BuildScripts/gradle/apiGeneration.gradle

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.squareup:javapoet:1.8.0'
    }
}

import com.squareup.javapoet.*

import javax.lang.model.element.Modifier

interface SchemeObject {

    void writeToFile(File directory)

    void readLine(String line)

}

class EnumObject implements SchemeObject {

    enum Type {
        STRING, NUMBER, BOOLEAN
    }

    static final String SIGNATURE = "enum"

    final String name
    Type type

    Map<String, Object> values = new HashMap<>()

    EnumObject(String firstLine) {
        name = firstLine.substring(SIGNATURE.length()).trim()
    }

    @Override
    void writeToFile(File directory) {
        TypeSpec.Builder enumBuilder = TypeSpec.enumBuilder(name)
                .addModifiers(Modifier.PUBLIC)
                .addSuperinterface(ClassName.bestGuess("ru.touchin.templates.logansquare.LoganSquareEnum"))

        enumBuilder.addField(FieldSpec.builder(ClassName.get(String.class), "valueName",
                Modifier.PRIVATE,
                Modifier.FINAL)
                .addAnnotation(ClassName.bestGuess("android.support.annotation.NonNull"))
                .build())

        enumBuilder.addMethod(MethodSpec.constructorBuilder()
                .addParameter(ClassName.get(String.class), "valueName", Modifier.FINAL)
                .addStatement("this.valueName = valueName")
                .build())

        enumBuilder.addMethod(MethodSpec.methodBuilder("getValueName")
                .returns(ClassName.get(String.class))
                .addModifiers(Modifier.PUBLIC)
                .addAnnotation(ClassName.get(Override.class))
                .addAnnotation(ClassName.bestGuess("android.support.annotation.NonNull"))
                .addStatement("return valueName")
                .build())

        enumBuilder.addType(TypeSpec.classBuilder("LoganSquareConverter")
                .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                .superclass(ParameterizedTypeName.get(ClassName.bestGuess("ru.touchin.templates.logansquare.LoganSquareEnumConverter"), ClassName.bestGuess(name)))
                .addMethod(MethodSpec.constructorBuilder()
                .addModifiers(Modifier.PUBLIC)
                .addStatement("super(values())")
                .build())
                .build())

        for (Map.Entry<String, Object> entry : values) {
            enumBuilder.addEnumConstant(entry.key, TypeSpec.anonymousClassBuilder(entry.value.toString()).build())
        }

        JavaFile.builder("com.touchin.sberinkas", enumBuilder.build()).build().writeTo(directory);
    }

    Type typeOf(String value) {
        if (value.equals("true") || value.equals("false")) {
            return Type.BOOLEAN
        } else if (value.startsWith('"') && value.endsWith('"')) {
            return Type.STRING
        }
        try {
            Integer.parseInt(value)
            return Type.NUMBER
        } catch (NumberFormatException ignored) {
            throw new Exception("Can't define type of value: " + value)
        }
    }

    @Override
    void readLine(final String line) {
        String[] parts = line.split(':')
        String name = parts[0].trim();
        if (name.isEmpty()) {
            throw new Exception("Name of enum is empty")
        }
        if (values.containsKey(name)) {
            throw new Exception("Name '" + value + "' already added to enum")
        }
        String value = parts[1].trim();
        Type type = typeOf(value)
        if (this.type == null) {
            this.type = type
        } else if (this.type != type) {
            throw new Exception("Type of value '" + value + "' conflicts with previous value type: " + this.type)
        }
        values.put(name, value)
    }

}

class ClassObject implements SchemeObject {

    static final String SIGNATURE = "class"

    final String name

    ClassObject(String firstLine) {
        name = firstLine.substring(SIGNATURE.length()).trim()
    }

    @Override
    void writeToFile(File directory) {

    }

    @Override
    void readLine(final String line) {
    }

}

android.applicationVariants.all { variant ->
    File generatedModels = new File("${project.buildDir}/generated/source/models/${variant.dirName}")
    File schemeFile = new File("${project.projectDir}/src/main/res/raw/scheme.txt")

    def apiModelsGenerationTask = tasks.create("apiModelsGeneration${variant.name}") << {

        BufferedReader reader = new BufferedReader(new FileReader(schemeFile))
        String line
        List<SchemeObject> schemeObjects = new ArrayList<>()
        SchemeObject currentSchemeObject = null
        while ((line = reader.readLine()) != null) {
            if (line.startsWith(EnumObject.SIGNATURE)) {
                currentSchemeObject = new EnumObject(line)
                schemeObjects.add(currentSchemeObject)
            } else if (line.startsWith(ClassObject.SIGNATURE)) {
                currentSchemeObject = new EnumObject(line)
                schemeObjects.add(currentSchemeObject)
            } else if (currentSchemeObject != null) {
                currentSchemeObject.readLine(line)
            } else if (!line.trim().isEmpty()) {
                throw new Exception("No objects in scheme")
            }
        }

        for (SchemeObject schemeObject : schemeObjects) {
            schemeObject.writeToFile(generatedModels)
        }
    }

    apiModelsGenerationTask.description = 'Generates API models'
    variant.registerJavaGeneratingTask apiModelsGenerationTask, generatedModels
}