1 /*
2  *  Make.org Core API
3  *  Copyright (C) 2020 Make.org
4  *
5  * This program is free software: you can redistribute it and/or modify
6  *  it under the terms of the GNU Affero General Public License as
7  *  published by the Free Software Foundation, either version 3 of the
8  *  License, or (at your option) any later version.
9  *
10  *  This program is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *  GNU Affero General Public License for more details.
14  *
15  *  You should have received a copy of the GNU Affero General Public License
16  *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
17  *
18  */
19 
20 package org.make.core.technical
21 
22 import scala.util.Try
23 import eu.timepit.refined.refineV
24 import eu.timepit.refined.numeric.NonNegative
25 import eu.timepit.refined.api.Refined
26 import eu.timepit.refined.auto._
27 import io.circe.Decoder
28 
29 trait Pagination {
30 
31   val value: Int Refined NonNegative
32 
33   def extractInt: Int = value
34 }
35 
36 object Pagination {
37 
38   final case class Offset(value: Int Refined NonNegative) extends Pagination
39 
40   private val RefinedZero: Int Refined NonNegative = 0
41 
42   private def nonNegativeOrZero(number: Int): Int Refined NonNegative =
43     refineV[NonNegative](number).getOrElse(RefinedZero)
44 
45   object Offset {
46 
47     def zero: Offset = new Offset(RefinedZero)
48 
49     def apply(offset: Int): Offset =
50       new Offset(nonNegativeOrZero(offset))
51   }
52 
53   final case class End(value: Int Refined NonNegative) extends Pagination {
54 
55     def toLimit(offset: Offset): Limit =
56       new Limit(nonNegativeOrZero(value - offset.value))
57   }
58 
59   object End {
60 
61     def apply(end: Int): End =
62       new End(nonNegativeOrZero(end))
63   }
64 
65   final case class Limit(value: Int Refined NonNegative) extends Pagination {
66 
67     def toEnd(offset: Offset): End =
68       End(value + offset.value)
69   }
70 
71   object Limit {
72 
73     def apply(limit: Int): Limit =
74       new Limit(nonNegativeOrZero(limit))
75   }
76 
77   implicit class RichOptionOffset(val self: Option[Offset]) extends AnyVal {
78     def orZero: Offset = self.getOrElse(Offset.zero)
79   }
80 
81   private val nonNegativeDecoder: Decoder[Int Refined NonNegative] =
82     Decoder.decodeString
83       .emapTry(str => Try(str.toInt))
84       .emap(refineV[NonNegative](_))
85 
86   implicit val offsetDecoder: Decoder[Offset] =
87     nonNegativeDecoder.map(Offset(_))
88 
89   implicit val limitDecoder: Decoder[Limit] =
90     nonNegativeDecoder.map(Limit(_))
91 }