;;; ob-sqlite.el --- org-babel functions for sqlite database interaction

;; Copyright (C) 2010-2017 Free Software Foundation, Inc.

;; Author: Eric Schulte
;; Keywords: literate programming, reproducible research
;; Homepage: http://orgmode.org

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Org-Babel support for evaluating sqlite source code.

;;; Code:
(require 'ob)

(declare-function org-fill-template "org" (template alist))
(declare-function org-table-convert-region "org-table"
		  (beg0 end0 &optional separator))
(declare-function orgtbl-to-csv "org-table" (table params))
(declare-function org-table-to-lisp "org-table" (&optional txt))

(defvar org-babel-default-header-args:sqlite '())

(defvar org-babel-header-args:sqlite
  '((db        . :any)
    (header    . :any)
    (echo      . :any)
    (bail      . :any)
    (csv       . :any)
    (column    . :any)
    (html      . :any)
    (line      . :any)
    (list      . :any)
    (separator . :any)
    (nullvalue . :any))
  "Sqlite specific header args.")

(defun org-babel-expand-body:sqlite (body params)
  "Expand BODY according to the values of PARAMS."
  (org-babel-sqlite-expand-vars
   body (mapcar #'cdr (org-babel-get-header params :var))))

(defvar org-babel-sqlite3-command "sqlite3")

(defun org-babel-execute:sqlite (body params)
  "Execute a block of Sqlite code with Babel.
This function is called by `org-babel-execute-src-block'."
  (let ((result-params (split-string (or (cdr (assoc :results params)) "")))
	(db (cdr (assoc :db params)))
	(separator (cdr (assoc :separator params)))
	(nullvalue (cdr (assoc :nullvalue params)))
	(headers-p (equal "yes" (cdr (assoc :colnames params))))
	(others (delq nil (mapcar
			   (lambda (arg) (car (assoc arg params)))
			   (list :header :echo :bail :column
				 :csv :html :line :list))))
	exit-code)
    (unless db (error "ob-sqlite: can't evaluate without a database"))
    (with-temp-buffer
      (insert
       (org-babel-eval
	(org-fill-template
	 "%cmd %header %separator %nullvalue %others %csv %db "
	 (list
	  (cons "cmd" org-babel-sqlite3-command)
	  (cons "header" (if headers-p "-header" "-noheader"))
	  (cons "separator"
		(if separator (format "-separator %s" separator) ""))
	  (cons "nullvalue"
		(if nullvalue (format "-nullvalue %s" nullvalue) ""))
	  (cons "others"
		(mapconcat
		 (lambda (arg) (format "-%s" (substring (symbol-name arg) 1)))
		 others " "))
	  ;; for easy table parsing, default header type should be -csv
	  (cons "csv" (if (or (member :csv others) (member :column others)
			      (member :line others) (member :list others)
			      (member :html others) separator)
			  ""
			"-csv"))
	  (cons "db " db)))
	;; body of the code block
	(org-babel-expand-body:sqlite body params)))
      (org-babel-result-cond result-params
	(buffer-string)
	(if (equal (point-min) (point-max))
	    ""
	  (org-table-convert-region (point-min) (point-max)
				    (if (or (member :csv others)
					    (member :column others)
					    (member :line others)
					    (member :list others)
					    (member :html others) separator)
					nil
				      '(4)))
	  (org-babel-sqlite-table-or-scalar
	   (org-babel-sqlite-offset-colnames
	    (org-table-to-lisp) headers-p)))))))

(defun org-babel-sqlite-expand-vars (body vars)
  "Expand the variables held in VARS in BODY."
  ;; FIXME: Redundancy with org-babel-sql-expand-vars!
  (mapc
   (lambda (pair)
     (setq body
	   (replace-regexp-in-string
	    (format "$%s" (car pair))
	    (let ((val (cdr pair)))
              (if (listp val)
                  (let ((data-file (org-babel-temp-file "sqlite-data-")))
                    (with-temp-file data-file
                      (insert (orgtbl-to-csv
                               val '(:fmt (lambda (el) (if (stringp el)
                                                      el
                                                    (format "%S" el)))))))
                    data-file)
                (if (stringp val) val (format "%S" val))))
	    body)))
   vars)
  body)

(defun org-babel-sqlite-table-or-scalar (result)
  "If RESULT looks like a trivial table, then unwrap it."
  (if (and (equal 1 (length result))
	   (equal 1 (length (car result))))
      (org-babel-read (caar result))
    (mapcar (lambda (row)
	      (if (equal 'hline row)
		  'hline
		(mapcar #'org-babel-string-read row))) result)))

(defun org-babel-sqlite-offset-colnames (table headers-p)
  "If HEADERS-P is non-nil then offset the first row as column names."
  (if headers-p
      (cons (car table) (cons 'hline (cdr table)))
    table))

(defun org-babel-prep-session:sqlite (session params)
  "Raise an error because support for SQLite sessions isn't implemented.
Prepare SESSION according to the header arguments specified in PARAMS."
  (error "SQLite sessions not yet implemented"))

(provide 'ob-sqlite)



;;; ob-sqlite.el ends here
