;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-reader.ss" "lang")((modname 16.3.4) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "dir.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "dir.ss" "teachpack" "htdp")))))
;(define-struct file (name size content))

;A file is a structure
;(make-file name size content) where name is a symbol, size is a number, and content is a Scheme datum.

;A list-of-files (lof) is either
;1. empty or
;2. (cons f lof) where f is a file and lof is a list-of-files.

;(define-struct dir (name dirs files))

;A directory (dir) is a structure (make-dir n d f) where n is a symbol, d is a list-of-dirs, and f is a list-of-files.
;
;A list-of-dirs (lod) is either
;1. empty or
;2. (cons d lod) where d is a dir and lod is a list-of-dirs.

;Template
;fun-for-file : file -> ???
;(define (fun-for-file a-file)
;  (... (file-name a-file) ...
;   ... (file-size a-file) ...
;   ... (file-content a-file) ...))
;
;fun-for-dir : dir -> ???
;(define (fun-for-dir a-dir)
;  (... (dir-name a-dir) ...
;   ... (fun-for-lod (dir-dirs a-dir)) ...
;   ... (fun-for-lof (dir-files a-dir)) ...))
;
;fun-for-lof : lof -> ???
;(define (fun-for-lof a-lof)
;  (cond
;    [(empty? a-lof) ...]
;    [(cons? a-lof) ... (first a-lof) ...
;                   ... (fun-for-lof (rest a-lof)) ...]))
;
;fun-for-lod : lod -> ???
;(define (fun-for-lod a-lod)
;  (cond
;    [(empty? a-lod) ...]
;    [(cons? a-lod) ... (fun-for-dir (first a-lod)) ...
;                   ... (fun-for-lod (rest a-lod)) ...]))
  
(define hang (make-file 'hang 8 empty))
(define draw-1 (make-file 'draw 2 empty))
(define read!-1 (make-file 'read! 19 empty))
(define part1 (make-file 'part1 99 empty))
(define part2 (make-file 'part2 52 empty))
(define part3 (make-file 'part3 17 empty))
(define read!-2 (make-file 'read! 10 empty))
(define Code (make-dir 'Code empty (list hang draw-1)))
(define Docs (make-dir 'Docs empty (list read!-1)))
(define Libs (make-dir 'Libs (list Code Docs) empty))
(define Text (make-dir 'Text empty (list part1 part2 part3)))
(define TS (make-dir 'TS (list Text Libs) (list read!-2)))

;how-many : dir -> number
;Given a-dir, determine the number of files in the dir tree.
(define (how-many a-dir)
  (+ (length (dir-files a-dir))
     (how-many-lod (dir-dirs a-dir))))

;how-many-lod : lod -> number
;Given a-lod, determine the number of files in the list of directories, counting files contained in all subdirectories.
(define (how-many-lod a-lod)
  (cond
    [(empty? a-lod) 0]
    [(cons? a-lod) (+ (how-many (first a-lod))
                      (how-many-lod (rest a-lod)))]))

;du-dir : dir -> number
;Given a-dir, computes the total size (disk usage, du) of all files in the directory tree.  Assumes that for a given directory, storing a file or a directory costs 1 unit of storage space.

(define (du-dir a-dir)
  (+ (length (dir-dirs a-dir))
     (length (dir-files a-dir))
     (du-lod (dir-dirs a-dir))
     (du-lof (dir-files a-dir))))

;du-lof : lof -> number
;Given a-lof, compute the disk usage of the list-of-files.
(define (du-lof a-lof)
  (cond
    [(empty? a-lof) 0]
    [(cons? a-lof) (+ (file-size (first a-lof))
                      (du-lof (rest a-lof)))]))

;du-lod : lod -> number
(define (du-lod a-lod)
  (cond
    [(empty? a-lod) 0]
    [(cons? a-lod) (+ (du-dir (first a-lod))
                      (du-lod (rest a-lod)))]))

;find? : dir symbol -> boolean
;Given a-dir and a-filename, determine if the file is located within the dir tree.
(define (find? a-dir a-filename)
  (or (find?-for-lod (dir-dirs a-dir) a-filename)
      (find?-for-lof (dir-files a-dir) a-filename)))

;find?-for-lof : lof symbol -> boolean
(define (find?-for-lof a-lof a-filename)
  (cond
    [(empty? a-lof) false]
    [(cons? a-lof) (or
                    (symbol=? a-filename (file-name (first a-lof)))
                    (find?-for-lof (rest a-lof) a-filename))]))

;find?-for-lod : lod symbol -> boolean
(define (find?-for-lod a-lod a-filename)
  (cond
    [(empty? a-lod) false]
    [(cons? a-lod) (or (find? (first a-lod) a-filename)
                       (find?-for-lod (rest a-lod) a-filename))]))
;Data Definition:
;A path is a list of directory names (list-of-symbols).  In this instance, a path is a list which contains the name of the directory being searched as well as the sub-directory (or subdirectories) containing the file.
;
;A list-of-symbols is either
;1. empty or
;2. (cons s los) where s is a symbol and los is a list-of-symbols.

;find : dir symbol -> path/false
;Given a-dir and a-filename, find the subdirectory of a-dir which contains the file with the corresponding name.  Return a path containing a-dir as well as the subdirectory (or subdirectories) containing a-filename.  If the file is not present in the dir tree, return false.

(define (find a-dir a-filename)
  (cond
    [(find?-for-lof (dir-files a-dir) a-filename)
     (find-path-for-dir a-dir a-filename)]
    [(find? a-dir a-filename) (append (list (dir-name a-dir))
                                      (find-path-for-dir a-dir a-filename))]
    [else false]))

;find-path-for-dir : dir symbol -> path (list-of-symbols)
;Given a-dir and a-filename, return the name of the subdirectory (or subdirectories) that contains a-filename as a list-of-symbols.  If the file is not present in the dir tree, return empty.

(define (find-path-for-dir a-dir a-filename)
  (cond
    [(find?-for-lof (dir-files a-dir) a-filename)
     (append (list (dir-name a-dir))
             (find-path-for-lod (dir-dirs a-dir) a-filename))]
    [else (find-path-for-lod (dir-dirs a-dir) a-filename)]))

;find-path-for-lod : lod symbol -> path (list-of-symbols)
;Given a-lod and a-filename, return the name of the subdirectory (or subdirectories) that contains a-filename as a list-of-symbols.  If the file is not present in the dir trees of the list-of-directories, return empty.

(define (find-path-for-lod a-lod a-filename)
  (cond
    [(empty? a-lod) empty]
    [(cons? a-lod) (append (find-path-for-dir (first a-lod) a-filename)
                           (find-path-for-lod (rest a-lod) a-filename))]))
(find (create-dir "C:\\Documents and Settings\\Aaron Lin\\Desktop\\Scheme Test") '|file A.txt|)