger-all-accounts)))
         (payees (mapcar 'list (two-pi-r-ledger-all-payees))))
     (list (read-string "Date: " (format-time-string "%Y/%m/%d" (current-time)))
           (completing-read "Who did you pay? " payees)
           (completing-read "Where did the money go? " accounts)
           (format "$%.2f" (read-number "How much did you pay? "))
           (completing-read "Where did the money come from? " accounts))))
  (newline)
  (insert date) (insert " ") (insert title) (newline)
  (indent-to 4) (insert in) (indent-to (- 80 (length amount))) (insert amount) (newline)
  (indent-to 4) (insert out) (newline))
(load "ledger")
(define-key ledger-mode-map "\C-ca" 'two-pi-r-ledger-add-entry)
(define-key ledger-mode-map "\C-m" 'newline)