;;; cmk.el --- CMK livestatus -*- lexical-binding: t; -*-
;;
;; Copyright (C) 2022 Óscar Nájera
;;
;; Author: Óscar Nájera <hi@oscarnajera.com>
;; Maintainer: Óscar Nájera <hi@oscarnajera.com>
;; Created: July 08, 2022
;; Modified: July 08, 2022
;; Version: 0.0.1
;; Keywords: abbrev bib c calendar comm convenience data docs emulations extensions faces files frames games hardware help hypermedia i18n internal languages lisp local maint mail matching mouse multimedia news outlines processes terminals tex tools unix vc wp
;; Homepage: https://github.com/titan/cmk
;; Package-Requires: ((emacs "29.1"))
;;
;; This file is not part of GNU Emacs.
;;
;;; Commentary:
;;
;;  CMK livestatus
;;
;;; Code:

(require 'cl-lib)
;; (require 'company)
(require 'map)
(require 'csv-mode)
(require 'dash)
(require 'subr-x)
(require 'vtable)

(defun cmk-state-coloring (state)
  "Font color for numeric STATE input as string."
  (pcase state
    (0 (propertize "OK" 'face 'font-lock-string-face))
    (1 (propertize "WARN" 'face 'font-lock-warning-face))
    (2 (propertize "CRIT" 'face 'font-lock-keyword-face))
    (3 (propertize "UNKN" 'face 'font-lock-builtin-face))
    (_ state)))

(defun cmk-timestamp-to-date (timestamp &optional fmt-str)
  "TIMESTAMP to human readable date follownig FMT-STR.
Default is  \"%Y-%m-%d %H:%M\"."
  (thread-last
    (if (stringp timestamp)
        (string-to-number timestamp)
      timestamp)
    (seconds-to-time)
    (format-time-string (or fmt-str "%Y-%m-%d %H:%M"))))

(defun cmk-purge-bangs (str)
  "Remove cmk status output bangs from STR."
  (replace-regexp-in-string (rx "(" (+ "!") ")") "" str))

(defun cmk-oneshot (&optional keep-buffer)
  "One shot socket connection. non-nil KEEP-BUFFER after socket closes."
  (make-network-process
   :name "Checkmk"
   :host 'local
   :service 6565
   :buffer "CMK"
   :sentinel (lambda (process event)
               (message "Process: %s had the event '%s'" process (string-trim event))
               (unless keep-buffer
                 (kill-buffer (process-buffer process))))))

(defun cmk-colums-from-spec (spec)
  "Extract the column names from SPEC and return a livestatus column command."
  (concat "Columns: "
          (mapconcat
           (lambda (column)
             (or (plist-get column :column)
                 (plist-get column :name)))
           spec
           " ")))

(defconst cmk-problem-col-spec
  `((:name "STATE"        :column "service_state" :formatter cmk-state-coloring :min-width 6)
    (:name "Host"         :column "host_name")
    (:name "Service"      :column "service_description")
    (:name "Since"        :column "service_last_state_change" :formatter cmk-timestamp-to-date :min-width 18)
    (:name "Check output" :column "service_plugin_output" :formatter cmk-purge-bangs)))

(defconst cmk-log-col-spec
  '(;("host_state" :column "host_state" :parser cmk-state-coloring)
    (:name "STATE" :min-width 5 :column "log_state" :formatter cmk-state-coloring)
    ;; ("lsttype" :column "log_state_type")
    (:name "Host" :column "host_name")
    (:name "Service" :column "service_description")
    (:name "log_time" :min-width 18 :column "log_time" :formatter cmk-timestamp-to-date)
    ;; ("log_command_name" :column "log_command_name")
    ;; ("log_comment" :column "log_comment")
    ;; ("lineno" :column "log_lineno")
    (:name "log_type" :column "log_type")
    ;; ("host_scheduled_downtime_depth" :column "host_scheduled_downtime_depth")
    ;; ("host_has_been_checked" :column "host_has_been_checked")
    (:name "log_plugin_output" :column "log_plugin_output")))

(defun cmk-livestatus-query (query)
  "One shot livestatus QUERY, return network process."
  (let ((cmks (cmk-oneshot 'keep)))
    (with-current-buffer (process-buffer cmks) (erase-buffer))
    (process-send-string cmks query)
    cmks))

(defvar-local cmk-livestatus-query ""
  "Livestatus query in buffer.")

(defun cmk-timestamp-eldoc-documentation ()
  (when-let ((number (thing-at-point 'number)))
    (format-time-string "%Y-%m-%d %H:%M" (seconds-to-time number))))

(defconst cmk-livestatus-headers
  '("Filter" "Columns" "Stats" "Limit" "ColumnHeaders" "OutputFormat"))

(define-derived-mode cmk-livestatus-mode prog-mode "livestatus"
  "Major mode for viewing journalctl output."
  (add-function :before-until (local 'eldoc-documentation-function)
                #'cmk-timestamp-eldoc-documentation)
  ;; (setq-local company-backends (cons 'company-cmk-lq company-backends))
  ;; (setq-local completion-at-point-functions '(cmk-lq-capf))
  (add-hook 'completion-at-point-functions 'cmk-lq-capf nil 'local)
  ;; code for syntax highlighting
  (setq font-lock-defaults `(((,(rx bol "GET" eow) . font-lock-keyword-face)
                              (,(rx word-start (or "hosts" "services")  word-end) . font-lock-constant-face)
                              (,(concat "^" (regexp-opt cmk-livestatus-headers 'words) ":[[:space:]]") . font-lock-function-name-face)
                              (,(rx bol (or "And" "Or" "Negate") ":" whitespace) . font-lock-keyword-face)
                              (,(rx whitespace (or "~" "=" "=~" "~~" "<" ">" "<=" ">=") whitespace) . font-lock-keyword-face)))))

(defun cmk-custom-livestatus-query ()
  (interactive)
  (let ((query cmk-livestatus-query)
        (edit-buffer (get-buffer-create "*LQ*")))
    (with-current-buffer edit-buffer
      (cmk-livestatus-mode)
      (if (string-blank-p query) (insert "GET ") (insert query))
      (local-set-key "\C-c\C-c"
                     (lambda ()
                       (interactive)
                       (let ((new-query (-> (buffer-string) (string-trim) (concat "\n\n"))))
                         (kill-buffer)
                         (let ((cmk (cmk-livestatus-query new-query)))
                           (switch-to-buffer (process-buffer cmk))
                           (csv-set-separator ?\;)
                           (csv-align-mode)
                           (setq-local cmk-livestatus-query new-query))))))
    (switch-to-buffer edit-buffer)))

(defun company-cmk-lq (command &optional arg &rest ignored)
  (interactive (list 'interactive))
  (cl-case command
    (interactive (company-begin-backend 'company-cmk-lq))
    (prefix (company-grab-word))
    (candidates (cl-loop for header in cmk-livestatus-headers
                         when (string-prefix-p arg header t) collect header))
    (meta (format "This value is named %s" arg))))

(defun cmk-lq-capf ()
  (when (looking-back (rx bol (+ alpha)) 1)
    (list (match-beginning 0)
          (match-end 0)
          (cl-loop for header in cmk-livestatus-headers
                   when (string-prefix-p (match-string-no-properties 0) header t)
                   collect (concat header ": ")))))

(defun cmk-edit-lq (buffer)
  "Open window to edit the livestatus query of current BUFFER."
  (interactive (list (current-buffer)))
  (let ((query cmk-livestatus-query)
        (edit-buffer (get-buffer-create "*LQ*")))
    (with-current-buffer edit-buffer
      (cmk-livestatus-mode)
      (insert query)
      (local-set-key "\C-c\C-c"
                     (lambda ()
                       (interactive)
                       (let ((new-query (-> (buffer-string) (string-trim) (concat "\n\n"))))
                         (kill-buffer)
                         (switch-to-buffer buffer)
                         (setq-local cmk-livestatus-query new-query)
                         (vtable-revert-command)))))
    (switch-to-buffer edit-buffer)))

(defun cmk-vtable (table spec filters)
  "Render a tabular view for livestatus TABLE with SPEC columns using FILTERS."
  (let ((livestatus-query
         (format "GET %s\n%s\n%s\n%s\n\n"
                 table
                 (cmk-colums-from-spec spec)
                 filters
                 "OutputFormat: json")))
    (make-vtable
     :columns (mapcar (lambda (li) (map-delete (map-copy li) :column)) spec)
     :use-header-line nil
     :objects-function
     (lambda ()
       (let ((cmks (cmk-livestatus-query livestatus-query)))
         (accept-process-output cmks 0.1)
         (with-current-buffer (process-buffer cmks)
           (goto-char (point-min))
           (json-parse-buffer :array-type 'list))))
     :keymap (define-keymap
               "Q" #'cmk-edit-lq
               "q" #'kill-buffer-and-window
               "v" (lambda ()
                     (interactive)
                     (message "loc %S" livestatus-query))))))

(defun cmk-problems ()
  "Render default problems view."
  (interactive)
  (with-current-buffer (get-buffer-create "*CMK View*")
    (fundamental-mode)
    (erase-buffer)
    (cmk-vtable "services" cmk-problem-col-spec
                "Filter: service_state = 0
Filter: service_has_been_checked = 1
And: 2
Negate:
Filter: service_has_been_checked = 1
Filter: service_scheduled_downtime_depth = 0
Filter: host_scheduled_downtime_depth = 0
And: 2
Filter: service_acknowledged = 0
Filter: host_state = 1
Filter: host_has_been_checked = 1
And: 2
Negate:
Filter: host_state = 2
Filter: host_has_been_checked = 1
And: 2
Negate:")
    (goto-char (point-max))
    (insert "\n")
    (cmk-vtable "log" cmk-log-col-spec
                (format
                 "Filter: log_time >= %d
Filter: class = 1
Filter: class = 3
Filter: class = 8
Or: 3
Filter: log_state_type = HARD"
                 (floor
                  (- (time-to-seconds (current-time))
                     (* 24 3600)))))
    (switch-to-buffer (current-buffer))))

;;; Get a different csv
;; (let* ((cmks (cmk-oneshot t)))
;;   (with-current-buffer (process-buffer cmks) (erase-buffer))
;;   (process-send-string cmks "GET services
;; Columns: service_description host_name service_perf_data
;; Filter: service_description ~ CPU utilization
;; OutputFormat: csv
;; Separators: 10 9 44 124\n\n")
;;   (accept-process-output cmks 0.1)
;;   (display-buffer (process-buffer cmks)))

;;; Get some metric data
;; (let* ((now (time-convert nil 'integer))
;;        (start (- now 7200))
;;        (cmks (cmk-oneshot t)))
;;   (with-current-buffer (process-buffer cmks) (erase-buffer))
;;   (process-send-string cmks (format "GET services
;; Columns: host_name rrddata:1:user:%d:%d:1
;; Filter: service_description ~ CPU utilization
;; OutputFormat: json\n\n" start now))
;;   (accept-process-output cmks 0.1)
;;   (with-current-buffer (process-buffer cmks)
;;     (goto-char (point-min))
;;     (display-buffer (current-buffer))
;;     (json-parse-buffer)))

(provide 'cmk)
;;; cmk.el ends here