+(: prog Prog)
+(define prog
+ (Prog "tt" (info:#%info-lookup 'version)))
+
+(: user-default User)
+(define user-default
+ (User (string->url "https://github.com/xandkar/tt") #f))
+
+(: user->str (-> User String))
+(define (user->str user)
+ (match-define (User u0 n) user)
+ (define u (url->string u0))
+ (if n
+ (format "+~a; @~a" u n)
+ (format "+~a" u )))
+
+(: user-agent->str (-> User-Agent String))
+(define (user-agent->str ua)
+ (match-define (User-Agent u p) ua)
+ (format "~a/~a (~a)" (Prog-name p) (Prog-version p) (user->str u)))
+
+(: user->user-agent User)
+(define (user->user-agent user)
+ (User-Agent user prog))
+
+(: user-agent-str String)
+(define user-agent-str
+ (user-agent->str (user->user-agent user-default)))
+
+(: set-user-agent-str (-> Path-String Void))
+(define (set-user-agent-str filename)
+ (set! user-agent-str (user-agent->str (user->user-agent (file->user filename))))
+ (log-info "User-Agent string is now set to: ~v" user-agent-str))
+
+(: file->user (-> Path-String User))
+(define (file->user filename)
+ (if (file-exists? filename)
+ (match (file->peers filename)
+ [(list p)
+ (log-info
+ "User-Agent. Found one peer in file: ~v. Using the found peer: ~a"
+ filename
+ (peer->str p))
+ (peer->user p)]
+ [(list* p _)
+ (log-warning
+ "User-Agent. Multiple peers in file: ~v. Picking arbitrary: ~a"
+ filename
+ (peer->str p))
+ (peer->user p)]
+ ['()
+ (log-warning
+ "User-Agent. No peers found in file: ~v. Using the default user: ~a"
+ filename
+ user-default)
+ user-default])
+ (begin
+ (log-warning
+ "User-Agent. File doesn't exist: ~v. Using the default user: ~a"
+ filename
+ user-default)
+ user-default)))
+
+(: peer->user (-> Peer User))
+(define (peer->user p)
+ (match-define (Peer n u _ _) p)
+ (User u n))
+
+(: peers-equal? (-> Peer Peer Boolean))
+(define (peers-equal? p1 p2)
+ (equal? (Peer-uri-str p1)
+ (Peer-uri-str p2)))
+
+(: peer-hash (-> Peer Fixnum))
+(define (peer-hash p)
+ (equal-hash-code (Peer-uri-str p)))
+