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

;; Copyright (C) 2010  Free Software Foundation

;; Author: Eric Schulte
;; Keywords: literate programming, reproducible research
;; Homepage: http://orgmode.org
;; Version: 0.01

;; 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)
(require 'ob-ref)

(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))

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

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

(defun org-babel-expand-body:sqlite (body params &optional processed-params)
  (org-babel-sqlite-expand-vars
   body (or (nth 1 processed-params) (org-babel-ref-variables params))))

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

(defun org-babel-execute:sqlite (body params)
  "Execute a block of Sqlite code with org-babel.  This function is
called by `org-babel-execute-src-block'."
  (message "executing Sqlite source code block")
  (let ((result-params (split-string (or (cdr (assoc :results params)) "")))
	(vars (org-babel-ref-variables 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
       (shell-command-to-string
	(org-fill-template
	 "%cmd -init %body %header %separator %nullvalue %others %csv %db "
	 (list
	  (cons "body" ((lambda (sql-file)
			  (with-temp-file sql-file
			    (insert (org-babel-expand-body:sqlite
				     body nil (list nil vars))))
			  sql-file)
			(make-temp-file "ob-sqlite-sql")))
	  (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)))))
      (if (or (member "scalar" result-params)
	      (member "html" result-params)
	      (member "code" result-params)
	      (equal (point-min) (point-max)))
	  (buffer-string)
	(org-table-convert-region (point-min) (point-max))
	(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."
  (mapc
   (lambda (pair)
     (setq body
	   (replace-regexp-in-string
	    (format "\$%s" (car pair))
	    ((lambda (val)
	       (if (listp val)
		   ((lambda (data-file)
		      (with-temp-file data-file
			(insert (orgtbl-to-csv
				 val '(:fmt (lambda (el) (if (stringp el)
							el
						      (format "%S" el)))))))
		      data-file)
		    (make-temp-file "ob-sqlite-data"))
		 (format "%S" val)))
	     (cdr pair))
	    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-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)
  "Prepare SESSION according to the header arguments specified in PARAMS."
  (error "sqlite sessions not yet implemented"))

(provide 'ob-sqlite)

;; arch-tag: 5c03d7f2-0f72-48b8-bbd1-35aafea248ac

;;; ob-sqlite.el ends here