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Fix chart date alignment: use date intersection instead of index-based pairing #58

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Merged
lukepring merged 3 commits into from
Mar 20, 2026
Merged

Fix chart date alignment: use date intersection instead of index-based pairing #58

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8d78a45
Initial plan
Copilot Mar 20, 2026
9ce7e53
Align chart series by date intersection to fix index-based date mismatch
Copilot Mar 20, 2026
235e75a
Merge branch 'Sprint-2-Jack' into copilot/sub-pr-55-another-one
lukepring Mar 20, 2026
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33 changes: 28 additions & 5 deletions stockscope/src/main/java/com/sharecomparison/presentation/WebPageController.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,11 @@
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
Expand Down Expand Up @@ -81,7 +84,26 @@ public String compare(
if (maxPrice == minPrice) maxPrice += 1.0;
double priceRange = maxPrice - minPrice;

int n = Math.min(data1.size(), data2.size());
// Align series by date: only plot dates present in both data sets
Map<LocalDate, PriceData> map1 = data1.stream()
.collect(Collectors.toMap(PriceData::getDate, p -> p, (existing, replacement) -> existing));
Map<LocalDate, PriceData> map2 = data2.stream()
.collect(Collectors.toMap(PriceData::getDate, p -> p, (existing, replacement) -> existing));

Set<LocalDate> commonDates = new LinkedHashSet<>(map1.keySet());
commonDates.retainAll(map2.keySet());
List<LocalDate> sortedDates = new ArrayList<>(commonDates);
sortedDates.sort(Comparator.naturalOrder());

int n = sortedDates.size();
if (n == 0) {
model.addAttribute("error", "No overlapping trading dates found for the two symbols in this range.");
model.addAttribute("symbol1", symbol1);
model.addAttribute("symbol2", symbol2);
model.addAttribute("startDate", start.toString());
model.addAttribute("endDate", end.toString());
return "index";
}
double xStep = n > 1 ? chartWidth / (n - 1) : 0;

StringBuilder path1 = new StringBuilder();
Expand All @@ -91,16 +113,17 @@ public String compare(

for (int i = 0; i < n; i++) {
double x = left + i * xStep;
LocalDate date = sortedDates.get(i);

PriceData p1 = data1.get(i);
PriceData p1 = map1.get(date);
double y1 = bottom - ((p1.getClosingPrice() - minPrice) / priceRange) * chartHeight;
path1.append(i == 0 ? "M" : "L").append(x).append(",").append(y1).append(" ");
points1.add(Map.of("x", x, "y", y1, "value", p1.getClosingPrice()));
points1.add(Map.of("x", x, "y", y1, "value", p1.getClosingPrice(), "date", date.toString()));

PriceData p2 = data2.get(i);
PriceData p2 = map2.get(date);
double y2 = bottom - ((p2.getClosingPrice() - minPrice) / priceRange) * chartHeight;
path2.append(i == 0 ? "M" : "L").append(x).append(",").append(y2).append(" ");
points2.add(Map.of("x", x, "y", y2, "value", p2.getClosingPrice()));
points2.add(Map.of("x", x, "y", y2, "value", p2.getClosingPrice(), "date", date.toString()));
}

Map<String, Object> chartData = new HashMap<>();
Expand Down