generating customer invoice upon good shipment notification

SOLUTION.md

@@ -0,0 +1,102 @@
+Solution for Billie Pair Programming Exercise 
+=============
+### Requirements:
+
+* Issuing an invoice for the buyer once the merchant notifies us the goods have been shipped
+
+### Steps to test
+1- open the swagger ui:
+http://localhost:8080/swagger-ui/index.html
+
+2- find the list of available merchants or add a new one:
+
+```
+[
+  {
+    "id": "59267c88-a561-4e07-ab5d-75b64bed6a7c",
+    "name": "amazon.com"
+  },
+  {
+    "id": "a177028a-fcde-4b56-95aa-08c0fa9fca2e",
+    "name": "ebay.com"
+  }
+]
+```
+
+3- find the list of available customers or create a new one:
+```
+[
+  {
+    "id": "25fca542-cb2f-4c5d-81e1-cbe2f4a6fd83",
+    "name": "John Smith",
+    "address_details": "5703 Louetta Rd, Texas"
+  },
+  {
+    "id": "2867689a-f3b1-45ed-a1ad-7adf3b40a0ab",
+    "name": "Josh Long",
+    "address_details": "9069 Holman Rd NW, Seattle"
+  },
+  {
+    "id": "1325673e-ea2e-4b0b-822c-051204ecc7e8",
+    "name": "Esfandiyar Talebi",
+    "address_details": "Yavux su, burhabine, Istanbul"
+  }
+]
+```
+
+4- find the list of available Products or add new ones:
+```
+[
+  {
+    "id": "126ff1c1-1e28-4355-a5d2-1aab3f3c48b8",
+    "name": "iPhone 15 SE",
+    "price": 999
+  },
+  {
+    "id": "93e77e2e-30ea-40d2-b505-b46c00f15680",
+    "name": "iPhone 15 Max",
+    "price": 1299
+  }
+]
+```
+5- Create an Order for one of the Customers with available product uid:
+```
+{
+  "amount": 100.00,
+  "customerId": "25fca542-cb2f-4c5d-81e1-cbe2f4a6fd83"
+}
+```
+and note down the order uid:
+```
+{
+  "id": "94449231-63de-441a-bb9b-d70e802ab957"
+}
+```
+6- Notify the shipment of the order by using merchant resource
+
+```
+{
+ "shipmentUId": "94449231-63de-441a-bb9b-d70e802ab955",
+  "orderUId": "94449231-63de-441a-bb9b-d70e802ab957",
+  "customerUId": "25fca542-cb2f-4c5d-81e1-cbe2f4a6fd83"
+}
+```
+as a result, invoice will be generated for the customer.
+
+7- find the newly created Invoice within the list of invoices
+
+### work in progress
+1- Handling the deduplication of shipment event
+2- Adding more integration tests for DAO classes
+
+
+#### Prerequisites
+
+Running the tests:
+```shell
+cd <project_root>
+docker compose up database -d
+gradle flywayMigrate
+gradle clean build
+docs at -> http://localhost:8080/swagger-ui/index.html
+```

build.gradle.kts

@@ -26,6 +26,8 @@ repositories {
     mavenCentral()
 }
 
+extra["testcontainersVersion"] = "1.18.3"
+
 dependencies {
     implementation("org.springframework.boot:spring-boot-starter-validation")
     implementation("org.springframework.boot:spring-boot-starter-data-jdbc")
@@ -39,10 +41,21 @@ dependencies {
     implementation("org.jetbrains.kotlin:kotlin-reflect")
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
     runtimeOnly("org.postgresql:postgresql")
+    implementation ("org.flywaydb:flyway-core")
+
+    // adding test container support
+    testImplementation("org.testcontainers:junit-jupiter")
+    testImplementation("org.testcontainers:postgresql")
 
     testImplementation("org.springframework.boot:spring-boot-starter-test")
 }
 
+dependencyManagement {
+    imports {
+        mavenBom("org.testcontainers:testcontainers-bom:${property("testcontainersVersion")}")
+    }
+}
+
 flyway {
     url = dbConf.getProperty("DATABASE_URL")
     user = dbConf.getProperty("POSTGRES_USER")

src/main/kotlin/io/billie/countries/data/CountryRepository.kt

@@ -15,13 +15,21 @@ class CountryRepository {
     @Autowired
     lateinit var jdbcTemplate: JdbcTemplate
 
-    @Transactional(readOnly=true)
+    @Transactional(readOnly = true)
     fun findCountries(): List<CountryResponse> {
-        val query = jdbcTemplate.query(
-            "select id, name, country_code from organisations_schema.countries",
-            countryResponseMapper()
+        return jdbcTemplate.query(
+                "select id, name, country_code from organisations_schema.countries",
+                countryResponseMapper()
         )
-        return query
+    }
+
+    @Transactional
+    fun findCountryByCode (countryCode: String): Optional<CountryResponse>{
+        return jdbcTemplate.query(
+                "select id, name, country_code from organisations_schema.countries where country_code=?",
+                countryResponseMapper(),
+                countryCode
+        ).stream().findFirst()
     }
 
     private fun countryResponseMapper() = RowMapper<CountryResponse> { it: ResultSet, _: Int ->

src/main/kotlin/io/billie/countries/exception/CountryNotFoundException.kt

@@ -0,0 +1,4 @@
+package io.billie.countries.exception
+
+class CountryNotFoundException (message: String): RuntimeException(message) {
+}

src/main/kotlin/io/billie/countries/service/CountryService.kt

@@ -2,6 +2,7 @@ package io.billie.countries.service
 
 import io.billie.countries.data.CityRepository
 import io.billie.countries.data.CountryRepository
+import io.billie.countries.exception.CountryNotFoundException
 import io.billie.countries.model.CityResponse
 import io.billie.countries.model.CountryResponse
 import org.springframework.stereotype.Service
@@ -14,4 +15,7 @@ class CountryService(val dbCountry: CountryRepository, val dbCity: CityRepositor
     }
     fun findCities(countryCode: String): List<CityResponse> = dbCity.findByCountryCode(countryCode)
 
+    fun findCountryByCode (countryCode: String): CountryResponse {
+        return dbCountry.findCountryByCode(countryCode).orElseThrow { CountryNotFoundException("country with code: $countryCode was not found!") }
+    }
 }

src/main/kotlin/io/billie/customers/data/CustomerRepository.kt

@@ -0,0 +1,65 @@
+package io.billie.customers.data
+
+import io.billie.customers.dto.CustomerRequest
+import io.billie.customers.model.Customer
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.jdbc.core.JdbcTemplate
+import org.springframework.jdbc.core.RowMapper
+import org.springframework.jdbc.support.GeneratedKeyHolder
+import org.springframework.jdbc.support.KeyHolder
+import org.springframework.stereotype.Repository
+import org.springframework.transaction.annotation.Transactional
+import java.sql.ResultSet
+import java.util.*
+
+@Repository
+class CustomerRepository {
+    @Autowired
+    lateinit var jdbcTemplate: JdbcTemplate
+
+    @Transactional(readOnly=true)
+    fun findCustomerById(id: UUID): Optional<Customer> {
+        return jdbcTemplate.query(
+                "select id, name, address_details from organisations_schema.customers where id= ?",
+                customerResponseMapper(),
+                id
+        ).stream().findFirst();
+    }
+
+    private fun customerResponseMapper() = RowMapper<Customer> { it: ResultSet, _: Int ->
+        Customer(
+                it.getObject("id", UUID::class.java),
+                it.getString("name"),
+                it.getString("address_details")
+        )
+    }
+
+    @Transactional
+    fun findCustomers(): List<Customer> {
+        return jdbcTemplate.query(
+                "select id, name, address_details from organisations_schema.customers",
+                customerResponseMapper(),
+        )
+    }
+
+    @Transactional
+    fun createCustomer(customerRequest: CustomerRequest): UUID {
+        val keyHolder: KeyHolder = GeneratedKeyHolder()
+        jdbcTemplate.update(
+                { connection ->
+                    val ps = connection.prepareStatement(
+                            """
+                                INSERT INTO organisations_schema.customers 
+                                    (name, address_details)
+                                    VALUES (?, ?)
+                            """.trimIndent(),
+                            arrayOf("id")
+                    )
+                    ps.setString(1, customerRequest.name)
+                    ps.setString(2, customerRequest.address)
+                    ps
+                }, keyHolder
+        )
+        return keyHolder.getKeyAs(UUID::class.java)!!
+    }
+}

src/main/kotlin/io/billie/customers/dto/CustomerRequest.kt

@@ -0,0 +1,10 @@
+package io.billie.customers.dto
+
+import com.fasterxml.jackson.annotation.JsonProperty
+import javax.validation.constraints.NotBlank
+
+data class CustomerRequest (
+        @field:NotBlank val name: String,
+        @field:NotBlank @JsonProperty("address_details")
+        val address: String
+)

src/main/kotlin/io/billie/customers/dto/CustomerResponse.kt

@@ -0,0 +1,14 @@
+package io.billie.customers.dto
+
+import com.fasterxml.jackson.annotation.JsonProperty
+import java.util.UUID
+import javax.validation.constraints.NotBlank
+
+data class CustomerResponse (
+        val id: UUID,
+
+        @field:NotBlank val name: String,
+
+        @field:NotBlank @JsonProperty("address_details")
+        val address: String
+)

src/main/kotlin/io/billie/customers/exception/CustomerNotFoundException.kt

@@ -0,0 +1,4 @@
+package io.billie.customers.exception
+
+class CustomerNotFoundException (message: String): RuntimeException (message) {
+}

src/main/kotlin/io/billie/customers/mapper/CustomerResponseMapper.kt

@@ -0,0 +1,12 @@
+package io.billie.customers.mapper
+
+import io.billie.customers.dto.CustomerResponse
+import io.billie.customers.model.Customer
+
+
+fun Customer.toCustomerResponse(): CustomerResponse =
+    CustomerResponse(
+            id =  this.id,
+            name = this.name,
+            address = this.address
+    )

src/main/kotlin/io/billie/customers/model/Customer.kt

@@ -0,0 +1,14 @@
+package io.billie.customers.model
+
+import com.fasterxml.jackson.annotation.JsonProperty
+import java.util.UUID
+import javax.validation.constraints.NotBlank
+
+data class Customer (
+        val id: UUID,
+
+        @field:NotBlank val name: String,
+
+        // TODO: shall be replaced with AddressDetail later
+        @field:NotBlank @JsonProperty("address_details") val address: String
+)

src/main/kotlin/io/billie/customers/resource/CustomerResource.kt

@@ -0,0 +1,65 @@
+package io.billie.customers.resource
+
+import io.billie.customers.dto.CustomerRequest
+import io.billie.customers.dto.CustomerResponse
+import io.billie.customers.mapper.toCustomerResponse
+import io.billie.customers.service.CustomerService
+import io.billie.orders.dto.OrderResponse
+import io.billie.organisations.model.Entity
+import io.swagger.v3.oas.annotations.media.ArraySchema
+import io.swagger.v3.oas.annotations.media.Content
+import io.swagger.v3.oas.annotations.media.Schema
+import io.swagger.v3.oas.annotations.responses.ApiResponse
+import io.swagger.v3.oas.annotations.responses.ApiResponses
+import org.springframework.http.HttpStatus
+import org.springframework.http.ResponseEntity
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.PostMapping
+import org.springframework.web.bind.annotation.RequestBody
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RestController
+import kotlin.streams.toList
+
+@RestController
+@RequestMapping ("/customers")
+class CustomerResource (val customerService: CustomerService) {
+    @GetMapping
+    @ApiResponses(
+            value = [
+                ApiResponse(
+                        responseCode = "200",
+                        description = "returns all customers ",
+                        content = [
+                            (Content(
+                                    mediaType = "application/json",
+                                    array = (ArraySchema(schema = Schema(implementation = CustomerResponse::class)))
+                            ))]
+                )
+            ]
+    )
+    fun findCustomers (): ResponseEntity<List<CustomerResponse>>{
+        return ResponseEntity.ok(customerService.findCustomers()
+                .stream().map { it.toCustomerResponse() }
+                .toList())
+    }
+
+    @PostMapping
+    @ApiResponses(
+            value = [
+                ApiResponse(
+                        responseCode = "201",
+                        description = "Accepted the new customer",
+                        content = [
+                            (Content(
+                                    mediaType = "application/json",
+                                    array = (ArraySchema(schema = Schema(implementation = Entity::class)))
+                            ))]
+                ),
+                ApiResponse(responseCode = "400", description = "Bad request", content = [Content()])]
+    )
+    fun createCustomer(@RequestBody customerRequest: CustomerRequest): ResponseEntity<Entity>{
+        val customerId = customerService.createCustomer(customerRequest)
+
+        return ResponseEntity.status(HttpStatus.CREATED).body(Entity(customerId))
+    }
+}

src/main/kotlin/io/billie/customers/service/CustomerService.kt

@@ -0,0 +1,11 @@
+package io.billie.customers.service
+
+import io.billie.customers.dto.CustomerRequest
+import io.billie.customers.model.Customer
+import java.util.UUID
+
+interface CustomerService {
+    fun findCustomers(): List<Customer>
+    fun findCustomerByUid (uid: UUID): Customer
+    fun createCustomer(customerRequest: CustomerRequest): UUID
+}