import groovy.text.SimpleTemplateEngine
import org.codehaus.groovy.runtime.MethodClosure

ext.propertyString = this.&propertyString as MethodClosure
ext.propertyBool = this.&propertyBool as MethodClosure
ext.propertyStringList = this.&propertyStringList as MethodClosure
ext.interpolate = this.&interpolate as MethodClosure
ext.assertProperty = this.&assertProperty as MethodClosure
ext.assertSubProperties = this.&assertSubProperties as MethodClosure
ext.setDefaultProperty = this.&setDefaultProperty as MethodClosure
ext.assertEnvironmentVariable = this.&assertEnvironmentVariable as MethodClosure

String propertyString(String key) {
    return $property(key).toString()
}

boolean propertyBool(String key) {
    return propertyString(key).toBoolean()
}

Collection<String> propertyStringList(String key) {
    return propertyStringList(key, ' ')
}

Collection<String> propertyStringList(String key, String delimit) {
    return propertyString(key).split(delimit).findAll { !it.isEmpty() }
}

private Object $property(String key) {
    def value = project.findProperty(key)
    if (value instanceof String) {
        return interpolate(value)
    }
    return value
}

String interpolate(String value) {
    if (value.startsWith('${{') && value.endsWith('}}')) {
        value = value.substring(3, value.length() - 2)
        Binding newBinding = new Binding(this.binding.getVariables())
        newBinding.setProperty('it', this)
        return new GroovyShell(this.getClass().getClassLoader(), newBinding).evaluate(value)
    }
    if (value.contains('${')) {
        return new SimpleTemplateEngine().createTemplate(value).make(project.properties).toString()
    }
    return value
}

void assertProperty(String propertyName) {
    def property = property(propertyName)
    if (property == null) {
        throw new GradleException("Property ${propertyName} is not defined!")
    }
    if (property.isEmpty()) {
        throw new GradleException("Property ${propertyName} is empty!")
    }
}

void assertSubProperties(String propertyName, String... subPropertyNames) {
    assertProperty(propertyName)
    if (propertyBool(propertyName)) {
        for (String subPropertyName : subPropertyNames) {
            assertProperty(subPropertyName)
        }
    }
}

void setDefaultProperty(String propertyName, boolean warn, defaultValue) {
    def property = property(propertyName)
    def exists = true
    if (property == null) {
        exists = false
        if (warn) {
            project.logger.log(LogLevel.WARN, "Property ${propertyName} is not defined!")
        }
    } else if (property.isEmpty()) {
        exists = false
        if (warn) {
            project.logger.log(LogLevel.WARN, "Property ${propertyName} is empty!")
        }
    }
    if (!exists) {
        project.setProperty(propertyName, defaultValue.toString())
    }
}

void assertEnvironmentVariable(String propertyName) {
    def property = System.getenv(propertyName)
    if (property == null) {
        throw new GradleException("System Environment Variable $propertyName is not defined!")
    }
    if (property.isEmpty()) {
        throw new GradleException("Property $propertyName is empty!")
    }
}