;; ;;; stash.scm --- A Guile script for moving directories and creating symlinks with conflict resolution
;; ;;;
;; ;;; Author: Glenn Thompson <glenn@kirstol.org>
;; ;;; Version: 0.1.0-alpha.1
;; ;;; Created: 2024-12-03
;; ;;; Compatibility: Guile 3.0.9
;; ;;; Keywords: symlink, file management, conflict resolution, backup
;; ;;;
;; ;;; Commentary:
;; ;;;
;; ;;; Stash is a command-line utility written in Guile Scheme designed to facilitate the movement of directories and
;; ;;; creation of symbolic links (symlinks) for files and directories. It allows users to specify a source directory
;; ;;; and a target directory where the symlink should be created. The utility handles potential conflicts with existing
;; ;;; files or directories at the target location, offering users the choice to overwrite, back up, 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, backup, skip, or cancel).
;; ;;; - Moving directories and creating symlinks.
;; ;;; - Simple and interactive user interface for easy use.
;; ;;;
;; ;;; Usage:
;; ;;;
;; ;;; guile -L . stash.scm --target=<target-dir> --source=<source-dir>
;; ;;;
;; ;;; Replace <target-dir> with the directory where you want the symlink to be created,
;; ;;; and <source-dir> with the path to the source directory.
;; ;;;
;; ;;; License:
;; ;;;
;; ;;; This project is licensed under the GNU General Public License v3.
;; ;;;

;;; Code:

;; Import necessary modules
(use-modules (ice-9 getopt-long)
             (ice-9 popen)
             (ice-9 rdelim)
             (ice-9 format)
             (stash-help)    ;; Import the stash-help module for help functionality
             (srfi srfi-1)
             (srfi srfi-19))  ;; Use for list handling and date-time formatting

;;; 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))

;;; Helper function to get a formatted current time string
(define (current-timestamp)
  "Return the current date and time as a formatted string."
  (let* ((time (current-time))
         (seconds (time-second time)))
    (strftime "%Y-%m-%d-%H-%M-%S" (localtime seconds))))

;;; Improved logging function with timestamp
(define (log-action message)
  "Log an action with a timestamp to the stash.log file."
  (let ((log-port (open-file "stash.log" "a")))  ;; Open file in append mode
    (display (string-append "[" (current-timestamp) "] " message) log-port)
    (newline log-port)
    (close-port log-port)))

;;; Version function
(define (display-version)
  "Display the current version of the program."
  (display (format #f "Stash version ~a\n" "0.1.0-alpha.1"))
  (exit 0))

;;; Helper function to check for version flag and display version
(define (check-for-version args)
  "Check if --version or -v is in the arguments list."
  (if (or (member "--version" args)
          (member "-v" args))
      (display-version)))

;;; Expand ~ in paths to the full home directory path
(define (expand-home path)
  "Expand ~ to the user's home directory."
  (if (string-prefix? "~" path)
      (string-append (getenv "HOME") (substring path 1))
      path))

;;; Helper function to concatenate paths safely
(define (concat-path base path)
  "Concatenate two paths, ensuring there are no double slashes."
  (if (string-suffix? "/" base)
      (string-append (string-drop-right base 1) "/" path)
      (string-append base "/" path)))

;;; Conflict resolution handler with user options
(define (prompt-user-for-action)
  "Prompt the user to decide how to handle a conflict: overwrite (o), skip (s), or cancel (c)."
  (display (color-message "A conflict was detected. Choose action - Overwrite (o), Skip (s), or Cancel (c): " yellow-text))
  (let ((response (read-line)))
    (cond
      ((string-ci=? response "o") 'overwrite)
      ((string-ci=? response "s") 'skip)
      ((string-ci=? response "c") 'cancel)
      (else
       (display (color-message "Invalid input. Please try again.\n" red-text))
       (prompt-user-for-action)))))

;;; Helper function to delete a directory recursively
(define (delete-directory path)
  "Delete a directory recursively."
  (if (file-is-directory? path)
      (begin
        (system (string-append "rm -rf " (shell-quote-argument path)))
        (log-action (format #f "Deleted directory: ~a" path)))
      (display (color-message "Error: Path is not a directory.\n" red-text))))

;;; Helper function to handle conflicts
(define (handle-conflict target-source-dir source-dir)
  "Handle conflicts when the target directory already exists."
  (let ((choice (prompt-user-for-action)))
    (cond
      ((eq? choice 'overwrite)
       (delete-directory target-source-dir)
       (rename-file source-dir target-source-dir)
       (display (color-message (format #f "Overwriting directory ~a.\n" target-source-dir) green-text))
       (log-action (format #f "Overwritten directory: ~a" target-source-dir)))
      ((eq? choice 'skip)
       (display (color-message "Skipping move operation.\n" green-text))
       (log-action (format #f "Skipped moving directory: ~a" target-source-dir)))
      ((eq? choice 'cancel)
       (display (color-message "Operation cancelled by user.\n" yellow-text))
       (log-action "Operation cancelled by user.")
       (exit 0)))))

;;; Helper function to ensure target has .config appended, avoiding double slashes
(define (ensure-config-path target-dir)
  "Ensure that the target directory has .config appended, avoiding double slashes."
  (let ((target-dir (expand-home target-dir)))
    (if (string-suffix? "/" target-dir)
        (set! target-dir (string-drop-right target-dir 1)))  ;; Remove trailing slash if it exists
    (if (not (string-suffix? "/.config" target-dir))
        (string-append target-dir "/.config")
        target-dir)))

;;; Helper function to move source to target
(define (move-source-to-target source-dir target-dir)
  "Move the entire source directory to the target directory, ensuring .config in the target path."
  (let* ((target-dir (ensure-config-path target-dir))
         (source-dir (expand-home source-dir))
         (source-name (basename source-dir))
         (target-source-dir (concat-path target-dir source-name)))
    ;; Ensure that the .config directory exists in the target
    (if (not (file-exists? target-dir))
        (mkdir target-dir #o755))
    ;; Check if the target directory already exists
    (if (file-exists? target-source-dir)
        (handle-conflict target-source-dir source-dir)
        ;; If the target directory doesn't exist, proceed with the move
        (begin
          (rename-file source-dir target-source-dir)
          (display (color-message (format #f "Moved ~a to ~a\n" source-dir target-source-dir) green-text))
          (log-action (format #f "Moved ~a to ~a" source-dir target-source-dir))))
    target-source-dir))  ;; Return the path of the moved source directory

;;; Helper function to create a symlink in the parent directory of the original source
(define (create-symlink-in-parent source-dir target-dir)
  "Create a symlink in the parent directory of source-dir."
  (let* ((parent-dir (expand-home (dirname source-dir)))  ;; Ensure the parent path is expanded
         (symlink-target (concat-path parent-dir (basename source-dir)))
         (target-dir (expand-home target-dir)))  ;; Ensure the target path is expanded
    ;; Check if symlink already exists
    (if (file-exists? symlink-target)
        (let ((choice (prompt-user-for-action)))
          (cond
            ((eq? choice 'overwrite)
             (delete-file symlink-target)
             (symlink target-dir symlink-target)
             (display (color-message (format #f "Overwriting symlink ~a pointing to ~a\n" symlink-target target-dir) green-text))
             (log-action (format #f "Overwritten symlink: ~a pointing to ~a" symlink-target target-dir)))
            ((eq? choice 'skip)
             (display (color-message "Skipping symlink creation.\n" green-text))
             (log-action (format #f "Skipped symlink creation: ~a" symlink-target)))
            ((eq? choice 'cancel)
             (display (color-message "Operation cancelled by user.\n" yellow-text))
             (log-action "Operation cancelled by user.")
             (exit 0))))
        ;; Create the symlink if no conflict
        (begin
          (symlink target-dir symlink-target)
          (display (color-message (format #f "Symlink created at ~a pointing to ~a\n" symlink-target target-dir) green-text))
          (log-action (format #f "Symlink created at ~a pointing to ~a" symlink-target target-dir))))))

;;; Main function to handle source and target operations
(define (handle-source-and-target source-dir target-dir)
  "Move the source directory to the target and create a symlink in the parent directory."
  (let ((target-source-dir (move-source-to-target source-dir target-dir)))  ;; Move the directory
    (create-symlink-in-parent source-dir target-source-dir)))  ;; Create the symlink

;;; Function to handle command-line arguments
(define (parse-arguments args)
  "Parse command-line arguments."
  (getopt-long args
               '((target    (value #t) (single-char #\t))   ;; Support both --target and -t
                 (source    (value #t) (single-char #\s))   ;; Support both --source and -s
                 (help      (value #f) (single-char #\h))   ;; Support -h for help
                 (version   (value #f) (single-char #\v))))) ;; Support -v for version

;;; Main entry point
(define (main args)
  "Main function to parse arguments and execute the program."
  (setenv "GUILE_AUTO_COMPILE" "0")
  ;; Check if --help or -h was passed
  (if (or (member "--help" args) (member "-h" args))
      (display-help))

  ;; Check if --version or -v was passed
  (check-for-version args)

  ;; Parse remaining arguments
  (let* ((options (parse-arguments args))
         (target-dir (assoc-ref options 'target))
         (source-dir (assoc-ref options 'source)))
    (if (and target-dir source-dir)
        (handle-source-and-target source-dir target-dir)
        (begin
          (display (color-message "Error: Missing required arguments.\n" red-text))
          (display (color-message "Usage: stash.scm --target=<target-dir> --source=<source-dir>\n" yellow-text))
          (exit 1)))))

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