;;; ack-and-a-half.el --- Yet another front-end for ack
;;
;; Copyright (C) 2011 Jacob Helwig
;;
;; Author: Jacob Helwig <jacob+ack * technosorcery.net>
;; Version: 0.0.1
;; Homepage: http://technosorcery.net
;;
;; This file is NOT part of GNU Emacs.
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2, or (at
;; your option) any later version.
;;
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program ; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;
;;; Commentary:
;;
;; ack-and-a-half.el provides a simple compilation mode for the perl
;; grep-a-like ack (http://petdance.com/ack/).
;;
;; Add the following to your .emacs:
;;
;; (add-to-list 'load-path "/path/to/ack-and-a-half")
;; (autoload 'ack-and-a-half-same "ack-and-a-half" nil t)
;; (autoload 'ack-and-a-half "ack-and-a-half" nil t)
;; (autoload 'ack-and-a-half-find-file-same "ack-and-a-half" nil t)
;; (autoload 'ack-and-a-half-find-file "ack-and-a-half" nil t)
;; (defalias 'ack 'ack-and-a-half)
;; (defalias 'ack-same 'ack-and-a-half-same)
;; (defalias 'ack-find-file 'ack-and-a-half-find-file)
;; (defalias 'ack-find-file-same 'ack-and-a-half-find-file-same)
;;
;; Run `ack' to search for all files and `ack-same' to search for
;; files of the same type as the current buffer.
;;
;; `next-error' and `previous-error' can be used to jump to the
;; matches.
;;
;; `ack-find-file' and `ack-find-same-file' use ack to list the files
;; in the current project.  It's a convenient, though slow, way of
;; finding files.
;;

(eval-when-compile (require 'cl))
(require 'compile)
(require 'grep)

(add-to-list 'debug-ignored-errors
             "^Moved \\(back before fir\\|past la\\)st match$")
(add-to-list 'debug-ignored-errors "^File .* not found$")

(define-compilation-mode ack-and-a-half-mode "Ack"
  "Ack results compilation mode."
  (set (make-local-variable 'compilation-disable-input) t)
  (set (make-local-variable 'compilation-error-face) grep-hit-face))

(defgroup ack-and-a-half nil "Yet another front end for ack."
  :group 'tools
  :group 'matching)

; TODO Determine how to fall back to using ack-grep if ack is not found.
(defcustom ack-and-a-half-executable (executable-find "ack")
  "*The location of the ack executable"
  :group 'ack-and-a-half
  :type 'file)

(defcustom ack-and-a-half-arguments nil
  "*Extra arguments to pass to ack."
  :group 'ack-and-a-half
  :type '(repeat (string)))

(defcustom ack-and-a-half-mode-type-alist nil
  "*File type(s) to search per major mode. (ack-and-a-half-same)
This overrides values in `ack-and-a-half-mode-type-default-alist'.
The car in each list element is a major mode, and the rest
is a list of strings passed to the --type flag of ack when running
`ack-and-a-half-same'."
  :group 'ack-and-a-half
  :type '(repeat (cons (symbol :tag "Major mode")
                       (repeat (string :tag "ack --type")))))

(defcustom ack-and-a-half-mode-extension-alist nil
  "*File extensions to search per major mode. (ack-and-a-half-same)
This overrides values in `ack-and-a-half-mode-extension-default-alist'.
The car in each list element is a major mode, and the rest
is a list of file extensions to be searched in addition to
the type defined in `ack-and-a-half-mode-type-alist' when
running `ack-and-a-half-same'."
  :group 'ack-and-a-half
  :type '(repeat (cons (symbol :tag "Major mode")
                       (repeat :tag "File extensions" (string)))))

(defcustom ack-and-a-half-ignore-case 'smart
  "*Ignore case when searching
The special value 'smart enables the ack option \"smart-case\"."
  :group 'ack-and-a-half
  :type '(choice (const :tag "Case sensitive" nil)
                 (const :tag "Smart case" 'smart)
                 (const :tag "Case insensitive" t)))

(defcustom ack-and-a-half-regexp-search t
  "*Default to regular expression searching.
Giving a prefix argument to `ack-and-a-half' toggles this option."
  :group 'ack-and-a-half
  :type '(choice (const :tag "Literal searching" nil)
                 (const :tag "Regular expression searching" t)))

(defcustom ack-and-a-half-use-environment t
  "*Use .ackrc and ACK_OPTIONS when searching."
  :group 'ack-and-a-half
  :type '(choice (const :tag "Ignore environment" nil)
                 (const :tag "Use environment" t)))

(defcustom ack-and-a-half-root-directory-functions '(ack-and-a-half-guess-project-root)
  "*List of functions used to find the base directory to ack from.
These functions are called until one returns a directory.  If successful,
`ack-and-a-half' is run from that directory instead of from `default-directory'.
The directory is verified by the user depending on `ack-and-a-half-prompt-for-directory'."
  :group 'ack-and-a-half
  :type '(repeat function))

(defcustom ack-and-a-half-project-root-file-patterns
  '(".project\\'"
    ".xcodeproj\\'"
    ".sln\\'"
    "\\`Project.ede\\'"
    "\\`.git\\'"
    "\\`.bzr\\'"
    "\\`_darcs\\'"
    "\\`.hg\\'")
  "*List of file patterns for the project root (used by `ack-and-a-half-guess-project-root'.
Each element is a regular expression.  If a file matching any element is
found in a directory, then that directory is assumed to be the project
root by `ack-and-a-half-guess-project-root'."
  :group 'ack-and-a-half
  :type '(repeat (string :tag "Regular expression")))

(defcustom ack-and-a-half-prompt-for-directory 'unless-guessed
  "*Prompt for directory in which to run ack.
If this is 'unless-guessed, then the value determined by `ack-and-a-half-root-directory-functions'
is used without confirmation.  If it is nil, then the directory is never
confirmed.  If t, then always prompt for the directory to use."
  :group 'ack-and-a-half
  :type '(choice (const :tag "Don't prompt" nil)
                 (const :tag "Don't prompt when guessed" 'unless-guessed)
                 (const :tag "Always prompt" t)))

;;; Default setting lists ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defconst ack-and-a-half-mode-type-default-alist
  '((actionscript-mode "actionscript")
    (LaTeX-mode "tex")
    (TeX-mode "tex")
    (asm-mode "asm")
    (batch-file-mode "batch")
    (c++-mode "cpp")
    (c-mode "cc")
    (cfmx-mode "cfmx")
    (cperl-mode "perl")
    (csharp-mode "csharp")
    (css-mode "css")
    (emacs-lisp-mode "elisp")
    (erlang-mode "erlang")
    (espresso-mode "java")
    (fortran-mode "fortran")
    (haskell-mode "haskell")
    (hexl-mode "binary")
    (html-mode "html")
    (java-mode "java")
    (javascript-mode "js")
    (jde-mode "java")
    (js2-mode "js")
    (jsp-mode "jsp")
    (latex-mode "tex")
    (lisp-mode "lisp")
    (lua-mode "lua")
    (makefile-mode "make")
    (mason-mode "mason")
    (nxml-mode "xml")
    (objc-mode "objc" "objcpp")
    (ocaml-mode "ocaml")
    (parrot-mode "parrot")
    (perl-mode "perl")
    (php-mode "php")
    (plone-mode "plone")
    (python-mode "python")
    (ruby-mode "ruby")
    (scheme-mode "scheme")
    (shell-script-mode "shell")
    (skipped-mode "skipped")
    (smalltalk-mode "smalltalk")
    (sql-mode "sql")
    (tcl-mode "tcl")
    (tex-mode "tex")
    (tt-mode "tt")
    (vb-mode "vb")
    (vim-mode "vim")
    (xml-mode "xml")
    (yaml-mode "yaml"))
  "Default values for `ack-and-a-half-mode-type-alist'.")

(defconst ack-and-a-half-mode-extension-default-alist
  '((d-mode "d"))
  "Default values for `ack-and-a-half-mode-extension-alist'.")

(defun ack-and-a-half-create-type (extensions)
  (list "--type-set"
        (concat "ack-and-a-half-custom-type=" (mapconcat 'identity extensions ","))
        "--type" "ack-and-a-half-custom-type"))

(defun ack-and-a-half-type-for-major-mode (mode)
  "Return the --type and --type-set arguments to use with ack for major mode MODE."
  (let ((types (cdr (or (assoc mode ack-and-a-half-mode-type-alist)
                        (assoc mode ack-and-a-half-mode-type-default-alist))))
        (ext (cdr (or (assoc mode ack-and-a-half-mode-extension-alist)
                      (assoc mode ack-and-a-half-mode-extension-default-alist))))
        result)
    (dolist (type types)
      (push type result)
      (push "--type" result))
    (if ext
        (if types
            `("--type-add" ,(concat (car types)
                                    "=" (mapconcat 'identity ext ","))
              . ,result)
          (ack-and-a-half-create-type ext))
      result)))

;;; Project root ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun ack-and-a-half-guess-project-root ()
  "Guess the project root directory.
This is intended to be used in `ack-and-a-half-root-directory-functions'."
  (catch 'root
    (let ((dir (expand-file-name (if buffer-file-name
                                     (file-name-directory buffer-file-name)
                                   default-directory)))
          (pattern (mapconcat 'identity ack-and-a-half-project-root-file-patterns "\\|")))
      (while (not (equal dir "/"))
        (when (directory-files dir nil pattern t)
          (throw 'root dir))
        (setq dir (file-name-directory (directory-file-name dir)))))))

;;; Commands ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defvar ack-and-a-half-directory-history nil
  "Directories recently searched with `ack-and-a-half'.")
(defvar ack-and-a-half-literal-history nil
  "Strings recently searched for with `ack-and-a-half'.")
(defvar ack-and-a-half-regexp-history nil
  "Regular expressions recently searched for with `ack-and-a-half'.")

(defsubst ack-and-a-half-read (regexp)
  (read-from-minibuffer (if regexp "ack pattern: " "ack literal search: ")
                        nil nil nil
                        (if regexp 'ack-and-a-half-regexp-history 'ack-and-a-half-literal-history)))

(defun ack-and-a-half-read-dir ()
  (let ((dir (run-hook-with-args-until-success 'ack-and-a-half-root-directory-functions)))
    (if ack-and-a-half-prompt-for-directory
        (if (and dir (eq ack-and-a-half-prompt-for-directory 'unless-guessed))
            dir
          (read-directory-name "Directory: " dir dir t))
      (or dir
          (and buffer-file-name (file-name-and-directory buffer-file-name))
          default-directory))))

(defsubst ack-and-a-half-xor (a b)
  (if a (not b) b))

(defun ack-and-a-half-interactive ()
  "Return the (interactive) arguments for `ack-and-a-half' and `ack-and-a-half-same'."
  (let ((regexp (ack-and-a-half-xor current-prefix-arg ack-and-a-half-regexp-search)))
    (list (ack-and-a-half-read regexp)
          regexp
          (ack-and-a-half-read-dir))))

(defun ack-and-a-half-type ()
  (or (ack-and-a-half-type-for-major-mode major-mode)
      (when buffer-file-name
        (ack-and-a-half-create-type (list (file-name-extension buffer-file-name))))))

(defun ack-and-a-half-option (name enabled)
  (format "--%s%s" (if enabled "" "no") name))

(defun ack-and-a-half-arguments-from-options (regexp)
  (let ((arguments (list "--nocolor" "--nogroup"
                         (ack-and-a-half-option "smart-case" (eq ack-and-a-half-ignore-case 'smart-case))
                         (ack-and-a-half-option "env" ack-and-a-half-use-environment))))
    (unless ack-and-a-half-ignore-case
      (push "-i" arguments))
    (unless regexp
      (push "--literal" arguments))
    arguments))

(defun ack-and-a-half-string-replace (from to string &optional re)
  "Replace all occurrences of FROM with TO in STRING.
All arguments are strings.
When optional fourth argument is non-nil, treat the from as a regular expression."
  (let ((pos 0)
        (res "")
        (from (if re from (regexp-quote from))))
    (while (< pos (length string))
      (if (setq beg (string-match from string pos))
          (progn
            (setq res (concat res
                              (substring string pos (match-beginning 0))
                              to))
            (setq pos (match-end 0)))
        (progn
          (setq res (concat res (substring string pos (length string))))
          (setq pos (length string)))))
    res))

(defun ack-and-a-half-shell-quote (string)
  "Wrap in single quotes, and quote existing single quotes to make shell safe."
  (concat "'" (ack-and-a-half-string-replace "'" "'\\''" string) "'"))

(defun ack-and-a-half-run (directory regexp &rest arguments)
  "Run ack in DIRECTORY with ARGUMENTS."
  (setq default-directory
        (if directory
            (file-name-as-directory (expand-file-name directory))
          default-directory))
  (setq arguments (append ack-and-a-half-arguments
                          (nconc (ack-and-a-half-arguments-from-options regexp)
                                 arguments)))
  (compilation-start (mapconcat 'identity (nconc (list ack-and-a-half-executable) arguments) " ")
                     'ack-and-a-half-mode))

(defun ack-and-a-half-read-file (prompt choices)
  (if ido-mode
      (ido-completing-read prompt choices nil t)
    (require 'iswitchb)
    (with-no-warnings
      (let ((iswitchb-make-buflist-hook
             (lambda () (setq iswitchb-temp-buflist choices))))
        (iswitchb-read-buffer prompt nil t)))))

(defun ack-and-a-half-list-files (directory &rest arguments)
  (with-temp-buffer
    (let ((default-directory directory))
      (when (eq 0 (apply 'call-process ack-and-a-half-executable nil t nil "-f" "--print0"
                         arguments))
        (goto-char (point-min))
        (let ((beg (point-min))
              files)
          (while (re-search-forward "\0" nil t)
            (push (buffer-substring beg (match-beginning 0)) files)
            (setq beg (match-end 0)))
          files)))))

(defun ack-and-a-half-version-string ()
  "Return the ack version string."
  (with-temp-buffer
    (call-process ack-executable nil t nil "--version")
    (goto-char (point-min))
    (re-search-forward " +")
    (buffer-substring (point) (point-at-eol))))

;;; Public interface ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;;###autoload
(defun ack-and-a-half (pattern &optional regexp directory)
  "Run ack.
PATTERN is interpreted as a regular expression, iff REGEXP is non-nil.  If
called interactively, the value of REGEXP is determined by `ack-and-a-half-regexp-search'.
A prefix arg toggles the behavior.
DIRECTORY is the root directory.  If called interactively, it is determined by
`ack-and-a-half-project-root-file-patterns'.  The user is only prompted, if
`ack-and-a-half-prompt-for-directory' is set."
  (interactive (ack-and-a-half-interactive))
  (ack-and-a-half-run directory regexp (ack-and-a-half-shell-quote pattern)))

;;;###autoload
(defun ack-and-a-half-same (pattern &optional regexp directory)
  "Run ack with --type matching the current `major-mode'.
The types of files searched are determined by `ack-and-a-half-mode-type-alist' and
`ack-and-a-half-mode-extension-alist'.  If no type is configured, the buffer's
file extension is used for the search.
PATTERN is interpreted as a regular expression, iff REGEXP is non-nil.  If
called interactively, the value of REGEXP is determined by `ack-and-a-half-regexp-search'.
A prefix arg toggles that value.
DIRECTORY is the directory in which to start searching.  If called
interactively, it is determined by `ack-and-a-half-project-root-file-patterns`.
The user is only prompted, if `ack-and-a-half-prompt-for-directory' is set.`"
  (interactive (ack-and-a-half-interactive))
  (let ((type (ack-and-a-half-type)))
    (if type
        (apply 'ack-and-a-half-run directory regexp (append type (list (ack-and-a-half-shell-quote pattern))))
      (ack-and-a-half pattern regexp directory))))

;;;###autoload
(defun ack-and-a-half-find-file (&optional directory)
  "Prompt to find a file found by ack in DIRECTORY."
  (interactive (list (ack-and-a-half-read-dir)))
  (find-file (expand-file-name
              (ack-and-a-half-read-file
               "Find file: "
               (ack-and-a-half-list-files directory))
              directory)))

;;;###autoload
(defun ack-and-a-half-find-file-same (&optional directory)
  "Prompt to find a file found by ack in DIRECTORY."
  (interactive (list (ack-and-a-half-read-dir)))
  (find-file (expand-file-name
              (ack-and-a-half-read-file
               "Find file: "
               (apply 'ack-and-a-half-list-files directory (ack-and-a-half-type)))
              directory)))

;;; End ack-and-a-half.el ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(provide 'ack-and-a-half)