/**
 * PayUs Integrator Demo — Android (Kotlin)
 *
 * Single-file demo showing the full third-party integration flow using raw HTTP.
 * No SDK dependency — uses java.net.HttpURLConnection for clarity.
 *
 * Run as Kotlin script:  kotlin IntegratorDemo.kt
 * Or compile:            kotlinc IntegratorDemo.kt -include-runtime -d demo.jar && java -jar demo.jar
 *
 * ⚠️  Replace APP_ID, APP_SECRET, and BRANCH_ID with your real values.
 */

import java.io.OutputStreamWriter
import java.net.HttpURLConnection
import java.net.URL
import java.util.Base64

const val BASE = "https://payus.co.nz"
const val SYSTEM = "pos"
const val APP_ID = "YOUR_APP_ID"
const val APP_SECRET = "YOUR_APP_SECRET"
const val BRANCH_ID = 123L

fun main() {
    println("═══════════════════════════════════════════════════")
    println("  PayUs Integrator Demo — Android (Kotlin)")
    println("═══════════════════════════════════════════════════")

    // Step 1: Authenticate
    println("\n🔐 Step 1: Authenticating...")
    val credentials = Base64.getEncoder().encodeToString("$APP_ID:$APP_SECRET".toByteArray())
    val authResponse = post("$BASE/api/v1/oauth/token", null, mapOf("Authorization" to "Basic $credentials"))
    println("   ✅ Token acquired")
    // Parse token from JSON response (simple string extraction)
    val token = authResponse.substringAfter("\"token\":\"").substringBefore("\"")

    // Step 2: List terminals
    println("\n📱 Step 2: Listing terminals...")
    val terminalsResponse = get("$BASE/api/v1/$SYSTEM/listTerminals?branchId=$BRANCH_ID", token)
    println("   ✅ Response: ${terminalsResponse.take(200)}...")

    // Step 3: Send PRINT trigger (requires terminals:trigger scope)
    println("\n🖨️  Step 3: Sending PRINT trigger...")
    val triggerBody = """
        {"terminalId":"TERM001","accessId":"ACCESS001","requestType":"PRINT",
         "body":"Hello from Kotlin integrator!","branchId":$BRANCH_ID,"configId":1}
    """.trimIndent()
    try {
        val triggerResp = post("$BASE/api/v1/$SYSTEM/requestTerminal", triggerBody, bearerHeader(token))
        println("   ✅ Trigger sent: ${triggerResp.take(100)}")
    } catch (e: Exception) {
        println("   ⚠️  Trigger failed: ${e.message}")
    }

    // Step 4: Process payment (requires payments:direct scope)
    println("\n💳 Step 4: Processing test payment...")
    val payBody = """
        {"grandTotal":"0.01","referenceId":"kt_demo_${System.currentTimeMillis()}",
         "branchId":$BRANCH_ID,"configId":1,"terminalId":"TERM001","accessId":"ACCESS001",
         "channel":"WECHAT","qrMode":true}
    """.trimIndent()
    try {
        val payResp = post("$BASE/api/v1/$SYSTEM/payNow", payBody, bearerHeader(token))
        println("   ✅ Payment response: ${payResp.take(200)}")
    } catch (e: Exception) {
        println("   ⚠️  Payment failed: ${e.message} (expected without payments:direct scope)")
    }

    // Step 5: Query transactions (requires transactions:read scope)
    println("\n📊 Step 5: Querying transactions...")
    val today = java.time.LocalDate.now().toString()
    val queryBody = """{"branchId":$BRANCH_ID,"startDate":"$today","endDate":"$today"}"""
    try {
        val queryResp = post("$BASE/api/v1/$SYSTEM/getRecentTransactions", queryBody, bearerHeader(token))
        println("   ✅ Transactions: ${queryResp.take(200)}...")
    } catch (e: Exception) {
        println("   ⚠️  Query failed: ${e.message}")
    }

    println("\n✅ Demo complete!")
}

fun bearerHeader(token: String) = mapOf("Authorization" to "Bearer $token")

fun get(url: String, token: String): String {
    val conn = URL(url).openConnection() as HttpURLConnection
    conn.requestMethod = "GET"
    conn.setRequestProperty("Authorization", "Bearer $token")
    conn.setRequestProperty("Accept", "application/json")
    if (conn.responseCode != 200) throw Exception("${conn.responseCode}: ${conn.errorStream?.bufferedReader()?.readText()}")
    return conn.inputStream.bufferedReader().readText()
}

fun post(url: String, body: String?, headers: Map<String, String>): String {
    val conn = URL(url).openConnection() as HttpURLConnection
    conn.requestMethod = "POST"
    conn.setRequestProperty("Accept", "application/json")
    headers.forEach { (k, v) -> conn.setRequestProperty(k, v) }
    if (body != null) {
        conn.doOutput = true
        conn.setRequestProperty("Content-Type", "application/json")
        OutputStreamWriter(conn.outputStream).use { it.write(body) }
    }
    if (conn.responseCode !in 200..299) {
        val err = conn.errorStream?.bufferedReader()?.readText() ?: "No body"
        throw Exception("${conn.responseCode}: $err")
    }
    return conn.inputStream.bufferedReader().readText()
}