add transaction export option

internal/accounting/pnl.go

@@ -0,0 +1,117 @@
+package accounting
+
+import (
+	"github.com/ananthakumaran/paisa/internal/model/posting"
+	"github.com/ananthakumaran/paisa/internal/model/transaction"
+	"github.com/shopspring/decimal"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/exp/slices"
+)
+
+type BalancedPosting struct {
+	From posting.Posting `json:"from"`
+	To   posting.Posting `json:"to"`
+}
+
+type PostingPair struct {
+	Posting        posting.Posting
+	CounterPosting posting.Posting
+}
+
+func balancePostings(postings []posting.Posting) []PostingPair {
+	EPSILON := decimal.NewFromFloat(0.01)
+
+	var pairs []PostingPair
+	pending := slices.Clone(postings)
+	for len(pending) > 0 {
+		var pair PostingPair
+		pair.Posting = pending[0]
+		pending = pending[1:]
+		found := false
+		for i, p := range pending {
+			if pair.Posting.Commodity == p.Commodity && pair.Posting.Quantity.Neg().Equal(p.Quantity) {
+				pair.CounterPosting = p
+				pending = slices.Delete(pending, i, i+1)
+				pairs = append(pairs, pair)
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			for i, p := range pending {
+				if pair.Posting.Amount.Neg().Equal(p.Amount) {
+					pair.CounterPosting = p
+					pending = slices.Delete(pending, i, i+1)
+					pairs = append(pairs, pair)
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+		RESTART:
+			for i, p := range pending {
+				if (pair.Posting.Amount.Sign() == 1 && p.Amount.Sign() == -1) ||
+					(pair.Posting.Amount.Sign() == -1 && p.Amount.Sign() == 1) {
+
+					if pair.Posting.Amount.Abs().Equal(p.Amount.Abs()) {
+						pair.CounterPosting = p
+						pending = slices.Delete(pending, i, i+1)
+						pairs = append(pairs, pair)
+						found = true
+						break
+					} else if pair.Posting.Amount.Abs().LessThan(p.Amount.Abs()) {
+						counter, remaining := p.Split(pair.Posting.Amount.Neg())
+						pair.CounterPosting = counter
+						pending[i] = remaining
+						pairs = append(pairs, pair)
+						found = true
+						break
+					} else {
+						current, remaining := pair.Posting.Split(p.Amount.Neg())
+						pair.Posting = current
+						pair.CounterPosting = p
+						pending = slices.Delete(pending, i, i+1)
+						pairs = append(pairs, pair)
+
+						pair = PostingPair{}
+						pair.Posting = remaining
+						goto RESTART
+					}
+				}
+			}
+		}
+
+		if !found && pair.Posting.Amount.Abs().GreaterThan(EPSILON) {
+			log.Infof("No counter posting found for %v \npending: %v \npairs: %v e: %v", pair.Posting, pending, pairs, EPSILON)
+			break
+		}
+	}
+	return pairs
+}
+
+func BuildBalancedPostings(transactions []transaction.Transaction) []BalancedPosting {
+	var balancedPostings []BalancedPosting
+	for _, t := range transactions {
+		postings := t.Postings
+		pairs := balancePostings(postings)
+		for _, pair := range pairs {
+			var from, to posting.Posting
+			if pair.Posting.Quantity.IsPositive() {
+				to = pair.Posting
+				from = pair.CounterPosting
+			} else {
+				to = pair.CounterPosting
+				from = pair.Posting
+			}
+
+			balancedPostings = append(balancedPostings, BalancedPosting{
+				From: from,
+				To:   to,
+			})
+		}
+	}
+	return balancedPostings
+}

internal/model/posting/posting.go

@@ -87,6 +87,17 @@ func (p Posting) WithQuantity(quantity decimal.Decimal) Posting {
 	return clone
 }
 
+func (p Posting) WithAmount(amount decimal.Decimal) Posting {
+	clone := p
+	clone.Amount = amount
+	clone.Quantity = amount.Div(p.Price())
+	return clone
+}
+
+func (p Posting) Split(amount decimal.Decimal) (Posting, Posting) {
+	return p.WithAmount(amount), p.WithAmount(p.Amount.Sub(amount))
+}
+
 func (p Posting) Behaviours() []string {
 	if p.behaviours == nil {
 		p.behaviours = Behaviours(p.Account)

internal/server/server.go

@@ -194,6 +194,10 @@ func Build(db *gorm.DB, enableCompression bool) *gin.Engine {
 
 		c.JSON(200, GetPriceAutoCompletions(db, autoCompleteRequest))
 	})
+
+	router.GET("/api/transaction/balanced", func(c *gin.Context) {
+		c.JSON(200, GetBalancedPostings(db))
+	})
 	router.GET("/api/transaction", func(c *gin.Context) {
 		c.JSON(200, GetTransactions(db))
 	})

internal/server/transaction.go

@@ -1,10 +1,12 @@
 package server
 
 import (
+	"sort"
+
+	"github.com/ananthakumaran/paisa/internal/accounting"
 	"github.com/ananthakumaran/paisa/internal/model/transaction"
 	"github.com/ananthakumaran/paisa/internal/query"
 	"github.com/gin-gonic/gin"
-	"sort"
 
 	"gorm.io/gorm"
 )
@@ -19,6 +21,14 @@ func GetTransactions(db *gorm.DB) gin.H {
 	return gin.H{"transactions": transactions}
 }
 
+func GetBalancedPostings(db *gorm.DB) gin.H {
+	postings := query.Init(db).Desc().All()
+	transactions := transaction.Build(postings)
+	balancePostings := accounting.BuildBalancedPostings(transactions)
+
+	return gin.H{"balancedPostings": balancePostings}
+}
+
 func GetLatestTransactions(db *gorm.DB) []transaction.Transaction {
 	postings := query.Init(db).Desc().Limit(200).All()
 	transactions := transaction.Build(postings)

src/lib/export.ts

@@ -0,0 +1,27 @@
+import type { BalancedPosting } from "./utils";
+import Papa from "papaparse";
+
+export function download(balancedPostings: BalancedPosting[]) {
+  const rows = balancedPostings.map((balancedPosting) => {
+    console.log(balancedPosting);
+    return {
+      Date: balancedPosting.from.date.toISOString(),
+      Payee: balancedPosting.from.payee,
+      FromAccount: balancedPosting.from.account,
+      FromQuantity: balancedPosting.from.quantity,
+      FromAmount: balancedPosting.from.amount,
+      FromCommodity: balancedPosting.from.commodity,
+      ToAccount: balancedPosting.to.account,
+      ToQuantity: balancedPosting.to.quantity,
+      ToAmount: balancedPosting.to.amount,
+      ToCommodity: balancedPosting.to.commodity
+    };
+  });
+
+  const csv = Papa.unparse(rows);
+  const downloadLink = document.createElement("a");
+  const blob = new Blob([csv], { type: "text/csv;charset=utf-8;" });
+  downloadLink.href = window.URL.createObjectURL(blob);
+  downloadLink.download = "paisa-transactions.csv";
+  downloadLink.click();
+}

src/lib/utils.ts

@@ -106,6 +106,11 @@ export interface Transaction {
   postings: Posting[];
 }
 
+export interface BalancedPosting {
+  from: Posting;
+  to: Posting;
+}
+
 export interface Price {
   id: string;
   date: dayjs.Dayjs;
@@ -563,6 +568,9 @@ export function ajax(
 ): Promise<{ liability_breakdowns: LiabilityBreakdown[] }>;
 export function ajax(route: "/api/price"): Promise<{ prices: Record<string, Price[]> }>;
 export function ajax(route: "/api/transaction"): Promise<{ transactions: Transaction[] }>;
+export function ajax(
+  route: "/api/transaction/balanced"
+): Promise<{ balancedPostings: BalancedPosting[] }>;
 export function ajax(route: "/api/networth"): Promise<{
   networthTimeline: Networth[];
   xirr: number;

src/routes/(app)/ledger/transaction/+page.svelte

@@ -12,6 +12,7 @@
   import SearchQuery from "$lib/components/SearchQuery.svelte";
   import { editorState } from "$lib/search_query_editor";
   import { get } from "svelte/store";
+  import { download } from "$lib/export";
 
   let buldEditOpen = false;
   let transactions: T[] = null;
@@ -61,6 +62,11 @@
     newFiles = files;
   }
 
+  async function downloadTransactions() {
+    const { balancedPostings } = await ajax("/api/transaction/balanced");
+    download(balancedPostings);
+  }
+
   function showPreview(detail: any) {
     ({ newFiles, updatedTransactionsCount } = bulkEdit.applyChanges(
       files,
@@ -148,6 +154,14 @@
               <div class="level-item">
                 <p class="is-6"><b>{filtered.length}</b> transaction(s)</p>
               </div>
+              <div class="level-item">
+                <a on:click={(_e) => downloadTransactions()}>
+                  <span class="icon is-small">
+                    <i class="fa-solid fa-file-arrow-down"></i>
+                  </span>
+                  download
+                </a>
+              </div>
             </div>
           </nav>
         </div>