diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 1182c84..9de1fe2 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
 plugins {
     val kotlinVersion = "1.9.23"
     kotlin("jvm") version kotlinVersion
@@ -15,8 +17,13 @@ dependencies {
     implementation(platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES))
     implementation("org.springframework.boot:spring-boot-starter-web")
     implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
+    implementation("org.springframework.boot:spring-boot-starter-mustache")
+    implementation("com.google.code.gson:gson:2.10.1")
+    implementation("org.danilopianini:khttp:1.6.1")
     testImplementation(kotlin("test"))
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation("io.mockk:mockk:1.4.1")
+    implementation(kotlin("stdlib-jdk8"))
 }
 
 tasks.test {
@@ -26,3 +33,11 @@ tasks.test {
 kotlin {
     jvmToolchain(17)
 }
+val compileKotlin: KotlinCompile by tasks
+compileKotlin.kotlinOptions {
+    jvmTarget = "17"
+}
+val compileTestKotlin: KotlinCompile by tasks
+compileTestKotlin.kotlinOptions {
+    jvmTarget = "17"
+}
\ No newline at end of file
diff --git a/app/src/main/kotlin/HtmlController.kt b/app/src/main/kotlin/HtmlController.kt
new file mode 100644
index 0000000..1aae12c
--- /dev/null
+++ b/app/src/main/kotlin/HtmlController.kt
@@ -0,0 +1,35 @@
+package hu.vanio.kotlin.feladat.ms
+
+import com.google.gson.Gson
+import khttp.get
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.stereotype.Controller
+import org.springframework.ui.Model
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.ui.set
+
+@Controller
+class HtmlController {
+
+    @Autowired
+    lateinit var weatherAppService: WeatherAppService
+
+    @GetMapping("/")
+    fun index(model: Model): String {
+        model["title"] = "Average Daily temperature list"
+        val latitude = 47.4984
+        val longitude = 19.0404
+        val apiUrl = "https://api.open-meteo.com/v1/forecast?latitude=$latitude&longitude=$longitude&hourly=temperature_2m&timezone=auto"
+        try {
+            val meteoData = weatherAppService.fetchMeteoData(apiUrl)
+            model["averageTempList"] = weatherAppService.displayTemperatureDailyAverage(meteoData)
+        } catch (exception: Exception) {
+            println("Exception occured while fetching meteo data. Exception message: " + exception.message)
+            model["averageTempList"] = arrayListOf("Exception occured while fetching meteo data.")
+        }
+        return "index"
+    }
+
+
+
+}
diff --git a/app/src/main/kotlin/MeteoResponseData.kt b/app/src/main/kotlin/MeteoResponseData.kt
new file mode 100644
index 0000000..48c65ea
--- /dev/null
+++ b/app/src/main/kotlin/MeteoResponseData.kt
@@ -0,0 +1,23 @@
+package hu.vanio.kotlin.feladat.ms
+
+data class MeteoResponseData(
+    val latitude: Double,
+    val longitude: Double,
+    val generationtime_ms: Double,
+    val utc_offset_seconds: Int,
+    val timezone: String,
+    val timezone_abbreviation: String,
+    val elevation: Double,
+    val hourly_units: HourlyUnits,
+    val hourly: Hourly
+)
+
+data class HourlyUnits(
+    val time: String,
+    val temperature_2m: String
+)
+
+data class Hourly(
+    val time: List<String>,
+    val temperature_2m: List<Double>
+)
diff --git a/app/src/main/kotlin/WeatherApp.kt b/app/src/main/kotlin/WeatherApp.kt
index e0c098a..4dbdc63 100644
--- a/app/src/main/kotlin/WeatherApp.kt
+++ b/app/src/main/kotlin/WeatherApp.kt
@@ -2,11 +2,18 @@ package hu.vanio.kotlin.feladat.ms
 
 import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.boot.runApplication
+import com.google.gson.Gson
+import khttp.get
+import org.springframework.http.HttpStatusCode
 
 @SpringBootApplication
 class WeatherApp
 
 fun main() {
     runApplication<WeatherApp>()
+    println("STARTUP")
+
+
 }
 
+
diff --git a/app/src/main/kotlin/WeatherAppService.kt b/app/src/main/kotlin/WeatherAppService.kt
new file mode 100644
index 0000000..71d40fc
--- /dev/null
+++ b/app/src/main/kotlin/WeatherAppService.kt
@@ -0,0 +1,57 @@
+package hu.vanio.kotlin.feladat.ms
+
+import com.google.gson.Gson
+import khttp.get
+import org.springframework.http.HttpStatusCode
+import org.springframework.http.converter.HttpMessageNotReadableException
+import org.springframework.stereotype.Service
+import org.springframework.web.client.HttpClientErrorException
+import org.springframework.web.client.HttpServerErrorException
+
+@Service
+class WeatherAppService {
+    fun displayTemperatureDailyAverage(meteoData: MeteoResponseData?): List<String> {
+        val dailyAverage = mutableListOf<String>()
+        if (meteoData != null) {
+            var dailySum = 0.0
+            var actualDay = meteoData.hourly.time[0].substring(0, 10)
+            var dailyIndex = 0
+            meteoData.hourly.temperature_2m.forEachIndexed { index, temperature ->
+                val dayToCheck = meteoData.hourly.time[index].substring(0, 10)
+                if (dayToCheck != actualDay) {
+                    if (dailySum != 0.0) {
+                        val actualAverage = actualDay + " temperature: " + dailySum / dailyIndex
+                        println(actualAverage)
+                        dailyAverage.add(actualAverage)
+                    }
+                    dailySum = 0.0
+                    dailyIndex = 0
+                    actualDay = dayToCheck
+                }
+                dailyIndex++
+                dailySum += temperature
+            }
+
+            //last day too
+            if (dailySum != 0.0) {
+                val actualAverage = actualDay + " temperature: " + dailySum / dailyIndex
+                println(actualAverage)
+                dailyAverage.add(actualAverage)
+            }
+            return dailyAverage
+        } else {
+            println("Failed to calculate the daily average temperature.")
+            throw Exception("Failed to calculate the daily average temperature.")
+        }
+    }
+
+    fun fetchMeteoData(apiUrl: String): MeteoResponseData? {
+        val response = get(apiUrl)
+        if (response.statusCode == 200) {
+            return Gson().fromJson(response.text, MeteoResponseData::class.java)
+        } else {
+            throw HttpServerErrorException(HttpStatusCode.valueOf(response.statusCode))
+        }
+
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/resources/templates/footer.mustache b/app/src/main/resources/templates/footer.mustache
new file mode 100644
index 0000000..691287b
--- /dev/null
+++ b/app/src/main/resources/templates/footer.mustache
@@ -0,0 +1,2 @@
+</body>
+</html>
\ No newline at end of file
diff --git a/app/src/main/resources/templates/header.mustache b/app/src/main/resources/templates/header.mustache
new file mode 100644
index 0000000..71e0b08
--- /dev/null
+++ b/app/src/main/resources/templates/header.mustache
@@ -0,0 +1,5 @@
+<html>
+<head>
+    <title>{{title}}</title>
+</head>
+<body>
\ No newline at end of file
diff --git a/app/src/main/resources/templates/index.mustache b/app/src/main/resources/templates/index.mustache
new file mode 100644
index 0000000..63a5d64
--- /dev/null
+++ b/app/src/main/resources/templates/index.mustache
@@ -0,0 +1,9 @@
+{{> header}}
+
+<h1>{{title}}</h1>
+
+{{#averageTempList}}
+<h3>{{.}}</h3>
+{{/averageTempList}}
+
+{{> footer}}
\ No newline at end of file
diff --git a/app/src/test/kotlin/WeatherAppServiceTest.kt b/app/src/test/kotlin/WeatherAppServiceTest.kt
new file mode 100644
index 0000000..3d4459c
--- /dev/null
+++ b/app/src/test/kotlin/WeatherAppServiceTest.kt
@@ -0,0 +1,70 @@
+package hu.vanio.kotlin.feladat.ms
+
+import com.google.gson.Gson
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+import java.net.UnknownHostException
+
+class WeatherAppServiceTest {
+
+    var weatherAppService = WeatherAppService()
+    @Test
+    fun fetchDataTest() {
+        val latitude = 47.4984
+        val longitude = 19.0404
+        val apiUrl = "https://api.open-meteo.com/v1/forecast?latitude=$latitude&longitude=$longitude&hourly=temperature_2m&timezone=auto"
+
+        val meteoData = weatherAppService.fetchMeteoData(apiUrl)
+
+        assertTrue(meteoData != null)
+        assertEquals(24*7, meteoData!!.hourly.time.size)
+        assertEquals(24*7, meteoData!!.hourly.temperature_2m.size)
+    }
+
+    @Test
+    fun fetchDataTestBadUrl() {
+        val apiUrl = "https://badApi"
+        assertThrows(UnknownHostException::class.java) {
+            weatherAppService.fetchMeteoData(apiUrl)
+        }
+    }
+
+    @Test
+    fun displayTemperatureDailyAverageTest() {
+        val formattedString = """{
+   "latitude":47.5,
+   "longitude":19.0625,
+   "generationtime_ms":0.026941299438476562,
+   "utc_offset_seconds":3600,
+   "timezone":"Europe/Budapest",
+   "timezone_abbreviation":"CET",
+   "elevation":124.0,
+   "hourly_units":{
+      "time":"iso8601",
+      "temperature_2m":"°C"
+   },
+   "hourly":{
+      "time":[
+         "2024-03-19T00:00",
+         "2024-03-19T01:00",
+         "2024-03-19T02:00",
+         "2024-03-20T02:00",
+         "2024-03-20T03:00",
+         "2024-03-20T04:00"
+      ],
+      "temperature_2m":[
+         3.4,
+         3.2,
+         2.9,
+         2.7,
+         2.5,
+         2.6
+      ]
+    }
+   }"""
+        val meteoResponse = Gson().fromJson(formattedString, MeteoResponseData::class.java)
+        val result = weatherAppService.displayTemperatureDailyAverage(meteoResponse)
+        assertEquals("2024-03-19 temperature: 3.1666666666666665", result[0])
+        assertEquals("2024-03-20 temperature: 2.6", result[1])
+    }
+}
\ No newline at end of file
diff --git a/app/src/test/kotlin/WeatherAppTest.kt b/app/src/test/kotlin/WeatherAppTest.kt
index a81a55a..2920d9d 100644
--- a/app/src/test/kotlin/WeatherAppTest.kt
+++ b/app/src/test/kotlin/WeatherAppTest.kt
@@ -1,11 +1,79 @@
 package hu.vanio.kotlin.feladat.ms
 
+import org.assertj.core.api.Assertions.assertThat
+import org.mockito.Mock
+import org.mockito.Mockito
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.web.client.TestRestTemplate
+import org.springframework.boot.test.web.client.getForEntity
+import org.springframework.http.HttpStatus
 import kotlin.test.Test
+import org.mockito.Mockito.`when`
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
+import org.springframework.boot.test.mock.mockito.MockBean
+import org.springframework.http.HttpStatusCode
+import org.springframework.test.web.servlet.MockMvc
+import org.springframework.web.client.HttpServerErrorException
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.content
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
+
+
+@WebMvcTest(controllers = [HtmlController::class])
+class WeatherAppTest{
+
+    @MockBean
+    lateinit var weatherAppService: WeatherAppService
+
+    @MockBean
+    lateinit var meteoResponseData: MeteoResponseData
+
+    @Autowired
+    lateinit var mockMvc: MockMvc
+
+    object MockitoHelper {
+        fun <T> anyObject(): T {
+            Mockito.any<T>()
+            return uninitialized()
+        }
+        @Suppress("UNCHECKED_CAST")
+        fun <T> uninitialized(): T =  null as T
+    }
 
-class WeatherAppTest {
 
     @Test fun `sikeres lekerdezes`() {
-        TODO()
+        mockMvc.perform(get("/")).andExpect(status().isOk)
+            .andExpect(content()
+                .string("<html>\n" +
+                        "<head>\n" +
+                        "    <title>Average Daily temperature list</title>\n" +
+                        "</head>\n" +
+                        "<body>\n" +
+                        "\n" +
+                        "<h1>Average Daily temperature list</h1>\n" +
+                        "\n" +
+                        "\n" +
+                        "</body>\n" +
+                        "</html>"))
     }
 
+    @Test fun `sikertelen lekerdezes`() {
+        `when`(weatherAppService.fetchMeteoData(MockitoHelper.anyObject())).thenThrow(HttpServerErrorException(
+            HttpStatusCode.valueOf(500)))
+        mockMvc.perform(get("/")).andExpect(status().isOk)
+            .andExpect(content()
+                .string("<html>\n" +
+                        "<head>\n" +
+                        "    <title>Average Daily temperature list</title>\n" +
+                        "</head>\n" +
+                        "<body>\n" +
+                        "\n" +
+                        "<h1>Average Daily temperature list</h1>\n" +
+                        "\n" +
+                        "<h3>Exception occured while fetching meteo data.</h3>\n" +
+                        "\n" +
+                        "</body>\n" +
+                        "</html>"))
+    }
 }
\ No newline at end of file