# UKTT

Uktt provides a way to work with the UK Trade Tariff API, https://api.trade-tariff.service.gov.uk/#gov-uk-trade-tariff-api.

###  Features
- Fetches sections, chapters, headings, commodities, goods_nomenclatures, monetary exchange rates, and quota definitions from the Tariff API
- Covers both `v1` and `v2` of the API
- Tests local, production, and any other Frontend API servers using real (not mocked) API calls
- Produces printable Tariff PDF files for chapters
- Command-line interface

## Installation

The repository is here: __https://gitlab.bitzesty.com/open-source/uktt__

Add to your Gemfile:

```ruby
gem 'uktt', git: 'https://gitlab.bitzesty.com/open-source/uktt.git'
```

## Usage

### Set options

Set library-wide options using a hash. Here are the current defaults:
```ruby
opts = {
  host: 'http://localhost:3002',  #  use a local frontend server
  version: 'v1',                  #  `v1` and `v2` are supported
  debug: false,                   #  dislays request and response info
  return_json: false              #  returns OpenStruct by default
}
```

Set options upon instantiation, and change them on the instance by passing-in a hash to overwrite existing or create new options:
```ruby
# Instatiate an new object with options:

> s = Uktt::Section.new(opts.merge(section_id: '1'))

# or, set `section_id` with accessor. Only `*_id` options have accessors.

> s = Uktt::Section.new
> s.section_id = '1'

# => #<Uktt::Section @section_id="1", @config={:host=>"http://localhost:3002", :version=>"v1", :debug=>false, :return_json=>false}>

> s.config = {version: 'v2', return_json: true, section_id: '2'}
> s.inspect

# => #<Uktt::Section @section_id="2", @config={:host=>"http://localhost:3002", :version=>"v2", :debug=>false, :return_json=>true}>

# NOTE: `Uktt::Section` has accessors. Other objects also have *_id accessors.

> s.section_id

# => "2"

> s.section_id = '3'

# => #<Uktt::Section @section_id="3", @config={:host=>"http://localhost:3002", :version=>"v2", :debug=>false, :return_json=>true}> 

```

Options may be loaded from a YAML configuration file:

```yaml
# uktt.yaml
---
  host: http://foo.bar:999
  version: v2
  debug: false
  return_json: false
```


Load options from file:

```ruby
> Uktt.configure_with('./uktt.yaml')

# => {"host"=>"http://foo.bar:999", "version"=>"v2", "debug"=>false, "return_json"=>false}
```

### Retrieve one object

Retrieve an object as an OpenStruct, then retrieve it as JSON

```ruby
> s.retrieve

# => #<OpenStruct data=#<OpenStruct id="3", type="section", attributes=#<OpenStruct ... >>>

> s.config = {return_json: true}
> s.retrieve

# => {"data":{"id":"3","type":"section","attributes":{"id": ... }}}

```

### Retrieve collections of objects

Retrieve all sections using `v2`, then switch to `v1`:

```ruby
> s.retrieve_all

# => #<OpenStruct data=[#<OpenStruct id="1", type="section", attributes=#<OpenStruct ... >>]>

> s.config = {version: 'v1'}
> s.retrieve_all

# => [#<OpenStruct id=1, position=1, title="Live animals; animal products", numeral="I", ...>]
```

### Quota search

Retrieve quota definitions, optionally filtered by various criteria. The search criteria are passed-in with a hash:

```ruby
> criteria = {
    goods_nomenclature_item_id: '0805102200',
    year: '2018',
    geographical_area_id: 'EG',
    order_number: '091784',
    status: 'not blocked',
    critical: 'N'
  }
> quotas = Uktt::Quota.new(version: 'v2') # must use `v2`
> quotas.search(criteria)

# => #<OpenStruct data=[#<OpenStruct id="12202", type="definition", attributes=#<OpenStruct quota_definition_sid=12202, quota_order_number_id="091784" ... >>]>
```
### Goods nomenclatures

Retrieves goods nomenclatures by heading, chapter, or section.

E.g., use a heading object to retrieve all associated goods nomenclatures:

```ruby
> h = Uktt::Heading.new(heading_id: '0101')
> h.goods_nomenclatures

# => #<OpenStruct data=[#<OpenStruct id="27624", type="goods_nomenclature", attributes=#<OpenStruct goods_nomenclature_item_id="0101000000", ... >>]>
```

### API Testing

The Uktt gem may be used to test the Trade Tariff API. The specs _do not_ use mocks-- and will make real API requests against a Trade Tariff frontend server, e.g., local, dev, staging, or production.

Run tests using default server (localhost:3002) and default API version `v1`:

```bash
$ rake spec
```

To run tests using API version `v2`, set the `VER` environment variable:

```bash
$ VER=v2 rake spec
```

To run tests against any Trade Tariff Frontend server, set the `HOST` variable, or use a shortcut `PROD=true` to set the host to the production server:

```bash
$ HOST=https://dev.trade-tariff.service.gov.uk rake spec

# or using a shortcut for production:

$ PROD=true rake spec

# envorinment variables may be combined:

$ HOST=https://localhost:3002 VER=v2 rake spec
```

### PDF

The Uktt gem can produce PDF files for individual chapters of the Tariff.

Set `chapter_id` and optional `filepath` with a hash.

```ruby
> p = Uktt::Pdf.new
> p.config = {chapter_id: '01', filepath: './Chapter-01.pdf'}
> p.make_chapter
```

#### Currencies in PDF

The default currency for PDFs is the Euro. The PDF may be produced in certain other supported currencies. if one or more supported currencies is specified, all currency amounts in the PDF will be converted from EUR (the "parent" currency) into the specified child currency.

The exchange rates for each supported currency must be specified in one of the following ways:
1.  For any supported currency, set a `MX_RATE_EUR_***` environment variable, where `***` is the three-letter currency code
2.  For GBP, the gem will attempt to look up the EUR-GBP exchange rate using the Tariff API
3.  EUR is the default currency if no currency is specified

The Tariff PDF will be produced in any supported currency specified in the options:
```ruby
> Uktt::Pdf.new(chapter_id: '01', filepath: './Chapter-01-GBP.pdf', host:'https://www.trade-tariff.service.gov.uk/api', currency:'GBP').make_chapter
```

** In the backend (where we run the PDF gem), the exchange rate is fetched from the db and then set as an ENV variable before the chapters are produced:
```ruby
ENV["MX_RATE_EUR_#{currency}"] ||= MonetaryExchangeRate.latest(currency).to_s
```

The supported currencies are:
```ruby
SUPPORTED_CURRENCIES = {
    'BGN' => 'лв',
    'CZK' => 'Kč',
    'DKK' => 'kr.',
    'EUR' => '€', 
    'GBP' => '£',
    'HRK' => 'kn',
    'HUF' => 'Ft',
    'PLN' => 'zł',
    'RON' => 'lei',
    'SEK' => 'kr'
  }
```

## Command line interface

This gem provides a command-line interface (CLI).

```bash
$ uktt

Commands:
  uktt chapter                  # Retrieves a chapter
  uktt chapters                 # Retrieves all chapters
  uktt commodity                # Retrieves a commodity
  uktt heading                  # Retrieves a heading
  uktt help [COMMAND]           # Describe available commands or one specific command
  uktt info                     # Prints help for `uktt`
  uktt monetary_exchange_rates  # Retrieves monetary exchange rates
  uktt pdf                      # Makes a PDF of a chapter
  uktt section                  # Retrieves a section
  uktt sections                 # Retrieves all sections
  uktt test                     # Runs API specs

Options:
  -h, --host, [--host=http://localhost:3002]            # Use specified API host, otherwise `http://localhost:3002`
  -a, --api-version, [--version=v1]                     # Request a specific API version, otherwise `v1`
  -d, --debug, [--debug=true], [--no-debug]             # Show request and response headers, otherwise not shown
  -j, --json, [--return-json=true], [--no-return-json]  # Request JSON response, otherwise OpenStruct
  -p, --production, [--prod=true]                       # Use production API host, otherwise `http://localhost:3002`
  -g, --goods, [--goods=GOODS]                          # Retrieve goods nomenclatures in this object
  -n, --note, [--note=NOTE]                             # Retrieve a note for this object
  -c, --changes, [--changes=CHANGES]                    # Retrieve changes for this object
```

Here are some examples of the CLI:

```bash
# basic usage
$ uktt sections                 # get all sections
$ uktt section 1                # get one section
$ uktt section 1 -j             # get JSON
$ uktt section 1 -jp            # get JSON, from prod.
$ uktt section 1 -jp -a v2      # get JSON, from prod., use `v2`
$ uktt monetary_exchange_rates  # get a collection

# get an object
$ uktt chapter 01
$ uktt heading 0101
$ uktt commodity 0101210000

# make a PDF
$ uktt pdf 01                   # specify a chapter_id
$ uktt pdf 'test'               # use the magic filename 'test' for a PDF smoketest
                                # which _doesn't_ hit the API

# 'goods nomenclatures' resources are only availab=le on `v2` of the API
$ uktt heading 0101 -g -a v2
$ uktt chapter 01 -g -a v2 
$ uktt section 1 --goods --api-version v2 # using long format options
```

## Development

While developing the gem, and for use outside of a Rails app, I found it useful to have a console:

```bash
$ bundle console
```

After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` (or `bundle console` outside of a rails app) for an interactive prompt that will allow you to experiment.

## Contributing

Pull requests: https://gitlab.bitzesty.com/open-source/uktt/merge_requests.

Issues list: https://gitlab.bitzesty.com/open-source/uktt/issues.

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).

## Code of Conduct

Everyone interacting in the `uktt` project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://gitlab.bitzesty.com/open-source/uktt/blob/master/CODE_OF_CONDUCT.md).