(ns advent.actions
  (:require [play-clj.core :refer :all]
            [play-clj.ui :refer :all]
            [play-clj.utils :refer :all]
            [play-clj.g2d :refer :all]
            [clojure.pprint]
            [clojure.string :as s]
            [advent.pathfind]
            [advent.actions :as actions]
            [advent.screens.dialogue :as dialogue]
            [clojure.core.async :refer [put! <! <!! >! >!! chan go thread take! alts!!]])
  (:import [com.badlogic.gdx.graphics Pixmap Pixmap$Filter Texture Texture$TextureFilter]
           [com.badlogic.gdx.graphics.g2d TextureRegion]))

(defprotocol IAction
  (begin [this screen entities])
  (done? [this screen entities])
  (continue [this screen entities])
  (terminate [this screen entities])
  (get-channel [this]))

(defmacro get-script [entities & forms]
  `(fn [starting-entities#]
     (let [~entities (atom starting-entities#)]
       (thread ~@forms))))


(defn jump-to [screen entities entity [x y]]
  (let [scale-fn (-> entities :background :scale-fn)
        entity (assoc entity :x x
                      :y y
                      :baseline (- 240 y))]
    (if (:scaled entity)
      (assoc entity :scale-x (scale-fn y) :scale-y (scale-fn y))
      entity)))

(defn stop [screen entities target-id]
  (update-in entities [:background :entities target-id] #(merge %
                                                                {:anim nil}
                                                                (when (:anim %)
                                                                  (texture (animation! (:anim %) :get-key-frame 0.25))))))


(defn dist [x1 y1 x2 y2]
  (let [dx (- x1 x2)
        dy (- y1 y2)]
    (Math/sqrt (+ (* dx dx) (* dy dy)))))

(defmacro run-action [entities & forms]
  `(let [c# (chan)]
     (do
       (put! (get-in (deref ~entities) [:actions :channel])
             (reify IAction
               (get-channel [_] c#)
               ~@forms))
       (reset! ~entities (<!! c#)))))

(defn walk-to [entities target-id [final-x final-y]]
  (let [{start-x :x start-y :y} (get-in @entities [:background :entities target-id])
        final-x (int final-x)
        final-y (int final-y)
        path (vec (take-nth 5 (advent.pathfind/visit-all
                               (:collision (:background @entities))
                               [(int start-x) (int start-y)]
                               [final-x final-y])))
        path (if (seq path)
               (conj path [final-x final-y])
               [])
        targets-left (atom path)]
    (if (seq path)
      (run-action entities
                  (begin [this screen entities]
                         entities)

                  (continue [this screen entities]
                            (let [{from-x :x from-y :y :keys [left right] :as target-entity} (get-in entities [:background :entities target-id])
                                  [[target-x target-y] remainder] @targets-left]
                              (let [delta-x (- target-x from-x)
                                    delta-y (- target-y from-y)
                                    distance (dist from-x from-y target-x target-y)
                                    moved-x (if (= 0.0 distance)
                                              0
                                              (* 1.5 (/ delta-x distance)))
                                    moved-y (if (= 0.0 distance)
                                              0
                                              (* 1.5 (/ delta-y distance)))]
                                (if (< distance 1)
                                  (do (swap! targets-left rest)
                                      entities)
                                  (update-in entities [:background :entities target-id]
                                             #(assoc (jump-to screen entities % [(+ moved-x from-x) (+ moved-y from-y)])
                                                :anim (cond (< delta-x 0) left
                                                            (> delta-x 0) right
                                                            :else (:anim %))))))))

                  (done? [this screen entities]
                         (let [{from-x :x from-y :y :keys [left right anim] :as target-entity} (get-in entities [:background :entities target-id])]
                           (< (dist final-x final-y from-x from-y) 1)))

                  (terminate [this screen entities]
                             (stop screen entities target-id)))
      @entities)))

(defn get-text-duration [text]
  (* (count (s/split text #" ")) 0.75))

(defn talk [entities target-id text]
  (let [initial-time (atom nil)]
    (run-action entities
                (begin [this screen entities]
                       (let [_ (swap! initial-time #(or % (:total-time screen)))
                             target-y (get-in entities [:background :entities target-id :y])
                             scale-fn (get-in entities [:background :scale-fn])
                             scale (scale-fn target-y)
                             height (* scale 36)]
                         (run! dialogue/talking-screen :on-talk :text text 
                               :x (get-in entities [:background :entities target-id :x]) :y (+ (get-in entities [:background :entities target-id :y]) height)
                               :target-id target-id
                               :scale scale)
                         (assoc-in entities [:background :entities target-id :anim] (get-in entities [:background :entities target-id :talk]))))

                (continue [this screen entities] entities)

                (done? [this screen entities]
                       (> (- (:total-time screen)
                             @initial-time)
                          (get-text-duration text)))

                (terminate [this screen entities]
                           (run! dialogue/talking-screen :stop-talk :target-id target-id)
                           (stop screen entities target-id)))))

(defn give [entities target-id item]
  (run-action entities
              (begin [this screen entities]
                     (sound! (sound "pickup.mp3") :play)

                     (-> entities
                         (update-in [:background :entities target-id :inventory] #(conj % item))
                         (assoc-in [:cursor :current] item)))

              (continue [this screen entities] entities)

              (done? [this screen entities] true)

              (terminate [this screen entities] 
                         entities)))

(defn transition-background [entities new-background [x y]]
  (run-action entities
              (begin [this screen entities] 
                     
                     (-> entities
                         (assoc-in [:transition]
                                   (assoc (texture "black.png")
                                     :scale-x 20
                                     :scale-y 20
                                     :baseline 9500
                                     :opacity 0.1))))

              (continue [this screen entities]
                        (update-in entities [:transition :opacity] + 0.075))

              (done? [this screen entities]
                     (>= (get-in entities [:transition :opacity]) 1.0))

              (terminate [this screen entities]
                         entities))
  (run-action entities
              (begin [this screen entities] 
                     (let [ego (get-in entities [:background :entities :ego])]
                       (-> entities 
                           (assoc-in [:background] (get-in entities [:backgrounds new-background]))
                           (assoc-in [:background :entities :ego] ego)
                           (assoc-in [:background :entities :ego :x] x)
                           (assoc-in [:background :entities :ego :y] y))))

              (continue [this screen entities]
                        (update-in entities [:transition :opacity] - 0.075))

              (done? [this screen entities]
                     (<= (get-in entities [:transition :opacity]) 0.0))

              (terminate [this screen entities]
                         (dissoc entities :transition))))