package com.example.checkout

import android.os.Handler
import android.os.Looper
import org.json.JSONObject
import java.net.HttpURLConnection
import java.net.URL
import java.util.concurrent.Executors

// Application-owned API, not the platform API. Supply your customer's session token.
class CheckoutApi(private val origin: String, private val customerToken: () -> String) {
    private val worker = Executors.newSingleThreadExecutor()
    private val main = Handler(Looper.getMainLooper())

    init { require(origin.startsWith("https://") && !origin.endsWith("/")) }

    fun request(path: String, body: JSONObject? = null, done: (Result<JSONObject>) -> Unit) {
        require(path.startsWith("/api/"))
        worker.execute {
            val result = runCatching {
                val connection = URL(origin + path).openConnection() as HttpURLConnection
                try {
                    connection.instanceFollowRedirects = false
                    connection.connectTimeout = 15000
                    connection.readTimeout = 15000
                    connection.requestMethod = if (body == null) "GET" else "POST"
                    connection.setRequestProperty("Authorization", "Bearer ${customerToken()}")
                    connection.setRequestProperty("Accept", "application/json")
                    if (body != null) {
                        connection.doOutput = true
                        connection.setRequestProperty("Content-Type", "application/json")
                        connection.outputStream.use { it.write(body.toString().toByteArray(Charsets.UTF_8)) }
                    }
                    check(connection.responseCode in 200..299) { "Application API returned ${connection.responseCode}" }
                    JSONObject(connection.inputStream.bufferedReader(Charsets.UTF_8).use { it.readText() })
                } finally { connection.disconnect() }
            }
            main.post { done(result) }
        }
    }

    fun close() { worker.shutdown() }
}