Allow editing order with -1 and +1 buttons

15 files changed, 215 insertions, 25 deletions

diff --git a/app/build.gradle b/app/build.gradle
index 4eea459..ca16c9d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -10,7 +10,7 @@ android {
     buildToolsVersion "29.0.2"
     defaultConfig {
         applicationId "net.taler.merchantpos"
-        minSdkVersion 27
+        minSdkVersion 21
         targetSdkVersion 29
         versionCode 1
         versionName "1.0"
@@ -38,9 +38,10 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.core:core-ktx:1.2.0'
-    implementation 'com.google.android.material:material:1.1.0-rc02'
+    implementation 'com.google.android.material:material:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
     implementation "androidx.recyclerview:recyclerview:1.1.0"
+    implementation "androidx.recyclerview:recyclerview-selection:1.1.0-rc01"
 
     // Navigation
     def nav_version = "2.2.1"
@@ -61,9 +62,9 @@ dependencies {
     implementation "androidx.swiperefreshlayout:swiperefreshlayout:1.0.0"
 
     // JSON parsing and serialization
-    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.9.7"
+    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.10.2"
 
-    testImplementation 'junit:junit:4.12'
+    testImplementation 'junit:junit:4.13'
     androidTestImplementation 'androidx.test:runner:1.2.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
 }
diff --git a/app/src/main/java/net/taler/merchantpos/Utils.kt b/app/src/main/java/net/taler/merchantpos/Utils.kt
index 5ebb0b4..a318d23 100644
--- a/app/src/main/java/net/taler/merchantpos/Utils.kt
+++ b/app/src/main/java/net/taler/merchantpos/Utils.kt
@@ -1,5 +1,9 @@
 package net.taler.merchantpos
 
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MediatorLiveData
+import androidx.lifecycle.Observer
+
 object Utils {
 
     private const val HEX_CHARS = "0123456789ABCDEF"
@@ -34,3 +38,32 @@ object Utils {
     }
 
 }
+
+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/app/src/main/java/net/taler/merchantpos/config/ConfigFetcherFragment.kt b/app/src/main/java/net/taler/merchantpos/config/ConfigFetcherFragment.kt
index 4d387da..4520f8f 100644
--- a/app/src/main/java/net/taler/merchantpos/config/ConfigFetcherFragment.kt
+++ b/app/src/main/java/net/taler/merchantpos/config/ConfigFetcherFragment.kt
@@ -32,7 +32,7 @@ class ConfigFetcherFragment : Fragment() {
             when {
                 result == null -> return@Observer
                 result.error -> onNetworkError(result.authError)
-                else -> findNavController().navigate(R.id.order)
+                else -> findNavController().navigate(R.id.action_configFetcher_to_order)
             }
         })
     }
diff --git a/app/src/main/java/net/taler/merchantpos/order/Definitions.kt b/app/src/main/java/net/taler/merchantpos/order/Definitions.kt
index 57666d7..ce2e464 100644
--- a/app/src/main/java/net/taler/merchantpos/order/Definitions.kt
+++ b/app/src/main/java/net/taler/merchantpos/order/Definitions.kt
@@ -78,6 +78,14 @@ data class Order(val availableCategories: Map<Int, Category>) {
         products[product] = (products[product] ?: 0) + 1
         return this
     }
+
+    operator fun minus(product: ConfigProduct): Order {
+        var quantity = products[product] ?: throw IllegalStateException()
+        quantity -= 1
+        if (quantity > 0) products[product] = quantity
+        else products.remove(product)
+        return this
+    }
 }
 
 typealias OrderLine = Pair<ConfigProduct, Int>
diff --git a/app/src/main/java/net/taler/merchantpos/order/OrderFragment.kt b/app/src/main/java/net/taler/merchantpos/order/OrderFragment.kt
index 8856bda..6696afe 100644
--- a/app/src/main/java/net/taler/merchantpos/order/OrderFragment.kt
+++ b/app/src/main/java/net/taler/merchantpos/order/OrderFragment.kt
@@ -10,6 +10,7 @@ import androidx.lifecycle.Observer
 import androidx.navigation.NavController
 import androidx.navigation.Navigation.findNavController
 import androidx.navigation.fragment.findNavController
+import androidx.transition.TransitionManager.beginDelayedTransition
 import kotlinx.android.synthetic.main.fragment_order.*
 import net.taler.merchantpos.MainViewModel
 import net.taler.merchantpos.R
@@ -33,6 +34,7 @@ class OrderFragment : Fragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         restartButton.setOnClickListener { orderManager.restartOrUndo() }
         orderManager.restartState.observe(viewLifecycleOwner, Observer { state ->
+            beginDelayedTransition(view as ViewGroup)
             if (state == UNDO) {
                 restartButton.setText(R.string.order_undo)
                 restartButton.isEnabled = true
@@ -43,6 +45,12 @@ class OrderFragment : Fragment() {
                 completeButton.isEnabled = state == ENABLED
             }
         })
+        minusButton.setOnClickListener { orderManager.decreaseSelectedOrderLine() }
+        plusButton.setOnClickListener { orderManager.increaseSelectedOrderLine() }
+        orderManager.modifyOrderAllowed.observe(viewLifecycleOwner, Observer { allowed ->
+            minusButton.isEnabled = allowed
+            plusButton.isEnabled = allowed
+        })
     }
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
diff --git a/app/src/main/java/net/taler/merchantpos/order/OrderManager.kt b/app/src/main/java/net/taler/merchantpos/order/OrderManager.kt
index 124e73a..449d741 100644
--- a/app/src/main/java/net/taler/merchantpos/order/OrderManager.kt
+++ b/app/src/main/java/net/taler/merchantpos/order/OrderManager.kt
@@ -8,6 +8,7 @@ import androidx.lifecycle.Transformations.map
 import com.fasterxml.jackson.core.type.TypeReference
 import com.fasterxml.jackson.databind.ObjectMapper
 import net.taler.merchantpos.Amount.Companion.fromString
+import net.taler.merchantpos.CombinedLiveData
 import net.taler.merchantpos.config.ConfigurationReceiver
 import net.taler.merchantpos.order.RestartState.DISABLED
 import net.taler.merchantpos.order.RestartState.ENABLED
@@ -40,6 +41,13 @@ class OrderManager(private val mapper: ObjectMapper) : ConfigurationReceiver {
     private val mRestartState = MutableLiveData<RestartState>().apply { value = DISABLED }
     internal val restartState: LiveData<RestartState> = mRestartState
 
+    private val mSelectedOrderLine = MutableLiveData<OrderLine>()
+
+    internal val modifyOrderAllowed =
+        CombinedLiveData(restartState, mSelectedOrderLine) { restartState, selectedOrderLine ->
+            restartState != DISABLED && selectedOrderLine != null
+        }
+
     @Suppress("BlockingMethodInNonBlockingContext") // run on Dispatchers.Main
     override suspend fun onConfigurationReceived(json: JSONObject, currency: String): Boolean {
         // parse categories
@@ -105,6 +113,14 @@ class OrderManager(private val mapper: ObjectMapper) : ConfigurationReceiver {
     }
 
     @UiThread
+    internal fun removeProduct(product: ConfigProduct) {
+        val order = mOrder.value ?: throw IllegalStateException()
+        val modifiedOrder = order - product
+        mOrder.value = modifiedOrder
+        mRestartState.value = if (modifiedOrder.products.isEmpty()) DISABLED else ENABLED
+    }
+
+    @UiThread
     internal fun restartOrUndo() {
         if (restartState.value == UNDO) {
             mOrder.value = undoOrder
@@ -117,4 +133,21 @@ class OrderManager(private val mapper: ObjectMapper) : ConfigurationReceiver {
         }
     }
 
+    @UiThread
+    fun selectOrderLine(orderLine: OrderLine?) {
+        mSelectedOrderLine.value = orderLine
+    }
+
+    @UiThread
+    fun increaseSelectedOrderLine() {
+        val orderLine = mSelectedOrderLine.value ?: throw IllegalStateException()
+        addProduct(orderLine.first)
+    }
+
+    @UiThread
+    fun decreaseSelectedOrderLine() {
+        val orderLine = mSelectedOrderLine.value ?: throw IllegalStateException()
+        removeProduct(orderLine.first)
+    }
+
 }
diff --git a/app/src/main/java/net/taler/merchantpos/order/OrderStateFragment.kt b/app/src/main/java/net/taler/merchantpos/order/OrderStateFragment.kt
index 6a0aa2b..240ee3b 100644
--- a/app/src/main/java/net/taler/merchantpos/order/OrderStateFragment.kt
+++ b/app/src/main/java/net/taler/merchantpos/order/OrderStateFragment.kt
@@ -2,24 +2,35 @@ package net.taler.merchantpos.order
 
 import android.os.Bundle
 import android.view.LayoutInflater
+import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
 import android.widget.TextView
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
 import androidx.lifecycle.Observer
+import androidx.recyclerview.selection.ItemDetailsLookup
+import androidx.recyclerview.selection.ItemKeyProvider
+import androidx.recyclerview.selection.SelectionPredicates
+import androidx.recyclerview.selection.SelectionTracker
+import androidx.recyclerview.selection.StorageStrategy
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.RecyclerView.Adapter
+import androidx.recyclerview.widget.RecyclerView.ViewHolder
 import kotlinx.android.synthetic.main.fragment_order_state.*
 import net.taler.merchantpos.MainViewModel
 import net.taler.merchantpos.R
+import net.taler.merchantpos.order.OrderAdapter.OrderLineLookup
 import net.taler.merchantpos.order.OrderAdapter.OrderViewHolder
 
+
 class OrderStateFragment : Fragment() {
 
     private val viewModel: MainViewModel by activityViewModels()
     private val orderManager by lazy { viewModel.orderManager }
     private val adapter = OrderAdapter()
+    private var tracker: SelectionTracker<String>? = null
 
     override fun onCreateView(
         inflater: LayoutInflater,
@@ -34,6 +45,26 @@ class OrderStateFragment : Fragment() {
             adapter = this@OrderStateFragment.adapter
             layoutManager = LinearLayoutManager(requireContext())
         }
+        val detailsLookup = OrderLineLookup(orderList)
+        val tracker = SelectionTracker.Builder(
+            "order-selection-id",
+            orderList,
+            adapter.keyProvider,
+            detailsLookup,
+            StorageStrategy.createStringStorage()
+        ).withSelectionPredicate(
+            SelectionPredicates.createSelectSingleAnything()
+        ).build()
+        savedInstanceState?.let { tracker.onRestoreInstanceState(it) }
+        adapter.tracker = tracker
+        tracker.addObserver(object : SelectionTracker.SelectionObserver<String>() {
+            override fun onItemStateChanged(key: String, selected: Boolean) {
+                super.onItemStateChanged(key, selected)
+                val item = if (selected) adapter.getItemByKey(key) else null
+                orderManager.selectOrderLine(item)
+            }
+        })
+        this.tracker = tracker
 
         orderManager.order.observe(viewLifecycleOwner, Observer { order ->
             adapter.setItems(order.products)
@@ -47,10 +78,17 @@ class OrderStateFragment : Fragment() {
         })
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        tracker?.onSaveInstanceState(outState)
+    }
+
 }
 
-private class OrderAdapter : RecyclerView.Adapter<OrderViewHolder>() {
+private class OrderAdapter : Adapter<OrderViewHolder>() {
 
+    lateinit var tracker: SelectionTracker<String>
+    val keyProvider = OrderKeyProvider()
     private val orderLines = ArrayList<OrderLine>()
 
     override fun getItemCount() = orderLines.size
@@ -62,7 +100,8 @@ private class OrderAdapter : RecyclerView.Adapter<OrderViewHolder>() {
     }
 
     override fun onBindViewHolder(holder: OrderViewHolder, position: Int) {
-        holder.bind(orderLines[position])
+        val item = orderLines[position]
+        holder.bind(item, tracker.isSelected(item.first.id))
     }
 
     fun setItems(items: HashMap<ConfigProduct, Int>) {
@@ -71,16 +110,44 @@ private class OrderAdapter : RecyclerView.Adapter<OrderViewHolder>() {
         notifyDataSetChanged()
     }
 
-    private inner class OrderViewHolder(v: View) : RecyclerView.ViewHolder(v) {
+    fun getItemByKey(key: String): OrderLine? {
+        return orderLines.find { it.first.id == key }
+    }
+
+    private inner class OrderViewHolder(private val v: View) : ViewHolder(v) {
         private val quantity: TextView = v.findViewById(R.id.quantity)
         private val name: TextView = v.findViewById(R.id.name)
         private val price: TextView = v.findViewById(R.id.price)
 
-        fun bind(orderLine: OrderLine) {
+        fun bind(orderLine: OrderLine, selected: Boolean) {
+            v.isActivated = selected
             quantity.text = orderLine.second.toString()
             name.text = orderLine.first.description
             price.text = String.format("%.2f", orderLine.first.priceAsDouble * orderLine.second)
         }
     }
 
+    private inner class OrderKeyProvider : ItemKeyProvider<String>(SCOPE_MAPPED) {
+        override fun getKey(position: Int) = orderLines[position].first.id
+        override fun getPosition(key: String): Int {
+            return orderLines.indexOfFirst { it.first.id == key }
+        }
+    }
+
+    internal class OrderLineLookup(private val list: RecyclerView) : ItemDetailsLookup<String>() {
+        override fun getItemDetails(e: MotionEvent): ItemDetails<String>? {
+            list.findChildViewUnder(e.x, e.y)?.let { view ->
+                val holder = list.getChildViewHolder(view)
+                val adapter = list.adapter as OrderAdapter
+                val position = holder.adapterPosition
+                return object : ItemDetails<String>() {
+                    override fun getPosition(): Int = position
+                    override fun getSelectionKey(): String = adapter.keyProvider.getKey(position)
+                    override fun inSelectionHotspot(e: MotionEvent) = true
+                }
+            }
+            return null
+        }
+    }
+
 }
diff --git a/app/src/main/res/drawable/selectable_background.xml b/app/src/main/res/drawable/selectable_background.xml
new file mode 100644
index 0000000..b82de92
--- /dev/null
+++ b/app/src/main/res/drawable/selectable_background.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@color/selectedBackground" android:state_activated="true" />
+    <item android:drawable="@android:color/transparent" />
+</selector>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_order.xml b/app/src/main/res/layout/fragment_order.xml
index bcf8be8..136d1e7 100644
--- a/app/src/main/res/layout/fragment_order.xml
+++ b/app/src/main/res/layout/fragment_order.xml
@@ -63,6 +63,28 @@
             app:layout_constraintStart_toStartOf="parent" />
 
     <Button
+            android:id="@+id/plusButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="16dp"
+            android:minWidth="48dp"
+            android:text="+1"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toEndOf="@+id/minusButton"
+            tools:ignore="HardcodedText" />
+
+    <Button
+            android:id="@+id/minusButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="16dp"
+            android:minWidth="48dp"
+            android:text="-1"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toEndOf="@+id/restartButton"
+            tools:ignore="HardcodedText" />
+
+    <Button
             android:id="@+id/reconfigureButton"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
@@ -70,7 +92,7 @@
             android:backgroundTint="@color/bottomButtons"
             android:text="@string/button_reconfigure"
             app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintStart_toEndOf="@+id/restartButton" />
+            app:layout_constraintStart_toEndOf="@+id/plusButton" />
 
     <Button
             android:id="@+id/historyButton"
diff --git a/app/src/main/res/layout/list_item_order.xml b/app/src/main/res/layout/list_item_order.xml
index 5dc2f86..03b15a8 100644
--- a/app/src/main/res/layout/list_item_order.xml
+++ b/app/src/main/res/layout/list_item_order.xml
@@ -4,9 +4,9 @@
         xmlns:tools="http://schemas.android.com/tools"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:paddingStart="8dp"
-        android:paddingTop="8dp"
-        android:paddingEnd="8dp">
+        android:background="@drawable/selectable_background"
+        android:minHeight="48dp"
+        android:padding="8dp">
 
     <TextView
             android:id="@+id/quantity"
@@ -14,8 +14,10 @@
             android:layout_height="wrap_content"
             android:gravity="end"
             android:minWidth="24dp"
+            app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintTop_toTopOf="@+id/name"
+            app:layout_constraintVertical_bias="0.0"
             tools:text="31" />
 
     <TextView
@@ -24,6 +26,7 @@
             android:layout_height="wrap_content"
             android:layout_marginStart="8dp"
             android:layout_marginEnd="8dp"
+            app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toStartOf="@+id/price"
             app:layout_constraintStart_toEndOf="@+id/quantity"
             app:layout_constraintTop_toTopOf="parent"
@@ -33,8 +36,10 @@
             android:id="@+id/price"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
+            app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintTop_toTopOf="@+id/name"
+            app:layout_constraintVertical_bias="0.0"
             tools:text="23.42" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>
diff --git a/app/src/main/res/navigation/nav_graph.xml b/app/src/main/res/navigation/nav_graph.xml
index f615ba2..dc4015f 100644
--- a/app/src/main/res/navigation/nav_graph.xml
+++ b/app/src/main/res/navigation/nav_graph.xml
@@ -42,7 +42,7 @@
             android:id="@+id/merchantSettings"
             android:name="net.taler.merchantpos.config.MerchantConfigFragment"
             android:label="Merchant Settings"
-            tools:layout="@layout/fragment_merchant_settings"/>
+            tools:layout="@layout/fragment_merchant_settings" />
 
     <fragment
             android:id="@+id/configFetcher"
@@ -53,6 +53,11 @@
                 android:id="@+id/action_configFetcher_to_merchantSettings"
                 app:destination="@id/merchantSettings"
                 app:popUpToInclusive="true" />
+        <action
+                android:id="@+id/action_configFetcher_to_order"
+                app:destination="@id/order"
+                app:launchSingleTop="true"
+                app:popUpTo="@+id/order" />
     </fragment>
 
     <fragment
diff --git a/app/src/main/res/values-night/colors.xml b/app/src/main/res/values-night/colors.xml
new file mode 100644
index 0000000..47721b4
--- /dev/null
+++ b/app/src/main/res/values-night/colors.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="selectedBackground">#363636</color>
+</resources>
diff --git a/app/src/main/res/values-v21/styles.xml b/app/src/main/res/values-v21/styles.xml
deleted file mode 100644
index e546804..0000000
--- a/app/src/main/res/values-v21/styles.xml
+++ /dev/null
@@ -1,7 +0,0 @@
-<resources>
-    <style name="AppTheme.NoActionBar">
-        <item name="windowActionBar">false</item>
-        <item name="windowNoTitle">true</item>
-        <item name="android:statusBarColor">@android:color/transparent</item>
-    </style>
-</resources>
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index 10354c5..3ed8874 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -4,6 +4,7 @@
     <color name="colorPrimaryDark">#5D4037</color>
     <color name="colorAccent">#FFEB3B</color>
 
+    <color name="selectedBackground">#DADADA</color>
     <color name="bottomButtons">#9E9D24</color>
     <color name="logoutButton">#C62828</color>
 </resources>
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index 9eac8b0..4445a01 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -3,14 +3,19 @@
     <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
         <!-- Customize your theme here. -->
         <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorOnPrimary">@android:color/white</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorAccent">@color/colorAccent</item>
     </style>
+
     <style name="AppTheme.NoActionBar">
         <item name="windowActionBar">false</item>
         <item name="windowNoTitle">true</item>
+        <item name="android:statusBarColor">@android:color/transparent</item>
     </style>
-    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar"/>
-    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light"/>
+
+    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />
+
+    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />
 
 </resources>