#lang racket

(provide quoted->contract
         explain-iface)

(require syrup
         goblins/actor-lib/ward)

(define (quoted->contract interface)
  (define (convert-one iface)
    (match iface
      [(list '-> args ... return-type)
       (define converted-args
         (map convert-one args))
       (dynamic->* #:mandatory-domain-contracts converted-args
                   #:range-contracts (list (convert-one return-type)))]
      [(list 'and/c ifaces ...)
       (apply and/c (map convert-one ifaces))]
      [(list 'or/c ifaces ...)
       (apply or/c (map convert-one ifaces))]
      ['string? string?]
      ['integer? integer?]
      ['positive-integer? positive-integer?]
      ['float? (and/c number? inexact?)]
      ['symbol? symbol?]
      ['boolean? boolean?]))
  (convert-one interface))

(define (explain-iface iface [indent-level 0] [bullet? #f])
  (define first-line? #t)
  (define (displayln-indent str)
    (display "; ")
    ;; indent
    (for ([i (* indent-level 2)])
      (display " "))
    ;; maybe display a bullet
    (when bullet?
      (if first-line?
          (begin (set! first-line? #f)
                 (display "- "))
          (display "  ")))
    ;; display the rest
    (displayln str))
  (define next-indent-level
    (if bullet?
        (+ indent-level 2)
        (+ indent-level 1)))
  (match iface
    [(list '-> args ... return-type)
     (displayln-indent (format "A procedure which takes ~a arguments:"
                               (length args)))
     (for ([arg args])
       (explain-iface arg next-indent-level #t))
     (displayln-indent "... and returns:")
     (explain-iface return-type next-indent-level)]
    [(list 'and/c ifaces ...)
     (displayln-indent "Something which meets *all* of:")
     (for ([iface ifaces])
       (explain-iface iface next-indent-level #t))]
    [(list 'or/c ifaces ...)
     (displayln-indent "Something which meets *any* of:")
     (for ([iface ifaces])
       (explain-iface iface next-indent-level #t))]
    ['string? (displayln-indent "A string")]
    ['integer? (displayln-indent "An integer")]
    ['positive-integer? (displayln-indent "A positive integer")]
    ['float? (displayln-indent "A floating point number")]
    ['symbol? (displayln-indent "A symbol")]
    ['boolean? (displayln-indent "A boolean")]))