import Foundation
import PathKit

extension String : Error {
  public var description:String {
    return self
  }
}

public class IncludeNode : Node {
  public let templateName:String

  public class func parse(parser:TokenParser, token:Token) -> TokenParser.Result {
    let bits = token.contents.componentsSeparatedByString("\"")

    if bits.count != 3 {
      return .Error(error:NodeError(token: token, message: "Tag takes one argument, the template file to be included"))
    }

    return .Success(node:IncludeNode(templateName: bits[1]))
  }

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

  public func render(context: Context) -> Result {
    if let loader =  context["loader"] as? TemplateLoader {
      if let template = loader.loadTemplate(templateName) {
        return template.render(context)
      }

      let paths:String = loader.paths.map { path in
        return path.description
        }.joinWithSeparator(", ")
      let error = "Template '\(templateName)' not found in \(paths)"
      return .Error(error)
    }

    let error = "Template loader not in context"
    return .Error(error)
  }
}