docs: add full documentation

README.md

@@ -1,18 +1,55 @@
 # CSharp to Flutter
 
+## Requirements
+
+All the following tools must be in your `PATH` :
+
+* All platforms
+  + [Bash >= 4.0](https://www.gnu.org/software/bash/)
+  + [BeyondNetGen](https://github.com/royalapplications/beyondnet)
+  + [Android NDK](https://developer.android.com/ndk/downloads) if you want to build for Android
+* MacOS
+  + [XCode](https://developer.apple.com/xcode/) if you want to build for iOS
+
 ## Quick start
 
 Simply run the build script
 
 ```bash
-./build.sh
+./build.sh -i MyLib.Managed
+```
+
+More advanced usage:
+
+> Context: You want to build a library named `AwesomeFeature` for Android only, and you have the Android NDK installed in `$ANDROID_NDK_ROOT` but not in `$ANDROID_NDK_HOME`.
+
+```bash
+./build.sh -i AwesomeFeature --ndk $ANDROID_NDK_ROOT --no-ios
+```
+
+## Usage
+
+```shell-session
+Usage: ./build.sh [options]
+Options:
+  -h, --help     Print this help and exit
+  -i             Input project name (required)
+  -g             Generated project name (default: <input-project-name>.Generated)
+  -o             Output folder name (default: libs)
+  --ndk          Android NDK path (default: ANDROID_NDK_HOME environment variable)
+  --no-android   Disable Android build (default: false)
+  --no-ios       Disable iOS build (default: false)
 ```
 
 ## What is this?
 
 This script:
-- Run `dotnet publish` on the CoreRT managed library to get intermediate dlls
-- Run `beyondnetgen` to generate the C header file and the *unmanaged* csharp code
-- Run `dotnet publish` on the *unmanaged* csharp code for the target platforms.
-- Copy the header file and the libs to the flutter project
-- Run `ffigen` to generate the dart bindings against the header file
+* Run `dotnet publish` on the CoreRT managed library to get intermediate dlls
+* Copy configuration files templates
+* Android:
+  * Run `beyondnetgen` to generate the C header file and the *unmanaged* csharp code
+  * Build a complete intermediate csproject with the *unmanaged* csharp code and the generated header file
+  * Run `dotnet publish` on the *unmanaged* csharp code for the target platforms.
+* iOS:
+  * Run `beyondnetgen` and follow full process to get xframework
+* Copy the generated files to the output folder