/*
 * Copyright 2017-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */
package sample

import kotlinx.serialization.*
import kotlinx.serialization.descriptors.SerialDescriptor
import kotlinx.serialization.encoding.AbstractDecoder
import kotlinx.serialization.encoding.AbstractEncoder
import kotlinx.serialization.encoding.CompositeDecoder
import kotlinx.serialization.encoding.CompositeEncoder
import kotlinx.serialization.modules.*
import kotlin.test.Test
import kotlin.test.assertEquals
import kotlin.test.assertNotSame

class BasicTypesSerializationTest {

    enum class Attitude { POSITIVE, NEUTRAL, NEGATIVE }

    @Serializable
    data class Tree(val name: String, val left: Tree? = null, val right: Tree? = null)

    @Serializable
    data class TypesUmbrella(
        val unit: Unit,
        val boolean: Boolean,
        val byte: Byte,
        val short: Short,
        val int: Int,
        val long: Long,
        val float: Float,
        val double: Double,
        val char: Char,
        val string: String,
        val enum: Attitude,
        val intData: IntData,
        val unitN: Unit?,
        val booleanN: Boolean?,
        val byteN: Byte?,
        val shortN: Short?,
        val intN: Int?,
        val longN: Long?,
        val floatN: Float?,
        val doubleN: Double?,
        val charN: Char?,
        val stringN: String?,
        val enumN: Attitude?,
        val intDataN: IntData?,
        val listInt: List<Int>,
        val listIntN: List<Int?>,
        val listNInt: Set<Int>?,
        val listNIntN: MutableSet<Int?>?,
        val listListEnumN: List<List<Attitude?>>,
        val listIntData: List<IntData>,
        val listIntDataN: MutableList<IntData?>,
        val tree: Tree,
        val mapStringInt: Map<String, Int>,
        val mapIntStringN: Map<Int, String?>,
        val arrays: ArraysUmbrella
    )

    @Serializable
    data class ArraysUmbrella(
        val arrByte: Array<Byte>,
        val arrInt: Array<Int>,
        val arrIntN: Array<Int?>,
        val arrIntData: Array<IntData>
    ) {
        override fun equals(other: Any?) = other is ArraysUmbrella &&
                arrByte.contentEquals(other.arrByte) &&
                arrInt.contentEquals(other.arrInt) &&
                arrIntN.contentEquals(other.arrIntN) &&
                arrIntData.contentEquals(other.arrIntData)
    }

    val data = TypesUmbrella(
        Unit, true, 10, 20, 30, 40, 50f, 60.0, 'A', "Str0", Attitude.POSITIVE, IntData(70),
        null, null, 11, 21, 31, 41, 51f, 61.0, 'B', "Str1", Attitude.NEUTRAL, null,
        listOf(1, 2, 3),
        listOf(4, 5, null),
        setOf(6, 7, 8),
        mutableSetOf(null, 9, 10),
        listOf(listOf(Attitude.NEGATIVE, null)),
        listOf(IntData(1), IntData(2), IntData(3)),
        mutableListOf(IntData(1), null, IntData(3)),
        Tree("root", Tree("left"), Tree("right", Tree("right.left"), Tree("right.right"))),
        mapOf("one" to 1, "two" to 2, "three" to 3),
        mapOf(0 to null, 1 to "first", 2 to "second"),
        ArraysUmbrella(
            arrayOf(1, 2, 3),
            arrayOf(100, 200, 300),
            arrayOf(null, -1, -2),
            arrayOf(IntData(1), IntData(2))
        )
    )

    @Serializable
    class WithSecondaryConstructor(var someProperty: Int) {
        var test: String = "Test"

        constructor() : this(42)

        override fun equals(other: Any?): Boolean {
            if (this === other) return true
            if (other !is WithSecondaryConstructor) return false

            if (someProperty != other.someProperty) return false
            if (test != other.test) return false

            return true
        }

        override fun hashCode(): Int {
            var result = someProperty
            result = 31 * result + test.hashCode()
            return result
        }
    }


    // KeyValue Input/Output

    @OptIn(ExperimentalSerializationApi::class)
    class KeyValueOutput(val sb: StringBuilder) : AbstractEncoder() {

        override val serializersModule: SerializersModule = EmptySerializersModule()

        override fun beginStructure(descriptor: SerialDescriptor): CompositeEncoder {
            sb.append('{')
            return this
        }

        override fun endStructure(descriptor: SerialDescriptor) {
            sb.append('}')
        }

        override fun encodeElement(descriptor: SerialDescriptor, index: Int): Boolean {
            if (index > 0) sb.append(", ")
            sb.append(descriptor.getElementName(index))
            sb.append(':')
            return true
        }

        override fun encodeNull() {
            sb.append("null")
        }

        override fun encodeValue(value: Any) {
            sb.append(value)
        }

        override fun encodeString(value: String) {
            sb.append('"')
            sb.append(value)
            sb.append('"')
        }

        override fun encodeChar(value: Char) = encodeString(value.toString())
    }

    class KeyValueInput(val inp: Parser) : AbstractDecoder() {

        override val serializersModule: SerializersModule = EmptySerializersModule()

        override fun beginStructure(descriptor: SerialDescriptor): CompositeDecoder {
            inp.expectAfterWhiteSpace('{')
            return this
        }

        override fun endStructure(descriptor: SerialDescriptor) = inp.expectAfterWhiteSpace('}')

        override fun decodeElementIndex(descriptor: SerialDescriptor): Int {
            inp.skipWhitespace(',')
            val name = inp.nextUntil(':', '}')
            if (name.isEmpty())
                return CompositeDecoder.DECODE_DONE
            val index = descriptor.getElementIndex(name)
            inp.expect(':')
            return index
        }

        private fun readToken(): String {
            inp.skipWhitespace()
            return inp.nextUntil(' ', ',', '}')
        }

        override fun decodeNotNullMark(): Boolean {
            inp.skipWhitespace()
            if (inp.cur != 'n'.code) return true
            return false
        }

        override fun decodeNull(): Nothing? {
            check(readToken() == "null") { "'null' expected" }
            return null
        }

        override fun decodeBoolean(): Boolean = readToken() == "true"
        override fun decodeByte(): Byte = readToken().toByte()
        override fun decodeShort(): Short = readToken().toShort()
        override fun decodeInt(): Int = readToken().toInt()
        override fun decodeLong(): Long = readToken().toLong()
        override fun decodeFloat(): Float = readToken().toFloat()
        override fun decodeDouble(): Double = readToken().toDouble()

        override fun decodeEnum(enumDescriptor: SerialDescriptor): Int {
            return readToken().toInt()
        }

        override fun decodeString(): String {
            inp.expectAfterWhiteSpace('"')
            val value = inp.nextUntil('"')
            inp.expect('"')
            return value
        }

        override fun decodeChar(): Char = decodeString().single()
    }

    // Very simple char-by-char parser
    class Parser(private val inp: StringReader) {
        var cur: Int = inp.read()

        fun next() {
            cur = inp.read()
        }

        fun skipWhitespace(vararg c: Char) {
            while (cur >= 0 && (cur.toChar().isWhitespace() || cur.toChar() in c))
                next()
        }

        fun expect(c: Char) {
            check(cur == c.code) { "Expected '$c'" }
            next()
        }

        fun expectAfterWhiteSpace(c: Char) {
            skipWhitespace()
            expect(c)
        }

        fun  nextUntil(vararg c: Char): String {
            val sb = StringBuilder()
            while (cur >= 0 && cur.toChar() !in c) {
                sb.append(cur.toChar())
                next()
            }
            return sb.toString()
        }
    }


    class StringReader(val str: String) {
        private var position: Int = 0
        fun read(): Int = when (position) {
            str.length -> -1
            else -> str[position++].code
        }
    }

    @Test
    fun testKvSerialization() {
        // serialize to string
        val sb = StringBuilder()
        val out = KeyValueOutput(sb)
        out.encodeSerializableValue(TypesUmbrella.serializer(), data)
        // deserialize from string
        val str = sb.toString()
        val inp = KeyValueInput(Parser(StringReader(str)))
        val other = inp.decodeSerializableValue(TypesUmbrella.serializer())
        // assert we've got it back from string
        assertEquals(data, other)
        assertNotSame(data, other)
    }

    @Test
    fun someConstructor() {
        assertStringFormAndRestored("""{"someProperty":42,"test":"Test"}""", WithSecondaryConstructor(), WithSecondaryConstructor.serializer())
    }
}