#!/usr/bin/guile
!#

; depends on guile and sph-lib
;

(import (rnrs base) (rnrs sorting)
  (sph) (sph alist) (rnrs sorting) (sph cli) (sph filesystem) (sph string))

(define (get-target-file-name arg) (get-unique-path (remove-filename-extension arg)))

(define (show-message arg options)
  (if (assoc-ref options (q gui)) (system* "zenity" "--info" "--text" arg)
    (begin (display arg) (newline))))

(define (merge-files source-paths options)
  (let*
    ( (dry-run (assoc-ref options (q dry-run))) (source-paths (list-sort string< source-paths))
      (target-size (apply + (map (l (ele) (stat:size (stat ele))) source-paths)))
      (target-file-name (get-target-file-name (first source-paths))))
    ( (if dry-run (l (arg) (show-message arg options)) system)
      (string-append "cat" (string-join (map string-quote source-paths) " " (q prefix))
        " >" (string-quote target-file-name)))
    (if (not dry-run)
      (if (= target-size (stat:size (stat target-file-name)))
        (show-message (string-append (string-quote (basename target-file-name)) " success") options)
        (show-message
          (string-append (string-quote (basename target-file-name))
            "target file has not the expected size")
          options)))))

(let*
  ( (cli
      (cli-create #:description "merge files and check result size"
        #:options (q ((dry-run) (gui) ((source-paths ...) #:required? #t)))))
    (options (cli)))
  (if (null? options) (cli (list "--help"))
    (merge-files (assoc-ref options (q source-paths)) options)))