... This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
... If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.

(.require
 [library
  [lux (.except)
   [abstract
    [monad (.only do)]
    ["[0]" equivalence
     ["[1]T" \\test]]
    ["[0]" order
     ["[1]T" \\test]]]
   [control
    ["[0]" maybe (.use "[1]#[0]" functor)]]
   [data
    ["[0]" bit (.use "[1]#[0]" equivalence)]
    ["[0]" text (.only)
     ["%" \\format]]]
   [math
    ["[0]" random (.only Random)]
    [number
     ["n" nat]
     ["i" int]]]
   [test
    ["_" property (.only Test)]]]]
 [\\library
  ["[0]" / (.only)
   [///
    ["[0]" money (.only)
     ["[0]" currency (.only Currency)]]]]]
 [///
  ["[0]T" money]])

(def .public (random $ max_sub_units)
  (All (_ $)
    (-> (Currency $) Nat
        (Random (/.Action $))))
  (do random.monad
    [from (moneyT.random $ max_sub_units)
     to (moneyT.random $ max_sub_units)]
    (in (/.action from to))))

(def .public test
  Test
  (<| (_.covering /._)
      (do [! random.monad]
        [parameter (..random currency.usd 1000,00)
         subject (..random currency.usd 1000,00)

         from (moneyT.random currency.usd 1000,00)
         to (moneyT.random currency.usd 1000,00)])
      (_.for [/.Price /.Action])
      (all _.and
           (_.for [/.equivalence /.=]
                  (equivalenceT.spec /.equivalence (..random currency.usd 1000,00)))
           (_.for [/.order /.<]
                  (orderT.spec /.order (..random currency.usd 1000,00)))
           
           (_.coverage [/.action /.currency /.movement]
             (let [it (/.action from to)]
               (and (same? currency.usd (/.currency it))
                    (i.= (int (n.- (money.amount from) (money.amount to)))
                         (/.movement it)))))
           (_.coverage [/.+ /.-]
             (and (|> subject
                      (/.+ parameter)
                      (of /.equivalence = subject)
                      not)
                  (|> subject
                      (/.+ parameter)
                      (/.- parameter)
                      (of /.equivalence = subject))))
           (_.coverage [/.min]
             (and (/.<= parameter
                        (/.min parameter subject))
                  (/.<= subject
                        (/.min parameter subject))))
           (_.coverage [/.max]
             (and (/.>= parameter
                        (/.max parameter subject))
                  (/.>= subject
                        (/.max parameter subject))))
           (_.coverage [/.>]
             (bit#= (/.> parameter subject)
                    (/.< subject parameter)))
           (_.coverage [/.<= /.>=]
             (bit#= (/.<= parameter subject)
                    (/.>= subject parameter)))
           (_.coverage [/.units /.sub_units
                        /.of_units /.of_sub_units]
             (/.= subject
                  (/.+ (/.of_units currency.usd (/.units subject))
                       (/.of_sub_units currency.usd (/.sub_units subject)))))
           (do !
             [it (..random currency.usd 1000,00)]
             (_.coverage [/.format]
               (let [starts_with_quantity!
                     (text.starts_with? (%.int (/.movement it))
                                        (text.replaced_once "." "" (/.format it)))

                     ends_with_currency!
                     (text.ends_with? (currency.alphabetic_code (/.currency it))
                                      (/.format it))]
                 (and starts_with_quantity!
                      ends_with_currency!))))
           )))