(ns the-great-game.gossip.gossip
  "Interchange of news events between gossip agents"
  (:require [the-great-game.utils :refer [deep-merge]]
            [the-great-game.gossip.news-items :refer [learn-news-item]]))

;; Note that habitual travellers are all gossip agents; specifically, at this
;; stage, that means merchants. When merchants are moved we also need to
;; update the location of the gossip with the same key.

(defn dialogue
  "Dialogue between an `enquirer` and an `agent` in this `world`; returns a
  map identical to `enquirer` except that its `:gossip` collection may have
  additional entries."
  ;; TODO: not yet written, this is a stub.
  [enquirer respondent world]
  enquirer)

(defn gather-news
  ([world]
   (reduce
     deep-merge
     world
     (map
       #(gather-news world %)
       (keys (:gossips world)))))
  ([world gossip]
   (let [g (cond (keyword? gossip)
                 (-> world :gossips gossip)
                 (map? gossip)
                 gossip)]
     {:gossips
      {(:id g)
       (reduce
         deep-merge
         {}
         (map
           #(dialogue g % world)
           (remove
             #( = g %)
             (filter
               #(= (:location %) (:location g))
               (vals (:gossips world))))))}})))

(defn move-gossip
  "Return a world like this `world` but with this `gossip` moved to this
  `new-location`. Many gossips are essentially shadow-records of agents of
  other types, and the movement of the gossip should be controlled by the
  run function of the type of the record they shadow. The [[#run]] function
  below does NOT call this function."
  [gossip world new-location]
  (let [id (cond
            (map? gossip)
            (-> world :gossips gossip :id)
            (keyword? gossip)
            gossip)]
  (deep-merge
    world
    {:gossips
     {id
      {:location new-location}}})))

(defn run
  "Return a world like this `world`, with news items exchanged between gossip
  agents."
  [world]
  (gather-news world))