#lang racket

(require rackunit
         racket/file
         racket/runtime-path
         racket/system)

(define racket-executable
  (find-system-path 'exec-file))

(define tmp (make-temporary-file "racket-makefile-refresh~a" 'directory))

(define (write-lines path . lines)
  (call-with-output-file path
    #:exists 'truncate/replace
    (lambda (out)
      (for ([line (in-list lines)])
        (displayln line out)))))

(dynamic-wind
  void
  (lambda ()
    ;; This module records how often it is instantiated. A refresh must reuse
    ;; the existing module instance instead of loading it a second time.
    (write-lines
     (build-path tmp "slow.rkt")
     "#lang racket/base"
     "(require racket/file)"
     "(define count-file \"slow-count.txt\")"
     "(define count (if (file-exists? count-file) (string->number (file->string count-file)) 0))"
     "(call-with-output-file count-file #:exists 'truncate/replace (lambda (out) (display (add1 count) out)))"
     "(provide slow-value)"
     "(define slow-value \"loaded\")")

    (write-lines
     (build-path tmp "Makefile.rkt")
     "#lang racket-makefile"
     "(require \"slow.rkt\")"
     "(phony change)"
     "(target change (copy-file \"NewMakefile.rkt\" \"Makefile.rkt\" #t))")

    (write-lines
     (build-path tmp "NewMakefile.rkt")
     "#lang racket-makefile"
     "(require \"slow.rkt\")"
     "(phony changed)"
     "(target changed"
     "  (call-with-output-file \"result.txt\" #:exists 'truncate/replace"
     "    (lambda (out) (display slow-value out))))")

    (parameterize ([current-directory tmp])
      (check-true
       (system* racket-executable
                "-t" "Makefile.rkt"
                "-e" "(make change)"
                "-e" "(refresh-makefile)"
                "-e" "(make changed)")))

    (check-equal? (file->string (build-path tmp "result.txt")) "loaded")
    (check-equal? (file->string (build-path tmp "slow-count.txt")) "1")
    (check-equal?
     (filter (lambda (path)
               (regexp-match? #rx"^racket-makefile-refresh.*[.]rkt$"
                              (path->string (file-name-from-path path))))
             (directory-list tmp #:build? #t))
     '()))
  (lambda ()
    (delete-directory/files tmp #:must-exist? #f)))

;; A makefile can also use ordinary #lang racket and require main.rkt directly.
;; This is the style used by racket-makefile's own development Makefile. The
;; declaration macros must remember the source file in that case, because the
;; custom racket-makefile #%module-begin is not involved.
(define direct-tmp (make-temporary-file "racket-makefile-direct-refresh~a" 'directory))
(define-runtime-path package-main "../main.rkt")
(define-runtime-path package-commands "../private/commands.rkt")
(define-runtime-path package-engine "../private/engine.rkt")

(dynamic-wind
  void
  (lambda ()
    (make-directory (build-path direct-tmp "private"))
    (copy-file package-main (build-path direct-tmp "main.rkt"))
    (copy-file package-commands (build-path direct-tmp "private" "commands.rkt"))
    (copy-file package-engine (build-path direct-tmp "private" "engine.rkt"))

    (write-lines
     (build-path direct-tmp "slow.rkt")
     "#lang racket/base"
     "(require racket/file)"
     "(define count-file \"slow-count.txt\")"
     "(define count (if (file-exists? count-file) (string->number (file->string count-file)) 0))"
     "(call-with-output-file count-file #:exists 'truncate/replace (lambda (out) (display (add1 count) out)))"
     "(provide slow-value)"
     "(define slow-value \"loaded\")")

    (write-lines
     (build-path direct-tmp "Makefile.rkt")
     "#lang racket"
     "(require \"main.rkt\" \"slow.rkt\")"
     "(phony change old)"
     "(target old (displayln \"old\"))"
     "(target change (copy-file \"NewMakefile.rkt\" \"Makefile.rkt\" #t))")

    (write-lines
     (build-path direct-tmp "NewMakefile.rkt")
     "#lang racket"
     "(require \"main.rkt\" \"slow.rkt\")"
     "(phony changed)"
     "(target changed"
     "  (call-with-output-file \"result.txt\" #:exists 'truncate/replace"
     "    (lambda (out) (display slow-value out))))")

    (write-lines
     (build-path direct-tmp "driver.rkt")
     "#lang racket"
     "(require \"main.rkt\")"
     "(dynamic-require \"Makefile.rkt\" #f)"
     "(make change)"
     "(refresh-makefile)"
     "(make changed)"
     "(with-handlers ([exn:fail? (lambda (e) (displayln \"old target removed\"))])"
     "  (make old)"
     "  (error 'refresh-test \"old target survived refresh\"))")

    (parameterize ([current-directory direct-tmp])
      (check-true (system* racket-executable "driver.rkt")))

    (check-equal? (file->string (build-path direct-tmp "result.txt")) "loaded")
    (check-equal? (file->string (build-path direct-tmp "slow-count.txt")) "1"))
  (lambda ()
    (delete-directory/files direct-tmp #:must-exist? #f)))