Direct Settlement

app/src/main/java/net/helcel/cowspent/android/project/settle/ProjectSettlementScreen.kt

@@ -48,8 +48,10 @@ import net.helcel.cowspent.model.Transaction
 import net.helcel.cowspent.model.UserItem
 import net.helcel.cowspent.persistence.CowspentSQLiteOpenHelper
 import net.helcel.cowspent.util.SupportUtil
+import net.helcel.cowspent.util.SupportUtil.SETTLE_DIRECT
 import net.helcel.cowspent.util.SupportUtil.SETTLE_OPTIMAL
 import net.helcel.cowspent.util.SupportUtil.settleBills
+import net.helcel.cowspent.util.SupportUtil.settleBillsDirect
 
 @Composable
 fun ProjectSettlementDialogContent(
@@ -60,10 +62,12 @@ fun ProjectSettlementDialogContent(
     onDismiss: () -> Unit
 ) {
     val centerNoneStr = stringResource(R.string.center_none)
+    val centerDirectStr = stringResource(R.string.center_none_direct)
     val memberList = remember(proj.id) { db.getMembersOfProject(proj.id, null) }
-    val userList = remember(memberList, centerNoneStr) {
+    val userList = remember(memberList, centerNoneStr, centerDirectStr) {
         buildList {
             add(UserItem(SETTLE_OPTIMAL, centerNoneStr))
+            add(UserItem(SETTLE_DIRECT, centerDirectStr))
             addAll(memberList.map { UserItem(it.id, it.name) })
         }
     }
@@ -91,8 +95,12 @@ fun ProjectSettlementDialogContent(
     }
 
     val transactions = remember(selectedMemberId, membersBalance, membersSortedByName) {
+        if (selectedMemberId == SETTLE_DIRECT) {
+            settleBillsDirect(membersSortedByName, db.getBillsOfProject(proj.id))
+        } else {
             settleBills(membersSortedByName, membersBalance, selectedMemberId)
         }
+    }
 
     ProjectSettlementUI(
         transactions = transactions,

app/src/main/java/net/helcel/cowspent/util/SupportUtil.kt

@@ -167,6 +167,39 @@ object SupportUtil {
     }
 
     const val SETTLE_OPTIMAL: Long = 0
+    const val SETTLE_DIRECT: Long = -1
+
+    @JvmStatic
+    fun settleBillsDirect(members: List<DBMember>, bills: List<DBBill>): List<Transaction> {
+        val membersWeight = members.associate { it.id to it.weight }
+        // owed[debtor][creditor] = total the debtor owes the creditor over all bills
+        val owed = HashMap<Long, HashMap<Long, Double>>()
+
+        for (b in bills) {
+            if (b.state == DBBill.STATE_DELETED) continue
+            val nbOwerShares = b.billOwers.sumOf { membersWeight[it.memberId] ?: 0.0 }
+            if (nbOwerShares <= 0.0) continue
+            for (bo in b.billOwers) {
+                if (bo.memberId == b.payerId) continue
+                val share = b.amount / nbOwerShares * (membersWeight[bo.memberId] ?: 0.0)
+                val row = owed.getOrPut(bo.memberId) { HashMap() }
+                row[b.payerId] = (row[b.payerId] ?: 0.0) + share
+            }
+        }
+
+        val results: MutableList<Transaction> = ArrayList()
+        for (debtor in members) {
+            for (creditor in members) {
+                if (debtor.id == creditor.id) continue
+                val net = (owed[debtor.id]?.get(creditor.id) ?: 0.0) -
+                        (owed[creditor.id]?.get(debtor.id) ?: 0.0)
+                if (round2(net) > 0.0) {
+                    results.add(Transaction(debtor.id, creditor.id, round2(net)))
+                }
+            }
+        }
+        return results
+    }
 
     @JvmStatic
     fun settleBills(

app/src/main/res/values-de-rDE/strings.xml

@@ -209,6 +209,7 @@
 
     <!-- Settlement -->
     <string name="center_none">Keine (optimal)</string>
+    <string name="center_none_direct">Keine (direkt)</string>
     <string name="settle_who">Wer zahlt</string>
     <string name="settle_to_whom">An wen</string>
     <string name="settle_how_much">Betrag</string>

app/src/main/res/values-es-rES/strings.xml

@@ -210,6 +210,7 @@
 
     <!-- Settlement -->
     <string name="center_none">Ninguno (óptimo)</string>
+    <string name="center_none_direct">Ninguno (directo)</string>
     <string name="settle_who">Quién paga</string>
     <string name="settle_to_whom">A quién</string>
     <string name="settle_how_much">Importe</string>

app/src/main/res/values-fr-rFR/strings.xml

@@ -213,6 +213,7 @@
 
     <!-- Settlement -->
     <string name="center_none">Aucun (optimal)</string>
+    <string name="center_none_direct">Aucun (direct)</string>
     <string name="settle_who">Qui paie</string>
     <string name="settle_to_whom">À qui</string>
     <string name="settle_how_much">Montant</string>

app/src/main/res/values-ru-rRU/strings.xml

@@ -209,6 +209,7 @@
 
     <!-- Settlement -->
     <string name="center_none">Нет (оптимально)</string>
+    <string name="center_none_direct">Нет (напрямую)</string>
     <string name="settle_who">Кто платит</string>
     <string name="settle_to_whom">Кому</string>
     <string name="settle_how_much">Сумма</string>

app/src/main/res/values/strings.xml

@@ -247,6 +247,7 @@
 
     <!-- Settlement -->
     <string name="center_none">None (Optimal)</string>
+    <string name="center_none_direct">None (Direct)</string>
     <string name="settle_who">Who pays</string>
     <string name="settle_to_whom">To whom</string>
     <string name="settle_how_much">Amount</string>