import XCTest
import Spectre
@testable import Stencil

class TokenParserTests: XCTestCase {
  func testTokenParser() {
    describe("TokenParser") {
      $0.it("can parse a text token") {
        let parser = TokenParser(tokens: [
          .text(value: "Hello World", at: .unknown)
          ], environment: Environment())

        let nodes = try parser.parse()
        let node = nodes.first as? TextNode

        try expect(nodes.count) == 1
        try expect(node?.text) == "Hello World"
      }

      $0.it("can parse a variable token") {
        let parser = TokenParser(tokens: [
          .variable(value: "'name'", at: .unknown)
          ], environment: Environment())

        let nodes = try parser.parse()
        let node = nodes.first as? VariableNode
        try expect(nodes.count) == 1
        let result = try node?.render(Context())
        try expect(result) == "name"
      }

      $0.it("can parse a comment token") {
        let parser = TokenParser(tokens: [
          .comment(value: "Secret stuff!", at: .unknown)
          ], environment: Environment())

        let nodes = try parser.parse()
        try expect(nodes.count) == 0
      }

      $0.it("can parse a tag token") {
        let simpleExtension = Extension()
        simpleExtension.registerSimpleTag("known") { _ in
          return ""
        }

        let parser = TokenParser(tokens: [
          .block(value: "known", at: .unknown),
          ], environment: Environment(extensions: [simpleExtension]))

        let nodes = try parser.parse()
        try expect(nodes.count) == 1
      }

      $0.it("errors when parsing an unknown tag") {
        let tokens: [Token] = [.block(value: "unknown", at: .unknown)]
        let parser = TokenParser(tokens: tokens, environment: Environment())

        try expect(try parser.parse()).toThrow(TemplateSyntaxError(reason: "Unknown template tag 'unknown'", token: tokens.first))
      }
    }
  }
}