Introduce some architecture and dependency injection for status-histo…

…ry. (#47)

.gitignore

@@ -3,6 +3,7 @@ build/
 /Android/src/main/assets/LondonTravel.data.*.sql
 
 /.idea/
+!/.idea/runConfigurations/
 *.ipr
 *.iml
 *.iws

docs/DEVELOPMENT.md

@@ -19,13 +19,13 @@ After this runs hit:
 ### Update AppEngine
 
 ```shell
-$ gradlew appengineRun
-> Task :AppEngine:checkCloudSdk FAILED
+$ gradlew :web:status-history:appengineRun
+> Task :web:status-history:checkCloudSdk FAILED
 
 FAILURE: Build failed with an exception.
 
 * What went wrong:
-  Execution failed for task ':AppEngine:checkCloudSdk'.
+  Execution failed for task ':web:status-history:checkCloudSdk'.
 > Specified Cloud SDK version (347.0.0) does not match installed version (319.0.0).
 ```
 

domain/status/build.gradle

@@ -0,0 +1,30 @@
+plugins {
+	id("net.twisterrob.blt.convention")
+	id("org.jetbrains.kotlin.multiplatform")
+	id("com.google.devtools.ksp")
+}
+
+kotlin {
+	jvm()
+	sourceSets {
+		commonMain {
+			dependencies {
+				api(libs.kotlin.datetime)
+				api(libs.kotlin.serialization)
+				//implementation("io.github.oshai:kotlin-logging:6.0.1")
+			}
+		}
+		commonTest {
+			dependencies {
+				implementation(libs.kotlin.test)
+				implementation(libs.test.mockative)
+			}
+		}
+	}
+}
+
+configurations
+		.matching { Configuration it -> it.name.startsWith("ksp") && it.name.endsWith("Test") }
+		.configureEach { Configuration it ->
+			project.dependencies.add(it.name, libs.test.mockative.processor)
+		}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/DomainHistoryUseCase.kt

@@ -0,0 +1,44 @@
+package net.twisterrob.travel.domain.london.status
+
+import net.twisterrob.travel.domain.london.status.api.FeedParser
+import net.twisterrob.travel.domain.london.status.api.HistoryUseCase
+import net.twisterrob.travel.domain.london.status.api.ParsedStatusItem
+import net.twisterrob.travel.domain.london.status.api.StatusHistoryRepository
+import net.twisterrob.travel.domain.london.status.api.StatusInteractor
+
+class DomainHistoryUseCase(
+	private val statusHistoryRepository: StatusHistoryRepository,
+	private val statusInteractor: StatusInteractor,
+	private val feedParser: FeedParser,
+) : HistoryUseCase {
+
+	/**
+	 * @param max maximum number of items to return, current is not included in the count.
+	 * @param includeCurrent whether to include the current status in the result.
+	 */
+	override fun history(feed: Feed, max: Int, includeCurrent: Boolean): List<ParsedStatusItem> {
+		val result = mutableListOf<StatusItem>()
+		if (includeCurrent) {
+			result.add(statusInteractor.getCurrent(feed))
+		}
+		val history = statusHistoryRepository.getAll(feed, max)
+		result.addAll(history)
+		return result.map { it.parse() }
+	}
+
+	private fun StatusItem.parse(): ParsedStatusItem =
+		when (this) {
+			is StatusItem.SuccessfulStatusItem -> {
+				try {
+					val feedContents = feedParser.parse(this.feed, this.content)
+					ParsedStatusItem.ParsedFeed(this, feedContents)
+				} catch (ex: Exception) {
+					ParsedStatusItem.ParseFailed(this, Stacktrace(ex.stackTraceToString()))
+				}
+			}
+
+			is StatusItem.FailedStatusItem -> {
+				ParsedStatusItem.AlreadyFailed(this)
+			}
+		}
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/DomainRefreshUseCase.kt

@@ -0,0 +1,51 @@
+package net.twisterrob.travel.domain.london.status
+
+import net.twisterrob.travel.domain.london.status.api.RefreshResult
+import net.twisterrob.travel.domain.london.status.api.RefreshUseCase
+import net.twisterrob.travel.domain.london.status.api.StatusHistoryRepository
+import net.twisterrob.travel.domain.london.status.api.StatusInteractor
+
+class DomainRefreshUseCase(
+	private val statusHistoryRepository: StatusHistoryRepository,
+	private val statusInteractor: StatusInteractor,
+) : RefreshUseCase {
+
+	override fun refreshLatest(feed: Feed): RefreshResult {
+		val current = statusInteractor.getCurrent(feed)
+		val latest = statusHistoryRepository.getAll(feed, 1).singleOrNull()
+
+		return when {
+			latest == null -> {
+				statusHistoryRepository.add(current)
+				RefreshResult.Created(current)
+			}
+
+			sameContent(latest, current) -> {
+				RefreshResult.NoChange(current, latest)
+			}
+
+			sameError(latest, current) -> {
+				RefreshResult.NoChange(current, latest)
+			}
+
+			else -> {
+				statusHistoryRepository.add(current)
+				RefreshResult.Refreshed(current, latest)
+			}
+		}
+	}
+
+	private fun sameContent(latest: StatusItem, current: StatusItem): Boolean =
+		if (latest is StatusItem.SuccessfulStatusItem && current is StatusItem.SuccessfulStatusItem) {
+			latest.content == current.content
+		} else {
+			false
+		}
+
+	private fun sameError(latest: StatusItem, current: StatusItem): Boolean =
+		if (latest is StatusItem.FailedStatusItem && current is StatusItem.FailedStatusItem) {
+			latest.error == current.error
+		} else {
+			false
+		}
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/Feed.kt

@@ -0,0 +1,6 @@
+package net.twisterrob.travel.domain.london.status
+
+enum class Feed {
+	TubeDepartureBoardsLineStatus,
+	TubeDepartureBoardsLineStatusIncidents,
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/Stacktrace.kt

@@ -0,0 +1,5 @@
+package net.twisterrob.travel.domain.london.status
+
+data class Stacktrace(
+	val stacktrace: String,
+)

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/StatusContent.kt

@@ -0,0 +1,5 @@
+package net.twisterrob.travel.domain.london.status
+
+data class StatusContent(
+	val content: String,
+)

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/StatusItem.kt

@@ -0,0 +1,21 @@
+package net.twisterrob.travel.domain.london.status
+
+import kotlinx.datetime.Instant
+
+sealed class StatusItem {
+
+	abstract val retrievedDate: Instant
+	abstract val feed: Feed
+
+	data class SuccessfulStatusItem(
+		override val feed: Feed,
+		val content: StatusContent,
+		override val retrievedDate: Instant,
+	) : StatusItem()
+
+	data class FailedStatusItem(
+		override val feed: Feed,
+		val error: Stacktrace,
+		override val retrievedDate: Instant,
+	) : StatusItem()
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/api/FeedParser.kt

@@ -0,0 +1,10 @@
+package net.twisterrob.travel.domain.london.status.api
+
+import net.twisterrob.travel.domain.london.status.Feed
+import net.twisterrob.travel.domain.london.status.StatusContent
+
+interface FeedParser {
+
+	@Throws(Exception::class)
+	fun parse(feed: Feed, content: StatusContent): Any
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/api/HistoryUseCase.kt

@@ -0,0 +1,29 @@
+package net.twisterrob.travel.domain.london.status.api
+
+import net.twisterrob.travel.domain.london.status.Feed
+import net.twisterrob.travel.domain.london.status.Stacktrace
+import net.twisterrob.travel.domain.london.status.StatusItem
+
+interface HistoryUseCase {
+
+	fun history(feed: Feed, max: Int, includeCurrent: Boolean): List<ParsedStatusItem>
+}
+
+sealed class ParsedStatusItem {
+
+	abstract val item: StatusItem
+
+	data class ParsedFeed(
+		override val item: StatusItem.SuccessfulStatusItem,
+		val content: Any,
+	) : ParsedStatusItem()
+
+	data class AlreadyFailed(
+		override val item: StatusItem.FailedStatusItem,
+	) : ParsedStatusItem()
+
+	data class ParseFailed(
+		override val item: StatusItem.SuccessfulStatusItem,
+		val error: Stacktrace,
+	) : ParsedStatusItem()
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/api/RefreshUseCase.kt

@@ -0,0 +1,26 @@
+package net.twisterrob.travel.domain.london.status.api
+
+import net.twisterrob.travel.domain.london.status.Feed
+import net.twisterrob.travel.domain.london.status.StatusItem
+
+interface RefreshUseCase {
+
+	fun refreshLatest(feed: Feed): RefreshResult
+}
+
+sealed class RefreshResult {
+
+	data class Created(
+		val current: StatusItem,
+	) : RefreshResult()
+
+	data class Refreshed(
+		val current: StatusItem,
+		val latest: StatusItem,
+	) : RefreshResult()
+
+	data class NoChange(
+		val current: StatusItem,
+		val latest: StatusItem,
+	) : RefreshResult()
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/api/StatusHistoryRepository.kt

@@ -0,0 +1,11 @@
+package net.twisterrob.travel.domain.london.status.api
+
+import net.twisterrob.travel.domain.london.status.Feed
+import net.twisterrob.travel.domain.london.status.StatusItem
+
+interface StatusHistoryRepository {
+
+	fun add(current: StatusItem)
+
+	fun getAll(feed: Feed, max: Int): List<StatusItem>
+}

domain/status/src/commonMain/kotlin/net/twisterrob/travel/domain/london/status/api/StatusInteractor.kt

@@ -0,0 +1,9 @@
+package net.twisterrob.travel.domain.london.status.api
+
+import net.twisterrob.travel.domain.london.status.Feed
+import net.twisterrob.travel.domain.london.status.StatusItem
+
+interface StatusInteractor {
+
+	fun getCurrent(feed: Feed): StatusItem
+}