diff options
| -rwxr-xr-x | curr | 84 |
1 files changed, 84 insertions, 0 deletions
@@ -0,0 +1,84 @@ +#!/usr/bin/env kscript +@file:DependsOnMaven("com.beust:klaxon:5.5") + +import com.beust.klaxon.Klaxon +import java.net.URL +import kotlin.system.exitProcess + +fun path(key: String) = "https://currencyapi.net/api/v1/rates?key=$key&base=USD" + +data class CurrencyApi( + var valid: Boolean = false, + var base: String = "", + var rates: Map<String, Double> = mapOf() +) { + fun fromBase(amount: Double, currencyCode: String): Double? = rate(currencyCode)?.let { amount * it } + fun toBase(amount: Double, currencyCode: String): Double? = rate(currencyCode)?.let { amount / it } + + fun convert(from: String, amount: Double, to: String): Double? = + toBase(amount, from)?.let { fromBase(it, to) } + + + fun rate(currencyCode: String): Double? = + currencyCode.toUpperCase().let { return@let if (currencyCode == base) 1.0 else rates[currencyCode] } + +} + +val apiKey: String? = System.getenv("CURRENCY_API_KEY") + +fun E(text: String): Int { + System.err.println("curr: $text") + return 1 +} + +fun E_UNKNOWN_USAGE(): Int = + E("Unknown usage. See curr --help") + +fun E_NO_API_KEY(): Int = + E("Missing currency api key. Get one at https://currencyapi.net/ and set in \$CURRENCY_API_KEY") + +fun E_APIERR(): Int = + E("Failed to parse currency api response. This might be a rate limit.") + +fun E_INVALID_AMOUNT(): Int = + E("Invalid amount. See curr --help") + +fun E_INVALID_CODE(code: String): Int = + E("Invalid code: $code. See curr --codes") + +fun getApi(key: String): CurrencyApi? = URL(path(key)).openStream().use { Klaxon().parse<CurrencyApi>(it) } + +fun main(): Int { + if (args.size == 1 && args[0] == "--help") { + System.err.println( + """ + Usage: curr <from> <to> <amount> + Usage: curr --codes + Usage: curr --help + + Set your https://currencyapi.net/ api key in ${'$'}CURRENCY_API_KEY + """.trimIndent() + ) + return 0 + } + if (args.size == 1 && args[0] == "--codes") { + val api = getApi(apiKey ?: return E_NO_API_KEY()) ?: return E_APIERR() + println((api.rates.keys + api.base).joinToString("\n")) + return 0 + } + if (args.size == 3) { + val amount: Double = try { + args[2].toDouble() + } catch (e: NumberFormatException) { + return E_INVALID_AMOUNT() + } + val api = getApi(apiKey ?: return E_NO_API_KEY()) ?: return E_APIERR() + if (api.rate(args[0]) == null) return E_INVALID_CODE(args[0]) + if (api.rate(args[1]) == null) return E_INVALID_CODE(args[1]) + println("$amount ${args[0]} to ${args[1]}: ${api.convert(args[0], amount, args[1])}") + return 0 + } + return E_UNKNOWN_USAGE() +} + +exitProcess(main()) |