Assertions.kt

package com.keyboardr.testing

import com.google.common.truth.*
import com.google.common.truth.Truth.assertWithMessage
import com.google.common.truth.Truth.assert_
import java.math.BigDecimal
import kotlin.contracts.ExperimentalContracts
import kotlin.contracts.InvocationKind
import kotlin.contracts.contract

open class AssertionBuilder<T : AssertionScope>
internal constructor(val scope: T) {
  inline infix fun that(block: T.() -> Unit) {
    scope.block()
  }

  infix fun that(actual: BigDecimal?): BigDecimalSubject = scope.startAssert().that(actual)
  infix fun that(actual: Any?): Subject = scope.startAssert().that(actual)
  infix fun that(actual: Class<*>?): ClassSubject = scope.startAssert().that(actual)
  infix fun that(actual: Throwable?): ThrowableSubject = scope.startAssert().that(actual)
  infix fun that(actual: Long?): LongSubject = scope.startAssert().that(actual)
  infix fun that(actual: Double?): DoubleSubject = scope.startAssert().that(actual)
  infix fun that(actual: Float?): FloatSubject = scope.startAssert().that(actual)
  infix fun that(actual: Int?): IntegerSubject = scope.startAssert().that(actual)
  infix fun that(actual: Boolean?): BooleanSubject = scope.startAssert().that(actual)
  infix fun that(actual: String?): StringSubject = scope.startAssert().that(actual)
  infix fun that(actual: Iterable<*>?): IterableSubject = scope.startAssert().that(actual)
  infix fun <T> that(actual: Array<T>?): ObjectArraySubject<T> = scope.startAssert().that(actual)
  infix fun that(actual: Map<*, *>?): MapSubject = scope.startAssert().that(actual)
}

object Assert : AssertionBuilder<AssertionScope>(Assertions) {
  fun withMessage(message: String) = AssertionBuilder(MessageAssertionScope(message))
  fun <T : AssertionScope> withExtension(extension: T) = AssertionBuilder(extension)
}

@OptIn(ExperimentalContracts::class)
inline fun assertThat(block: AssertionScope.() -> Unit) {
  contract {
    callsInPlace(block, InvocationKind.EXACTLY_ONCE)
  }

  Assert that block
}

@OptIn(ExperimentalContracts::class)
inline fun assertWithMessage(message: String, block: AssertionScope.() -> Unit) {
  contract {
    callsInPlace(block, InvocationKind.EXACTLY_ONCE)
  }
  Assert.withMessage(message) that block
}

@Suppress("unused", "NOTHING_TO_INLINE")
@AssertionDsl
abstract class AssertionScope {
  open fun startAssert(): StandardSubjectBuilder = assert_()

  inline infix fun Boolean?.shouldBe(expected: Boolean?) = when (expected) {
    null -> startAssert().that(this).isNull()
    true -> startAssert().that(this).isTrue()
    false -> startAssert().that(this).isFalse()
  }

  inline infix fun Int?.shouldEqual(expected: Int) = startAssert().that(this).isEqualTo(expected)
  inline infix fun Long?.shouldEqual(expected: Long) = startAssert().that(this).isEqualTo(expected)
  inline infix fun Float?.shouldEqual(expected: Float) = startAssert().that(this).isEqualTo(expected)
  inline infix fun Any?.shouldEqual(expected: Any?) = startAssert().that(this).isEqualTo(expected)

  inline infix fun Int?.shouldNotEqual(expected: Int) = startAssert().that(this).isNotEqualTo(expected)
  inline infix fun Long?.shouldNotEqual(expected: Long) = startAssert().that(this).isNotEqualTo(expected)
  inline infix fun Float?.shouldNotEqual(expected: Float) = startAssert().that(this).isNotEqualTo(expected)
  inline infix fun Any?.shouldNotEqual(expected: Any) = startAssert().that(this).isNotEqualTo(expected)

  inline infix fun Int?.shouldBeSameAs(expected: Int) = startAssert().that(this).isSameInstanceAs(expected)
  inline infix fun Long?.shouldBeSameAs(expected: Long) = startAssert().that(this).isSameInstanceAs(expected)
  inline infix fun Float?.shouldBeSameAs(expected: Float) = startAssert().that(this).isSameInstanceAs(expected)
  inline infix fun Any?.shouldBeSameAs(expected: Any?) = startAssert().that(this).isSameInstanceAs(expected)

  inline infix fun Int?.shouldBeAtLeast(expected: Int) = startAssert().that(this).isAtLeast(expected)
  inline infix fun Long?.shouldBeAtLeast(expected: Long) = startAssert().that(this).isAtLeast(expected)
  inline infix fun Float?.shouldBeAtLeast(expected: Float) = startAssert().that(this).isAtLeast(expected)

  // foo shouldBe null
  inline infix fun Any?.shouldBe(@Suppress("UNUSED_PARAMETER") nothing: Nothing?) = startAssert().that(this).isNull()
  // foo shouldBe !null
  inline infix fun Any?.shouldBe(@Suppress("UNUSED_PARAMETER") nonNull: NonNull) = startAssert().that(this).isNotNull()

  inline fun Iterable<*>?.shouldBeEmpty() = startAssert().that(this).isEmpty()
  inline fun Iterable<*>?.shouldNotBeEmpty() = startAssert().that(this).isNotEmpty()
  inline fun Iterable<*>?.shouldNotContainDuplicates() = startAssert().that(this).containsNoDuplicates()
  inline infix fun Iterable<*>?.shouldHaveSize(expectedSize: Int) = startAssert().that(this).hasSize(expectedSize)
  inline infix fun Iterable<*>?.shouldContain(element: Any?) = startAssert().that(this).contains(element)
  inline infix fun Iterable<*>?.shouldNotContain(element: Any?) = startAssert().that(this).doesNotContain(element)

  inline infix fun Iterable<*>?.shouldContainOnly(element: Any?): Ordered = startAssert().that(this).containsExactly(element)
  inline fun Iterable<*>?.shouldContainExactlyElements(vararg varargs: Any): Ordered = startAssert().that(this).containsExactly(*varargs)
  inline infix fun Iterable<*>?.shouldContainExactly(expected: Iterable<*>): Ordered = startAssert().that(this).containsExactlyElementsIn(expected)
  inline infix fun Iterable<*>?.shouldContainExactly(expected: Array<*>): Ordered = startAssert().that(this).containsExactlyElementsIn(expected)

  inline operator fun Nothing?.not() = NonNull

  object NonNull
}

object Assertions : AssertionScope()

class MessageAssertionScope(private val message: String) :
    AssertionScope() {
  override fun startAssert(): StandardSubjectBuilder = assertWithMessage(message)

}

@DslMarker
annotation class AssertionDsl