Kata04: Data Munging

CombineData.kt

import java.io.File

open class CombineData(private val fileName: String) {

    private fun getColumnValue(line: String, column: Pair<Int, Int>): String {
        return line.substring(column.first, column.first + column.second - 1).trim().replace("*", "")
    }

    fun calculate(
        value: Pair<Int, Int>,
        columnA: Pair<Int, Int>,
        columnB: Pair<Int, Int>, diffFunction: (Float, Float) -> Float
    ): String {
        with(File(fileName)) {
            if (this.exists()) {
                val lines = this.readLines()
                var minTeam = ""
                var minDiff = Float.MAX_VALUE
                var first = true
                lines.forEach { line ->
                    if (!first) {
                        if (line.length > 15) {
                            val valueColumn = getColumnValue(line, value)
                            if (valueColumn != "----------------") {
                                val a = getColumnValue(line, columnA).toFloat()
                                val b = getColumnValue(line, columnB).toFloat()
                                val diff = diffFunction(a, b)
                                if (diff < minDiff) {
                                    minDiff = diff
                                    minTeam = valueColumn
                                }
                                println("$valueColumn $a $b $diff")
                            }
                        }
                    } else {
                        first = false
                    }
                }

                return minTeam;
            }
        }
        return ""
    }

}

CombineDataTests.kt

import com.natpryce.hamkrest.assertion.assertThat
import com.natpryce.hamkrest.equalTo
import org.junit.jupiter.api.Test

//http://codekata.com/kata/kata04-data-munging/
class CombineDataTests {
    companion object {
        fun getDataFilePath(file: String): String = {}.javaClass.getResource(file).file
    }

    @Test
    fun `we can read the football data`() {
        val footballData = FootballDataWithCombine(getDataFilePath("football.dat"))

        val teamSmallDifference = footballData.smallDifference()
        assertThat(teamSmallDifference, equalTo("Arsenal"))
    }

    @Test
    fun `we can read the weather data`() {
        val weatherData = WeatherDataWithCombine(getDataFilePath("weather.dat"))

        val dayWithMimSpread = weatherData.minSpreadDay()
        assertThat(dayWithMimSpread, equalTo(14))
    }
}

FootballDataWithCombine.kt

class FootballDataWithCombine(private val fileName: String) : CombineData(fileName) {
    fun smallDifference() = calculate(7 to 17, 43 to 3, 50 to 3) { a, b -> b - a }
}

WeatherDataWithCombine.kt

import kotlin.math.absoluteValue

class WeatherDataWithCombine(private val fileName: String) : CombineData(fileName) {
    fun minSpreadDay() = calculate(2 to 3, 6 to 4, 11 to 4) { a, b -> (a - b).absoluteValue }.toInt()
}