Factor out some cashier code into common library

9 files changed, 10 insertions, 420 deletions

diff --git a/cashier/src/main/AndroidManifest.xml b/cashier/src/main/AndroidManifest.xml
index 345c9a1..bdc5ec0 100644
--- a/cashier/src/main/AndroidManifest.xml
+++ b/cashier/src/main/AndroidManifest.xml
@@ -3,10 +3,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="net.taler.cashier">
 
-    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
-    <uses-permission android:name="android.permission.INTERNET" />
-    <uses-permission android:name="android.permission.NFC" />
-
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
diff --git a/cashier/src/main/java/net/taler/cashier/Amount.kt b/cashier/src/main/java/net/taler/cashier/Amount.kt
deleted file mode 100644
index 2c237c8..0000000
--- a/cashier/src/main/java/net/taler/cashier/Amount.kt
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * This file is part of GNU Taler
- * (C) 2020 Taler Systems S.A.
- *
- * GNU Taler is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free Software
- * Foundation; either version 3, or (at your option) any later version.
- *
- * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-package net.taler.cashier
-
-data class Amount(val currency: String, val amount: String) {
-
-    companion object {
-
-        private val SIGNED_REGEX = Regex("""([+\-])(\w+):([0-9.]+)""")
-
-        @Suppress("unused")
-        fun fromString(strAmount: String): Amount {
-            val components = strAmount.split(":")
-            return Amount(components[0], components[1])
-        }
-
-        fun fromStringSigned(strAmount: String): Amount? {
-            val groups = SIGNED_REGEX.matchEntire(strAmount)?.groupValues ?: emptyList()
-            if (groups.size < 4) return null
-            var amount = groups[3].toDoubleOrNull() ?: return null
-            if (groups[1] == "-") amount *= -1
-            val currency = groups[2]
-            val amountStr = amount.toString()
-            // only display as many digits as required to precisely render the balance
-            return Amount(currency, amountStr.removeSuffix(".0"))
-        }
-    }
-
-    override fun toString() = "$amount $currency"
-
-}
diff --git a/cashier/src/main/java/net/taler/cashier/BalanceFragment.kt b/cashier/src/main/java/net/taler/cashier/BalanceFragment.kt
index b3a0221..2178a78 100644
--- a/cashier/src/main/java/net/taler/cashier/BalanceFragment.kt
+++ b/cashier/src/main/java/net/taler/cashier/BalanceFragment.kt
@@ -34,6 +34,9 @@ import kotlinx.android.synthetic.main.fragment_balance.*
 import net.taler.cashier.BalanceFragmentDirections.Companion.actionBalanceFragmentToTransactionFragment
 import net.taler.cashier.withdraw.LastTransaction
 import net.taler.cashier.withdraw.WithdrawStatus
+import net.taler.common.Amount
+import net.taler.common.fadeIn
+import net.taler.common.fadeOut
 
 sealed class BalanceResult {
     object Error : BalanceResult()
diff --git a/cashier/src/main/java/net/taler/cashier/MainViewModel.kt b/cashier/src/main/java/net/taler/cashier/MainViewModel.kt
index 3874038..6cd12ff 100644
--- a/cashier/src/main/java/net/taler/cashier/MainViewModel.kt
+++ b/cashier/src/main/java/net/taler/cashier/MainViewModel.kt
@@ -32,9 +32,10 @@ import androidx.security.crypto.MasterKeys
 import androidx.security.crypto.MasterKeys.AES256_GCM_SPEC
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
-import net.taler.cashier.Amount.Companion.fromStringSigned
 import net.taler.cashier.HttpHelper.makeJsonGetRequest
 import net.taler.cashier.withdraw.WithdrawManager
+import net.taler.common.Amount.Companion.fromStringSigned
+import net.taler.common.isOnline
 
 private val TAG = MainViewModel::class.java.simpleName
 
diff --git a/cashier/src/main/java/net/taler/cashier/Utils.kt b/cashier/src/main/java/net/taler/cashier/Utils.kt
deleted file mode 100644
index 62f7a77..0000000
--- a/cashier/src/main/java/net/taler/cashier/Utils.kt
+++ /dev/null
@@ -1,91 +0,0 @@
-/*
- * This file is part of GNU Taler
- * (C) 2020 Taler Systems S.A.
- *
- * GNU Taler is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free Software
- * Foundation; either version 3, or (at your option) any later version.
- *
- * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-package net.taler.cashier
-
-import android.content.Context
-import android.content.Context.CONNECTIVITY_SERVICE
-import android.net.ConnectivityManager
-import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
-import android.os.Build.VERSION.SDK_INT
-import android.view.View
-import android.view.View.INVISIBLE
-import android.view.View.VISIBLE
-
-object Utils {
-
-    private const val HEX_CHARS = "0123456789ABCDEF"
-
-    fun hexStringToByteArray(data: String): ByteArray {
-        val result = ByteArray(data.length / 2)
-
-        for (i in data.indices step 2) {
-            val firstIndex = HEX_CHARS.indexOf(data[i])
-            val secondIndex = HEX_CHARS.indexOf(data[i + 1])
-
-            val octet = firstIndex.shl(4).or(secondIndex)
-            result[i.shr(1)] = octet.toByte()
-        }
-        return result
-    }
-
-
-    private val HEX_CHARS_ARRAY = HEX_CHARS.toCharArray()
-
-    @Suppress("unused")
-    fun toHex(byteArray: ByteArray): String {
-        val result = StringBuffer()
-
-        byteArray.forEach {
-            val octet = it.toInt()
-            val firstIndex = (octet and 0xF0).ushr(4)
-            val secondIndex = octet and 0x0F
-            result.append(HEX_CHARS_ARRAY[firstIndex])
-            result.append(HEX_CHARS_ARRAY[secondIndex])
-        }
-        return result.toString()
-    }
-
-}
-
-fun View.fadeIn(endAction: () -> Unit = {}) {
-    if (visibility == VISIBLE) return
-    alpha = 0f
-    visibility = VISIBLE
-    animate().alpha(1f).withEndAction {
-        endAction.invoke()
-    }.start()
-}
-
-fun View.fadeOut(endAction: () -> Unit = {}) {
-    if (visibility == INVISIBLE) return
-    animate().alpha(0f).withEndAction {
-        visibility = INVISIBLE
-        alpha = 1f
-        endAction.invoke()
-    }.start()
-}
-
-fun Context.isOnline(): Boolean {
-    val cm = getSystemService(CONNECTIVITY_SERVICE) as ConnectivityManager
-    return if (SDK_INT < 29) {
-        @Suppress("DEPRECATION")
-        cm.activeNetworkInfo?.isConnected == true
-    } else {
-        val capabilities = cm.getNetworkCapabilities(cm.activeNetwork) ?: return false
-        capabilities.hasCapability(NET_CAPABILITY_INTERNET)
-    }
-}
diff --git a/cashier/src/main/java/net/taler/cashier/withdraw/NfcManager.kt b/cashier/src/main/java/net/taler/cashier/withdraw/NfcManager.kt
deleted file mode 100644
index a487b5f..0000000
--- a/cashier/src/main/java/net/taler/cashier/withdraw/NfcManager.kt
+++ /dev/null
@@ -1,234 +0,0 @@
-/*
- * This file is part of GNU Taler
- * (C) 2020 Taler Systems S.A.
- *
- * GNU Taler is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free Software
- * Foundation; either version 3, or (at your option) any later version.
- *
- * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-package net.taler.cashier.withdraw
-
-import android.app.Activity
-import android.content.Context
-import android.nfc.NfcAdapter
-import android.nfc.NfcAdapter.FLAG_READER_NFC_A
-import android.nfc.NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK
-import android.nfc.NfcAdapter.getDefaultAdapter
-import android.nfc.Tag
-import android.nfc.tech.IsoDep
-import android.util.Log
-import net.taler.cashier.Utils.hexStringToByteArray
-import org.json.JSONObject
-import java.io.ByteArrayOutputStream
-import java.net.URL
-import javax.net.ssl.HttpsURLConnection
-
-@Suppress("unused")
-private const val TALER_AID = "A0000002471001"
-
-class NfcManager : NfcAdapter.ReaderCallback {
-
-    companion object {
-        const val TAG = "taler-merchant"
-
-        /**
-         * Returns true if NFC is supported and false otherwise.
-         */
-        fun hasNfc(context: Context): Boolean {
-            return getNfcAdapter(context) != null
-        }
-
-        /**
-         * Enables NFC reader mode. Don't forget to call [stop] afterwards.
-         */
-        fun start(activity: Activity, nfcManager: NfcManager) {
-            getNfcAdapter(activity)?.enableReaderMode(activity, nfcManager, nfcManager.flags, null)
-        }
-
-        /**
-         * Disables NFC reader mode. Call after [start].
-         */
-        fun stop(activity: Activity) {
-            getNfcAdapter(activity)?.disableReaderMode(activity)
-        }
-
-        private fun getNfcAdapter(context: Context): NfcAdapter? {
-            return getDefaultAdapter(context)
-        }
-    }
-
-    private val flags = FLAG_READER_NFC_A or FLAG_READER_SKIP_NDEF_CHECK
-
-    private var tagString: String? = null
-    private var currentTag: IsoDep? = null
-
-    fun setTagString(tagString: String) {
-        this.tagString = tagString
-    }
-
-    override fun onTagDiscovered(tag: Tag?) {
-
-        Log.v(TAG, "tag discovered")
-
-        val isoDep = IsoDep.get(tag)
-        isoDep.connect()
-
-        currentTag = isoDep
-
-        isoDep.transceive(apduSelectFile())
-
-        val tagString: String? = tagString
-        if (tagString != null) {
-            isoDep.transceive(apduPutTalerData(1, tagString.toByteArray()))
-        }
-
-        // FIXME: use better pattern for sleeps in between requests
-        // -> start with fast polling, poll more slowly if no requests are coming
-
-        while (true) {
-            try {
-                val reqFrame = isoDep.transceive(apduGetData())
-                if (reqFrame.size < 2) {
-                    Log.v(TAG, "request frame too small")
-                    break
-                }
-                val req = ByteArray(reqFrame.size - 2)
-                if (req.isEmpty()) {
-                    continue
-                }
-                reqFrame.copyInto(req, 0, 0, reqFrame.size - 2)
-                val jsonReq = JSONObject(req.toString(Charsets.UTF_8))
-                val reqId = jsonReq.getInt("id")
-                Log.v(TAG, "got request $jsonReq")
-                val jsonInnerReq = jsonReq.getJSONObject("request")
-                val method = jsonInnerReq.getString("method")
-                val urlStr = jsonInnerReq.getString("url")
-                Log.v(TAG, "url '$urlStr'")
-                Log.v(TAG, "method '$method'")
-                val url = URL(urlStr)
-                val conn: HttpsURLConnection = url.openConnection() as HttpsURLConnection
-                conn.setRequestProperty("Accept", "application/json")
-                conn.connectTimeout = 5000
-                conn.doInput = true
-                when (method) {
-                    "get" -> {
-                        conn.requestMethod = "GET"
-                    }
-                    "postJson" -> {
-                        conn.requestMethod = "POST"
-                        conn.doOutput = true
-                        conn.setRequestProperty("Content-Type", "application/json; utf-8")
-                        val body = jsonInnerReq.getString("body")
-                        conn.outputStream.write(body.toByteArray(Charsets.UTF_8))
-                    }
-                    else -> {
-                        throw Exception("method not supported")
-                    }
-                }
-                Log.v(TAG, "connecting")
-                conn.connect()
-                Log.v(TAG, "connected")
-
-                val statusCode = conn.responseCode
-                val tunnelResp = JSONObject()
-                tunnelResp.put("id", reqId)
-                tunnelResp.put("status", conn.responseCode)
-
-                if (statusCode == 200) {
-                    val stream = conn.inputStream
-                    val httpResp = stream.buffered().readBytes()
-                    tunnelResp.put("responseJson", JSONObject(httpResp.toString(Charsets.UTF_8)))
-                }
-
-                Log.v(TAG, "sending: $tunnelResp")
-
-                isoDep.transceive(apduPutTalerData(2, tunnelResp.toString().toByteArray()))
-            } catch (e: Exception) {
-                Log.v(TAG, "exception during NFC loop: $e")
-                break
-            }
-        }
-
-        isoDep.close()
-    }
-
-    private fun writeApduLength(stream: ByteArrayOutputStream, size: Int) {
-        when {
-            size == 0 -> {
-                // No size field needed!
-            }
-            size <= 255 -> // One byte size field
-                stream.write(size)
-            size <= 65535 -> {
-                stream.write(0)
-                // FIXME: is this supposed to be little or big endian?
-                stream.write(size and 0xFF)
-                stream.write((size ushr 8) and 0xFF)
-            }
-            else -> throw Error("payload too big")
-        }
-    }
-
-    private fun apduSelectFile(): ByteArray {
-        return hexStringToByteArray("00A4040007A0000002471001")
-    }
-
-    private fun apduPutData(payload: ByteArray): ByteArray {
-        val stream = ByteArrayOutputStream()
-
-        // Class
-        stream.write(0x00)
-
-        // Instruction 0xDA = put data
-        stream.write(0xDA)
-
-        // Instruction parameters
-        // (proprietary encoding)
-        stream.write(0x01)
-        stream.write(0x00)
-
-        writeApduLength(stream, payload.size)
-
-        stream.write(payload)
-
-        return stream.toByteArray()
-    }
-
-    private fun apduPutTalerData(talerInst: Int, payload: ByteArray): ByteArray {
-        val realPayload = ByteArrayOutputStream()
-        realPayload.write(talerInst)
-        realPayload.write(payload)
-        return apduPutData(realPayload.toByteArray())
-    }
-
-    private fun apduGetData(): ByteArray {
-        val stream = ByteArrayOutputStream()
-
-        // Class
-        stream.write(0x00)
-
-        // Instruction 0xCA = get data
-        stream.write(0xCA)
-
-        // Instruction parameters
-        // (proprietary encoding)
-        stream.write(0x01)
-        stream.write(0x00)
-
-        // Max expected response size, two
-        // zero bytes denotes 65536
-        stream.write(0x0)
-        stream.write(0x0)
-
-        return stream.toByteArray()
-    }
-
-}
diff --git a/cashier/src/main/java/net/taler/cashier/withdraw/QrCodeManager.kt b/cashier/src/main/java/net/taler/cashier/withdraw/QrCodeManager.kt
deleted file mode 100644
index e3ffa92..0000000
--- a/cashier/src/main/java/net/taler/cashier/withdraw/QrCodeManager.kt
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * This file is part of GNU Taler
- * (C) 2020 Taler Systems S.A.
- *
- * GNU Taler is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free Software
- * Foundation; either version 3, or (at your option) any later version.
- *
- * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
- */
-
-package net.taler.cashier.withdraw
-
-import android.graphics.Bitmap
-import android.graphics.Bitmap.Config.RGB_565
-import android.graphics.Color.BLACK
-import android.graphics.Color.WHITE
-import com.google.zxing.BarcodeFormat.QR_CODE
-import com.google.zxing.qrcode.QRCodeWriter
-
-object QrCodeManager {
-
-    fun makeQrCode(text: String, size: Int = 256): Bitmap {
-        val qrCodeWriter = QRCodeWriter()
-        val bitMatrix = qrCodeWriter.encode(text, QR_CODE, size, size)
-        val height = bitMatrix.height
-        val width = bitMatrix.width
-        val bmp = Bitmap.createBitmap(width, height, RGB_565)
-        for (x in 0 until width) {
-            for (y in 0 until height) {
-                bmp.setPixel(x, y, if (bitMatrix.get(x, y)) BLACK else WHITE)
-            }
-        }
-        return bmp
-    }
-
-}
diff --git a/cashier/src/main/java/net/taler/cashier/withdraw/TransactionFragment.kt b/cashier/src/main/java/net/taler/cashier/withdraw/TransactionFragment.kt
index 8b782b0..8857bfa 100644
--- a/cashier/src/main/java/net/taler/cashier/withdraw/TransactionFragment.kt
+++ b/cashier/src/main/java/net/taler/cashier/withdraw/TransactionFragment.kt
@@ -30,13 +30,14 @@ import androidx.navigation.fragment.findNavController
 import kotlinx.android.synthetic.main.fragment_transaction.*
 import net.taler.cashier.MainViewModel
 import net.taler.cashier.R
-import net.taler.cashier.fadeIn
-import net.taler.cashier.fadeOut
 import net.taler.cashier.withdraw.TransactionFragmentDirections.Companion.actionTransactionFragmentToBalanceFragment
 import net.taler.cashier.withdraw.TransactionFragmentDirections.Companion.actionTransactionFragmentToErrorFragment
 import net.taler.cashier.withdraw.WithdrawResult.Error
 import net.taler.cashier.withdraw.WithdrawResult.InsufficientBalance
 import net.taler.cashier.withdraw.WithdrawResult.Success
+import net.taler.common.NfcManager
+import net.taler.common.fadeIn
+import net.taler.common.fadeOut
 
 class TransactionFragment : Fragment() {
 
diff --git a/cashier/src/main/java/net/taler/cashier/withdraw/WithdrawManager.kt b/cashier/src/main/java/net/taler/cashier/withdraw/WithdrawManager.kt
index 4c618ac..bfc82ce 100644
--- a/cashier/src/main/java/net/taler/cashier/withdraw/WithdrawManager.kt
+++ b/cashier/src/main/java/net/taler/cashier/withdraw/WithdrawManager.kt
@@ -34,6 +34,7 @@ import net.taler.cashier.HttpJsonResult.Error
 import net.taler.cashier.HttpJsonResult.Success
 import net.taler.cashier.MainViewModel
 import net.taler.cashier.R
+import net.taler.common.QrCodeManager.makeQrCode
 import org.json.JSONObject
 import java.util.concurrent.TimeUnit.MINUTES
 import java.util.concurrent.TimeUnit.SECONDS
@@ -95,7 +96,7 @@ class WithdrawManager(
                     val withdrawResult = WithdrawResult.Success(
                         id = result.json.getString("withdrawal_id"),
                         talerUri = talerUri,
-                        qrCode = QrCodeManager.makeQrCode(talerUri)
+                        qrCode = makeQrCode(talerUri)
                     )
                     mWithdrawResult.postValue(withdrawResult)
                     timer.start()