(ns auto-ap.ledger.unit-test
  (:require
   [auto-ap.ledger.reports :as l-reports]
   [auto-ap.ledger :as ledger]
   [clojure.test :refer [deftest testing is]]))

;; 38.1: Compute debit/credit sums (unit test)
(deftest test-compute-debit-credit-sums
  (testing "38.1: Compute debit and credit sums per entry"
    (let [line-items [{:journal-entry-line/debit 100.0 :journal-entry-line/credit 0.0}
                      {:journal-entry-line/debit 0.0 :journal-entry-line/credit 100.0}]
          debit-sum (reduce + 0.0 (map :journal-entry-line/debit line-items))
          credit-sum (reduce + 0.0 (map :journal-entry-line/credit line-items))]
      (is (= 100.0 debit-sum))
      (is (= 100.0 credit-sum)))))

;; 17.3: Percent of sales calculation (unit test)
(deftest test-percent-of-sales-calculation
  (testing "17.3: Percent of sales calculation"
    (let [sales 200.0
          cogs 100.0
          percent (/ cogs sales)]
      (is (= 0.5 percent)))))

;; 26.3: Cash flow effect calculation (unit test)
(deftest test-cash-flow-effect
  (testing "26.3: Cash flow effect by account code range"
    (let [effect (l-reports/cashflow-account->amount 20100 100.0)]
      ;; Operating activities accounts add
      (is (= 100.0 effect)))
    (let [effect (l-reports/cashflow-account->amount 15000 100.0)]
      ;; Investment activities accounts subtract
      (is (= -100.0 effect)))
    (let [effect (l-reports/cashflow-account->amount 99999 100.0)]
      ;; Unknown accounts return original amount
      (is (= 100.0 effect)))))

;; 16.3-16.4: Amount calculation by account type (unit test)
(deftest test-amount-calculation-by-type
  (testing "16.3: Assets, dividends, expenses = debits - credits"
    (let [debit 100.0
          credit 50.0
          amount (- debit credit)]
      (is (= 50.0 amount))))
  (testing "16.4: Liabilities, equity, revenue = credits - debits"
    (let [debit 50.0
          credit 100.0
          amount (- credit debit)]
      (is (= 50.0 amount)))))

;; 21.4: Retained earnings calculation (unit test)
(deftest test-retained-earnings
  (testing "21.4: Retained earnings as net income across P&L categories"
    (let [sales 1000.0
          cogs 400.0
          payroll 200.0
          overhead 150.0
          net-income (- sales cogs payroll overhead)]
      (is (= 250.0 net-income)))))