;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;;
;;;; $Id$
;;;;
;;;; Generic postgresql layer, used by db-postgresql and db-postgresql-socket
;;;;
;;;; This file is part of CLSQL.
;;;;
;;;; CLSQL users are granted the rights to distribute and use this software
;;;; as governed by the terms of the Lisp Lesser GNU Public License
;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
;;;; *************************************************************************

(in-package #:clsql-sys)

(defclass generic-postgresql-database (database)
  ()
  (:documentation "Encapsulate same behavior across postgresql and postgresql-socket backends."))



;; Object functions

(defmethod database-get-type-specifier (type args database
					(db-type (eql :postgresql)))
  (declare (ignore type args database))
  "VARCHAR")

(defmethod database-get-type-specifier ((type (eql 'simple-base-string)) args database
					(db-type (eql :postgresql)))
  (declare (ignore database))
  (if args
      (format nil "VARCHAR(~A)" (car args))
      "VARCHAR"))

(defmethod database-get-type-specifier ((type (eql 'simple-string)) args database
					(db-type (eql :postgresql)))
  (declare (ignore database))
  (if args
      (format nil "VARCHAR(~A)" (car args))
      "VARCHAR"))

(defmethod database-get-type-specifier ((type (eql 'string)) args database
					(db-type (eql :postgresql)))
  (declare (ignore database))
  (if args
      (format nil "VARCHAR(~A)" (car args))
      "VARCHAR"))

(defmethod database-get-type-specifier ((type (eql 'wall-time)) args database
					(db-type (eql :postgresql)))
  (declare (ignore args database))
  "TIMESTAMP WITHOUT TIME ZONE")


;;; Backend functions

(defun owner-clause (owner)
  (cond 
   ((stringp owner)
    (format
     nil
     " AND (relowner=(SELECT usesysid FROM pg_user WHERE (usename='~A')))" 
     owner))
   ((null owner)
    (format nil " AND (NOT (relowner=1))"))
   (t "")))

(defun database-list-objects-of-type (database type owner)
  (mapcar #'car
	  (database-query
	   (format nil
		   "SELECT relname FROM pg_class WHERE (relkind = '~A')~A"
		   type
		   (owner-clause owner))
	   database nil nil)))

(defmethod database-list-tables ((database generic-postgresql-database)
                                 &key (owner nil))
  (database-list-objects-of-type database "r" owner))
  
(defmethod database-list-views ((database generic-postgresql-database)
                                &key (owner nil))
  (database-list-objects-of-type database "v" owner))
  
(defmethod database-list-indexes ((database generic-postgresql-database)
                                  &key (owner nil))
  (database-list-objects-of-type database "i" owner))


(defmethod database-list-table-indexes (table (database generic-postgresql-database)
					&key (owner nil))
  (let ((indexrelids
	 (database-query
	  (format 
	   nil
	   "select indexrelid from pg_index where indrelid=(select relfilenode from pg_class where relname='~A'~A)"
	   (string-downcase table)
	   (owner-clause owner))
	  database :auto nil))
	(result nil))
    (dolist (indexrelid indexrelids (nreverse result))
      (push 
       (caar (database-query
	      (format nil "select relname from pg_class where relfilenode='~A'"
		      (car indexrelid))
	      database nil nil))
       result))))

(defmethod database-list-attributes ((table string)
				     (database generic-postgresql-database)
                                     &key (owner nil))
  (let* ((owner-clause
          (cond ((stringp owner)
                 (format nil " AND (relowner=(SELECT usesysid FROM pg_user WHERE usename='~A'))" owner))
                ((null owner) " AND (not (relowner=1))")
                (t "")))
         (result
	  (mapcar #'car
		  (database-query
		   (format nil "SELECT attname FROM pg_class,pg_attribute WHERE pg_class.oid=attrelid AND relname='~A'~A"
                           (string-downcase table)
                           owner-clause)
                   database nil nil))))
    (if result
        (remove-if #'(lambda (it) (member it '("cmin"
                                               "cmax"
                                               "xmax"
                                               "xmin"
                                               "oid"
                                               "ctid"
                                               ;; kmr -- added tableoid
                                               "tableoid") :test #'equal)) 
                   result))))

(defmethod database-attribute-type (attribute (table string)
				    (database generic-postgresql-database)
                                    &key (owner nil))
  (let ((row (car (database-query
		   (format nil "SELECT pg_type.typname,pg_attribute.attlen,pg_attribute.atttypmod,pg_attribute.attnotnull FROM pg_type,pg_class,pg_attribute WHERE pg_class.oid=pg_attribute.attrelid AND pg_class.relname='~A' AND pg_attribute.attname='~A' AND pg_attribute.atttypid=pg_type.oid~A"
			   (string-downcase table)
			   (string-downcase attribute)
			   (owner-clause owner))
		   database nil nil))))
    (when row
      (values
       (ensure-keyword (first row))
       (if (string= "-1" (second row))
	   (- (parse-integer (third row) :junk-allowed t) 4)
	 (parse-integer (second row)))
       nil
       (if (string-equal "f" (fourth row))
	   1
	 0)))))

(defmethod database-create-sequence (sequence-name
				     (database generic-postgresql-database))
  (database-execute-command
   (concatenate 'string "CREATE SEQUENCE " (sql-escape sequence-name))
   database))

(defmethod database-drop-sequence (sequence-name
				   (database generic-postgresql-database))
  (database-execute-command
   (concatenate 'string "DROP SEQUENCE " (sql-escape sequence-name)) database))

(defmethod database-list-sequences ((database generic-postgresql-database)
                                    &key (owner nil))
  (database-list-objects-of-type database "S" owner))

(defmethod database-set-sequence-position (name (position integer)
                                                (database generic-postgresql-database))
  (values
   (parse-integer
    (caar
     (database-query
      (format nil "SELECT SETVAL ('~A', ~A)" name position)
      database nil nil)))))

(defmethod database-sequence-next (sequence-name 
				   (database generic-postgresql-database))
  (values
   (parse-integer
    (caar
     (database-query
      (concatenate 'string "SELECT NEXTVAL ('" (sql-escape sequence-name) "')")
      database nil nil)))))

(defmethod database-sequence-last (sequence-name (database generic-postgresql-database))
  (values
   (parse-integer
    (caar
     (database-query
      (concatenate 'string "SELECT LAST_VALUE ('" sequence-name "')")
      database nil nil)))))

(defun postgresql-database-list (connection-spec type)
  (destructuring-bind (host name user password) connection-spec
    (declare (ignore name))
    (let ((database (database-connect (list host "template1" user password)
				      type)))
      (unwind-protect
	   (progn
	     (setf (slot-value database 'clsql-sys::state) :open)
	     (mapcar #'car (database-query "select datname from pg_database" 
					   database nil nil)))
	(progn
	  (database-disconnect database)
	  (setf (slot-value database 'clsql-sys::state) :closed))))))

(defmethod database-list (connection-spec (type (eql :postgresql)))
  (postgresql-database-list connection-spec type))

(defmethod database-list (connection-spec (type (eql :postgresql-socket)))
  (postgresql-database-list connection-spec type))


(defmethod database-describe-table ((database generic-postgresql-database) table)
  (database-query 
   (format nil "select a.attname, t.typname
                               from pg_class c, pg_attribute a, pg_type t
                               where c.relname = '~a'
                                   and a.attnum > 0
                                   and a.attrelid = c.oid
                                   and a.atttypid = t.oid"
           (sql-escape (string-downcase table)))
   database :auto nil))


;; Capabilities

(defmethod db-type-has-fancy-math? ((db-type (eql :postgresql)))
  t)

(defmethod db-type-default-case ((db-type (eql :postgresql)))
  :lower)