feat: complete day 3

day3/routes/evaluation.js

@@ -0,0 +1,89 @@
+const express = require("express");
+const router = express.Router();
+const db = require("../models");
+
+// Helper to cast value to type
+function castToType(value, type) {
+  if (type === "INTEGER") return parseInt(value, 10);
+  if (type === "FLOAT") return parseFloat(value);
+  if (type === "STRING") return String(value);
+  return value;
+}
+
+// Helper to safely evaluate condition
+function safeEval(condition, context) {
+  // Only allow access to context variables
+  return Function(
+    ...Object.keys(context),
+    `return (${condition});`
+  )(...Object.values(context));
+}
+
+router.get("/", async (req, res) => {
+  try {
+    const { variable } = req.query;
+    if (!variable) {
+      return res
+        .status(400)
+        .json({ success: false, error: "Missing variable parameter" });
+    }
+    // Decode base64
+    let decoded;
+    try {
+      decoded = Buffer.from(variable, "base64").toString("utf-8");
+    } catch (e) {
+      return res
+        .status(400)
+        .json({ success: false, error: "Invalid base64 encoding" });
+    }
+    let payload;
+    try {
+      payload = JSON.parse(decoded);
+    } catch (e) {
+      return res
+        .status(400)
+        .json({ success: false, error: "Invalid JSON in variable payload" });
+    }
+
+    // Fetch all variables and rules
+    const [dbVariables, rules] = await Promise.all([
+      db.variables.findAll(),
+      db.rules.findAll(),
+    ]);
+
+    // Build a map of variable types
+    const variableTypeMap = {};
+    dbVariables.forEach((v) => {
+      variableTypeMap[v.name] = v.type;
+    });
+
+    // Prepare context for evaluation: only include variables that exist in db
+    const context = {};
+    for (const [key, value] of Object.entries(payload)) {
+      if (variableTypeMap[key]) {
+        context[key] = castToType(value, variableTypeMap[key]);
+      }
+    }
+
+    // Evaluate each rule
+    const results = [];
+    for (const rule of rules) {
+      let passed = false;
+      try {
+        passed = safeEval(rule.condition, context);
+      } catch (e) {
+        // Ignore rules with invalid conditions or missing variables
+        continue;
+      }
+      if (passed) {
+        results.push({ rule_id: rule.id, result: rule.action });
+      }
+    }
+
+    return res.json({ success: true, data: results });
+  } catch (err) {
+    return res.status(500).json({ success: false, error: err.message });
+  }
+});
+
+module.exports = router;