#lang racket/base

(require rackunit
         racket/file
         git)

(define tmp (make-temporary-file "racket-git-branch-merge-test~a" 'directory))

(define (write-file path text)
  (call-with-output-file path
    #:exists 'truncate/replace
    (lambda (out) (display text out))))

(dynamic-wind
  void
  (lambda ()
    (parameterize ([current-directory tmp])
      (git 'init)
      (git 'config "user.name" "Racket Git Test")
      (git 'config "user.email" "racket-git-test@example.invalid")

      (write-file "README.md" "base\n")
      (git 'add "README.md")
      (define base (git 'commit "base"))

      ;; Reproduce the recovery case: create a commit while HEAD is detached,
      ;; give that commit a branch name, switch back, and merge it.
      (git 'checkout base)
      (check-false (git 'branch-current))
      (write-file "README.md" "base\nrescued\n")
      (git 'add "README.md")
      (define rescued (git 'commit "detached README change"))
      (check-false (git 'branch-current))

      (check-equal? (git 'branch-create "rescue-readme") "rescue-readme")
      (check-not-false (member "rescue-readme" (git 'branch)))
      (git 'switch "master")
      (check-equal? (git 'branch-current) "master")
      (check-equal? (git 'merge "rescue-readme") rescued)
      (check-equal? (git-head) rescued)
      (check-equal? (file->string "README.md") "base\nrescued\n")
      (check-false (git 'merge "rescue-readme"))
      (git 'branch '-d "rescue-readme")
      (check-false (member "rescue-readme" (git 'branch)))

      ;; Also exercise a real two-parent, conflict-free merge.
      (git 'branch-create "feature")
      (git 'switch "feature")
      (write-file "feature.txt" "feature\n")
      (git 'add "feature.txt")
      (git 'commit "feature change")

      (git 'switch "master")
      (write-file "master.txt" "master\n")
      (git 'add "master.txt")
      (git 'commit "master change")
      (define merge-id (git 'merge "feature"))
      (check-equal? (string-length merge-id) 40)
      (check-equal? (file->string "feature.txt") "feature\n")
      (check-equal? (file->string "master.txt") "master\n")
      (check-true (git-clean?))
      (check-equal? (git 'branch-current) "master")
      (check-true (>= (length (git 'log 10)) 5))
      (git 'branch '-d "feature")))
  (lambda ()
    (delete-directory/files tmp)))