;; SPDX-License-Identifier: EUPL-1.2
;; SPDX-FileCopyrightText: 2025 Uko Kokņevičs <perkontevs@gmail.com>
(defpackage :ukkoclot/bot/impl
  (:use :c2cl :iterate :ukkoclot/config :ukkoclot/log)
  (:import-from :anaphora :aand :acond :it)
  (:import-from :dex)
  (:import-from :ukkoclot/strings :lisp->snake-case)
  (:local-nicknames
   (:jzon :com.inuoe.jzon))
  (:export
   :arg-encode :bot :bot-p :make-bot :do-call

   :bot-config :bot-db :bot-base-uri :bot-power-on :bot-username% :bot-id%))
(in-package :ukkoclot/bot/impl)

(defgeneric will-arg-encode (object)
  (:documentation "Whether the OBJECT has any transformation done to it by arg-encode")
  (:method (obj)
    nil)
  (:method ((obj cons))
    (or (will-arg-encode (car obj))
        (will-arg-encode (cdr obj)))))

(defgeneric arg-encode (object)
  (:documentation "Encode the OBJECT to a form that our HTTP code is happy about.")
  (:method (obj)
    obj)
  (:method ((obj cons))
    (if (not (will-arg-encode obj))
        obj
        (cons (arg-encode (car obj))
              (arg-encode (cdr obj))))))

(defgeneric fixup-arg (value)
  (:documentation "Make sure Telegram & QURI & whatever like the arg")
  (:method (value)
    (error "Unsupported argument type ~S (~S)" (class-name (class-of value)) value))
  (:method ((value null))
    value)
  (:method ((value number))
    value)
  (:method ((value string))
    value)
  (:method ((value hash-table))
    (jzon:stringify value)))

(defstruct (bot (:constructor make-bot%))
  (config (error "No value given for config") :read-only t)
  (db (error "No value given for DB") :read-only t)
  (base-uri (error "No value given for base-uri") :read-only t)
  (power-on t :type boolean)
  (username% nil :type (or string null))
  (id% nil :type (or integer null)))

(defun make-bot (config db)
  (let ((base-uri (concatenate 'string
                               "https://api.telegram.org/bot"
                               (config-bot-token config) "/")))
    (make-bot% :config config :db db :base-uri base-uri)))

(defun args-plist->alist (args-plist)
  (iter (for (old-key value) on args-plist by #'cddr)
    (collect
        (let ((new-key (string-downcase (lisp->snake-case (symbol-name old-key)))))
          (cons new-key value)))))

(defun fixup-args (args-alist)
  (iter (for (name . value) in args-alist)
    (collecting (cons name (fixup-arg (arg-encode value))))))

(defun req (uri method content)
  ;; We deal with this manually
  (handler-bind ((dex:http-request-too-many-requests #'dex:ignore-and-continue))
    (dex:request uri :method method :content content)))

(defun do-call% (bot method uri mapfn args-encoded)
  (let ((body (req uri method args-encoded)))
    (let ((hash (jzon:parse body)))
      (acond
        ((gethash "ok" hash) (funcall mapfn (gethash "result" hash)))
        ((aand (gethash "parameters" hash)
               (gethash "retry_after" it))
         (log-info "Should sleep for ~A seconds" it)
         (sleep it)
         (log-info "Good morning!")
         (do-call% bot method uri mapfn args-encoded))
        (t (error "TG error ~A: ~A ~:A"
                  (gethash "error_code" hash)
                  (gethash "description" hash)
                  (gethash "parameters" hash)))))))

(defun do-call (bot method path mapfn args-plist)
  (let ((uri (concatenate 'string (bot-base-uri bot) path))
        (args-encoded (fixup-args (args-plist->alist args-plist))))
    (log-debug "~A .../~A ~S" method path args-encoded)
    (do-call% bot method uri mapfn args-encoded)))