Welcome to PowerDale

PowerDale is a small town with around 100 residents. Most houses have a smart meter installed that can save and send
information about how much power a house is drawing/using.

There are three major providers of energy in town that charge different amounts for the power they supply.

• Dr Evil's Dark Energy
• The Green Eco
• Power for Everyone

Introducing JOI Energy

JOI Energy is a new start-up in the energy industry. Rather than selling energy they want to differentiate themselves
from the market by recording their customers' energy usage from their smart meters and recommending the best supplier to
meet their needs.

You have been placed into their development team, whose current goal is to produce an API which their customers and
smart meters will interact with.

Unfortunately, two members of the team are on annual leave, and another one has called in sick! You are left with
another ThoughtWorker to progress with the current user stories on the story wall. This is your chance to make an impact
on the business, improve the code base and deliver value.

Story Wall

At JOI energy the development team use a story wall or Kanban board to keep track of features or "stories" as they are
worked on.

The wall you will be working from today has 7 columns:

• Backlog
• Ready for Dev
• In Dev
• Ready for Testing
• In Testing
• Ready for sign off
• Done

Examples can be found
here https://leankit.com/learn/kanban/kanban-board/

Users

To trial the new JOI software 5 people from the JOI accounts team have agreed to test the service and share their energy
data.

These values are used in the code and in the following examples too.

Requirements

The project requires Node v14.

Useful Node commands

The project makes use of node and its package manager to help you out carrying some common tasks such as building the
project or running it.

Install dependencies

$ npm install

Run the tests

There are two options to run the tests

• Run the tests once

  $ npm test

• Keep running the tests with every change

  $ npm run test-watch

Run the application

Run the application which will be listening on port 8080. There are two ways to run the application.

• Run the application with the current code

  $ npm start

• Run the application with reload on save

  $ npm run dev

API

Below is a list of API endpoints with their respective input and output. Please note that the application needs to be
running for the following endpoints to work. For more information about how to run the application, please refer
to run the application section above.

Store readings

Endpoint

POST /readings/store

Example of body

{
  "smartMeterId": <smartMeterId>,
  "electricityReadings": [
    {
      "time": <time>,
      "reading": <reading>
    }
  ]
}

Parameters

Example readings

In the above example, the smart meter sampled readings, in kW, every minute. Note that the reading is in kW and
not kWH, which means that each reading represents the consumption at the reading time. If no power is being consumed
at the time of reading, then the reading value will be 0. Given that 0 may introduce new challenges, we can assume
that there is always some consumption, and we will never have a 0 reading value. These readings are then sent by the
smart meter to the application using REST. There is a service in the application that calculates the kWH from these
readings.

The following POST request, is an example request using CURL, sends the readings shown in the table above.

$ curl \
  -X POST \
  -H "Content-Type: application/json" \
  "http://localhost:8080/readings/store" \
  -d '{"smartMeterId":"smart-meter-0","electricityReadings":[{"time":1606636800,"reading":0.0503},{"time":1606636860,"reading":0.0621},{"time":1606636920,"reading":0.0222},{"time":1606636980,"reading":0.0423},{"time":1606637040,"reading":0.0191}]}'

The above command will return an array with all readings for the given smart meter id.

Example output

[
  {
    "time": 1607686125,
    "reading": 0.9258396634545867
  },
  {
    "time": 1607682525,
    "reading": 1.4237064184605117
  },
  {
    "time": 1607678925,
    "reading": 0.9974238262070414
  },
  {
    "time": 1607675325,
    "reading": 0.7347072120638889
  },
  {
    "time": 1607671725,
    "reading": 0.27168077193505225
  },
  {
    "time": 1607668125,
    "reading": 0.1981733770158689
  },
  {
    "time": 1606636800,
    "reading": 0.0503
  },
  {
    "time": 1606636860,
    "reading": 0.0621
  },
  {
    "time": 1606636920,
    "reading": 0.0222
  },
  {
    "time": 1606636980,
    "reading": 0.0423
  },
  {
    "time": 1606637040,
    "reading": 0.0191
  }
]

Get Stored Readings

Endpoint

GET /readings/read/<smartMeterId>

Parameters

Retrieving readings using CURL

$ curl "http://localhost:8080/readings/read/smart-meter-0"

Example output

[
  {
    "time": 1607686125,
    "reading": 0.9258396634545867
  },
  {
    "time": 1607682525,
    "reading": 1.4237064184605117
  },
  {
    "time": 1607678925,
    "reading": 0.9974238262070414
  },
  {
    "time": 1607675325,
    "reading": 0.7347072120638889
  },
  {
    "time": 1607671725,
    "reading": 0.27168077193505225
  },
  {
    "time": 1607668125,
    "reading": 0.1981733770158689
  },
  {
    "time": 1606636800,
    "reading": 0.0503
  },
  {
    "time": 1606636860,
    "reading": 0.0621
  },
  {
    "time": 1606636920,
    "reading": 0.0222
  },
  {
    "time": 1606636980,
    "reading": 0.0423
  },
  {
    "time": 1606637040,
    "reading": 0.0191
  }
]

View Current Price Plan and Compare Usage Cost Against all Price Plans

Endpoint

GET /price-plans/compare-all/<smartMeterId>

Parameters

Retrieving readings using CURL

$ curl "http://localhost:8080/price-plans/compare-all/smart-meter-0"

Example output

{
  "smartMeterId": "smart-meter-0",
  "pricePlanComparisons": [
    {
      "price-plan-0": 0.0148314004034269
    },
    {
      "price-plan-1": 0.0029662800806853793
    },
    {
      "price-plan-2": 0.0014831400403426897
    }
  ]
}

View Recommended Price Plans for Usage

Endpoint

GET /price-plans/recommend/<smartMeterId>[?limit=<limit>]

Parameters

Retrieving readings using CURL

$ curl "http://localhost:8080/price-plans/recommend/smart-meter-0?limit=2"

Example output

[
  {
    "price-plan-2": 0.0014831400403426897
  },
  {
    "price-plan-1": 0.0029662800806853793
  }
]