;;; guile-stash.scm --- A Guile script for creating and managing symlinks with conflict resolution
;;;
;;; Author: Glenn Thompson <glenn@kirstol.org>
;;; Version: 1.1
;;; Created: 2024-12-03
;;; Compatibility: Guile 3.0.9
;;; Keywords: symlink, file management, conflict resolution
;;;
;;; Commentary:
;;;
;;; Guile-Stash is a command-line utility written in Guile Scheme designed to facilitate the creation of symbolic links (symlinks)
;;; for files and directories. It allows users to specify a source file or directory and a target directory where the symlink(s)
;;; should be created. The utility handles potential conflicts with existing files or directories at the target location,
;;; offering users the choice to overwrite or skip the creation of new symlinks.
;;;
;;; Main Features:
;;; - Command-line argument parsing for specifying source and target paths.
;;; - Conflict detection with interactive user resolution options (overwrite or skip).
;;; - Support for symlinking both files and directories.
;;; - Simple and interactive user interface for easy use.
;;;
;;; Usage:
;;;
;;; guile -L . guile-stash.scm --target=<target-dir> --package-dir=<package-dir>
;;;
;;; Replace <target-dir> with the directory where you want the symlink(s) to be created,
;;; and <package-dir> with the path to the source file or directory.
;;;
;;; License:
;;;
;;; ;;; guile-stash.scm --- Description of the script
;;;
;;; Copyright (c) 2024 Glenn Thompson
;;;
;;; Permission is hereby granted, free of charge, to any person obtaining a copy
;;; of this software and associated documentation files (the "Software"), to deal
;;; in the Software without restriction, including without limitation the rights
;;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;;; copies of the Software, and to permit persons to whom the Software is
;;; furnished to do so, subject to the following conditions:
;;;
;;; The above copyright notice and this permission notice shall be included in all
;;; copies or substantial portions of the Software.
;;;
;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;;; SOFTWARE.
;;;
;;; For the full license text, see the LICENSE file.

;;; Code:

;; Import necessary modules
(use-modules (ice-9 getopt-long)
             (ice-9 popen)  ;; Additional module for executing system commands
             (ice-9 rdelim))

;;; ANSI Color Codes for terminal output
(define red-text "\x1b[31m")
(define yellow-text "\x1b[33m")
(define green-text "\x1b[32m")
(define reset-text "\x1b[0m")

;;; Function to wrap messages in color
(define (color-message message color)
  (string-append color message reset-text))

(define (shell-quote-argument arg)
  (if (string-contains arg " ")
      (string-append "\"" (string-replace arg "\"" "\\\"") "\"")
      arg))

(define (parse-arguments args)
  "Parse command-line arguments."
  (let* ((opts (getopt-long args
                            '((target (value #t) (required? #t))
                              (package-dir (value #t) (required? #t))))))
    opts))

(define (delete-directory path)
  (if (file-is-directory? path)
      (begin
        (system (string-append "rm -r " (shell-quote-argument path)))
        #t)
      #f))

(define (prompt-user-for-action)
  "Prompt the user to decide how to handle a conflict: overwrite (o), skip (s), or rename (r)."
  (display (color-message "A conflict was detected. Choose action - Overwrite (o), Skip (s), or Rename (r): " yellow-text))
  (let ((response (read-line)))
    (cond
      ((string-ci=? response "o") 'overwrite)
      ((string-ci=? response "s") 'skip)
      ((string-ci=? response "r") 'rename)
      (else
       (display (color-message "Invalid input. " red-text))
       (prompt-user-for-action))))) ; Recursive call on invalid input.

(define (handle-conflicts existing-path new-symlink-path)
  "Handle conflicts between existing files and new symlinks."
  (case (prompt-user-for-action)
    ((overwrite)
     (if (file-is-directory? existing-path)
         (delete-directory existing-path)  ;; Call the delete-directory function
         (delete-file existing-path))  ;; Use Guile's built-in delete-file for files
     (symlink new-symlink-path existing-path)
     (format #t (color-message (string-append "Existing file/directory overwritten with new symlink: " existing-path " -> " new-symlink-path "\n") green-text)))
    ((skip)
     (display (color-message "Skipped creating new symlink due to conflict.\n" red-text)))
    ((rename)
     ;; Prompt for new name and execute renaming
     (display (color-message "Enter new name for the existing symlink or file: " yellow-text))
     (let ((new-name (read-line)))
       (let ((new-path (string-append (dirname existing-path) "/" new-name)))
         (rename-file existing-path new-path)
         (format #t (color-message (string-append "Renamed " existing-path " to " new-name "\n") green-text)))))
    (else
     (display (color-message "No valid action selected, no changes made.\n" red-text)))))


(define (create-symlink source target)
  "Create a symlink for the source directory at the target location."
  (let ((target-symlink-path (string-append target "/" (basename source))))
    (if (file-exists? target-symlink-path) ; Checks if the path exists (file, directory, or symlink)
        (handle-conflicts target-symlink-path source) ; Handle existing path
        (begin
          (catch 'system-error
            (lambda () (symlink source target-symlink-path)
                      (display (color-message (string-append "Symlink created for: " target-symlink-path " -> " source "\n") green-text)))
            (lambda args
              (display (color-message "File exists.  Unable to create symlink.\n" red-text))))))))

(define (main args)
  "Main function to parse arguments and initiate processing."
  (let* ((options (parse-arguments args))
         (target-dir (assoc-ref options 'target))
         (package-dir (assoc-ref options 'package-dir)))
    (if (and target-dir package-dir)
        (create-symlink package-dir target-dir)
        (begin
          (display (color-message "Error: Missing required arguments.\n" red-text))
          (display (color-message "Usage: guile stash.scm --target=<target-dir> --package-dir=<package-dir>\n" yellow-text))
          (exit 1)))))

;; Entry point for guile-stash
(main (command-line))