1 files changed, 108 insertions, 0 deletions
diff --git a/src/data/parse-replay-csv.js b/src/data/parse-replay-csv.js
new file mode 100644
index 0000000..b6ce97a
--- /dev/null
+++ b/src/data/parse-replay-csv.js
@@ -0,0 +1,108 @@
+function splitRow(line) {
+    return line.split(/[;,\t]/).map((value) => value.trim());
+}
+
+function isNumeric(value) {
+    return value !== '' && Number.isFinite(Number(value));
+}
+
+function detectHeader(rows) {
+    if (rows.length === 0) {
+        return { hasHeader: false, headers: [] };
+    }
+
+    const [firstRow] = rows;
+    const hasHeader = firstRow.some((value) => !isNumeric(value));
+    return {
+        hasHeader,
+        headers: hasHeader ? firstRow.map((value) => value.toLowerCase()) : [],
+    };
+}
+
+function detectTimeScale(headers) {
+    const timeHeader = headers.find((header) => header.includes('time') || header.includes('timestamp'));
+    if (!timeHeader) {
+        return 1;
+    }
+
+    if (timeHeader.includes('sec') && !timeHeader.includes('msec') && !timeHeader.includes('ms')) {
+        return 1000;
+    }
+
+    return 1;
+}
+
+function detectColumnIndexes(headers, columnCount) {
+    if (headers.length === 0) {
+        return {
+            timeIndex: columnCount > 1 ? 0 : -1,
+            valueIndex: columnCount > 1 ? 1 : 0,
+        };
+    }
+
+    const timeIndex = headers.findIndex((header) => header.includes('time') || header.includes('timestamp'));
+    const valueIndex = headers.findIndex((header) => header.includes('value') || header.includes('signal') || header.includes('y'));
+
+    return {
+        timeIndex,
+        valueIndex: valueIndex >= 0 ? valueIndex : (headers.length > 1 ? 1 : 0),
+    };
+}
+
+export function parseReplayCsv(text, { sampleRateHz = 60 } = {}) {
+    const rows = text
+        .split(/\r?\n/)
+        .map((line) => line.trim())
+        .filter((line) => line && !line.startsWith('#'))
+        .map(splitRow)
+        .filter((row) => row.some((value) => value !== ''));
+
+    if (rows.length === 0) {
+        throw new Error('CSV file is empty');
+    }
+
+    const { hasHeader, headers } = detectHeader(rows);
+    const dataRows = hasHeader ? rows.slice(1) : rows;
+    const columnCount = rows[0].length;
+    const { timeIndex, valueIndex } = detectColumnIndexes(headers, columnCount);
+    const timeScale = detectTimeScale(headers);
+    const intervalMs = 1000 / Math.max(1, sampleRateHz);
+
+    const points = dataRows
+        .map((row, index) => {
+            const rawValue = row[valueIndex];
+            if (!isNumeric(rawValue)) {
+                return null;
+            }
+
+            const parsedValue = Number(rawValue);
+            const parsedTime = timeIndex >= 0 && isNumeric(row[timeIndex])
+                ? Number(row[timeIndex]) * timeScale
+                : index * intervalMs;
+
+            return {
+                timeMs: parsedTime,
+                value: parsedValue,
+            };
+        })
+        .filter(Boolean)
+        .sort((left, right) => left.timeMs - right.timeMs);
+
+    if (points.length === 0) {
+        throw new Error('CSV file did not contain any numeric data points');
+    }
+
+    const firstTime = points[0].timeMs;
+    const normalizedPoints = points.map((point) => ({
+        timeMs: point.timeMs - firstTime,
+        value: point.value,
+    }));
+
+    return {
+        points: normalizedPoints,
+        metadata: {
+            pointCount: normalizedPoints.length,
+            durationMs: normalizedPoints.at(-1)?.timeMs ?? 0,
+        },
+    };
+}