;;; cider-stacktrace.el --- Stacktrace navigator -*- lexical-binding: t -*-

;; Copyright © 2014 Jeff Valk

;; Author: Jeff Valk <jv@jeffvalk.com>

;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.

;; This file is not part of GNU Emacs.

;;; Commentary:

;; Stacktrace filtering and stack frame source navigation

;;; Code:

(require 'cl-lib)
(require 'button)
(require 'dash)
(require 'easymenu)

;; Variables

(defgroup cider-stacktrace nil
  "Stacktrace filtering and navigation."
  :prefix "cider-stacktrace-"
  :group 'cider)

(defcustom cider-stacktrace-fill-column t
  "Fill column for error messages in stacktrace display.
If nil, messages will not be wrapped.  If truthy but non-numeric,
`fill-column' will be used."
  :type 'list
  :group 'cider-stacktrace
  :package-version '(cider . "0.7.0"))

(defcustom cider-stacktrace-default-filters '(tooling dup)
  "Frame types to omit from initial stacktrace display."
  :type 'list
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defvar cider-stacktrace-detail-max 2
  "The maximum detail level for causes.")

(defvar-local cider-stacktrace-hidden-frame-count 0)
(defvar-local cider-stacktrace-filters nil)
(defvar-local cider-stacktrace-prior-filters nil)
(defvar-local cider-stacktrace-cause-visibility nil)


;; Faces

(defface cider-stacktrace-error-class-face
  '((t (:inherit font-lock-warning-face)))
  "Face for exception class names"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defface cider-stacktrace-error-message-face
  '((t (:inherit font-lock-doc-face)))
  "Face for exception messages"
  :group 'cider-stacktrace
  :package-version '(cider . "0.7.0"))

(defface cider-stacktrace-filter-shown-face
  '((t (:inherit button :underline t :weight normal)))
  "Face for filter buttons representing frames currently visible"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defface cider-stacktrace-filter-hidden-face
  '((t (:inherit button :underline nil :weight normal)))
  "Face for filter buttons representing frames currently filtered out"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defface cider-stacktrace-face
  '((t (:inherit default)))
  "Face for stack frame text"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defface cider-stacktrace-ns-face
  '((t (:inherit font-lock-comment-face)))
  "Face for stack frame namespace name"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))

(defface cider-stacktrace-fn-face
  '((t (:inherit default :weight bold)))
  "Face for stack frame function name"
  :group 'cider-stacktrace
  :package-version '(cider . "0.6.0"))


;; Colors & Theme Support

(defvar cider-stacktrace-frames-background-color
  (cider-scale-background-color)
  "Background color for stacktrace frames.")

(defadvice enable-theme (after cider-stacktrace-adapt-to-theme activate)
  "When theme is changed, update `cider-stacktrace-frames-background-color'."
  (setq cider-stacktrace-frames-background-color (cider-scale-background-color)))


;; Mode & key bindings

(defvar cider-stacktrace-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map (kbd "M-p") 'cider-stacktrace-previous-cause)
    (define-key map (kbd "M-n") 'cider-stacktrace-next-cause)
    (define-key map (kbd "M-.") 'cider-stacktrace-jump)
    (define-key map "q" 'cider-popup-buffer-quit-function)
    (define-key map "j" 'cider-stacktrace-toggle-java)
    (define-key map "c" 'cider-stacktrace-toggle-clj)
    (define-key map "r" 'cider-stacktrace-toggle-repl)
    (define-key map "t" 'cider-stacktrace-toggle-tooling)
    (define-key map "d" 'cider-stacktrace-toggle-duplicates)
    (define-key map "a" 'cider-stacktrace-toggle-all)
    (define-key map "1" 'cider-stacktrace-cycle-cause-1)
    (define-key map "2" 'cider-stacktrace-cycle-cause-2)
    (define-key map "3" 'cider-stacktrace-cycle-cause-3)
    (define-key map "4" 'cider-stacktrace-cycle-cause-4)
    (define-key map "5" 'cider-stacktrace-cycle-cause-5)
    (define-key map "0" 'cider-stacktrace-cycle-all-causes)
    (define-key map [tab] 'cider-stacktrace-cycle-current-cause)
    (define-key map [backtab] 'cider-stacktrace-cycle-all-causes)
    (easy-menu-define cider-stacktrace-mode-menu map
      "Menu for CIDER's stacktrace mode"
      '("Stacktrace"
        ["Previous cause" cider-stacktrace-previous-cause]
        ["Next cause" cider-stacktrace-next-cause]
        "--"
        ["Jump to frame source" cider-stacktrace-jump]
        "--"
        ["Cycle current cause detail" cider-stacktrace-cycle-current-cause]
        ["Cycle cause #1 detail" cider-stacktrace-cycle-cause-1]
        ["Cycle cause #2 detail" cider-stacktrace-cycle-cause-2]
        ["Cycle cause #3 detail" cider-stacktrace-cycle-cause-3]
        ["Cycle cause #4 detail" cider-stacktrace-cycle-cause-4]
        ["Cycle cause #5 detail" cider-stacktrace-cycle-cause-5]
        ["Cycle all cause detail" cider-stacktrace-cycle-all-causes]
        "--"
        ["Show/hide Java frames" cider-stacktrace-toggle-java]
        ["Show/hide Clojure frames" cider-stacktrace-toggle-clj]
        ["Show/hide REPL frames" cider-stacktrace-toggle-repl]
        ["Show/hide tooling frames" cider-stacktrace-toggle-tooling]
        ["Show/hide duplicate frames" cider-stacktrace-toggle-duplicates]
        ["Show/hide all frames" cider-stacktrace-toggle-all]))
    map))

(define-derived-mode cider-stacktrace-mode fundamental-mode "Stacktrace"
  "Major mode for filtering and navigating CIDER stacktraces.

\\{cider-stacktrace-mode-map}"
  (setq buffer-read-only t)
  (setq-local truncate-lines t)
  (setq-local electric-indent-chars nil)
  (setq-local cider-stacktrace-prior-filters nil)
  (setq-local cider-stacktrace-hidden-frame-count 0)
  (setq-local cider-stacktrace-filters cider-stacktrace-default-filters)
  (setq-local cider-stacktrace-cause-visibility (apply 'vector (-repeat 10 0))))


;; Stacktrace filtering

(defun cider-stacktrace-indicate-filters (filters)
  "Update enabled state of filter buttons.

Find buttons with a 'filter property; if filter is a member of FILTERS, or
if filter is nil ('show all') and the argument list is non-nil, fontify the
button as disabled.  Upon finding text with a 'hidden-count property, stop
searching and update the hidden count text."
  (with-current-buffer (get-buffer cider-error-buffer)
    (save-excursion
      (goto-char (point-min))
      (let ((inhibit-read-only t)
            (get-face (lambda (hide)
                        (if hide
                            'cider-stacktrace-filter-hidden-face
                          'cider-stacktrace-filter-shown-face))))
        ;; Toggle buttons
        (while (not (or (get-text-property (point) 'hidden-count) (eobp)))
          (let ((button (button-at (point))))
            (when button
              (let* ((filter (button-get button 'filter))
                     (face (funcall get-face (if filter
                                                 (member filter filters)
                                               filters))))
                (button-put button 'face face)))
            (goto-char (or (next-property-change (point))
                           (point-max)))))
        ;; Update hidden count
        (when (and (get-text-property (point) 'hidden-count)
                   (re-search-forward "[0-9]+" (line-end-position) t))
          (replace-match
           (number-to-string cider-stacktrace-hidden-frame-count)))))))

(defun cider-stacktrace-apply-filters (filters)
  "Set visibility on stack frames using FILTERS.
Update `cider-stacktrace-hidden-frame-count' and indicate filters applied.
Currently collapsed stacktraces are ignored, and do not contribute to the
hidden count."
  (with-current-buffer (get-buffer cider-error-buffer)
    (save-excursion
      (goto-char (point-min))
      (let ((inhibit-read-only t)
            (hidden 0))
        (while (not (eobp))
          (unless (get-text-property (point) 'collapsed)
            (let* ((flags (get-text-property (point) 'flags))
                   (hide (if (-intersection filters flags) t nil)))
              (when hide (setq hidden (+ 1 hidden)))
              (put-text-property (point) (line-beginning-position 2) 'invisible hide)))
          (forward-line 1))
        (setq cider-stacktrace-hidden-frame-count hidden)))
    (cider-stacktrace-indicate-filters filters)))

(defun cider-stacktrace-apply-cause-visibility ()
  "Apply `cider-stacktrace-cause-visibility' to causes and reapply filters."
  (with-current-buffer (get-buffer cider-error-buffer)
    (save-excursion
      (goto-char (point-min))
      (cl-flet ((next-detail (end)
                             (-when-let (pos (next-single-property-change (point) 'detail))
                               (when (< pos end)
                                 (goto-char pos)))))
        (let ((inhibit-read-only t))
          ;; For each cause...
          (while (cider-stacktrace-next-cause)
            (let* ((num   (get-text-property (point) 'cause))
                   (level (elt cider-stacktrace-cause-visibility num))
                   (cause-end (cadr (cider-property-bounds 'cause))))
              ;; For each detail level within the cause, set visibility.
              (while (next-detail cause-end)
                (let* ((detail (get-text-property (point) 'detail))
                       (detail-end (cadr (cider-property-bounds 'detail)))
                       (hide (if (> detail level) t nil)))
                  (add-text-properties (point) detail-end
                                       (list 'invisible hide
                                             'collapsed hide))))))))
      (cider-stacktrace-apply-filters
       cider-stacktrace-filters))))


;; Interactive functions

(defun cider-stacktrace-previous-cause ()
  "Move point to the previous exception cause, if one exists."
  (interactive)
  (with-current-buffer (get-buffer cider-error-buffer)
    (-when-let (pos (previous-single-property-change (point) 'cause))
      (goto-char pos))))

(defun cider-stacktrace-next-cause ()
  "Move point to the next exception cause, if one exists."
  (interactive)
  (with-current-buffer (get-buffer cider-error-buffer)
    (-when-let (pos (next-single-property-change (point) 'cause))
      (goto-char pos))))


(defun cider-stacktrace-cycle-cause (num &optional level)
  "Update element NUM of `cider-stacktrace-cause-visibility', optionally to LEVEL.
If LEVEL is not specified, its current value is incremented. When it reaches 3,
it wraps to 0."
  (let ((level (or level (1+ (elt cider-stacktrace-cause-visibility num)))))
    (aset cider-stacktrace-cause-visibility num (mod level 3))
    (cider-stacktrace-apply-cause-visibility)))

(defun cider-stacktrace-cycle-all-causes ()
  "Cycle the visibility of all exception causes."
  (interactive)
  (with-current-buffer (get-buffer cider-error-buffer)
    (save-excursion
      ;; Find nearest cause.
      (unless (get-text-property (point) 'cause)
        (cider-stacktrace-next-cause)
        (unless (get-text-property (point) 'cause)
          (cider-stacktrace-previous-cause)))
      ;; Cycle its level, and apply that to all causes.
      (let* ((num (get-text-property (point) 'cause))
             (level (1+ (elt cider-stacktrace-cause-visibility num))))
        (setq-local cider-stacktrace-cause-visibility
                    (apply 'vector (-repeat 10 (mod level 3))))
        (cider-stacktrace-apply-cause-visibility)))))

(defun cider-stacktrace-cycle-current-cause ()
  "Cycle the visibility of current exception at point, if any."
  (interactive)
  (with-current-buffer (get-buffer cider-error-buffer)
    (-when-let (num (get-text-property (point) 'cause))
      (cider-stacktrace-cycle-cause num))))

(defun cider-stacktrace-cycle-cause-1 ()
  "Cycle the visibility of exception cause #1."
  (interactive)
  (cider-stacktrace-cycle-cause 1))

(defun cider-stacktrace-cycle-cause-2 ()
  "Cycle the visibility of exception cause #2."
  (interactive)
  (cider-stacktrace-cycle-cause 2))

(defun cider-stacktrace-cycle-cause-3 ()
  "Cycle the visibility of exception cause #3."
  (interactive)
  (cider-stacktrace-cycle-cause 3))

(defun cider-stacktrace-cycle-cause-4 ()
  "Cycle the visibility of exception cause #4."
  (interactive)
  (cider-stacktrace-cycle-cause 4))

(defun cider-stacktrace-cycle-cause-5 ()
  "Cycle the visibility of exception cause #5."
  (interactive)
  (cider-stacktrace-cycle-cause 5))


(defun cider-stacktrace-toggle-all ()
  "Reset `cider-stacktrace-filters' if present; otherwise restore prior filters."
  (interactive)
  (when cider-stacktrace-filters
    (setq-local cider-stacktrace-prior-filters
                cider-stacktrace-filters))
  (cider-stacktrace-apply-filters
   (setq cider-stacktrace-filters
         (unless cider-stacktrace-filters      ; when current filters are nil,
           cider-stacktrace-prior-filters))))  ;  reenable prior filter set

(defun cider-stacktrace-toggle (flag)
  "Update `cider-stacktrace-filters' to add or remove FLAG, and apply filters."
  (cider-stacktrace-apply-filters
   (setq cider-stacktrace-filters
         (if (memq flag cider-stacktrace-filters)
             (remq flag cider-stacktrace-filters)
           (cons flag cider-stacktrace-filters)))))

(defun cider-stacktrace-toggle-java ()
  "Toggle display of Java stack frames."
  (interactive)
  (cider-stacktrace-toggle 'java))

(defun cider-stacktrace-toggle-clj ()
  "Toggle display of Clojure stack frames."
  (interactive)
  (cider-stacktrace-toggle 'clj))

(defun cider-stacktrace-toggle-repl ()
  "Toggle display of REPL stack frames."
  (interactive)
  (cider-stacktrace-toggle 'repl))

(defun cider-stacktrace-toggle-tooling ()
  "Toggle display of Tooling stack frames (compiler, nREPL middleware, etc)."
  (interactive)
  (cider-stacktrace-toggle 'tooling))

(defun cider-stacktrace-toggle-duplicates ()
  "Toggle display of stack frames that are duplicates of their descendents."
  (interactive)
  (cider-stacktrace-toggle 'dup))


;; Text button functions

(defun cider-stacktrace-filter (button)
  "Apply filter(s) indicated by the BUTTON."
  (with-temp-message "Filters may also be toggled with the keyboard."
    (let ((flag (button-get button 'filter)))
      (if flag
          (cider-stacktrace-toggle flag)
        (cider-stacktrace-toggle-all)))
    (sit-for 5)))

(defun cider-stacktrace-navigate (button)
  "Navigate to the stack frame source represented by the BUTTON."
  (let ((var (button-get button 'var))
        (class (button-get button 'class))
        (method (button-get button 'method))
        (line (button-get button 'line)))
    (-if-let* ((info (if var
                         (cider-var-info var)
                       (cider-member-info class method)))
               (file (cadr (assoc "file" info)))
               (buffer (cider-find-file file)))
        (cider-jump-to buffer line)
      (message "No source info"))))

(defun cider-stacktrace-jump ()
  "Like `cider-jump', but uses the stack frame source at point, if available."
  (interactive)
  (let ((button (button-at (point))))
    (if (and button (button-get button 'line))
        (cider-stacktrace-navigate button)
      (call-interactively 'cider-jump))))


;; Rendering

(defun cider-stacktrace-emit-indented (text indent &optional fill)
  "Insert TEXT, and INDENT and optionally FILL the entire block."
  (let ((beg (point)))
    (insert text)
    (goto-char beg)
    (while (not (eobp))
      (insert indent)
      (forward-line))
    (when (and fill cider-stacktrace-fill-column)
      (when (and (numberp cider-stacktrace-fill-column))
        (setq-local fill-column cider-stacktrace-fill-column))
      (setq-local fill-prefix indent)
      (fill-region beg (point)))))

(defun cider-stacktrace-render-filters (buffer filters)
  "Emit into BUFFER toggle buttons for each of the FILTERS."
  (with-current-buffer buffer
    (insert "  Show: ")
    (dolist (filter filters)
      (insert-text-button (first filter)
                          'filter (second filter)
                          'follow-link t
                          'action 'cider-stacktrace-filter
                          'help-echo (format "Toggle %s stack frames"
                                             (first filter)))
      (insert " "))
    (let ((hidden "(0 frames hidden)"))
      (put-text-property 0 (length hidden) 'hidden-count t hidden)
      (insert " " hidden))
    (newline)))

(defun cider-stacktrace-render-frame (buffer frame)
  "Emit into BUFFER function call site info for the stack FRAME.
This associates text properties to enable filtering and source navigation."
  (with-current-buffer buffer
    (nrepl-dbind-response frame (file line flags class method name var ns fn)
      (let ((flags (mapcar 'intern flags))) ; strings -> symbols
        (insert-text-button (format "%30s:%5d  %s/%s"
                                    (if (member 'repl flags) "REPL" file) line
                                    (if (member 'clj flags) ns class)
                                    (if (member 'clj flags) fn method))
                            'var var 'class class 'method method
                            'name name 'line line 'flags flags
                            'follow-link t
                            'action 'cider-stacktrace-navigate
                            'help-echo "View source at this location"
                            'face 'cider-stacktrace-face)
        (save-excursion
          (let ((p4 (point))
                (p1 (search-backward " "))
                (p2 (search-forward "/"))
                (p3 (search-forward-regexp "[^/$]+")))
            (put-text-property p1 p4 'face 'cider-stacktrace-ns-face)
            (put-text-property p2 p3 'face 'cider-stacktrace-fn-face)))
        (newline)))))

(defun cider-stacktrace-render-cause (buffer cause num note)
  "Emit into BUFFER the CAUSE NUM, exception class, message, data, and NOTE."
  (with-current-buffer buffer
    (nrepl-dbind-response cause (class message data stacktrace)
      (let ((indent "   ")
            (class-face 'cider-stacktrace-error-class-face)
            (message-face 'cider-stacktrace-error-message-face))
        (cider-propertize-region `(cause ,num)
          ;; Detail level 0: exception class
          (cider-propertize-region '(detail 0)
            (insert (format "%d. " num)
                    (propertize note 'face 'font-lock-comment-face) " "
                    (propertize class 'face class-face))
            (newline))
          ;; Detail level 1: message + ex-data
          (cider-propertize-region '(detail 1)
            (cider-stacktrace-emit-indented
             (propertize (or message "(No message)") 'face message-face) indent t)
            (newline)
            (when data
              (cider-stacktrace-emit-indented
               (cider-font-lock-as-clojure data) indent nil)))
          ;; Detail level 2: stacktrace
          (cider-propertize-region '(detail 2)
            (newline)
            (let ((beg (point))
                  (bg `(:background ,cider-stacktrace-frames-background-color)))
              (dolist (frame stacktrace)
                (cider-stacktrace-render-frame buffer frame))
              (overlay-put (make-overlay beg (point)) 'face bg)))
          ;; Add line break between causes, even when collapsed.
          (cider-propertize-region '(detail 0)
            (newline)))))))

(defun cider-stacktrace-initialize (causes)
  "Set and apply CAUSES initial visibility, filters, and cursor position."
  ;; Partially display outermost cause if it's a compiler exception (the
  ;; description reports reader location of the error).
  (nrepl-dbind-response (first causes) (class)
    (when (equal class "clojure.lang.Compiler$CompilerException")
      (cider-stacktrace-cycle-cause (length causes) 1)))
  ;; Fully display innermost cause. This also applies visibility/filters.
  (cider-stacktrace-cycle-cause 1 cider-stacktrace-detail-max)
  ;; Move point to first stacktrace frame in displayed cause.
  (goto-char (point-min))
  (while (cider-stacktrace-next-cause))
  (goto-char (next-single-property-change (point) 'flags)))

(defun cider-stacktrace-render (buffer causes)
  "Emit into BUFFER useful stacktrace information for the CAUSES."
  (with-current-buffer buffer
    (cider-stacktrace-mode)
    (let ((inhibit-read-only t))
      (newline)
      ;; Stacktrace filters
      (cider-stacktrace-render-filters
       buffer
       `(("Clojure" clj) ("Java" java) ("REPL" repl)
         ("Tooling" tooling) ("Duplicates" dup) ("All" ,nil)))
      (newline)
      ;; Stacktrace exceptions & frames
      (let ((num (length causes)))
        (dolist (cause causes)
          (let ((note (if (= num (length causes)) "Unhandled" "Caused by")))
            (cider-stacktrace-render-cause buffer cause num note)
            (setq num (1- num))))))
    (cider-stacktrace-initialize causes)
    (font-lock-refresh-defaults)))

(provide 'cider-stacktrace)

;;; cider-stacktrace.el ends here