From 5f6b6e10fc167d9b0b6117c67a79b52bff85da8f Mon Sep 17 00:00:00 2001
From: Manish <manish@radii.dev>
Date: Sun, 23 Apr 2023 20:11:26 +1000
Subject: [PATCH] Impl API

---
 controllers/convertHandler.js | 124 ++++++++++++++++++++++++----------
 routes/api.js                 |  48 +++++++++++--
 2 files changed, 132 insertions(+), 40 deletions(-)

diff --git a/controllers/convertHandler.js b/controllers/convertHandler.js
index 90273d2..8060691 100644
--- a/controllers/convertHandler.js
+++ b/controllers/convertHandler.js
@@ -1,44 +1,98 @@
 function ConvertHandler() {
-  
-  this.getNum = function(input) {
-    let result;
-    
-    return result;
-  };
-  
-  this.getUnit = function(input) {
-    let result;
-    
-    return result;
-  };
-  
-  this.getReturnUnit = function(initUnit) {
-    let result;
-    
-    return result;
-  };
-
-  this.spellOutUnit = function(unit) {
-    let result;
-    
-    return result;
-  };
-  
-  this.convert = function(initNum, initUnit) {
+  this.standardUnit = {
+    gal: "gal",
+    l: "L",
+    lbs: "lbs",
+    kg: "kg",
+    mi: "mi",
+    km: "km",
+  };
+
+  this.alternateUnits = {
+    gal: "L",
+    l: "gal",
+    lbs: "kg",
+    kg: "lbs",
+    mi: "km",
+    km: "mi",
+  };
+
+  this.spellOutUnits = {
+    gal: "gallons",
+    l: "liters",
+    lbs: "pounds",
+    kg: "kilograms",
+    mi: "miles",
+    km: "kilometers",
+  };
+
+  this.getNum = function (input) {
+    const matches = input.match(/[^a-zA-Z]+/g);
+    if (!matches) return 1;
+    if (matches.length != 1) return null;
+    const num_parts = matches[0].split("/");
+    if (num_parts.length == 1) {
+      const num = Number(num_parts[0]);
+      return num >= 0 ? num : null;
+    }
+    if (num_parts.length == 2) {
+      const [numerator, denominator] = [
+        Number(num_parts[0]),
+        Number(num_parts[1]),
+      ];
+      if (
+        Number.isNaN(numerator) ||
+        Number.isNaN(denominator) ||
+        denominator == 0
+      )
+        return null;
+      const num = numerator / denominator;
+      return num >= 0 ? num : null;
+    }
+    return null;
+  };
+
+  this.getUnit = function (input) {
+    const matches = input.match(/[a-zA-Z]+/g);
+    if (matches.length != 1) return null;
+    return this.standardUnit[matches[0].toLocaleLowerCase()] || null;
+  };
+
+  this.getReturnUnit = function (initUnit) {
+    return this.alternateUnits[initUnit.toLocaleLowerCase()];
+  };
+
+  this.spellOutUnit = function (unit) {
+    return this.spellOutUnits[unit.toLocaleLowerCase()];
+  };
+
+  this.convert = function (initNum, initUnit) {
     const galToL = 3.78541;
     const lbsToKg = 0.453592;
     const miToKm = 1.60934;
-    let result;
-    
-    return result;
+    switch (initUnit.toLocaleLowerCase()) {
+      case "gal":
+        return initNum * galToL;
+      case "l":
+        return initNum / galToL;
+      case "lbs":
+        return initNum * lbsToKg;
+      case "kg":
+        return initNum / lbsToKg;
+      case "mi":
+        return initNum * miToKm;
+      case "km":
+        return initNum / miToKm;
+      default:
+        return null;
+    }
   };
-  
-  this.getString = function(initNum, initUnit, returnNum, returnUnit) {
-    let result;
-    
-    return result;
+
+  this.getString = function (initNum, initUnit, returnNum, returnUnit) {
+    return `${initNum} ${this.spellOutUnit(
+      initUnit
+    )} converts to ${returnNum} ${this.spellOutUnit(returnUnit)}`;
   };
-  
 }
 
 module.exports = ConvertHandler;
diff --git a/routes/api.js b/routes/api.js
index f488327..3f51e6c 100644
--- a/routes/api.js
+++ b/routes/api.js
@@ -1,10 +1,48 @@
-'use strict';
+"use strict";
 
-const expect = require('chai').expect;
-const ConvertHandler = require('../controllers/convertHandler.js');
+const expect = require("chai").expect;
+const ConvertHandler = require("../controllers/convertHandler.js");
 
 module.exports = function (app) {
-  
   let convertHandler = new ConvertHandler();
-
+  app.route("/api/convert").get((req, res) => {
+    const input = req.query.input;
+    if (
+      input &&
+      convertHandler.getUnit(input) &&
+      convertHandler.getNum(input)
+    ) {
+      const initNum = convertHandler.getNum(input);
+      const initUnit = convertHandler.getUnit(input);
+      const returnNum = Number(
+        convertHandler.convert(initNum, initUnit)?.toFixed(5)
+      );
+      const returnUnit = convertHandler.getReturnUnit(initUnit);
+      const string = convertHandler.getString(
+        initNum,
+        initUnit,
+        returnNum,
+        returnUnit
+      );
+      res.json({
+        initNum: initNum,
+        initUnit: initUnit,
+        returnNum: returnNum,
+        returnUnit: returnUnit,
+        string: string,
+      });
+    } else if (
+      !convertHandler.getUnit(input) &&
+      !convertHandler.getNum(input)
+    ) {
+      console.log(`1: ${input}`);
+      res.send("invalid number and unit");
+    } else if (!convertHandler.getUnit(input)) {
+      console.log(`2: ${input}`);
+      res.send("invalid unit");
+    } else if (!convertHandler.getNum(input)) {
+      console.log(`3: ${input}`);
+      res.send("invalid number");
+    }
+  });
 };