feat: add price history support

server.js

@@ -18,6 +18,10 @@ const DATA_DIR = process.env.DATA_DIR
 const DATA_FILE = process.env.DATA_FILE
   ? path.resolve(process.env.DATA_FILE)
   : path.join(DATA_DIR, 'votes.json');
+const DEFAULT_PRICE_HISTORY_FILE = path.join(__dirname, 'price-watch', 'history.jsonl');
+const PRICE_HISTORY_FILE = process.env.PRICE_HISTORY_FILE
+  ? path.resolve(process.env.PRICE_HISTORY_FILE)
+  : DEFAULT_PRICE_HISTORY_FILE;
 
 app.use(cors());
 app.use(express.json());
@@ -51,6 +55,160 @@ function saveData(nextData) {
   fs.writeFileSync(DATA_FILE, JSON.stringify(nextData, null, 2));
 }
 
+function normalizeKey(value) {
+  return String(value || '')
+    .trim()
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/^-+|-+$/g, '');
+}
+
+function readJsonLines(filePath) {
+  if (!fs.existsSync(filePath)) return [];
+
+  return fs.readFileSync(filePath, 'utf8')
+    .split(/\r?\n/)
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .map((line) => {
+      try {
+        return JSON.parse(line);
+      } catch {
+        return null;
+      }
+    })
+    .filter(Boolean);
+}
+
+function getOptionHistoryKeys(option) {
+  const nameKey = normalizeKey(option.name);
+  const categoryNameKey = option.categoryId && nameKey ? `${option.categoryId}-${nameKey}` : '';
+
+  return [...new Set([
+    option.seedKey,
+    option.id,
+    option.priceKey,
+    option.optionKey,
+    option.slug,
+    categoryNameKey,
+    nameKey,
+  ].filter(Boolean).map(normalizeKey))];
+}
+
+function extractNumericPrice(point) {
+  const candidates = [
+    point.price,
+    point.value,
+    point.amount,
+    point.perPerson,
+    point.groupTotal,
+  ];
+
+  for (const candidate of candidates) {
+    if (typeof candidate === 'number' && Number.isFinite(candidate)) return candidate;
+    if (typeof candidate === 'string') {
+      const parsed = Number(candidate.replace(/[^0-9.-]/g, ''));
+      if (Number.isFinite(parsed)) return parsed;
+    }
+  }
+
+  return null;
+}
+
+function loadPriceHistoryState() {
+  const runs = readJsonLines(PRICE_HISTORY_FILE)
+    .map((entry, index) => {
+      const checkedAtRaw = entry.checkedAt || entry.checked_at || entry.runAt || entry.timestamp || entry.date || null;
+      const checkedAtMs = checkedAtRaw ? Date.parse(checkedAtRaw) : Date.now() + index;
+
+      return {
+        ...entry,
+        checkedAt: Number.isNaN(checkedAtMs) ? null : new Date(checkedAtMs).toISOString(),
+        checkedAtMs: Number.isNaN(checkedAtMs) ? Date.now() + index : checkedAtMs,
+      };
+    })
+    .sort((a, b) => a.checkedAtMs - b.checkedAtMs);
+
+  runs.forEach((run, index) => {
+    run.runIndex = index;
+  });
+
+  const seriesByKey = new Map();
+
+  runs.forEach((run) => {
+    const pricePoints = Array.isArray(run.optionPrices)
+      ? run.optionPrices
+      : Array.isArray(run.prices)
+        ? run.prices
+        : Array.isArray(run.trackedPrices)
+          ? run.trackedPrices
+          : [];
+
+    pricePoints.forEach((point) => {
+      const key = normalizeKey(
+        point.optionKey || point.optionId || point.seedKey || point.slug || point.key || point.name,
+      );
+      const price = extractNumericPrice(point);
+
+      if (!key || price === null) return;
+
+      const nextPoint = {
+        checkedAt: run.checkedAt,
+        checkedAtMs: run.checkedAtMs,
+        runIndex: run.runIndex,
+        price,
+        currency: point.currency || 'USD',
+        displayPrice: point.displayPrice || point.priceLabel || point.label || null,
+        source: point.source || null,
+        sourceUrl: point.sourceUrl || point.url || null,
+        note: point.note || point.description || null,
+      };
+
+      if (!seriesByKey.has(key)) seriesByKey.set(key, []);
+      seriesByKey.get(key).push(nextPoint);
+    });
+  });
+
+  seriesByKey.forEach((series) => {
+    series.sort((a, b) => a.runIndex - b.runIndex);
+  });
+
+  return {
+    runs,
+    seriesByKey,
+    latestCheckedAt: runs.at(-1)?.checkedAt || null,
+    totalRuns: runs.length,
+  };
+}
+
+function getPriceHistoryForOption(option, priceHistoryState) {
+  const optionKeys = getOptionHistoryKeys(option);
+  for (const key of optionKeys) {
+    const series = priceHistoryState.seriesByKey.get(key);
+    if (series && series.length) {
+      return series;
+    }
+  }
+
+  return [];
+}
+
+function decorateOptionWithPriceHistory(option, priceHistoryState) {
+  const priceHistory = getPriceHistoryForOption(option, priceHistoryState);
+  const latestPricePoint = priceHistory.at(-1) || null;
+
+  return {
+    ...option,
+    priceHistory,
+    latestPricePoint,
+    currentPrice: latestPricePoint?.price ?? null,
+  };
+}
+
+function decorateOptionsWithPriceHistory(options, priceHistoryState) {
+  return options.map((option) => decorateOptionWithPriceHistory(option, priceHistoryState));
+}
+
 function approvedOptionsWithVoteSummary() {
   return data.options
     .filter((option) => option.approved)
@@ -69,15 +227,19 @@ function broadcast(payload) {
 }
 
 function buildRealtimeSnapshot() {
+  const priceHistoryState = loadPriceHistoryState();
+  const approvedOptions = data.options.filter((option) => option.approved);
+
   return {
     type: 'init',
     pollsOpen: data.pollsOpen,
     categories: data.categories,
-    options: data.options.filter((option) => option.approved),
+    options: decorateOptionsWithPriceHistory(approvedOptions, priceHistoryState),
     results: approvedOptionsWithVoteSummary(),
     totalVoters: data.voters.length,
     budgetScenarios: data.budgetScenarios || [],
-    priceUpdatedAt: data.priceUpdatedAt || null,
+    priceUpdatedAt: priceHistoryState.latestCheckedAt || data.priceUpdatedAt || null,
+    priceHistoryRunCount: priceHistoryState.totalRuns,
   };
 }
 
@@ -109,19 +271,24 @@ app.get('/api/categories', (req, res) => {
 app.get('/api/options', (req, res) => {
   const { category, includeUnapproved } = req.query;
   let options = data.options;
+  const priceHistoryState = loadPriceHistoryState();
 
   if (category) options = options.filter((option) => option.categoryId === category);
   if (!includeUnapproved) options = options.filter((option) => option.approved);
 
-  res.json(options);
+  res.json(decorateOptionsWithPriceHistory(options, priceHistoryState));
 });
 
 app.get('/api/results', (req, res) => {
+  const priceHistoryState = loadPriceHistoryState();
   const results = data.categories.map((category) => ({
     ...category,
     options: data.options
       .filter((option) => option.approved && option.categoryId === category.id)
-      .map((option) => ({ ...option, voteCount: option.votes.length })),
+      .map((option) => ({
+        ...decorateOptionWithPriceHistory(option, priceHistoryState),
+        voteCount: option.votes.length,
+      })),
   }));
 
   res.json({
@@ -129,17 +296,32 @@ app.get('/api/results', (req, res) => {
     results,
     totalVoters: data.voters.length,
     budgetScenarios: data.budgetScenarios || [],
-    priceUpdatedAt: data.priceUpdatedAt || null,
+    priceUpdatedAt: priceHistoryState.latestCheckedAt || data.priceUpdatedAt || null,
+    priceHistoryRunCount: priceHistoryState.totalRuns,
   });
 });
 
 app.get('/api/budgets', (req, res) => {
+  const priceHistoryState = loadPriceHistoryState();
   res.json({
-    updatedAt: data.priceUpdatedAt || null,
+    updatedAt: priceHistoryState.latestCheckedAt || data.priceUpdatedAt || null,
     scenarios: data.budgetScenarios || [],
   });
 });
 
+app.get('/api/price-history', (req, res) => {
+  const priceHistoryState = loadPriceHistoryState();
+  const seriesByOption = Object.fromEntries(
+    [...priceHistoryState.seriesByKey.entries()],
+  );
+
+  res.json({
+    latestCheckedAt: priceHistoryState.latestCheckedAt,
+    totalRuns: priceHistoryState.totalRuns,
+    seriesByOption,
+  });
+});
+
 app.post('/api/vote', (req, res) => {
   const { optionId, voterName } = req.body;