import PathKit


public class IncludeNode : NodeType {
  public let templateName: String

  public class func parse(parser: TokenParser, token: Token) throws -> NodeType {
    let bits = token.contents.characters.split("\"", allowEmptySlices: true).map(String.init)

    guard bits.count == 3 else {
      throw TemplateSyntaxError("'include' tag takes one argument, the template file to be included")
    }

    return IncludeNode(templateName: bits[1])
  }

  public init(templateName: String) {
    self.templateName = templateName
  }

  public func render(context: Context) throws -> String {
    guard let loader = context["loader"] as? TemplateLoader else {
      throw TemplateSyntaxError("Template loader not in context")
    }

    guard let template = loader.loadTemplate(templateName) else {
      let paths = loader.paths.map { $0.description }.joinWithSeparator(", ")
      throw TemplateSyntaxError("'\(templateName)' template not found in \(paths)")
    }

    return try template.render(context)
  }
}