;;; coqdev.el --- Emacs helpers for Rocq development  -*- lexical-binding:t -*-

;; Copyright (C) 2018 The Rocq Development Team

;; Maintainer: coqdev@inria.fr

;;; Commentary:

;; Helpers to set compilation commands, proof general variables, etc
;; for Rocq development

;; You can disable individual features without editing this file by
;; using `remove-hook', for instance
;; (remove-hook 'hack-local-variables-hook #'coqdev-setup-compile-command)

;;; Installation:

;; To use this, with coqdev.el located at /path/to/coqdev.el, add the
;; following to your init:

;; (add-to-list 'load-path "/path/to/coqdev/")
;; (require 'coqdev)

;; If you load this file from a git repository, checking out an old
;; commit will make it disappear and cause errors for your Emacs
;; startup.  To ignore those errors use (require 'coqdev nil t).  If you
;; check out a malicious commit Emacs startup would allow it to run
;; arbitrary code, to avoid this you can copy coqdev.el to any
;; location and adjust the load path accordingly (of course if you run
;; ./configure to compile Rocq it is already too late).

;;; Code:
(require 'ocamldebug nil 'noerror)

(require 'seq)
(require 'subr-x)

;; locate-dominating-file would call tramp handlers which call
;; hack-local-variables-hook which call this recursively
;; a proper fix would use some hook other than hack-local-variables
;; for now just return nil for remote files
(defun coqdev-default-directory ()
  "Return the Rocq repository containing `default-directory'."
  (unless (file-remote-p default-directory)
    (let ((dir (seq-some
                (lambda (f) (locate-dominating-file default-directory f))
                '("META.coq" "META.coq.in" "META.coq-core.in" "coqpp"))))
      (when dir (expand-file-name dir)))))

(defun coqdev-setup-compile-command ()
  "Setup `compile-command' for Rocq development."
  (let ((dir (coqdev-default-directory)))
    (when dir (setq-local compile-command (concat "cd " (shell-quote-argument dir) "
dune build @check # rocq-runtime.install")))))
(add-hook 'hack-local-variables-hook #'coqdev-setup-compile-command)

(defvar camldebug-command-name) ; from camldebug.el (caml package)
(defvar ocamldebug-command-name) ; from ocamldebug.el (tuareg package)
(defun coqdev-setup-camldebug ()
  "Setup ocamldebug for Rocq development.

Specifically `camldebug-command-name' and `ocamldebug-command-name'."
  (let ((dir (coqdev-default-directory)))
    (when dir
      (setq-local camldebug-command-name
                  (concat dir "dev/ocamldebug-coq"))
      (setq-local ocamldebug-command-name
                  (concat dir "dev/ocamldebug-coq")))))
(add-hook 'hack-local-variables-hook #'coqdev-setup-camldebug)

(defun coqdev-setup-tags ()
  "Setup `tags-file-name' for Rocq development."
  (let ((dir (coqdev-default-directory)))
    (when dir (setq-local tags-file-name (concat dir "TAGS")))))
(add-hook 'hack-local-variables-hook #'coqdev-setup-tags)

(defvar coq-prog-args)
(defvar coq-prog-name)

;; Lets us detect whether there are file local variables
;; even though PG sets it with `setq' when there's a _Coqproject.
;; Also makes sense generally, so might make it into PG someday.
(make-variable-buffer-local 'coq-prog-args)
(setq-default coq-prog-args nil)

(defun coqdev-setup-proofgeneral ()
  "Setup Proofgeneral variables for Rocq development.

Note that this function is executed before _Coqproject is read if it exists."
  (let ((dir (coqdev-default-directory)))
    (when dir
      (setq-local coq-prog-name (concat dir "_build/install/default/bin/coqtop")))))
(add-hook 'hack-local-variables-hook #'coqdev-setup-proofgeneral)

(defvar coqdev-ocamldebug-command "dune exec -- dev/dune-dbg -emacs coqc /tmp/foo.v"
  "Command run by `coqdev-ocamldebug'")

(declare-function comint-check-proc "comint")
(declare-function tuareg--split-args "tuareg")
(declare-function ocamldebug-filter "ocamldebug")
(declare-function ocamldebug-sentinel "ocamldebug")
(declare-function ocamldebug-mode "ocamldebug")
(declare-function ocamldebug-set-buffer "ocamldebug")
(defun coqdev-ocamldebug ()
  "Runs a command in an ocamldebug buffer."
  (interactive)
  (require 'ocamldebug)
  (let* ((dir (read-directory-name "Run from directory: "
                                   (coqdev-default-directory)))
         (name "ocamldebug-coq")
         (buffer-name (concat "*" name "*")))
    (pop-to-buffer buffer-name)
    (unless (comint-check-proc buffer-name)
      (setq default-directory dir)
      (setq coqdev-ocamldebug-command
            (read-from-minibuffer "Command to run: "
                                  coqdev-ocamldebug-command))
      (let* ((cmdlist (tuareg--split-args coqdev-ocamldebug-command))
             (cmdlist (mapcar #'substitute-in-file-name cmdlist)))
        (apply #'make-comint name
               (car cmdlist)
               nil
               (cdr cmdlist))
        (set-process-filter (get-buffer-process (current-buffer))
                            #'ocamldebug-filter)
        (set-process-sentinel (get-buffer-process (current-buffer))
                              #'ocamldebug-sentinel)
        (ocamldebug-mode)))
    (ocamldebug-set-buffer)
    (insert "source db")))

;; Provide correct breakpoint setting in dune wrapped libraries
;; (assuming only 1 library/dune file)
(defun coqdev--read-from-file (file)
  "Read FILE as a list of sexps. If invalid syntax, return nil and message the error."
  (with-temp-buffer
    (save-excursion
      (insert "(\n")
      (insert-file-contents file)
      (goto-char (point-max))
      (insert "\n)\n"))
    (condition-case err
        (read (current-buffer))
      ((error err) (progn (message "Error reading file %S: %S" file err) nil)))))

(defun coqdev--find-single-library (sexps)
  "If list SEXPS has an element whose `car' is \"library\", return the first one.
Otherwise return `nil'."
  (let ((libs (seq-filter (lambda (elt) (equal (car elt) 'library)) sexps)))
    (and libs (car libs))))

(defun coqdev--dune-library-name (lib)
  "With LIB a dune-syntax library stanza, get its name as a string."
  (let ((field (or (seq-find (lambda (field) (and (consp field) (equal (car field) 'name))) lib)
                   (seq-find (lambda (field) (and (consp field) (equal (car field) 'public\_name))) lib))))
    (symbol-name (car (cdr field)))))

(defun coqdev--upcase-first-char (arg)
  "Set the first character of ARG to uppercase."
  (concat (upcase (substring arg 0 1)) (substring arg 1 (length arg))))

(defun coqdev--real-module-name (filename)
  "Return module name for ocamldebug, taking into account dune wrapping.
(for now only understands dune files with a single library stanza)"
  (let ((mod (substring filename (string-match "\\([^/]*\\)\\.ml$" filename) (match-end 1)))
        (dune (concat (file-name-directory filename) "dune")))
    (if (file-exists-p dune)
        (if-let* ((contents (coqdev--read-from-file dune))
                  (lib (coqdev--find-single-library contents))
                  (is-wrapped (null (seq-contains-p lib '(wrapped false))))
                  (libname (coqdev--dune-library-name lib)))
            (concat libname "__" (coqdev--upcase-first-char mod))
          mod)
      mod)))

(with-eval-after-load 'ocamldebug
  (defun ocamldebug-module-name (arg)
    (coqdev--real-module-name arg)))

;; This Elisp snippet adds a regexp parser for the format of Anomaly
;; backtraces (coqc -bt ...), to the error parser of the Compilation
;; mode (C-c C-c: "Compile command: ..."). File locations in traces
;; are recognized and can be jumped from easily in the *compilation*
;; buffer.
(defvar compilation-error-regexp-alist-alist)
(defvar compilation-error-regexp-alist)
(with-eval-after-load 'compile
  (add-to-list
   'compilation-error-regexp-alist-alist
   '(coq-backtrace
     "^ *\\(?:raise\\|frame\\) @ file \\(\"?\\)\\([^,\" \n\t<>]+\\)\\1,\
      lines? \\([0-9]+\\)-?\\([0-9]+\\)?\\(?:$\\|,\
      \\(?: characters? \\([0-9]+\\)-?\\([0-9]+\\)?:?\\)?\\)"
     2 (3 . 4) (5 . 6)))
  (add-to-list 'compilation-error-regexp-alist 'coq-backtrace))

(defvar bug-reference-bug-regexp)
(defvar bug-reference-url-format)
(defun coqdev-setup-bug-reference-mode ()
  "Setup `bug-reference-bug-regexp' and `bug-reference-url-format' for Rocq.

This does not enable `bug-reference-mode'."
  (let ((dir (coqdev-default-directory)))
    (when dir
      (setq-local bug-reference-bug-regexp "\\(#\\(?2:[0-9]+\\)\\)")
      (setq-local bug-reference-url-format "https://github.com/rocq-prover/rocq/issues/%s")
      (when (derived-mode-p 'prog-mode) (bug-reference-prog-mode 1)))))
(add-hook 'hack-local-variables-hook #'coqdev-setup-bug-reference-mode)

(defun coqdev-sphinx-quote-coq-refman-region (left right &optional offset beg end)
  "Add LEFT and RIGHT around the BEG..END.
Leave the point after RIGHT.  BEG and END default to the bounds
of the current region.  Leave point OFFSET characters after the
left quote (if OFFSET is nil, leave the point after the right
quote)."
  (unless beg
    (if (region-active-p)
        (setq beg (region-beginning) end (region-end))
      (setq beg (point) end nil)))
  (save-excursion
    (goto-char (or end beg))
    (insert right))
  (save-excursion
    (goto-char beg)
    (insert left))
  (if (and end (not offset)) ;; Second test handles the ::`` case
      (goto-char (+ end (length left) (length right)))
    (goto-char (+ beg (or offset (length left))))))

(defun coqdev-sphinx-rst-coq-action ()
  "Insert a Sphinx role template or quote the current region."
  (interactive)
  (pcase (read-char "Command [gntm:`]?")
    (?g (coqdev-sphinx-quote-coq-refman-region ":g:`" "`"))
    (?n (coqdev-sphinx-quote-coq-refman-region ":n:`" "`"))
    (?t (coqdev-sphinx-quote-coq-refman-region ":token:`" "`"))
    (?m (coqdev-sphinx-quote-coq-refman-region ":math:`" "`"))
    (?: (coqdev-sphinx-quote-coq-refman-region "::`" "`" 1))
    (?` (coqdev-sphinx-quote-coq-refman-region "``" "``"))))

(provide 'coqdev)
;;; coqdev ends here
