# Hacking

Here is some wisdom to help you build and test this project as a developer and
potential contributor.

If you plan to contribute, please read the [CONTRIBUTING](CONTRIBUTING.md)
guide.

## Developer mode

Build system targets that are only useful for developers of this project are
hidden if the `DEVELOPER_MODE` option is disabled. Enabling this option makes
tests and other developer targets and options available. Not enabling this
option means that you are a consumer of this project and thus you have no need
for these targets and options.

Developer mode is always set to on in CI workflows.

### Presets

This project makes use of [presets][1] to simplify the process of configuring
the project. As a developer, you are recommended to always have the [latest
CMake version][latest cmake] installed to make use of the latest
Quality-of-Life additions.

You have a few options to pass `DEVELOPER_MODE` to the configure command, but
this project prefers to use presets.

As a developer, you should create a `CMakeUserPresets.json` file at the root of
the project:

```json
{
  "version": 2,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 14,
    "patch": 0
  },
  "configurePresets": [
    {
      "name": "dev",
      "binaryDir": "${sourceDir}/build/dev",
      "inherits": ["dev-mode", "vcpkg", "ci-<os>"],
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Debug"
      }
    }
  ],
  "buildPresets": [
    {
      "name": "dev",
      "configurePreset": "dev",
      "configuration": "Debug"
    }
  ],
  "testPresets": [
    {
      "name": "dev",
      "configurePreset": "dev",
      "configuration": "Debug",
      "output": {
        "outputOnFailure": true
      }
    }
  ]
}
```

You should replace `<os>` in your newly created presets file with the name of
the operating system you have, which may be `win64`, `linux` or `darwin`. You
can see what these correspond to in the
[`CMakePresets.json`](CMakePresets.json) file.

`CMakeUserPresets.json` is also the perfect place in which you can put all
sorts of things that you would otherwise want to pass to the configure command
in the terminal.

> **Note**
> Some editors are pretty greedy with how they open projects with presets.
> Some just pick a preset and start configuring without further input from the developer,
> which can be confusing. Make sure that your editor configures what and when you
> actually want it to, for example in CLion you have to make sure only the
> `dev-dev preset` has `Enable profile` ticked in
> `File > Settings... > Build, Execution, Deployment > CMake` and in Visual
> Studio you have to set the option `Never run configure step automatically`
> in `Tools > Options > CMake` **prior to opening the project**, after which
> you can manually configure using `Project > Configure Cache`.

### Dependency manager

The above preset will make use of the [vcpkg][vcpkg] dependency manager. After
installing it, make sure the `VCPKG_ROOT` environment variable is pointing at
the directory where the vcpkg executable is or you can directly set
`CMAKE_TOOLCHAIN_FILE` with an absolute path. On Windows, you might also want
to inherit from the `vcpkg-win64-static` preset, which will make vcpkg install
the dependencies as static libraries. This is only necessary if you don't want
to setup `PATH` to run tests.

### Configure, build and test

If you followed the above instructions, then you can configure, build and test
the project respectively with the following commands from the project root on
any operating system with any build system:

```sh
cmake --preset=dev
cmake --build --preset=dev
ctest --preset=dev
```

If you are using a compatible editor (e.g. VSCode) or IDE (e.g. VS), you will
also be able to select the above created user presets for automatic
integration.

Please note that both the build and test commands accept a `-j` flag to specify
the number of jobs to use, which should ideally be specified to the number of
threads your CPU has. You may also want to add that to your user preset using
the `jobs` property, see the [presets documentation][presets] for more
details.

[latest cmake]: https://cmake.org/download/
[vcpkg]: https://github.com/microsoft/vcpkg
[presets]: https://cmake.org/cmake/help/latest/manual/cmake-presets.7.html