(defvar haskell-packages
  '(
    flycheck
    flycheck-haskell
    ghc
    haskell-mode
    ghci-completion
    ))

;; Only load company-ghc if company-mode is enabled
(when (member 'company-mode dotspacemacs-configuration-layers)
  (add-to-list 'haskell-packages 'company-ghc))

(defun haskell/init-flycheck ()
  ;;(add-hook 'haskell-mode-hook 'flycheck-mode))
  (add-hook 'flycheck-mode-hook 'flycheck-haskell-setup))

(defun haskell/init-haskell-mode ()
  (require 'haskell-yas)
  (use-package haskell-mode
    :defer t
    :config
    (progn
      ;; Customization
      (custom-set-variables
       ;; Use cabal-repl for the GHCi session. Ensures our dependencies are in scope.
       ;; cabal-dev is deprecated
       '(haskell-process-type 'cabal-repl)

       ;; Use notify.el (if you have it installed) at the end of running
       ;; Cabal commands or generally things worth notifying.
       '(haskell-notify-p t)

       ;; To enable tags generation on save.
       '(haskell-tags-on-save t)

       ;; Remove annoying error popups
       '(haskell-interactive-popup-error nil)

       ;; Better import handling
       '(haskell-process-suggest-remove-import-lines t)
       '(haskell-process-auto-import-loaded-modules t)

       ;; Disable haskell-stylish on save, it breaks flycheck highlighting
       '(haskell-stylish-on-save nil))

      ;; Make sure company-ghc is properly initialized
      (autoload 'ghc-init "ghc" nil t)
      (autoload 'ghc-debug "ghc" nil t)

      (add-hook 'haskell-mode-hook 'haskell-hook)
      (add-hook 'haskell-cabal-mode-hook 'haskell-cabal-hook)

      ;; Make "RET" behaviour in REPL saner
      (evil-define-key 'insert haskell-interactive-mode-map (kbd "RET") 'haskell-interactive-mode-return)
      (evil-define-key 'normal haskell-interactive-mode-map (kbd "RET") 'haskell-interactive-mode-return)

      ;;;;;;;;; Keybindings ;;;;;;;;;;

      ;; ;; use "mc" as prefix for cabal commands
      ;; (setq spacemacs/key-binding-prefixes '(("mc" . "cabal")))

      ;; ;; use "ms" as prefix for REPL commands
      ;; (setq spacemacs/key-binding-prefixes '(("ms" . "Haskell REPL")))

      ;; ;; use "md" as prefix for debug commands
      ;; (setq spacemacs/key-binding-prefixes '(("md" . "Haskell Debug")))

      ;; ;; use "mh" as prefix for documentation commands
      ;; (setq spacemacs/key-binding-prefixes '(("mh" . "Haskell Documentation")))

      
      (evil-leader/set-key-for-mode 'haskell-mode
        "mt"   'haskell-process-do-type
        "mi"   'haskell-process-do-info
        "mu"   'haskell-mode-find-uses
        "mg"   'haskell-mode-jump-to-def-or-tag
        "mf"   'haskell-mode-stylish-buffer

        "msb"  'haskell-process-load-or-reload
        "msc"  'haskell-interactive-mode-clear
        "mss"  'haskell-interactive-bring
        "msS"  'haskell-interactive-switch

        "mca"  'haskell-process-cabal
        "mcb"  'haskell-process-cabal-build
        "mcc"  'haskell-compile
        "mcv"  'haskell-cabal-visit-file

        "mhh"  'hoogle
        "mhy"  'hayoo
        "mhd"  'inferior-haskell-find-haddock

        "mdd"  'haskell-debug
        "mdb"  'haskell-debug/break-on-function
        "mdn"  'haskell-debug/next
        "mdN"  'haskell-debug/previous
        "mdB"  'haskell-debug/delete
        "mdc"  'haskell-debug/continue
        "mda"  'haskell-debug/abandon
        "mdr"  'haskell-debug/refresh
        )
      ;; Switch back to editor from REPL
      (evil-leader/set-key-for-mode 'interactive-haskell-mode
        "msS"  'haskell-interactive-switch
        )

      ;; Compile
      (evil-leader/set-key-for-mode 'haskell-cabal
        "mC"  'haskell-compile
        )

      ;; Cabal-file bindings
      (evil-leader/set-key-for-mode 'haskell-cabal-mode
        "md" 'haskell-cabal-add-dependency
        "mb" 'haskell-cabal-goto-benchmark-section
        "me" 'haskell-cabal-goto-executable-section
        "mt" 'haskell-cabal-goto-test-suite-section
        "mm" 'haskell-cabal-goto-exposed-modules
        "ml" 'haskell-cabal-goto-library-section
        "mn" 'haskell-cabal-next-subsection
        "mp" 'haskell-cabal-previous-subsection
        "mN" 'haskell-cabal-next-section
        "mP" 'haskell-cabal-previous-section
        "mf" 'haskell-cabal-find-or-create-source-file
        ;; "m="  'haskell-cabal-subsection-arrange-lines ;; Does a bad job, 'gg=G' works better
        )

      ;; Haskell main editing mode key bindings.
      (defun haskell-hook ()
        (lambda () (ghc-init))
        ;; Use advanced indention
        (turn-on-haskell-indentation)

        ;; Indent the below lines on columns after the current column.
        ;; Might need better bindings for spacemacs and OS X
        (define-key haskell-mode-map (kbd "C-<right>")
          (lambda ()
            (interactive)
            (haskell-move-nested 1)))
        ;; Same as above but backwards.
        (define-key haskell-mode-map (kbd "C-<left>")
          (lambda ()
            (interactive)
            (haskell-move-nested -1))))

      ;; Useful to have these keybindings for .cabal files, too.
      (defun haskell-cabal-hook ()
        (define-key haskell-cabal-mode-map [?\C-c ?\C-z] 'haskell-interactive-switch)))))

(defun haskell/init-company-ghc ()
  (use-package ghc
    :init 
    (add-to-list 'company-backends 'company-ghc)
    (ghc-comp-init)
    ))