;;; ldg-complete.el --- Helper code for use with the "ledger" command-line tool

;; Copyright (C) 2003-2013 John Wiegley (johnw AT gnu DOT org)

;; This file is not part of GNU Emacs.

;; This is free software; you can redistribute it and/or modify it under
;; the terms of the GNU General Public License as published by the Free
;; Software Foundation; either version 2, or (at your option) any later
;; version.
;;
;; This is distributed in the hope that it will be useful, but WITHOUT
;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
;; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
;; for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
;; MA 02111-1307, USA.

;;(require 'esh-util)
;;(require 'esh-arg)
(require 'pcomplete)

;; In-place completion support

(defun ledger-thing-at-point ()
  (let ((here (point)))
    (goto-char (line-beginning-position))
    (cond ((looking-at "^[0-9/.=-]+\\(\\s-+\\*\\)?\\(\\s-+(.+?)\\)?\\s-+")
           (goto-char (match-end 0))
           'entry)
          ((looking-at "^\\s-+\\([*!]\\s-+\\)?[[(]?\\(.\\)")
           (goto-char (match-beginning 2))
           'transaction)
          ((looking-at "^\\(sun\\|mon\\|tue\\|wed\\|thu\\|fri\\|sat\\)\\s-+")
           (goto-char (match-end 0))
           'entry)
          (t
           (ignore (goto-char here))))))

(defun ledger-parse-arguments ()
  "Parse whitespace separated arguments in the current region."
  (let* ((info (save-excursion
                 (cons (ledger-thing-at-point) (point))))
         (begin (cdr info))
         (end (point))
         begins args)
    (save-excursion
      (goto-char begin)
      (when (< (point) end)
        (skip-chars-forward " \t\n")
        (setq begins (cons (point) begins))
        (setq args (cons (buffer-substring-no-properties
                          (car begins) end)
                         args)))
      (cons (reverse args) (reverse begins)))))

(defun ledger-entries ()
  (let ((origin (point))
        entries-list)
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward
              (concat "^[0-9/.=-]+\\(\\s-+\\*\\)?\\(\\s-+(.*?)\\)?\\s-+"
                      "\\(.+?\\)\\(\t\\|\n\\| [ \t]\\)") nil t)
        (unless (and (>= origin (match-beginning 0))
                     (< origin (match-end 0)))
          (setq entries-list (cons (match-string-no-properties 3)
                                   entries-list)))))
    (pcomplete-uniqify-list (nreverse entries-list))))

(defvar ledger-account-tree nil)

(defun ledger-find-accounts ()
  (let ((origin (point)) account-path elements)
    (save-excursion
      (setq ledger-account-tree (list t))
      (goto-char (point-min))
      (while (re-search-forward
              "^[ \t]+\\([*!]\\s-+\\)?[[(]?\\(.+?\\)\\(\t\\|\n\\| [ \t]\\)" nil t)
        (unless (and (>= origin (match-beginning 0))
                     (< origin (match-end 0)))
          (setq account-path (match-string-no-properties 2))
          (setq elements (split-string account-path ":"))
          (let ((root ledger-account-tree))
            (while elements
              (let ((entry (assoc (car elements) root)))
                (if entry
                    (setq root (cdr entry))
                  (setq entry (cons (car elements) (list t)))
                  (nconc root (list entry))
                  (setq root (cdr entry))))
              (setq elements (cdr elements)))))))))

(defun ledger-accounts ()
  (ledger-find-accounts)
  (let* ((current (caar (ledger-parse-arguments)))
         (elements (and current (split-string current ":")))
         (root ledger-account-tree)
         (prefix nil))
    (while (cdr elements)
      (let ((entry (assoc (car elements) root)))
        (if entry
            (setq prefix (concat prefix (and prefix ":")
                                 (car elements))
                  root (cdr entry))
          (setq root nil elements nil)))
      (setq elements (cdr elements)))
    (and root
         (sort
          (mapcar (function
                   (lambda (x)
                     (let ((term (if prefix
                                     (concat prefix ":" (car x))
                                   (car x))))
                       (if (> (length (cdr x)) 1)
                           (concat term ":")
                         term))))
                  (cdr root))
          'string-lessp))))

(defun ledger-complete-at-point ()
  "Do appropriate completion for the thing at point"
  (interactive)
  (while (pcomplete-here
          (if (eq (save-excursion
                    (ledger-thing-at-point)) 'entry)
              (if (null current-prefix-arg)
                  (ledger-entries)  ; this completes against entry names
                (progn
                  (let ((text (buffer-substring (line-beginning-position)
                                                (line-end-position))))
                    (delete-region (line-beginning-position)
                                   (line-end-position))
                    (condition-case err
                        (ledger-add-entry text t)
                      ((error)
                       (insert text))))
                  (forward-line)
                  (goto-char (line-end-position))
                  (search-backward ";" (line-beginning-position) t)
                  (skip-chars-backward " \t0123456789.,")
                  (throw 'pcompleted t)))
            (ledger-accounts)))))

(defun ledger-fully-complete-entry ()
  "Do appropriate completion for the thing at point"
  (interactive)
  (let ((name (caar (ledger-parse-arguments)))
        xacts)
    (save-excursion
      (when (eq 'entry (ledger-thing-at-point))
        (when (re-search-backward
               (concat "^[0-9/.=-]+\\(\\s-+\\*\\)?\\(\\s-+(.*?)\\)?\\s-+"
                       (regexp-quote name) "\\(\t\\|\n\\| [ \t]\\)") nil t)
          (forward-line)
          (while (looking-at "^\\s-+")
            (setq xacts (cons (buffer-substring-no-properties
                               (line-beginning-position)
                               (line-end-position))
                              xacts))
            (forward-line))
          (setq xacts (nreverse xacts)))))
    (when xacts
      (save-excursion
        (insert ?\n)
        (while xacts
          (insert (car xacts) ?\n)
          (setq xacts (cdr xacts))))
      (forward-line)
      (goto-char (line-end-position))
      (if (re-search-backward "\\(\t\\| [ \t]\\)" nil t)
          (goto-char (match-end 0))))))

(provide 'ldg-complete)