;;; rcd-hash-edit.el --- Edit hashes visually and collaboratively  -*- lexical-binding: t; -*-

;; Copyright (C) 2021 by Jean Louis

;; Author: Jean Louis <bugs@gnu.support>
;; Version: 0.2
;; Package-Requires: (rcd-utilities)
;; Keywords: convenience
;; URL: https://hyperscope.link/3/7/6/6/1/Emacs-Lisp-package-rcd-hash-edit-37661.html

;; This file is not part of GNU Emacs.

;; This program 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 3 of the
;; License, or (at your option) any later version.
;;
;; This program 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 this program. If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; 1. Create a hash any how or use M-x rcd-hash-edit

;; (setq hash (make-hash-table :test #'equal))
;; (puthash "ID" 29 hash)
;; (rcd-hash-edit-hash 'hash)
;; 
;; M-x rcd-hash-edit
;; choose the hash to edit
;; if hash does not exist, new one can be created
;;
;; Key bindings:
;;
;; d - nullify the value
;; D - remove the key and value from hash
;; a - add new value to hash
;; e - edit value
;; 
;; This file requires the GNU Emacs package: rcd-utilities.el:
;; https://gnu.support/gnu-emacs/packages/rcd-utilities-el.html
;;
;; Use `rcd-utilities' to save hash or read hash from file.  Send file
;; to other people to collaborate on the hash structure, let them send
;; it back by email.
;;
;; For example M-x rcd-save-symbol-to-file may be used to save the
;; symbol value to file.
;;
;; You may read the hash into memory by using:
;; M-x rcd-read-symbol-from-file
;;
;; Send file to your collaborators.  Receive the file from
;; collaborators.  Collaborate on Emacs Lisp hash.  Send back and forth
;; by using chat.
;;
;; Example uses:
;;
;; - Convert a single database column and send to collaborator to edit
;;   it and send it back.
;;
;; - Use it as a mini database, create fields and values, save it for
;;   later.  Load again, save it again.
;;
;; - Prepare one template empty hash, send it to collaborator to
;;   insert new information for you. Receive it back and continue
;;   processing your data.

;; RCD is acronym for Reach, Connect, Deliver, my personal
;; principle and formula for Wealth.

;;; Change Log:

;;; Code:

(require 'rcd-utilities nil t)

(defvar-local rcd-hash-current-hash nil
  "Buffer local variable to designate the symbol of edited hash.")

(define-derived-mode rcd-hash-list-mode tabulated-list-mode "RCD Hash List"
  "RCD Hash List is derived from `tabulated-list-mode'.")

(defvar rcd-hash-mode-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-parent map tabulated-list-mode-map)
    (define-key map "D" #'rcd-hash-delete-key-value)
    (define-key map "a" #'rcd-hash-add-key)
    (define-key map "d" #'rcd-hash-nullify-entry)
    (define-key map "e" #'rcd-hash-edit-entry)
    (define-key map "g" #'rcd-hash-refresh)
    (define-key map "h" #'backward-char)
    (define-key map "j" #'next-line)
    (define-key map "k" #'previous-line)
    (define-key map "l" #'forward-char)
    (define-key map "q" #'quit-window)
    (define-key map "s" #'(lambda () (interactive) (rcd-hash-save rcd-hash-current-hash)))
    map)
  "The RCD hash keymap.")

(defun rcd-hash-entries (hash)
  "Convert symbol or hash HASH to `tabulated-list-entries'."
  (let* ((entries '())
	 (type (type-of hash))
	 (hash (cond ((eq type 'symbol) (symbol-value hash))
		     ((eq type 'hash-table) hash)
		     (t hash))))
    (if (eq (type-of hash) 'hash-table)
	(progn
	  (maphash
	   (lambda (key value)
	     (push (list key (vector
			      (string-or-empty-string key)
			      (string-or-empty-string (prin1-to-string value))))
		   entries))
	   hash)
	  (reverse entries))
      (error "%s is not hash or symbol for hash" hash))))

(defun rcd-hash-edit-hash (rcd-hash)
  "Edit HASH with `rcd-hash-list-mode'."
  (let ((rcd-hash-current-hash rcd-hash)
	(entries (rcd-hash-entries rcd-hash)))
    (rcd-hash-report "Edit hash" entries [("Key" 20 t :right-align t :pad-right 3) ("Value" 40 t)] rcd-hash 'rcd-hash-refresh)))

(defun rcd-hash-edit ()
  "Interactively choose a hash to edit.
Optionally provide symbol RCD-HASH for editing or creation."
  (interactive)
  (let ((rcd-hash (read--expression "Hash to edit: ")))
    (if (boundp rcd-hash)
	(if (eq (type-of (symbol-value rcd-hash)) 'hash-table)
	    (rcd-hash-edit-hash rcd-hash)
	  (message "Symbol is not a hash"))
      (progn
	(rcd-hash-create rcd-hash)
	;; (puthash "ID" "ID" (symbol-value rcd-hash))
	;; (remhash "ID" (symbol-value rcd-hash))
	(rcd-hash-edit-hash rcd-hash)))))

(defun rcd-hash-create (symbol)
  "Create hash NAME.
Argument SYMBOL will be created in global space."
  (eval `(defvar ,(intern (symbol-name symbol)) (make-hash-table :test 'equal))))

(defun rcd-hash-edit-entry-1 (hash key)
  "Edit HASH value by using KEY."
  (let* ((hash (symbol-value hash))
	 (value (gethash key hash))
	 (prompt (format "Value for key `%s': " (if (not (stringp key)) (prin1-to-string key) key)))
	 (type (type-of value))
	 (new-value (cond  ((eq type 'cons) (read--expression prompt (prin1-to-string value)))
			   ((or (eq type 'integer)
				(eq type 'float))
			    (read-number prompt value))
			   ((eq type 'string) (read-from-minibuffer prompt value nil nil nil value))
			   (t (error "Not recognized type %s" type)))))
    (puthash key new-value hash)))

(defun rcd-hash-add-key ()
  "Add key to edited hash."
  (interactive)
  (let* ((key (read-from-minibuffer "New key: "))
	 (completion-ignore-case t)
	 (type (completing-read "Type: " '("Number" "String" "Cons") nil t))
	 (prompt (format "Value for key `%s': " key))
	 (value (cond ((string= type "Number") (read-number prompt))
		      ((string= type "String") (read-from-minibuffer prompt))
		      ((string= type "Cons") (read--expression prompt))
		      (t (read-from-minibuffer prompt)))))
    (when (and key value)
      (let ((point (point))
	    (rcd-hash rcd-hash-current-hash))
	(setf (gethash key (symbol-value rcd-hash-current-hash)) value)
	(kill-this-buffer)
	(rcd-hash-edit-hash rcd-hash)
	(goto-char point)))))

(defun rcd-hash-report (title entries format rcd-hash &optional refresh)
  "Handles visual HASH editing.
TITLE is used for the name of buffer.
ENTRIES is in the format of `tabulated-list-entries'.
FORMAT is is in the format of `tabulated-list-format'."
  (let* ((buffer (generate-new-buffer-name (concat "*RCD Hash Editing: " title "*"))))
    (let* ((buffer (get-buffer-create buffer)))
      (switch-to-buffer buffer)
      (setq tabulated-list-format format)
      (setq tabulated-list-entries entries)
      (setq rcd-tabulated-refresh-function refresh)
      (rcd-hash-list-mode)
      (use-local-map rcd-hash-mode-map)
      (hl-line-mode 1)
      (setq rcd-hash-current-hash rcd-hash)
      (setq tabulated-list-padding 1)
      (tabulated-list-init-header))
    (tabulated-list-print t)))

(defun rcd-hash-delete-key-value ()
  "Delete the key and value from edited hash."
  (interactive)
  (let* ((key (tabulated-list-get-id)))
    (when key
      (let ((point (point))
	    (rcd-hash rcd-hash-current-hash))
	(when (y-or-n-p (format "Remove key `%s'? " key))
	  (remhash key (symbol-value rcd-hash))
	  (kill-this-buffer)
	  (rcd-hash-edit-hash rcd-hash)
	  (goto-char point))))))

(defun rcd-hash-refresh ()
  "Refresh the `rcd-hash-list-mode'."
  (interactive)
  (when (eq major-mode 'rcd-hash-list-mode)
    (let ((rcd-hash rcd-hash-current-hash)
	  (point (point)))
      (kill-this-buffer)
      (rcd-hash-edit-hash rcd-hash)
      (goto-char point))))

(defun rcd-hash-edit-entry ()
  "Edit entry."
  (interactive)
  (let* ((key (tabulated-list-get-id))
	 (hash rcd-hash-current-hash)
	 (point (point)))
    (when (and key rcd-hash-current-hash)
      (rcd-hash-edit-entry-1 rcd-hash-current-hash key)
      (kill-this-buffer)
      (rcd-hash-edit-hash hash)
      (goto-char point))))

(defun rcd-hash-nullify-entry ()
  "Nullify the entry for the specific hash key."
  (interactive)
  (let* ((key (tabulated-list-get-id))
	 (entry (tabulated-list-get-entry)))
    (when (and key entry)
      (let* ((point (point))
	     (rcd-hash rcd-hash-current-hash)
	     (value (gethash key (symbol-value rcd-hash-current-hash))))
	(when (y-or-n-p (format "Delete `%s'? " value))
	  (puthash key (rcd-hash-nullify-by-type value) (symbol-value rcd-hash-current-hash))
	  (kill-this-buffer)
	  (rcd-hash-edit-hash rcd-hash)
	  (goto-char point))))))

(defun rcd-hash-nullify-by-type (value)
  "Return the nullified value depending of the type of VALUE."
  (let ((type (type-of value)))
    (cond  ((or (eq type 'cons) (car (read-from-string "nil"))))
	   ((or (eq type 'symbol) (car (read-from-string "nil"))))
	   ((or (eq type 'integer)
		(eq type 'float))
	    0)
	   ((eq type 'string) "")
	   (t (error "Not recognized type %s" type)))))

(defalias 'rcd-hash-load 'rcd-read-symbol-from-file
  "Uses the package `rcd-utilities' to read hash from file.")

(defalias 'rcd-hash-save 'rcd-save-symbol-to-file
  "Uses the package `rcd-utilities' to save hash into file")

;;; rcd-hash-edit.el ends here