#lang racket/base

(require racket/string
         "git-provider.rkt")

(provide exn:fail:git-auth?
         exn:fail:git-auth-command
         exn:fail:git-auth-args
         exn:fail:git-auth-exit-code
         exn:fail:git-auth-output
         authentication-failure?
         raise-git-auth-error
         current-git-authentication-handler)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Authentication exception
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(struct exn:fail:git-auth exn:fail
  (command args exit-code output)
  #:transparent)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; goal   : Recognize output that indicates Git authentication failed.
; pre    : exit-code and output belong to a completed Git command.
; post   : output has only been inspected.
; result : #t when a known authentication failure is present, otherwise #f.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (authentication-failure? exit-code output)
  (and (not (= exit-code 0))
       (ormap
        (λ (entry)
          (let ((line (string-downcase (format "~a" (cadr entry)))))
            (or (string-contains? line "authentication failed")
                (string-contains? line "failed to authenticate")
                (string-contains? line "could not read username")
                (string-contains? line "could not read password")
                (string-contains? line "http basic: access denied")
                (string-contains? line "terminal prompts disabled"))))
        output)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; goal   : Raise a Git authentication exception containing the failed invocation.
; pre    : cmd, args, exit-code and output describe a failed Git command.
; post   : An exn:fail:git-auth exception has been raised.
; result : No normal return value.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (raise-git-auth-error cmd args exit-code output)
  (let ((msg (format "git ~a: authentication failed" cmd)))
    (raise
     (exn:fail:git-auth msg
                        (current-continuation-marks)
                        cmd
                        args
                        exit-code
                        output))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; goal   : Supply the callback that can resolve an authentication failure.
; pre    : The callback accepts command, arguments and an exn:fail:git-auth value.
; post   : The callback is used by command proxies before one authentication retry.
; result : A parameter containing the current authentication callback.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define current-git-authentication-handler
  (make-parameter
   (λ (cmd args e)
     #f)))