;; -*- lexical-binding: t; -*-

;; Configuration as code!
(use-package terraform-mode
  :mode "\\.tf\\'"
  :config
  (defun devdocs-terraform-resource-string (resource type)
    "Returns the devdocs for Terraform resource RESOURCE of type TYPE (\"data\" or \"resource\")as a string."
    (devdocs-as-string resource "terraform" type))

  (with-eval-after-load 'devdocs
    (add-to-list 'devdocs-entry-aliases '("aws_alb" . "aws_lb")))

  (defun terraform-block-metadata-at-pos (pos)
    (let* ((parser (treesit-parser-create 'hcl))
           (current-node (treesit-node-at pos parser))
           (block (treesit-node-top-level current-node "block"))
           (capture (when block
                      (treesit-query-capture block
                                             '((block (identifier) @type (:match "^\\(data\\|resource\\)$" @type)
                                                (string_lit (_) (template_literal) @name (_)))))))
           (capture (let ((-compare-fn (lambda (a b) (eq (car a) (car b)))))
                      (-distinct capture))))
      (-map (lambda (r) (cons (car r) (treesit-node-text (cdr r) t))) capture)))

  (defun terraform-block-metadata-at-point ()
    (terraform-block-metadata-at-pos (point)))

  (defun terraform-devdocs-eldoc-function (cb)
    (when-let* ((metadata (terraform-block-metadata-at-point))
                (resource-name (alist-get 'name metadata))
                (resource-type (alist-get 'type metadata))
                (doc (devdocs-terraform-resource-string resource-name resource-type))
                (summary (with-temp-buffer
                           (insert doc)
                           (goto-char (point-min))
                           (forward-line)
                           (while (and (looking-at (rx space) t) (not (eobp)))
                             (forward-line))
                           (buffer-substring-no-properties (line-beginning-position) (line-end-position)))))
      (funcall cb doc :echo summary)))

  (defun terraform-setup-eldoc ()
    (add-hook 'eldoc-documentation-functions #'terraform-devdocs-eldoc-function nil t))

  (add-hook 'terraform-mode-hook #'terraform-setup-eldoc)

  (defun find-terraform-root ()
    "Returns the highest-level parent directory containing a .tf file."
    (let ((current-dir default-directory)
          (root nil))
      (while (and (not (string-match locate-dominating-stop-dir-regexp current-dir))
                  (f-glob "*.tf" current-dir))
        (setq root current-dir)
        (setq current-dir (f-parent current-dir)))
      (when root (file-name-as-directory root))))

  ;; Use root terraform module to resolve providers
  (defun terraform-provider-ns-advice (oldfn &rest args)
    (let ((dir (or (find-terraform-root) default-directory)))
      (let ((default-directory dir))
        (apply oldfn args))))

  (advice-add 'terraform--get-resource-provider-namespace :around #'terraform-provider-ns-advice))

(provide 'init-terraform)