br.com.guiabolso.events.builder.EventBuilder.kt Maven / Gradle / Ivy

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Events Protocol
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package br.com.guiabolso.events.builder

import br.com.guiabolso.events.exception.MissingEventInformationException
import br.com.guiabolso.events.json.MapperHolder
import br.com.guiabolso.events.model.EventErrorType
import br.com.guiabolso.events.model.EventErrorType.BadProtocol
import br.com.guiabolso.events.model.EventErrorType.EventNotFound
import br.com.guiabolso.events.model.EventMessage
import br.com.guiabolso.events.model.RedirectPayload
import br.com.guiabolso.events.model.RequestEvent
import br.com.guiabolso.events.model.ResponseEvent
import br.com.guiabolso.events.utils.EventUtils
import com.google.gson.JsonNull
import com.google.gson.JsonObject
import java.util.UUID

class EventBuilder {

    companion object {

        @JvmStatic
        fun event(operations: EventBuilder.() -> Unit): RequestEvent {
            val builder = EventBuilder()
            builder.operations()
            return builder.buildRequestEvent()
        }

        @JvmStatic
        fun responseEvent(operations: EventBuilder.() -> Unit): ResponseEvent {
            val builder = EventBuilder()
            builder.operations()
            return builder.buildResponseEvent()
        }

        @JvmStatic
        suspend fun responseFor(event: RequestEvent, operations: suspend EventBuilder.() -> Unit): ResponseEvent {
            val builder = EventBuilder()
            builder.operations()

            builder.name = "${event.name}:response"
            builder.version = event.version
            builder.id = builder.id ?: event.id
            builder.flowId = builder.flowId ?: event.flowId

            return builder.buildResponseEvent()
        }

        @JvmStatic
        fun errorFor(event: RequestEvent, type: EventErrorType, message: EventMessage): ResponseEvent {
            if (type is EventErrorType.Unknown) {
                throw IllegalArgumentException(
                    "This error type should not be used to send events. This error error type only exists to provide " +
                            "future compatibility with newer versions of this API."
                )
            }

            val builder = EventBuilder()
            builder.name = "${event.name}:${type.typeName}"
            builder.version = event.version
            builder.payload = message
            builder.id = builder.id ?: event.id
            builder.flowId = builder.flowId ?: event.flowId

            return builder.buildResponseEvent()
        }

        @JvmStatic
        fun redirectFor(requestEvent: RequestEvent, payload: RedirectPayload): ResponseEvent {
            val builder = EventBuilder()
            builder.name = "${requestEvent.name}:redirect"
            builder.version = requestEvent.version
            builder.payload = payload
            builder.id = builder.id ?: requestEvent.id
            builder.flowId = builder.flowId ?: requestEvent.flowId

            return builder.buildResponseEvent()
        }

        @JvmStatic
        fun eventNotFound(event: RequestEvent): ResponseEvent {
            val builder = EventBuilder()
            builder.name = EventNotFound.typeName
            builder.version = 1
            builder.id = builder.id ?: event.id
            builder.flowId = builder.flowId ?: event.flowId
            builder.payload =
                EventMessage("NO_EVENT_HANDLER_FOUND", mapOf("event" to event.name, "version" to event.version))
            return builder.buildResponseEvent()
        }

        @JvmStatic
        fun badProtocol(message: EventMessage): ResponseEvent {
            val builder = EventBuilder()
            builder.name = BadProtocol.typeName
            builder.version = 1
            builder.id = UUID.randomUUID().toString()
            builder.flowId = UUID.randomUUID().toString()
            builder.payload = message
            return builder.buildResponseEvent()
        }
    }

    var name: String? = null
    var version: Int? = null
    var id = EventUtils.eventId
    var flowId = EventUtils.flowId
    var payload: Any? = null
    var identity: Any? = null
    var auth: Any? = null
    var metadata: Any? = null

    fun buildRequestEvent() = RequestEvent(
        name = this.name ?: throw MissingEventInformationException("Missing event name."),
        version = this.version ?: throw MissingEventInformationException("Missing event version."),
        id = this.id ?: throw MissingEventInformationException("Missing event id."),
        flowId = this.flowId ?: throw MissingEventInformationException("Missing event flowId."),
        payload = convertPayload(),
        identity = convertToJsonObjectOrEmpty(this.identity),
        auth = convertToJsonObjectOrEmpty(this.auth),
        metadata = convertToJsonObjectOrEmpty(this.metadata)
    )

    fun buildResponseEvent() = ResponseEvent(
        name = this.name ?: throw MissingEventInformationException("Missing event name."),
        version = this.version ?: throw MissingEventInformationException("Missing event version."),
        id = this.id ?: throw MissingEventInformationException("Missing event id."),
        flowId = this.flowId ?: throw MissingEventInformationException("Missing event flowId."),
        payload = convertPayload(),
        identity = convertToJsonObjectOrEmpty(this.identity),
        auth = convertToJsonObjectOrEmpty(this.auth),
        metadata = convertToJsonObjectOrEmpty(this.metadata)
    )

    private fun convertPayload() = when (this.payload) {
        null -> JsonNull.INSTANCE
        else -> MapperHolder.mapper.toJsonTree(this.payload)
    }

    private fun convertToJsonObjectOrEmpty(value: Any?) = when (value) {
        null -> JsonObject()
        JsonNull.INSTANCE -> JsonObject()
        else -> MapperHolder.mapper.toJsonTree(value).asJsonObject
    }
}