Initial interface design for sanity checks

Part of #137

README.md

@@ -110,6 +110,13 @@ Gets metering data from Fudura.
 Running locally
 ---
 
+Install dependencies:
+
+```
+docker compose run --rm gradle-base zummon:jsBrowserProductionLibraryDistribution
+docker compose run --rm npm install --include dev
+```
+
 Run the web application locally using Docker Compose:
 
 ```bash

zummon/src/commonMain/kotlin/companysurvey/Electricity.kt

@@ -40,6 +40,10 @@ data class Electricity (
     fun getContractedConnectionCapacityKw(): Int? {
         return kleinverbruik?.connectionCapacity?.toKw() ?: grootverbruik?.contractedConnectionDeliveryCapacity_kW
     }
+
+    fun getPhysicalConnectionCapacityKw(): Int? {
+        return kleinverbruik?.connectionCapacity?.toKw() ?: grootverbruik?.physicalCapacityKw
+    }
 }
 
 @Serializable

zummon/src/commonMain/kotlin/companysurvey/Validation.kt

@@ -0,0 +1,27 @@
+package com.zenmo.zummon.companysurvey
+
+fun interface Validator {
+    fun validate(survey: Survey): ValidationResult
+}
+
+data class ValidationResult(
+    val valid: Boolean,
+    val severity: Severity,
+    val message: String,
+)
+
+enum class Severity {
+    WARNING, ERROR
+}
+
+val validateContractedCapacity = Validator {survey: Survey ->
+    val gridConnection = survey.getSingleGridConnection()
+
+    val isValid = gridConnection.electricity.getContractedConnectionCapacityKw() <= gridConnection.electricity.getPhysicalConnectionCapacityKw()
+
+    ValidationResult(
+        valid = isValid,
+        severity = Severity.ERROR,
+        message = "Contracted connection capacity ${gridConnection.electricity.getContractedConnectionCapacityKw()} kW is too large for physical connection ${gridConnection.electricity.getPhysicalConnectionCapacityKw()}"
+    )
+}