;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname lab8-starter-file-2) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f () #f)))
; Starter file, Part 2

(define ENDS "Friends")
(define MIES "Enemies")
(define WORK "Work")
(define TEAM "Football Team")
(define GROUPS `(,ENDS ,MIES ,WORK ,TEAM))

(define-struct group [name people])
(define-struct user [name groups])

; A SocialNetwork (SN) is a [Listof User].
; A Group is a (make-group GroupName [Listof String])
; Interpretation: name is the type of group, and
; people is the names of the users in that group.
; A GroupName is on GROUPS.
 
; A User is a (make-user String [Listof Group])
; Interpretation: name is the user's name, and
; groups is a list of their groups of connections.

; examples
(define amanda-ends (make-group ENDS '("Carlo" "Diya" "Fran")))
(define amanda-team (make-group TEAM '("Fran")))
(define amanda (make-user "Amanda" (list amanda-ends amanda-team)))

(define bruce-ends (make-group ENDS '("Carlo" "Diya" "Emmi" "Fran" "Han")))
(define bruce-mies (make-group MIES '("Fran" "Diya" "Carlo")))
(define bruce-work (make-group WORK '("Carlo" "Amanda" "Diya" "Gregg")))
(define bruce (make-user "Bruce" (list bruce-ends bruce-mies bruce-work)))

(define clo-team (make-group TEAM '("Amanda" "Fran")))
(define clo-ends (make-group ENDS '("Diya" "Han")))
(define clo-mies (make-group MIES '("Amanda")))
(define clo-work (make-group WORK '("Amanda")))
(define carlo (make-user "Carlo" (list clo-team clo-ends clo-mies clo-work)))

(define diya-ends (make-group ENDS '("Emmi" "Fran" "Han")))
(define diya-mies (make-group MIES '("Fran" "Carlo")))
(define diya-work (make-group WORK '("Carlo" "Amanda")))
(define diya (make-user "Diya" (list diya-ends diya-mies diya-work)))

(define emmi-ends (make-group ENDS '("Fran" "Han")))
(define emmi-team (make-group TEAM '("Carlo")))
(define emmi-mies (make-group MIES '("Carlo" "Diya" "Bruce" "Fran" "Han")))
(define emmi (make-user "Emmi" (list emmi-ends emmi-team emmi-mies)))

(define fran-ends (make-group ENDS '("Gregg" "Han")))
(define fran-mies (make-group MIES '("Amanda" "Bruce" "Carlo")))
(define fran (make-user "Fran" (list fran-ends fran-mies)))

(define gregg-mies (make-group MIES '("Han" "Bruce" "Fran")))
(define gregg-team (make-group TEAM '("Amanda" "Emmi")))
(define gregg-work (make-group WORK '("Amanda" "Carlo" "Diya")))
(define gregg (make-user "Gregg" (list gregg-mies gregg-team gregg-work)))

(define han-ends (make-group ENDS '("Gregg")))
(define han-mies (make-group MIES '("Bruce" "Carlo")))
(define han (make-user "Han" (list han-ends han-mies)))
 
(define SN1 (list amanda bruce carlo diya emmi fran gregg han))







; LIBRARY FUNCTIONS -----------------------------------------------------------

; drop : String [Listof String] -> [Listof String]
; Remove all occurrences of the given element from the list, if it is present.

(define (drop str los)
  (filter (λ(x) (not (string=? str x))) los))

(check-expect (drop "hi" '()) '())
(check-expect (drop "hello" '("cats" "are not that affectionate"))
              '("cats" "are not that affectionate"))
(check-expect (drop "cats" '("cats" "hi" "i" "still" "love" "cats" "lots"))
              '("hi" "i" "still" "love" "lots"))


; count : String [Listof String] -> Number
; Count how many times the given string appears in the list.

(define (count str los)
  (foldr (λ(x y) (if (string=? str x) (+ y 1) y)) 0 los))

(check-expect (count "hi" '()) 0)
(check-expect (count "hello" '("cats" "are great")) 0)
(check-expect (count "cats" '("cats" "hi" "i" "love" "cats" "lots")) 2)