#lang racket/base
(require irc/core irc/bot irc/command irc/clean
         racket/match racket/format racket/port racket/function racket/system racket/string racket/path
         json)

(define (s cmd . args)
  (string-trim (with-output-to-string
    (thunk (apply system* cmd args #:set-pwd? #t)))))

(define syntax #px"^([[:alpha:]]+)>\\s(.*)$")
(define evaluator-dir (getenv "EVALUATORS"))
evaluator-dir

(define evaluators
  (let ([desc-dir (build-path evaluator-dir "desc")])
    (for/hash ([desc-path (directory-list desc-dir #:build? #t)])
      (values (path->string (file-name-from-path desc-path))
              (read-json (open-input-file desc-path))))))

(define (pretty-newlines s)
  (string-replace s "\n" "⏎ "))

(on (and (command-is 'PRIVMSG)
         (suffix-match (regexp-match syntax it)))
  (match-define (list all lang input) (regexp-match syntax (suffix)))
  (define evaluator-cmd (build-path evaluator-dir "bin" lang))
  (if (file-exists? evaluator-cmd)
    (let ([output (s evaluator-cmd input)])
      (if (zero? (string-length output))
        (reply "<eval succeeded, but no output>")
        (reply (string-append "> " (clean-control (pretty-newlines output))))))
    (reply "no such handler (yet, this is still new)")))

(define-command (eval)
  #:help "Display usage information for the qeval feature"
  (reply (format "The eval feature is invoked via 'name> code', where name is one of ~a. Use (eval-desc name) for further information"
            (hash-keys evaluators))))

(define-command (eval-desc name)
  #:help "Describe an evaluator"
  (define e (hash-ref evaluators (stringify name)))
  (reply (format "The ~a evaluator has the aliases ~a, and runs with ~a MB RAM and the following software: ~a"
                 (hash-ref e 'name)
                 (hash-ref e 'aliases)
                 (hash-ref e 'mem)
                 (hash-ref e 'available))))