(define-library (web request-handler)
  (export
    sx-url-to-expr
    sx-auto-quote
    sx-eval-page
    sx-handle-request)
  (begin

(define
  sx-url-to-expr
  (fn
    (path)
    (let
      ((prefix (cek-try (fn () (or (dict-get __app-config :path-prefix) "/sx/")) (fn (e) "/sx/")))
        (prefix-len (len prefix))
        (prefix-bare (slice prefix 0 (- prefix-len 1))))
      (cond
        (or (= path "/") (= path prefix) (= path prefix-bare))
        "home"
        (starts-with? path prefix)
        (join " " (split (slice path prefix-len (len path)) "."))
        (starts-with? path "/")
        (join " " (split (slice path 1 (len path)) "."))
        :else path))))

(define
  sx-auto-quote
  (fn
    (expr env)
    (cond
      (and (symbol? expr) (not (env-has? env (symbol-name expr))))
      (symbol-name expr)
      (list? expr)
      (map (fn (e) (sx-auto-quote e env)) expr)
      :else expr)))

(define
  sx-eval-page
  (fn
    (path-expr env)
    (cek-try
      (fn
        ()
        (let
          ((exprs (sx-parse path-expr)))
          (when
            (not (empty? exprs))
            (let
              ((expr (if (= (len exprs) 1) (first exprs) exprs))
                (quoted (sx-auto-quote expr env))
                (callable (if (symbol? quoted) (list quoted) quoted)))
              (eval-expr callable env)))))
      (fn (err) nil))))

(define
  sx-handle-request
  (fn
    (path headers env shell-vars)
    (let
      ((is-ajax (or (has-key? headers "sx-request") (has-key? headers "hx-request")))
        (path-expr (sx-url-to-expr path))
        (page-ast (sx-eval-page path-expr env)))
      (if
        (nil? page-ast)
        nil
        (let
          ((prefix (cek-try (fn () (or (dict-get __app-config :path-prefix) "/sx/")) (fn (e) "/sx/")))
            (prefix-len (len prefix))
            (nav-path
              (if
                (and
                  (>= (len path) prefix-len)
                  (= (slice path 0 prefix-len) prefix))
                path
                (str (slice prefix 0 (- prefix-len 1)) path))))
          {:page-ast page-ast :nav-path nav-path :is-ajax is-ajax})))))


)) ;; end define-library

;; Re-export to global namespace for backward compatibility
(import (web request-handler))