(ns pocketbook.server-test
  (:require [clojure.test :refer [deftest is testing use-fixtures]]
            [pocketbook.server :as server]
            [pocketbook.transit :as t])
  (:import [java.io File]
           [java.net URI]
           [java.net.http HttpClient HttpRequest HttpResponse$BodyHandlers HttpRequest$BodyPublishers]))

(def ^:dynamic *server* nil)
(def ^:dynamic *port* nil)

(defn- free-port []
  (with-open [s (java.net.ServerSocket. 0)]
    (.getLocalPort s)))

(use-fixtures :each
  (fn [f]
    (let [port    (free-port)
          db-path (str (File/createTempFile "pocketbook-server-test" ".db"))
          srv     (server/start! {:port port :db-path db-path})]
      (Thread/sleep 200) ;; let server start
      (try
        (binding [*server* srv *port* port]
          (f))
        (finally
          (server/stop! srv)
          (.delete (File. db-path)))))))

;; ---------------------------------------------------------------------------
;; HTTP helpers
;; ---------------------------------------------------------------------------

(def ^:private client (HttpClient/newHttpClient))

(defn- url [path & [query]]
  (str "http://localhost:" *port* path (when query (str "?" query))))

(defn- get-transit [path query]
  (let [req (-> (HttpRequest/newBuilder)
                (.uri (URI. (url path query)))
                (.header "Accept" "application/transit+json")
                (.GET)
                (.build))
        resp (.send client req (HttpResponse$BodyHandlers/ofByteArray))]
    {:status (.statusCode resp)
     :body   (t/decode (.body resp))}))

(defn- post-transit [path body]
  (let [bytes (t/encode body)
        req   (-> (HttpRequest/newBuilder)
                  (.uri (URI. (url path)))
                  (.header "Content-Type" "application/transit+json")
                  (.header "Accept" "application/transit+json")
                  (.POST (HttpRequest$BodyPublishers/ofByteArray bytes))
                  (.build))
        resp  (.send client req (HttpResponse$BodyHandlers/ofByteArray))]
    {:status (.statusCode resp)
     :body   (t/decode (.body resp))}))

;; ---------------------------------------------------------------------------
;; Tests
;; ---------------------------------------------------------------------------

(deftest root-returns-404-without-static-dir
  (let [req  (-> (HttpRequest/newBuilder)
                 (.uri (URI. (url "/")))
                 (.GET)
                 (.build))
        resp (.send client req (HttpResponse$BodyHandlers/ofString))]
    (is (= 404 (.statusCode resp)))))

(deftest push-and-pull
  (testing "Push new documents"
    (let [resp (post-transit "/sync"
                 [{:id "todo:1" :value {:text "Buy milk" :tags #{:groceries}} :base-version 0}
                  {:id "todo:2" :value {:text "Buy eggs"} :base-version 0}])]
      (is (= 200 (:status resp)))
      (is (every? #(= :ok (:status %)) (:body resp)))
      (is (= 1 (:version (first (:body resp)))))))

  (testing "Pull all docs"
    (let [resp (get-transit "/sync" "group=todo&since=0")]
      (is (= 200 (:status resp)))
      (is (= 2 (count (:body resp))))
      (is (= #{:groceries} (:tags (:value (first (:body resp))))))))

  (testing "Update a doc"
    (let [resp (post-transit "/sync"
                 [{:id "todo:1" :value {:text "Buy oat milk"} :base-version 1}])]
      (is (= :ok (:status (first (:body resp)))))
      (is (= 2 (:version (first (:body resp)))))))

  (testing "Pull only recent changes"
    (let [all  (get-transit "/sync" "group=todo&since=0")
          ts   (:updated (second (:body all)))
          recent (get-transit "/sync" (str "group=todo&since=" ts))]
      ;; Should get only todo:1 (updated) but not todo:2 (unchanged since ts)
      ;; (depends on timing, but at minimum we get at least 1)
      (is (<= (count (:body recent)) 2)))))

(deftest push-conflict
  (post-transit "/sync"
    [{:id "todo:1" :value {:text "v1"} :base-version 0}])
  (let [resp (post-transit "/sync"
               [{:id "todo:1" :value {:text "stale"} :base-version 0}])]
    (is (= :conflict (:status (first (:body resp)))))
    (is (= 1 (:current-version (first (:body resp)))))))

(deftest push-delete
  (post-transit "/sync"
    [{:id "todo:del" :value {:text "delete me"} :base-version 0}])
  (let [resp (post-transit "/sync"
               [{:id "todo:del" :deleted true :base-version 1}])]
    (is (= :ok (:status (first (:body resp))))))
  (let [resp (get-transit "/sync" "group=todo&since=0")]
    (is (some #(and (= "todo:del" (:id %)) (:deleted %)) (:body resp)))))

(deftest missing-group-param
  (let [resp (get-transit "/sync" "since=0")]
    (is (= 400 (:status resp)))))

(deftest type-preservation-over-wire
  (let [uuid (java.util.UUID/randomUUID)
        inst #inst "2026-04-04T10:00:00Z"
        value {:keyword :hello
               :set     #{1 2 3}
               :vec     [1 "two" :three]
               :uuid    uuid
               :inst    inst
               :nested  {:a {:b 42}}}]
    (post-transit "/sync"
      [{:id "types:1" :value value :base-version 0}])
    (let [resp   (get-transit "/sync" "group=types&since=0")
          pulled (:value (first (:body resp)))]
      ;; Transit preserves most types but nippy is used server-side
      ;; The round-trip is: transit-decode → nippy-freeze → nippy-thaw → transit-encode
      (is (= :hello (:keyword pulled)))
      (is (= #{1 2 3} (:set pulled)))
      (is (= [1 "two" :three] (:vec pulled)))
      (is (= uuid (:uuid pulled)))
      (is (= inst (:inst pulled)))
      (is (= {:a {:b 42}} (:nested pulled))))))