Factor out code from merchant-terminal into common library

6 files changed, 228 insertions, 11 deletions

diff --git a/taler-kotlin-common/build.gradle b/taler-kotlin-common/build.gradle
index d7c9362..1d45a54 100644
--- a/taler-kotlin-common/build.gradle
+++ b/taler-kotlin-common/build.gradle
@@ -47,10 +47,17 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.core:core-ktx:1.2.0'
 
+    // Navigation
+    implementation "androidx.navigation:navigation-ui-ktx:$nav_version"
+    implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
+
     // ViewModel and LiveData
     def lifecycle_version = "2.2.0"
     implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
 
     // QR codes
     implementation 'com.google.zxing:core:3.4.0'  // needs minSdkVersion 24+
+
+    // JSON parsing and serialization
+    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.10.2"
 }
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/Amount.kt b/taler-kotlin-common/src/main/java/net/taler/common/Amount.kt
index 428ddef..0389db1 100644
--- a/taler-kotlin-common/src/main/java/net/taler/common/Amount.kt
+++ b/taler-kotlin-common/src/main/java/net/taler/common/Amount.kt
@@ -16,13 +16,14 @@
 
 package net.taler.common
 
+import org.json.JSONObject
+
 data class Amount(val currency: String, val amount: String) {
 
     companion object {
-
+        private const val FRACTIONAL_BASE = 1e8
         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])
@@ -38,6 +39,22 @@ data class Amount(val currency: String, val amount: String) {
             // only display as many digits as required to precisely render the balance
             return Amount(currency, amountStr.removeSuffix(".0"))
         }
+
+        fun fromJson(jsonAmount: JSONObject): Amount {
+            val amountCurrency = jsonAmount.getString("currency")
+            val amountValue = jsonAmount.getString("value")
+            val amountFraction = jsonAmount.getString("fraction")
+            val amountIntValue = Integer.parseInt(amountValue)
+            val amountIntFraction = Integer.parseInt(amountFraction)
+            return Amount(
+                amountCurrency,
+                (amountIntValue + amountIntFraction / FRACTIONAL_BASE).toString()
+            )
+        }
+    }
+
+    fun isZero(): Boolean {
+        return amount.toDouble() == 0.0
     }
 
     override fun toString() = "$amount $currency"
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/AndroidUtils.kt b/taler-kotlin-common/src/main/java/net/taler/common/AndroidUtils.kt
index 2fafdf2..fc04da5 100644
--- a/taler-kotlin-common/src/main/java/net/taler/common/AndroidUtils.kt
+++ b/taler-kotlin-common/src/main/java/net/taler/common/AndroidUtils.kt
@@ -19,35 +19,65 @@ package net.taler.common
 import android.content.Context
 import android.content.Context.CONNECTIVITY_SERVICE
 import android.net.ConnectivityManager
-import android.net.NetworkCapabilities
-import android.os.Build
+import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
+import android.os.Build.VERSION.SDK_INT
+import android.text.format.DateUtils
+import android.text.format.DateUtils.DAY_IN_MILLIS
+import android.text.format.DateUtils.FORMAT_ABBREV_MONTH
+import android.text.format.DateUtils.FORMAT_ABBREV_RELATIVE
+import android.text.format.DateUtils.FORMAT_NO_YEAR
+import android.text.format.DateUtils.FORMAT_SHOW_DATE
+import android.text.format.DateUtils.FORMAT_SHOW_TIME
+import android.text.format.DateUtils.MINUTE_IN_MILLIS
 import android.view.View
+import android.view.View.INVISIBLE
+import android.view.View.VISIBLE
+import androidx.fragment.app.Fragment
+import androidx.navigation.NavDirections
+import androidx.navigation.fragment.findNavController
 
 fun View.fadeIn(endAction: () -> Unit = {}) {
-    if (visibility == View.VISIBLE) return
+    if (visibility == VISIBLE) return
     alpha = 0f
-    visibility = View.VISIBLE
+    visibility = VISIBLE
     animate().alpha(1f).withEndAction {
-        endAction.invoke()
+        if (context != null) endAction.invoke()
     }.start()
 }
 
 fun View.fadeOut(endAction: () -> Unit = {}) {
-    if (visibility == View.INVISIBLE) return
+    if (visibility == INVISIBLE) return
     animate().alpha(0f).withEndAction {
-        visibility = View.INVISIBLE
+        if (context == null) return@withEndAction
+        visibility = INVISIBLE
         alpha = 1f
         endAction.invoke()
     }.start()
 }
 
+/**
+ * Use this with 'when' expressions when you need it to handle all possibilities/branches.
+ */
+val <T> T.exhaustive: T
+    get() = this
+
 fun Context.isOnline(): Boolean {
     val cm = getSystemService(CONNECTIVITY_SERVICE) as ConnectivityManager
-    return if (Build.VERSION.SDK_INT < 29) {
+    return if (SDK_INT < 29) {
         @Suppress("DEPRECATION")
         cm.activeNetworkInfo?.isConnected == true
     } else {
         val capabilities = cm.getNetworkCapabilities(cm.activeNetwork) ?: return false
-        capabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
+        capabilities.hasCapability(NET_CAPABILITY_INTERNET)
     }
 }
+
+fun Fragment.navigate(directions: NavDirections) = findNavController().navigate(directions)
+
+fun Long.toRelativeTime(context: Context): CharSequence {
+    val now = System.currentTimeMillis()
+    return if (now - this > DAY_IN_MILLIS * 2) {
+        val flags = FORMAT_SHOW_TIME or FORMAT_SHOW_DATE or FORMAT_ABBREV_MONTH or FORMAT_NO_YEAR
+        DateUtils.formatDateTime(context, this, flags)
+    } else DateUtils.getRelativeTimeSpanString(this, now, MINUTE_IN_MILLIS, FORMAT_ABBREV_RELATIVE)
+}
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt b/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt
new file mode 100644
index 0000000..4e7016b
--- /dev/null
+++ b/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt
@@ -0,0 +1,51 @@
+/*
+ * 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.common
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MediatorLiveData
+import androidx.lifecycle.Observer
+
+class CombinedLiveData<T, K, S>(
+    source1: LiveData<T>,
+    source2: LiveData<K>,
+    private val combine: (data1: T?, data2: K?) -> S
+) : MediatorLiveData<S>() {
+
+    private var data1: T? = null
+    private var data2: K? = null
+
+    init {
+        super.addSource(source1) { t ->
+            data1 = t
+            value = combine(data1, data2)
+        }
+        super.addSource(source2) { k ->
+            data2 = k
+            value = combine(data1, data2)
+        }
+    }
+
+    override fun <S : Any?> addSource(source: LiveData<S>, onChanged: Observer<in S>) {
+        throw UnsupportedOperationException()
+    }
+
+    override fun <T : Any?> removeSource(toRemote: LiveData<T>) {
+        throw UnsupportedOperationException()
+    }
+
+}
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/ContractTerms.kt b/taler-kotlin-common/src/main/java/net/taler/common/ContractTerms.kt
new file mode 100644
index 0000000..1e70b6f
--- /dev/null
+++ b/taler-kotlin-common/src/main/java/net/taler/common/ContractTerms.kt
@@ -0,0 +1,61 @@
+/*
+ * 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.common
+
+import androidx.annotation.RequiresApi
+import com.fasterxml.jackson.annotation.JsonIgnore
+import com.fasterxml.jackson.annotation.JsonInclude
+import com.fasterxml.jackson.annotation.JsonInclude.Include.NON_EMPTY
+import com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL
+import com.fasterxml.jackson.annotation.JsonProperty
+import net.taler.common.TalerUtils.getLocalizedString
+
+@JsonInclude(NON_NULL)
+abstract class Product {
+    @get:JsonProperty("product_id")
+    abstract val productId: String?
+    abstract val description: String
+
+    @get:JsonProperty("description_i18n")
+    abstract val descriptionI18n: Map<String, String>?
+    abstract val price: String
+
+    @get:JsonProperty("delivery_location")
+    abstract val location: String?
+    abstract val image: String?
+
+    @get:JsonIgnore
+    val localizedDescription: String
+        @RequiresApi(26)
+        get() = getLocalizedString(descriptionI18n, description)
+}
+
+data class ContractProduct(
+    override val productId: String?,
+    override val description: String,
+    override val descriptionI18n: Map<String, String>?,
+    override val price: String,
+    override val location: String?,
+    override val image: String?,
+    val quantity: Int
+) : Product()
+
+@JsonInclude(NON_EMPTY)
+class Timestamp(
+    @JsonProperty("t_ms")
+    val ms: Long
+)
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/TalerUtils.kt b/taler-kotlin-common/src/main/java/net/taler/common/TalerUtils.kt
new file mode 100644
index 0000000..cb1622e
--- /dev/null
+++ b/taler-kotlin-common/src/main/java/net/taler/common/TalerUtils.kt
@@ -0,0 +1,51 @@
+/*
+ * 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.common
+
+import androidx.annotation.RequiresApi
+import androidx.core.os.LocaleListCompat
+import java.util.*
+import kotlin.collections.ArrayList
+
+object TalerUtils {
+
+    @RequiresApi(26)
+    fun getLocalizedString(map: Map<String, String>?, default: String): String {
+        // just return the default, if it is the only element
+        if (map == null) return default
+        // create a priority list of language ranges from system locales
+        val locales = LocaleListCompat.getDefault()
+        val priorityList = ArrayList<Locale.LanguageRange>(locales.size())
+        for (i in 0 until locales.size()) {
+            priorityList.add(Locale.LanguageRange(locales[i].toLanguageTag()))
+        }
+        // create a list of locales available in the given map
+        val availableLocales = map.keys.mapNotNull {
+            if (it == "_") return@mapNotNull null
+            val list = it.split("_")
+            when (list.size) {
+                1 -> Locale(list[0])
+                2 -> Locale(list[0], list[1])
+                3 -> Locale(list[0], list[1], list[2])
+                else -> null
+            }
+        }
+        val match = Locale.lookup(priorityList, availableLocales)
+        return match?.toString()?.let { map[it] } ?: default
+    }
+
+}