[Truly.co](https://truly.co/) is an enterprise VOIP company. They were hiring
for a Clojure developer. Even though I'm an expert in Clojure, I opted to use
Haskell because I really wanted to play with the
[acid-state](https://github.com/acid-state/acid-state) library, and this seemed
like a great opportunity to do so.

## The [exercise](https://docs.google.com/document/d/1ZWcTzQdQ9zSZ8Tv4XDyCrju40_FuSJ7W6qu4-pUU-ZA/pub) is a Caller Id Service:

The goal of this exercise is for you to implement a standalone service that will
respond to requests seeking caller id information.

### Api Requirements/Notes

- Api should return json
- Phone numbers should be in E.164 format.
- Appropriate http codes should be returned on error.

### API Endpoints

#### GET /query

Fetches caller id information.

Params:

    number - the number we want caller id information for.

Example query:

    GET http://localhost/query?number=%2B15556789090

Response:

    {results: [{ “name”: “Bob Barker”, “number”: “+15556789090”, “context”: “personal”}]}

#### `POST /number`

Adds caller id data to the service.

Body:

    name - contact name
    number - the number in E.164 format
    context - the context for the phone number.

Note: A phone number may be present multiple times, but can only appear once per
context. In other words you can think of a <number,context> pair as unique.

#### Seed Data

Normally a service like this would call other services in turn, but to keep
things simple we are going to provide seed data for the service as a csv
file. Your service will need to read in that initial data and use it to serve
requests.

Line format:

    <phone number>,<context>,<caller id>

Example:

    5556780909,work,John Doe

The seed data can be downloaded via [this
link](https://www.dropbox.com/s/0hmkx242o42g924/interview-callerid-data.csv.gz).

### Service Requirements

- We prefer if your service is standalone, this means that it shouldn’t require
  additional server software (tomcat/apache/etc) to run. If it does require such
  software you will need to provide setup instructions.
- The port on which the service listens should be configurable without editing
  code.
- Your code should include a README file with instructions on how to run your
  service. Shell scripts are also appreciated but not required.
- You may NOT use an external datastore.

### Misc/Other Notes

- Once again to keep things simple data submitted to your service does not need
  to be persisted.
- While our main goal is to look at your code, we will run your code and test
  it.
- There is no timeline, please take as long as you want. However if you take
  especially long we may check in.
- If you have any questions please ask.

## How to run this code

1. Have [stack](http://haskellstack.org/) installed
2. Optional: have [nix](https://nixos.org/nix/) installed. If you *don't* use nix, delete line 3 of `main.hs`.
3. Run `./main.hs` and the server will startup

To bootstrap the db, do `curl -XPOST "localhost:3000/bootstrap"`. This takes
like 3 seconds or so.

See `test.http` for some other examples.