(setq python-fill-docstring-style 'pep-257-nn)

(setq python-shell-interpreter "ipython"
      python-shell-prompt-detect-enabled nil)

(add-to-list 'interpreter-mode-alist '("python2" . python-mode))
(add-to-list 'interpreter-mode-alist '("python3" . python-mode))

(add-hook 'python-mode-hook 'km/python-set-local-vars)
(add-hook 'python-mode-hook
          (lambda ()
            (add-hook
             'post-self-insert-hook
             #'km/python-indent-post-self-insert-function 'append 'local)))

(defun km/python-set-local-vars ()
  (setq outline-regexp "####* ")
  (setq outline-level 'km/python-outline-level)
  ;; Stop semantic from taking over imenu.
  (setq imenu-create-index-function #'python-imenu-create-index)
  (set (make-local-variable 'compile-command) "py.test"))

(defun km/python-outline-level ()
  (and (looking-at (concat "^" outline-regexp))
       (- (match-end 0) (match-beginning 0) 3)))

(defun km/toggle-ipython-shell ()
  "Switch between using python and IPython for interactive shell."
  (interactive)
  (setq python-shell-interpreter
        (if (string= python-shell-interpreter "python") "ipython" "python")))

(defun km/find-python-test-file-other-window (arg)
  "Open test file for the current Python file in another window.
If the file does not already exist, import the original Python
file. Unless ARG is non-nil, py.test is also imported."
  (interactive "P")
  (let* ((py-file (file-name-nondirectory buffer-file-name))
         (test-file (concat "test_" py-file)))
    (find-file-other-window test-file)
    (unless (file-exists-p test-file)
      (insert (format "import %s\n" (file-name-sans-extension py-file)))
      (unless arg
        (insert "import pytest\n")))))

(defun km/python-shell-send-function-or-paragraph-and-step ()
  "Send function or paragraph to Python shell.

Send function if point is inside one. Otherwise, send the current
paragraph. After evaluation, step to the next code line.

This is inspired by `ess-eval-function-or-paragraph-and-step'."
  (interactive)
  (if (km/python-inside-defun-p)
      (progn
        (python-shell-send-defun 1)
        (python-nav-end-of-defun))
    (let (end)
      (save-excursion
        (forward-paragraph)
        (setq end (point))
        (backward-paragraph)
        (python-shell-send-region (point) end))
      (goto-char end)))
  (km/python-next-code-line 1))

(defun km/python-shell-send-buffer-up-to-line ()
  "Send beginning of buffer to the current line to Python shell."
  (interactive)
  (python-shell-send-region (point-min) (line-end-position)))

(defun km/python-inside-defun-p ()
  ;; I don't use `python-nav-beginning-of-defun' because it will go to
  ;; the function even when the point is not inside of it.
  (when (python-info-current-defun)
    t))

(defun km/python-next-code-line (&optional arg skip-to-eob)
  "This is copied nearly exactly from `ess-next-code-line'."
  (interactive "p")
  (or arg (setq arg 1))
  (beginning-of-line)
  (let ((pos (point))
        (n 0)
        (inc (if (> arg 0) 1 -1)))
    (while (and (/= arg 0) (= n 0))
      (setq n (forward-line inc)); n=0 is success
      (if (not (fboundp 'comment-beginning))
          (while (and (= n 0)
                      (looking-at "\\s-*\\($\\|\\s<\\)"))
            (setq n (forward-line inc)))
        (comment-beginning)
        (beginning-of-line)
        (forward-comment (* inc (buffer-size))) ;; as suggested in info file
        )
      (if (or skip-to-eob
              (not (looking-at "[ \t\n]*\\'"))) ;; don't go to eob or whatever
          (setq arg (- arg inc))
        (goto-char pos)
        (setq arg 0)
        (forward-line 1));; stop at next empty line
      (setq pos (point)))
    (goto-char pos)
    n))

(defvar km/python-shell-current-string nil)
(defun km/python-shell-send-set-string (set)
  "Send previously set string to Python shell.
If a string has not been set previously or SET is non-nil, prompt
for a new string."
  (interactive "P")
  (when (or set (not km/python-shell-current-string))
      (let ((initial (and (use-region-p)
                          (buffer-substring-no-properties
                           (region-beginning) (region-end)))))
        (setq km/python-shell-current-string (read-string "Python command: " initial))))
  (python-shell-send-string km/python-shell-current-string))

(defun km/python-indent-post-self-insert-function ()
  "Adjust indentation after insert of specfic characters.
This is taken from `python-indent-post-self-insert-function'.
Unlike that function, it does not rely on `electric-indent-mode'
being turned on."
  (when (and (not (bolp))
             (let ((paren-start (python-syntax-context 'paren)))
               ;; Check that point is inside parens.
               (when paren-start
                 (not
                  ;; Filter the case where input is happening in the same
                  ;; line where the open paren is.
                  (= (line-number-at-pos)
                     (line-number-at-pos paren-start)))))
             ;; When content has been added before the closing paren or a
             ;; comma has been inserted, it's ok to do the trick.
             (or
              (memq (char-after) '(?\) ?\] ?\}))
              (eq (char-before) ?,)))
    (save-excursion
      (goto-char (line-beginning-position))
      (let ((indentation (python-indent-calculate-indentation)))
        (when (< (current-indentation) indentation)
          (indent-line-to indentation))))))

(after 'python
  (define-key python-mode-map (kbd "C-c C-.")
    'km/python-shell-send-buffer-up-to-line)
  (define-key python-mode-map (kbd "C-c C-b") 'python-shell-send-buffer)
  ;; Rebind `python-shell-send-buffer'.
  (define-key python-mode-map (kbd "C-c C-c")
    'km/python-shell-send-function-or-paragraph-and-step)

  (define-key python-mode-map (kbd "C-c C-d") 'km/python-shell-send-set-string)

  ;; Swap `python-shell-send-defun' and `python-eldoc-at-point'.
  (define-key python-mode-map (kbd "C-c C-f") 'python-shell-send-defun)
  (define-key python-mode-map (kbd "C-M-x") 'python-eldoc-at-point)

  (define-prefix-command 'km/python-prefix-map)
  (define-key python-mode-map (kbd "C-c m") 'km/python-prefix-map)

  (define-key km/python-prefix-map "t" 'km/find-python-test-file-other-window))

(provide 'init-python)