From d925f33e44b48484ddd2fc36dd77e2b0aab583e2 Mon Sep 17 00:00:00 2001
From: DBotThePony <dbotthepony@yandex.ru>
Date: Fri, 30 Dec 2022 18:49:03 +0700
Subject: [PATCH] JsonPath

---
 .../kstarbound/util/FullJsonPath.kt           | 19 ++++
 .../dbotthepony/kstarbound/util/JsonPath.kt   | 96 +++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 src/main/kotlin/ru/dbotthepony/kstarbound/util/FullJsonPath.kt
 create mode 100644 src/main/kotlin/ru/dbotthepony/kstarbound/util/JsonPath.kt

diff --git a/src/main/kotlin/ru/dbotthepony/kstarbound/util/FullJsonPath.kt b/src/main/kotlin/ru/dbotthepony/kstarbound/util/FullJsonPath.kt
new file mode 100644
index 00000000..bd93a1af
--- /dev/null
+++ b/src/main/kotlin/ru/dbotthepony/kstarbound/util/FullJsonPath.kt
@@ -0,0 +1,19 @@
+package ru.dbotthepony.kstarbound.util
+
+class FullJsonPath(val fullPath: String) {
+	init {
+		val delimers = fullPath.count { it == ':' }
+		require(delimers < 2) { "Invalid path: $fullPath" }
+	}
+
+	val path = fullPath.substringBefore(':')
+	val subpath: JsonPath
+
+	init {
+		if (path.any { it == ':' }) {
+			subpath = JsonPath(fullPath.substringAfter(':'))
+		} else {
+			subpath = JsonPath.EMPTY
+		}
+	}
+}
diff --git a/src/main/kotlin/ru/dbotthepony/kstarbound/util/JsonPath.kt b/src/main/kotlin/ru/dbotthepony/kstarbound/util/JsonPath.kt
new file mode 100644
index 00000000..c1be930a
--- /dev/null
+++ b/src/main/kotlin/ru/dbotthepony/kstarbound/util/JsonPath.kt
@@ -0,0 +1,96 @@
+package ru.dbotthepony.kstarbound.util
+
+import com.google.common.collect.ImmutableList
+import com.google.gson.JsonArray
+import com.google.gson.JsonElement
+import com.google.gson.JsonObject
+
+class JsonPath(val path: String) {
+	private class Piece(private val value: String) {
+		private val asNumber = value.toIntOrNull()
+
+		fun navigate(element: JsonElement): JsonElement? {
+			if (element is JsonObject) {
+				return element[value]
+			}
+
+			if (element is JsonArray) {
+				if (asNumber == null) {
+					return null
+				}
+
+				return element[asNumber]
+			}
+
+			return null
+		}
+
+		fun navigate(element: Any): Any? {
+			if (element is List<*>) {
+				if (asNumber == null) {
+					return null
+				}
+
+				return element.getOrNull(asNumber)
+			}
+
+			if (element is Map<*, *>) {
+				return element[value]
+			}
+
+			return null
+		}
+	}
+
+	val parts: List<String> = ImmutableList.copyOf(path.split('.'))
+	private val pieces: List<Piece> = ImmutableList.copyOf(parts.map { Piece(it) })
+
+	fun navigate(element: JsonElement): JsonElement? {
+		var current: JsonElement? = element
+
+		for (piece in pieces) {
+			if (current == null)
+				return null
+
+			current = piece.navigate(current)
+		}
+
+		return current
+	}
+
+	fun navigate(element: List<Any>): Any? {
+		var current: Any? = element
+
+		for (piece in pieces) {
+			if (current == null)
+				return null
+
+			current = piece.navigate(current)
+		}
+
+		return current
+	}
+
+	fun navigate(element: Map<Any, Any>): Any? {
+		var current: Any? = element
+
+		for (piece in pieces) {
+			if (current == null)
+				return null
+
+			current = piece.navigate(current)
+		}
+
+		return current
+	}
+
+	val isEmpty: Boolean
+		get() = path.isEmpty()
+
+	val isBlank: Boolean
+		get() = path.isBlank()
+
+	companion object {
+		val EMPTY = JsonPath("")
+	}
+}