From d80f4872dc9cf060298f17bd8f5e76a12aa8f42d Mon Sep 17 00:00:00 2001
From: amueller <amueller@scopeset.de>
Date: Wed, 16 Oct 2024 18:41:06 +0200
Subject: [PATCH 1/2] #236 support currencies for markets widget

---
 internal/feed/primitives.go |  1 +
 internal/feed/yahoo.go      | 38 +++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/internal/feed/primitives.go b/internal/feed/primitives.go
index 755b0026..3da888aa 100644
--- a/internal/feed/primitives.go
+++ b/internal/feed/primitives.go
@@ -113,6 +113,7 @@ type DNSStatsBlockedDomain struct {
 type MarketRequest struct {
 	Name       string `yaml:"name"`
 	Symbol     string `yaml:"symbol"`
+	Currency   string `yaml:"currency"`
 	ChartLink  string `yaml:"chart-link"`
 	SymbolLink string `yaml:"symbol-link"`
 }
diff --git a/internal/feed/yahoo.go b/internal/feed/yahoo.go
index f9626952..2535864e 100644
--- a/internal/feed/yahoo.go
+++ b/internal/feed/yahoo.go
@@ -1,6 +1,7 @@
 package feed
 
 import (
+	"encoding/json"
 	"fmt"
 	"log/slog"
 	"net/http"
@@ -27,6 +28,30 @@ type marketResponseJson struct {
 // TODO: allow changing chart time frame
 const marketChartDays = 21
 
+func FetchUSDExchangeRate(currency string) (float64, error) {
+	url := fmt.Sprintf("https://query1.finance.yahoo.com/v8/finance/chart/USD%s=X?range=1d&interval=1d", currency)
+	resp, err := http.Get(url)
+	if err != nil {
+		return 0, fmt.Errorf("failed to fetch exchange rate: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return 0, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	var response marketResponseJson
+	if err := json.NewDecoder(resp.Body).Decode(&response); err != nil {
+		return 0, fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	if len(response.Chart.Result) == 0 {
+		return 0, fmt.Errorf("no result in response")
+	}
+
+	return response.Chart.Result[0].Meta.RegularMarketPrice, nil
+}
+
 func FetchMarketsDataFromYahoo(marketRequests []MarketRequest) (Markets, error) {
 	requests := make([]*http.Request, 0, len(marketRequests))
 
@@ -80,6 +105,19 @@ func FetchMarketsDataFromYahoo(marketRequests []MarketRequest) (Markets, error)
 			currency = response.Chart.Result[0].Meta.Currency
 		}
 
+		if marketRequests[i].Currency != "" {
+			exchangeRate, err := FetchUSDExchangeRate(marketRequests[i].Currency)
+			if err != nil {
+				slog.Error("Failed to fetch USD/EUR exchange rate", "error", err)
+				continue
+			}
+
+			if response.Chart.Result[0].Meta.Currency == "USD" {
+				response.Chart.Result[0].Meta.RegularMarketPrice *= exchangeRate
+				currency = currencyToSymbol[marketRequests[i].Currency]
+			}
+		}
+
 		markets = append(markets, Market{
 			MarketRequest: marketRequests[i],
 			Price:         response.Chart.Result[0].Meta.RegularMarketPrice,

From 5f27218dcbf13872c8726c04e5a2ea79966b31fb Mon Sep 17 00:00:00 2001
From: amueller <amueller@scopeset.de>
Date: Thu, 17 Oct 2024 17:22:46 +0200
Subject: [PATCH 2/2] #236 fixed change rate calc bug

---
 internal/feed/yahoo.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/internal/feed/yahoo.go b/internal/feed/yahoo.go
index 2535864e..f3979af8 100644
--- a/internal/feed/yahoo.go
+++ b/internal/feed/yahoo.go
@@ -108,12 +108,13 @@ func FetchMarketsDataFromYahoo(marketRequests []MarketRequest) (Markets, error)
 		if marketRequests[i].Currency != "" {
 			exchangeRate, err := FetchUSDExchangeRate(marketRequests[i].Currency)
 			if err != nil {
-				slog.Error("Failed to fetch USD/EUR exchange rate", "error", err)
+				slog.Error("Failed to fetch USD exchange rate", "error", err)
 				continue
 			}
 
 			if response.Chart.Result[0].Meta.Currency == "USD" {
 				response.Chart.Result[0].Meta.RegularMarketPrice *= exchangeRate
+				previous *= exchangeRate
 				currency = currencyToSymbol[marketRequests[i].Currency]
 			}
 		}