(ns microtables-frontend.events-test
  (:require
   [cljs.test :refer-macros [deftest testing is]]
   [microtables-frontend.evaluation :as evaluation]
   [microtables-frontend.utils.data :as data-utils]))

; Tests for the state-transition pipelines that event handlers compose.
; We test the pure functions directly rather than going through re-frame dispatch.
; The event handlers in events.cljs are thin wrappers around these functions.

(defn initial-table
  "Build a fully initialised table-data map (references wired, all formulas evaluated)."
  [raw-data]
  (-> raw-data
      (data-utils/walk-modify-data
       (fn [_c _r datum]
         (if (data-utils/formula? (:value datum))
           (assoc datum :dirty true)
           datum)))
      data-utils/create-all-references
      evaluation/create-all-back-references
      evaluation/evaluate-all))

;; --- Mirrors ::edit-cell-value then ::movement-leave-cell ---

(deftest editing-value-then-leaving-triggers-downstream-reevaluation
  ; Start: A1=3, B1=A1*2 → B1 displays 6
  ; Edit A1 to 10, then leave → B1 should display 20
  (let [table   (initial-table {"A" {1 {:value "3"}}
                                "B" {1 {:value "=A1*2"}}})
        updated (-> table
                    (data-utils/change-datum-value "A" 1 "10")
                    (evaluation/reset-references "A" 1)
                    (evaluation/evaluate-from-cell "A" 1))]
    (is (= 20 (get-in updated ["B" 1 :display])))))

(deftest edit-cell-value-marks-dirty-without-evaluating
  ; change-datum-value (::edit-cell-value) only updates :value and marks :dirty;
  ; it does not produce a :display value.
  (let [table   (initial-table {"A" {1 {:value "3"}}})
        updated (data-utils/change-datum-value table "A" 1 "=1+2")]
    (is (= "=1+2" (get-in updated ["A" 1 :value])))
    (is (= true (get-in updated ["A" 1 :dirty])))
    (is (nil? (get-in updated ["A" 1 :display])))))

(deftest downstream-cells-marked-dirty-on-edit
  ; When A1 is edited, B1 (which depends on A1) should also be marked dirty.
  (let [table   (initial-table {"A" {1 {:value "5"}}
                                "B" {1 {:value "=A1+1"}}})
        updated (data-utils/change-datum-value table "A" 1 "99")]
    (is (= true (get-in updated ["B" 1 :dirty])))))

;; --- Mirrors ::movement-leave-cell reference graph update ---

(deftest formula-change-removes-old-back-reference
  ; B1 starts referencing A1. When we change B1 to reference C1,
  ; A1's :inbound should no longer include B1.
  (let [table   (initial-table {"A" {1 {:value "5"}}
                                "B" {1 {:value "=A1"}}})
        updated (-> table
                    (data-utils/change-datum-value "B" 1 "=C1+1")
                    (evaluation/reset-references "B" 1)
                    (evaluation/evaluate-from-cell "B" 1))]
    (is (not (some #(= % {:col "B" :row 1})
                   (get-in updated ["A" 1 :inbound]))))))

(deftest formula-change-adds-new-back-reference
  ; Same scenario: after B1 is changed to reference C1, C1's :inbound should include B1.
  (let [table   (initial-table {"A" {1 {:value "5"}}
                                "B" {1 {:value "=A1"}}})
        updated (-> table
                    (data-utils/change-datum-value "B" 1 "=C1+1")
                    (evaluation/reset-references "B" 1)
                    (evaluation/evaluate-from-cell "B" 1))]
    (is (some #(= % {:col "B" :row 1})
              (get-in updated ["C" 1 :inbound])))))

;; --- Deeply nested dependency propagation ---

(deftest deep-dependency-chain-reevaluated
  ; A1 → B1 → C1 → D1; editing A1 should propagate all the way to D1.
  (let [table   (initial-table {"A" {1 {:value "1"}}
                                "B" {1 {:value "=A1+1"}}
                                "C" {1 {:value "=B1+1"}}
                                "D" {1 {:value "=C1+1"}}})
        updated (-> table
                    (data-utils/change-datum-value "A" 1 "10")
                    (evaluation/reset-references "A" 1)
                    (evaluation/evaluate-from-cell "A" 1))]
    (is (= 13 (get-in updated ["D" 1 :display])))))