/*
 * CSE 154 Summer 2019
 * Solution API for printing "Hello World" and doing various math operations.
 * /^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v/
 * Endpoint: /hello
 * Response Format: text
 * Prints "Hello World!" to the client.
 * /^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v/
 * Endpoint: /hello/name
 * Query Parameters: "first" - Someone's first name, "last" - Someone's last name.
 * Response Format: text
 * Responds with a hello to the given first/last named person.
 * /^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v/
 * Endpoint: /math/circle/:r
 * Response Format: JSON
 * Response Example: {"area": 3.14, "circumference": 6.28}
 * Returns the area and circumference of a circle with radius :r.
 * /^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v/
 * Endpoint: /math/rectangle/:width/:height
 * Response Format: JSON
 * Response Example: {"area": 6, "perimeter": 16}
 * Returns the area and perimeter of a rectangle with given :width and :height
 * /^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v/
 * Endpoint: /math/power/:base/:exponent
 * Response Format: JSON
 * Response Example {"result": 8}
 * Returns the :base raised to the :exponent
 */

"use strict";

const express = require("express");
const app = express();

app.get("/hello", function(req, res) {
  res.set("Content-Type", "text/plain");
  res.send("Hello World!");
});

app.get("/hello/name", function(req, res) {
  res.set("Content-Type", "text/plain");
  if (req.query["first"] && req.query["last"]) {
    res.send("Hello " + req.query["first"] + " " + req.query["last"]);
  } else {
    res.status(400).send("Error: missing first or last names.");
  }
});

app.get("/math/circle/:r", function(req, res) {
  res.set("Content-Type", "application/json");
  let radius = parseFloat(req.params["r"]);
  let area = Math.PI * radius * radius;
  let circumference = Math.PI * radius * 2;
  res.json({"area": area, "circumference": circumference});
});

app.get("/math/rectangle/:width/:height", function(req, res) {
  res.set("Content-Type", "application/json");
  let width = parseFloat(req.params["width"]);
  let height = parseFloat(req.params["height"]);
  let area = width * height;
  let perimeter = (width + height) * 2;
  res.json({"area": area, "perimeter": perimeter});
});

app.get("/math/power/:base/:exponent", function(req, res) {
  res.set("Content-Type", "application/json");
  let base = parseFloat(req.params["base"]);
  let exponent = parseFloat(req.params["exponent"]);
  let power = Math.pow(base, exponent);
  res.json({"result": power});
});

app.use(express.static("public"));
const PORT = process.env.PORT || 8000;
app.listen(PORT);