;;; database.scm -- store evaluation and build results
;;; Copyright © 2016, 2017 Mathieu Lirzin <mthl@gnu.org>
;;;
;;; This file is part of Cuirass.
;;;
;;; Cuirass 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.
;;;
;;; Cuirass 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 Cuirass.  If not, see <http://www.gnu.org/licenses/>.

(define-module (cuirass database)
  #:use-module (cuirass config)
  #:use-module (cuirass utils)
  #:use-module (ice-9 match)
  #:use-module (ice-9 rdelim)
  #:use-module (sqlite3)
  #:export (;; Procedures.
            assq-refs
            db-init
            db-open
            db-close
            db-add-specification
            db-get-specifications
            db-add-stamp
            db-get-stamp
            db-add-evaluation
            db-add-derivation
            db-get-derivation
            db-add-build
            read-sql-file
            read-quoted-string
            sqlite-exec
            ;; Parameters.
            %package-database
            %package-schema-file
            ;; Macros.
            with-database))

(define (sqlite-exec db msg . args)
  "Wrap 'sqlite-prepare', 'sqlite-step', and 'sqlite-finalize'. Send message
MSG to database DB.  MSG can contain '~A' and '~S' escape characters which
will be replaced by ARGS."
  (let* ((sql  (apply simple-format #f msg args))
         (stmt (sqlite-prepare db sql))
         (res  (let loop ((res '()))
                 (let ((row (sqlite-step stmt)))
                   (if (not row)
                       (reverse! res)
                       (loop (cons row res)))))))
    (sqlite-finalize stmt)
    res))

(define %package-database
  ;; Define to the database file name of this package.
  (make-parameter (string-append %localstatedir "/" %package ".db")))

(define %package-schema-file
  ;; Define to the database schema file of this package.
  (make-parameter (string-append (or (getenv "CUIRASS_DATADIR")
                                     (string-append %datadir "/" %package))
                                 "/schema.sql")))

(define (read-sql-file file-name)
  "Return a list of string containing SQL instructions from FILE-NAME."
  (call-with-input-file file-name
    (lambda (port)
      (let loop ((insts '()))
        (let ((inst (read-delimited ";" port 'concat)))
          (if (or (eof-object? inst)
                  ;; Don't cons the spaces after the last instructions.
                  (string-every char-whitespace? inst))
              (reverse! insts)
              (loop (cons inst insts))))))))

(define* (db-init #:optional (db-name (%package-database))
                  #:key (schema (%package-schema-file)))
  "Open the database to store and read jobs and builds informations.  Return a
database object."
  (when (file-exists? db-name)
    (format (current-error-port) "Removing leftover database ~a~%" db-name)
    (delete-file db-name))
  (let ((db (sqlite-open db-name (logior SQLITE_OPEN_CREATE
                                         SQLITE_OPEN_READWRITE))))
    (for-each (lambda (sql) (sqlite-exec db sql))
              (read-sql-file schema))
    db))

(define* (db-open #:optional (db (%package-database)))
  "Open database to store or read jobs and builds informations.  Return a
database object."
  (if (file-exists? db)
      (sqlite-open db SQLITE_OPEN_READWRITE)
      (db-init db)))

(define (db-close db)
  "Close database object DB."
  (sqlite-close db))

(define* (assq-refs alst keys #:optional default-value)
  (map (lambda (key) (or (assq-ref alst key) default-value))
       keys))

(define (last-insert-rowid db)
  (vector-ref (car (sqlite-exec db "SELECT last_insert_rowid();"))
              0))

(define (db-add-specification db spec)
  "Store specification SPEC in database DB and return its ID."
  (apply sqlite-exec db "\
INSERT OR IGNORE INTO Specifications (repo_name, url, load_path, file, \
                  proc, arguments, branch, tag, revision, no_compile_p) \
  VALUES ('~A', '~A', '~A', '~A', '~S', '~S', '~A', '~A', '~A', ~A);"
         (append
          (assq-refs spec '(#:name #:url #:load-path #:file #:proc #:arguments))
          (assq-refs spec '(#:branch #:tag #:commit) "NULL")
          (list (if (assq-ref spec #:no-compile?) "1" "0"))))
  (last-insert-rowid db))

(define (db-get-specifications db)
  (let loop ((rows  (sqlite-exec db "SELECT * FROM Specifications;"))
             (specs '()))
    (match rows
      (() specs)
      ((#(name url load-path file proc args branch tag rev no-compile?)
        . rest)
       (loop rest
             (cons `((#:name . ,name)
                     (#:url . ,url)
                     (#:load-path . ,load-path)
                     (#:file . ,file)
                     (#:proc . ,(with-input-from-string proc read))
                     (#:arguments . ,(with-input-from-string args read))
                     (#:branch . ,branch)
                     (#:tag . ,(if (string=? tag "NULL") #f tag))
                     (#:commit . ,(if (string=? rev "NULL") #f rev))
                     (#:no-compile? . ,(positive? no-compile?)))
                   specs))))))

(define (db-add-derivation db job)
  "Store a derivation result in database DB and return its ID."
  (sqlite-exec db "\
INSERT OR IGNORE INTO Derivations (derivation, job_name, evaluation)\
  VALUES ('~A', '~A', '~A');"
               (assq-ref job #:derivation)
               (assq-ref job #:job-name)
               (assq-ref job #:eval-id)))

(define (db-get-derivation db id)
  "Retrieve a job in database DB which corresponds to ID."
  (car (sqlite-exec db "SELECT * FROM Derivations WHERE derivation='~A';" id)))

(define (db-add-evaluation db eval)
  (sqlite-exec db "\
INSERT INTO Evaluations (specification, revision) VALUES ('~A', '~A');"
               (assq-ref eval #:specification)
               (assq-ref eval #:revision))
  (last-insert-rowid db))

(define-syntax-rule (with-database db body ...)
  "Run BODY with a connection to the database which is bound to DB in BODY."
  (let ((db (db-open)))
    (dynamic-wind
      (const #t)
      (lambda () body ...)
      (lambda () (db-close db)))))

(define* (read-quoted-string #:optional (port (current-input-port)))
  "Read all of the characters out of PORT and return them as a SQL quoted
string."
  (let loop ((chars '()))
    (let ((char (read-char port)))
      (cond ((eof-object? char) (list->string (reverse! chars)))
            ((char=? char #\')  (loop (cons* char char chars)))
            (else (loop (cons char chars)))))))

(define (db-add-build db build)
  "Store BUILD in database DB."
  (sqlite-exec db "\
INSERT INTO Builds (derivation, evaluation, log, output)\
  VALUES ('~A', '~A', '~A', '~A');"
               (assq-ref build #:derivation)
               (assq-ref build #:eval-id)
               (assq-ref build #:log)
               (assq-ref build #:output))
  (last-insert-rowid db))

(define (db-get-stamp db spec)
  "Return a stamp corresponding to specification SPEC in database DB."
  (let ((res (sqlite-exec db "SELECT * FROM Stamps WHERE specification='~A';"
                          (assq-ref spec #:name))))
    (match res
      (() "")
      ((#(spec commit)) commit))))

(define (db-add-stamp db spec commit)
  "Associate stamp COMMIT to specification SPEC in database DB."
  (if (string-null? (db-get-stamp db spec))
      (sqlite-exec db "\
INSERT INTO Stamps (specification, stamp) VALUES ('~A', '~A');"
                   (assq-ref spec #:name)
                   commit)
      (sqlite-exec db "\
UPDATE Stamps SET stamp='~A' WHERE specification='~A';"
                   commit
                   (assq-ref spec #:name))))